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Introduction: Hypotension is a common complication after spinal anesthesia for cesarean delivery which is caused by sympathetic block 1. This can result in adverse maternal and fetal outcomes. Hence prevention and early treatment of spinal hypotension early has been a key research area in obstetric anesthesia. Intermittent non-invasive blood pressure measurement is the standard practice that fails to detect episodes of hypotension in a timely fashion. Methods: Noninvasive PI and blood pressure were measured in 109 healthy parturients undergoing elective cesarean section under spinal anesthesia. Results: PI appeared to increase significantly and more quickly in parturients with significant hypotension. Discussion: Findings may be due to the thoracic sympathetic blockade. Conclusion: Perfusion index can be a useful tool to early predict hypotension following spinal anesthesia for cesarean section. Response to ephedrine can be quickly assessed by the change in the PI which helps to decide on further boluses of ephedrine. Effect on the vascular tone by oxytocin is significant with 5IU bolus, though it does not cause a significant blood pressure drop.

Abstract Background Intraoperative hemodynamic management is challenging because precise assessment of the adequacy of the intravascular volume is difficult during surgery. Perfusion index (PI) has been shown to reflect changes in peripheral circulation perfusion. Pulse pressure variation (PPV) reflects the preload responsiveness. The hypothesis of this study was that hemodynamic management using the trend of the PI and PPV would improve tissue perfusion. Methods This was a prospective, randomized, parallel design, single-blind, single-center pilot study. Patients undergoing elective open gynecological surgery requiring a direct arterial line were included. The patients were randomly allocated to two groups. The intervention group received hemodynamic management using the trend of the PI and PPV in an effort to improve tissue perfusion. The control group received hemodynamic management at the discretion of the anesthesia care provider. The primary outcome was the peak lactate level during surgery. The secondary outcomes were the duration of hypotension, intraoperative fluid balance, intraoperative urine output, and postoperative complication rate. Statistical analysis was performed using Student’s t test and Fisher’s exact test. A P value of

Purpose: We aimed to evaluate the ability of the peripheral perfusion index (PPI) to predict reintubation of critically ill surgical patients., Methods: This prospective observational study included mechanically ventilated adults who were extubated after a successful spontaneous breathing trial (SBT). The patients were followed up for the next 48 h for the need for reintubation. The heart rate, systolic blood pressure, respiratory rate, peripheral arterial oxygen saturation (SpO 2 ), and PPI were measured before-, at the end of SBT, 1 and 2 h postextubation. The primary outcome was the ability of PPI 1 h postextubation to predict reintubation using area under the receiver operating characteristic curve (AUC) analysis. Univariate and multivariate analyses were performed to identify predictors for reintubation., Results: Data from 62 patients were analysed. Reintubation occurred in 12/62 (19%) of the patients. Reintubated patients had higher heart rate and respiratory rate; and lower SpO 2 and PPI than successfully weaned patients. The AUC (95%confidence interval) for the ability of PPI at 1 h postextubation to predict reintubation was 0.82 (0.71-0.91) with a negative predictive value of 97%, at a cutoff value of ≤ 2.5. Low PPI and high respiratory rate were the independent predictors for reintubation., Conclusion: PPI early after extubation is a useful tool for prediction of reintubation. Low PPI is an independent risk factor for reintubation. A PPI > 2.5, one hour after extubation can confirm successful extubation., (© 2024. The Author(s).)

Sepsis is associated with hypoperfusion and organ failure. The aims of the study were: 1) to assess the effect of pimobendan on macrocirculation and perfusion and 2) to describe a multimodal approach to the assessment of perfusion in sepsis and compare the evolution of the perfusion parameters. Eighteen anaesthetized female piglets were equipped for macrocirculation monitoring. Sepsis was induced by an infusion of Pseudomonas aeruginosa. After the occurrence of hypotension, animals were resuscitated. Nine pigs received pimobendan at the start of resuscitation maneuvers, the others received saline. Tissue perfusion was assessed using temperature gradients measured with infrared thermography (TG = core temperature - tarsus temperature), urethral perfusion index (uPI) derived from photoplethysmography and sublingual microcirculation (Sidestream dark field imaging device): De Backer score (DBs), proportion of perfused vessels (PPV), microvascular flow index (MFI) and heterogeneity index (HI). Arterial lactate and ScvO 2 were also measured. Pimobendan did not improve tissue perfusion nor macrocirculation. It did not allow a reduction in the amount of noradrenaline and fluids administered. Sepsis was associated with tissue perfusion disorders: there were a significant decrease in uPI, PPV and ScvO 2 and a significant rise in TG. TG could significantly predict an increase in lactate. Resuscitation was associated with a significant increase in uPI, DBs, MFI, lactate and ScvO 2 . There were fair correlations between the different perfusion parameters. In this model, pimobendan did not show any benefit. The multimodal approach allowed the detection of tissue perfusion alteration but only temperature gradients predicted the increase in lactatemia., Competing Interests: Declaration of competing interest Boehringer Ingelheim Animal Health France (Lyon, France) provided the drugs necessary for the study. The authors declare that they have no other competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Peripheral perfusion index (PPI) is useful in a variety of neonatal settings. Currently, available reference values are from small numbers and highly variable., Methods: We sought to generate reference values of PPI by analysing previously collected data from newborns who underwent mandated universal pulse oximetry and PPI screening from 2018 to 2021 using uniform protocol and equipment. Q-Q plots and boxplots were used to visualise distributions. Kernel density estimation for heaped and rounded data was used to estimate percentiles of the distributions., Results: Data from 388 205 newborns who underwent universal pulse oximetry screening in the first week of life were used for this analysis. Pre and postductal values showed a non-normal distribution and skewed to the left, the former had a thicker tail with more extreme values. Minor, but statistically significant differences were seen in the PPI values from day 1 to 7. Median preductal PPI (2.77, IQR:1.83-3.93) was significantly higher than postductal (2.38 IQR: 1.41-3.55) (p<0.01). PPI values increased with weight and boys had higher PPI. Kernel estimates of the percentiles in the overall sample and subgroups for gender and weight have been provided for preductal and post-ductal values., Conclusion: This study, based on the largest available dataset, provides reference values for PPI in newborns. A significant influence of gender and birth weight on PPI values in newborns has been identified. Future research on understanding the influence of age, sex, birth weight, gestational age, ambient temperature and genetic factors on PPI is recommended., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The erector spinae plane block (ESPB) is an interfascial plane block for managing neuropathic thoracic pain. Although the ESPB is applied widely in various clinical situations, no studies have evaluated the association between the analgesic outcomes of the ESPB and the numerical changes in the perfusion index (PI) and PI ratio., Objectives: The purpose of this study is to investigate the association between the clinical response following ESPB and other possible factors, including changes in the PI and PI ratio., Study Design: A prospective, nonrandomized, and open-label study., Setting: The pain clinic of a tertiary university hospital., Methods: This study included 92 patients with neck or arm pain who received T2 ESPB using 20 mL of 0.2% ropivacaine. To aid in the prediction of clinical outcomes, the PI was measured at the blocked side for 30 minutes as soon as the ESPB was finished. Various demographic data were also analyzed to predict the clinical outcomes., Results: Among 92 patients, 59 patients (64%) showed successful treatment outcomes (> 50% reduction in the numerical rating scale score or > 30% reduction in the neck disability index). The baseline PI of the responders was statistically higher than the nonresponders' (P < 0.05). Also, the responders' PI demonstrated statistically higher values than the nonresponders' at the time points of 4, 6, and 8 minutes after the ESPB. Multivariate logistic regression analysis revealed that a higher baseline PI (OR, 1.91; 95% CI, 1.27-2.86; P = 0.002) was an independent factor associated with a successful outcome., Limitations: Only a small number of patients with nonspinal diseases were included, except for those who had cervical radiculopathy. Therefore, it is hard to conclude that thoracic ESPB has any therapeutic benefits to patients with nonspinal diseases such as complex regional pain syndrome, adhesive capsulitis, or post-thoracotomy pain syndrome., Conclusion: A successful outcome at 4 weeks after T2 ESPB was achieved in 64% of patients with cervical radiculopathy. A higher baseline PI value was an independent factor associated with a successful response to T2 ESPB.

Background and Aims: Perfusion index (PI) is a new simple, objective and non-invasive method for evaluation of the success of central neuraxial and peripheral nerve blocks. So, we conducted a study with an aim to evaluate PI as an indicator for success of ultrasound-guided supraclavicular block (SCB). Methods: 65 patients of either sex, age 18–60 years, American Society of Anesthesiologists physical status I and II posted for upper limb surgery under ultrasound (US)-guided SCB were included. PI was recorded at baseline every 2 minutes till 10 minutes and then every 5 minutes till 30 minutes after block. PI ratio was calculated as the ratio between PI at 10 minutes and baseline PI. Sensory and motor blocks were assessed at 5-minutes intervals up to 30 minutes. Descriptive analysis was applied by mean and standard deviation for quantitative, frequency and proportion for categorical variables. Results: Mean PI increased continuously from baseline and reached the maximum at 10 minutes and then slightly decreased up to 30 minutes, but values at subsequent time intervals were quite high as compared to baseline. In case of successful blocks, median PI started increasing 2 minutes after the block and then increased in a linear fashion till 10 minutes, whereas in case of failed blocks, it only increased minimally. Conclusion: PI is an objective and faster indicator for evaluating success of US-guided SCB. A cut-off value of 3.25 for PI and 3.03 for PI ratio showed a fairly good ability with high sensitivity and specificity for predicting the success of SCB. [ABSTRACT FROM AUTHOR]

To evaluate perfusion index (PI) as a noninvasive tool to determine effectiveness and onset of epidural anesthesia in dogs. Prospective clinical trial. A total of 21 adult dogs, aged 6.5 ± 3 years and weighing 34.9 ± 6.4 kg, undergoing a tibial plateau leveling osteotomy. Dogs were premedicated intramuscularly with acepromazine (0.03 mg kg–1) and hydromorphone (0.1 mg kg–1) and anesthetized with intravenous propofol (to effect) and isoflurane in oxygen. A surface transflectance probe was secured to the tail base to monitor PI and a dorsal pedal artery catheter was placed for invasive blood pressure monitoring. A lumbosacral epidural was performed with the dog in sternal recumbency. Dogs were randomly assigned for inclusion of epidural morphine (0.1 mg kg–1) or morphine (0.1 mg kg–1) and lidocaine (4 mg kg–1). PI was recorded following instrumentation of each dog just prior to the epidural (baseline), at 10 minute intervals for 30 minutes, before and after the surgical skin incision and before and after completion of the osteotomy. Physiological variables and end-tidal isoflurane were recorded at the same time points. There was no significant difference in PI between the groups at any time point. There was a significant change in end-tidal isoflurane before and after the skin incision in the epidural morphine and epidural morphine–lidocaine groups (p = 0.04, p = 0.05, respectively) and before and after the osteotomy in each group for heart rate (p = 0.001, p = 0.04), diastolic (p = 0.01, p = 0.01) and mean arterial blood pressure (p = 0.03, p = 0.05). PI did not provide an objective means for determining the onset or effectiveness of epidural anesthesia in anesthetized dogs and alternate methods of noninvasive assessment should be investigated. [ABSTRACT FROM AUTHOR]

Background: Despite numerous studies on tissue perfusion, capillary circulation, and their related factors, there is still no consensus on the utilization of pulsatile versus non-pulsatile perfusion methods to provide proper perfusion in patients undergoing Coronary Artery Bypass Graft (CABG) surgery. Objectives: This study aimed to compare the effects of pulsatile versus non-pulsatile perfusion methods on renal function in patients undergoing CABG surgery in Shahid Mohammadi hospital, Bandar Abbas, Iran in 2018. Methods: In this randomized clinical trial, 50 patients aged > 18 years who underwent CABG surgery were randomly divided into a pulsatile and a non-pulsatile group (n = 25 in each group). The two groups were compared in terms of laboratory findings including the plasma levels potassium, sodium, creatinine, and blood urea nitrogen, Glomerular Filtration Rate (GFR), urinary output, and ejection fraction. Results: The results revealed a significant difference between the two groups regarding the trend of GFR changes during the study (P = 0.01). Accordingly, postoperative GFR increased more in the pulsatile group than in the non-pulsatile group. Moreover, creatinine and blood urea nitrogen levels reduced in the pulsatile group compared to the baseline. However, no significant differences were observed in the mean levels of potassium, sodium, and creatinine, urinary output, and ejection fraction in the two groups before and after the surgery. Conclusions: According to the results, pulsatile method was preferred to the nonpulsatile perfusion method due to its positive effects on creatinine and blood urea nitrogen levels as well as on GFR during and after the CABG surgery. [ABSTRACT FROM AUTHOR]

Background: From its first reported use in 2002, the efficiency of pulse oximetry (POX) screening in detecting critical and severe congenital heart disease (c/s-CHD) in term neonates in early days after delivery has been proved by numerous studies. It is low-cost, non-invasive, easy to use, repeatable, time-saving, applicable by even less-skilled nursing staff, proven to have excellent sensitivity and high specificity. When used in addition to the initial physician’s examination before dismissing a newborn home, this postnatal test can increase the clinical accuracy of detecting c/s-CHD. In this sense, it must be used as an early detecting screening test. Its use is more important during the period in which the patent ductus arteriosus (PDA) conceals the signs and symptoms of low cardiac output syndrome (LCOs) or severe cyanosis that will lead to notably hypoxia and acidosis. These free-of-symptoms babies that leave maternity units although critically ill, as well as those that are born at home and assessed by primary care, will benefit the most through a compulsory use of this test. Despite the benefits, it has failed to become a universal screening test for early detection of c/s-CHD, especially in Europe. Aim: To discuss the existing evidence on safe, effective, and efficient screening, using POX in combination with initial pre-discharge physical examination at the end of its stay under maternity services, including births out of medical facilities, for every term baby as a compulsory health screening test in Greece. Methods: The authors, members of the Hellenic Society of Perinatal Medicine (HSPM), reviewed the existing up-to-date literature and the trend of using this test worldwide and especially in European countries. They also consulted with pioneers and experts in the field. Results: Based on published data, the authors clarify existing policies of using POX and initial clinical assessment, aiming to a standardized approach of screening and diagnostic follow-up, when needed. Key issues for future research and evaluation were identified and addressed. Conclusions: The authors clarify existing policies in the use of POX, aiming to suggest the most appropriate way of using the test for compulsory screening term newborns during the early neonatal period in Greece. Special conditions of screening are being discussed. Public health organizations and private health agencies will have an important role in quality assurance and surveillance of this screening test aiming to significantly reduce morbidity and mortality from c/s-CHD in Greece.

Background and Aims: Spinal anesthesia has become the choice of neuraxial anesthesia for cesarean delivery. Hypotension, the most common side effect of spinal anesthesia is more in parturients. Perfusion index (PI) is one of the newest methods, used noninvasively for the prediction of hypotension postspinal anesthesia, evaluation of regional block success, and a tool for pain assessment. In our study, we have used PI for predicting the occurrence of hypotension postsubarachnoid block in elective lower segment cesarean section (LSCS). Methods: In this prospective observational study, parturients posted for elective LSCS under spinal anesthesia were included. Spinal anesthesia was performed at L3-L4 interspace using 25G (gauge) Quincke needle, with 1.8 mL of 0.5% hyperbaric bupivacaine plus 20 μg fentanyl. Hypotension was defined as a decrease in systolic blood pressure >25% from the baseline. Statistical Analysis Used: Statistical analysis was performed using the paired sample t-test, Chi-square test, and independent t-test. Results: From our study, we had found that a positive correlation exists between the baseline PI of the patient and the occurrence of hypotension intraoperatively. A cutoff value of 1.75 (with P < 0.001) was found to be significant; above which the occurrence of hypotension was definite. The sensitivity of this cutoff value was 75% and specificity was 71% for this value. Conclusion: Baseline perfusion of >1.75 can predict hypotension postspinal anesthesia in LSCS. The incidence of hypotension was about 93% in parturients whose baseline was above the cutoff value. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the changes in perfusion index (PI), skin temperature, and mean arterial pressure (MAP) during spinal anesthesia and to determine the success of spinal anesthesia using the PI values. Methods: A total of 128 patients belonging to American Society of Anesthesiologists' physical status I-II undergoing elective surgery under spinal anesthesia at the T10 level were included in this study. MAP, heart rate, body temperature, PI, and spinal anesthesia level, determined with the pinprick test, were recorded from baseline to 30 min following anesthesia induction. Repeated measures ANOVA test was used to evaluate changes after spinal block and linear mixed models were created. Time-dependent receiver operating characteristics (ROC) curves, using post-anesthetic 2nd min PI measurements and time to T10 spinal anesthesia level, were estimated to predict further successful spinal blockade. In addition, standard ROC curve analysis was performed for the PI ratios. Results: There was a significant linear increase in PI values (β=0.14, standard error = 0.01, p<0.001). Time-dependent ROC curves became significant for the post-anesthetic 6th min and after. Specificity was 100% after the 15th min. The cutoff value of post-anesthetic 2nd min PI was 2.4 (Area under the ROC curve-AUC: 0.71, 95% confidence interval: 0.59--0.83, sensitivity: 47%, specificity: 100%) to predict successful spinal blockage for the 15th min. In standard ROC curve analysis, only the 2nd min ROC curve revealed a significant AUC. Conclusion: All of the patients whose PI measurement at the 2nd min after the induction of anesthesia was above 2.4, reached the T10 spinal block level at the 15th min after induction. This finding must be supported by the increasing trend in PI individually. Adaptation of the study findings to the operation room practice may be considered for the patients with limited compliance to the pinprick test. [ABSTRACT FROM AUTHOR]

The impact of patent ductus arteriosus (PDA) on vital sign trends represented as histograms, and perfusion index in particular, is unknown. This study aimed to split continuously obtained PI and other vital signs before, during, and after medical treatment of PDA, into histogram bins, and determine the utility of PI and other vital sign histograms in the early prediction of hemodynamically significant PDA (hsPDA). In 34 infants at a mean gestational age of 26 ± 2.1 weeks, we prospectively collected vital signs for three different periods, 24 h before starting treatment of PDA, during PDA treatment, and 24 h after completion of the course of treatment, and confirmed PDA closure by echo. Histograms with three comparable periods were obtained from preterm infants who did not require treatment for PDA and analyzed for comparison. The duration of time spent in each histogram bin was determined for each time epoch. Episodes of low PI < 0.4 and high PI > 2 were significantly longer in duration in infants with PDA before treatment compared to those in infants with PDA during and after treatment. The arterial oxygen saturation (SpO2) < 80% was also longer in duration in infants with PDA before compared to that in infants with PDA during and after treatment. Low PI < 0.4 correlated with most echocardiography indices of hsPDA. Conclusion: We conclude that a patent ductus arteriosus requiring treatment in preterm infants ≤ 29 weeks GA was associated with significant fluctuations between a low PI < 0.4 alternating with a high PI > 2, reflecting the dynamic nature of hsPDA shunt volume. PI variability may be an early marker of hsPDA. What is Known: • The perfusion index is a continuous underutilized parameter provided by pulse oximetry to assess the peripheral perfusion. • The perfusion index helps predict conditions with hemodynamic instability. What is New: • The perfusion index assessed as daily histogram trends can predict patent ductus arteriosus requiring treatment. [ABSTRACT FROM AUTHOR]

Aim: Adding perfusion index (PI) to pulse oximetry screening (POS) may increase neonatal detection of CoA (aortic coarctation). A cut-off <0.7% has been suggested but is associated with a high rate of false positives. We aimed to evaluate the specificity of PI when using repeated instead of single measurements.Methods: A pilot study was conducted in 50 neonates. PI was recorded in right hand and a foot by pulse oximeter. If PI was <0.7%, the measurement was immediately repeated up to 3 times. If all three measurements were <0.7% in hand and/or foot the screen was positive and echocardiography was performed. There were 3/50 false-positive screens. The protocol was therefore modified requiring 30 min intervals between measurements.Results: An additional 463 neonates were included using the modified protocol at a median age of 18 h. There were no false positives. The only neonate with CoA had a negative screen (PI hand 1.2% and foot 0.8%). The measurement required on average an extra 3 min and 30 s compared with POS only.Conclusion: The false-positive rate of PI was reduced by using repeated PI measurements. The sensitivity for CoA using this protocol should be evaluated in large-scale prospective studies. [ABSTRACT FROM AUTHOR]

Spinal anesthesia patients have a risk of hypotension as a result of decreased vascular tonus and venous pooling. Especially elderly patients may not tolerate this condition. Therefore, it is important to predict hypotension in elderly patients and to take precautions. In our study, the ability of the basal perfusion index (PI) to predict the incidence of hypotension in geriatric patients was tested. 80 patients over 65 years of age who were operated under spinal anesthesia were included in this study. Preoperative PI values, preoperative and after anesthesia systolic arterial pressure values were compared. High PI measurements of the patients can be interpreted as an indication that systolic blood pressure measurements will be low after spinal anesthesia (r = -0.155 p = 0.041). However, it was concluded that PI value is not a useful test for routine use in predicting hypotension. Although PI may be affected by fluid status, vascular tone or sympathetic activities of patients, with preoperative use of PI, A correlation between PI and systolic blood pressure may be guiding in perioperative follow-up. In fact, complications can be reduced by considering the signs of PI. [ABSTRACT FROM AUTHOR]

Background and Aims: The aim of this study was to evaluate the accuracy of non-invasive haemoglobin (SpHb) compared to laboratory venous haemoglobin (tHb) measurements among patients undergoing elective transurethral resection of prostate (TURP) surgery under spinal anaesthesia. Methods: In a prospective, observational, outcome-assessor blinded, cohort trial, we enroled 50 American Society of Anesthesiologists physical status (ASA-PS) I-II patients with benign prostatic hyperplasia. The primary outcome included SpHb and tHb measurements performed at four perioperative time-points: just before initiating the fluid preload (T1), and at 30 min (T2), 1 h (T3), and 2 h (T4) after starting the prostate resection, respectively. Statistical tool included intra-class correlation (ICC), Bland-Altman plots, and linear regression analysis. Results: We collected 200 SpHb/tHb data sets from 50 patients. The SpHb had a non-significant negative bias of -0.83 g/dL, -0.43 g/dL, -0.81 g/dL, and -0.46 g/dL, with limits of agreement of 2.6 g/dL to -4.2 g/dL, 2.4 g/dL to -3.3 g/dL, 1.3 g/dL to -2.8 g/dL, and 1.4 g/dL to -2.3 g/dL, for T1 to T4, respectively. The SpHb/tHb pairs correlated significantly (time-dependent increase in ICC from T1 to T4). The SpHb-tHb difference correlated significantly with corresponding serum sodium (T1 to T3), but not with perfusion index. No correlation existed between % change in SpHb-tHb difference (T1 to T4), and intraoperative blood loss or perioperative weight gain. Conclusion: The SpHb exhibited a clinically acceptable negative bias compared to tHb during TURP surgery. Although a wide limit of agreement between the SpHb/tHb pairs is a limitation, the real-time SpHb trends can still serve in clinical judgement. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the hemodynamic status of fasting emergency service professionals by measuring the inferior vena cava collapsibility index (IVCCI) using bedside ultrasonography and the perfusion index (PI) using a noninvasive method and examining the relationship between these two parameters. Materials and Methods: This was a prospective cross-sectional study. The IVCCI and PI were measured in emergency service professionals at 11:00 am, 07:00 pm, and 10:00 pm between May 16 and June 4, 2018, corresponding to the 11th and 20th days of Ramadan. IVCCI and PI levels at different times of fasting and after feeding were compared. Results: The IVCCI-2 value of the volunteers at the 16th hour of fasting was signifcantly higher than the IVCCI-1 value at the 8th hour of fasting (p < 0.001). The IVCCI-3 value at the postprandial 2nd hour after eating was signifcantly lower than both the average IVCCI-1 at the 8th hour of fasting (p < 0.001) and average IVCCI-2 at the 16th hour of fasting (p < 0.001). The PI-2 value at the 16th hour of fasting was signifcantly lower than the PI-1 value at the 8th hour of fasting. The PI-3 value at the postprandial 2nd hour after eating was signifcantly higher than both the average PI-1 at the 8th hour of fasting (p = 0.001) and the average PI-2 at the 16th hour of fasting (p < 0.001). Conclusion: The collapsibility increased at the longest time of fasting, and the collapsibility ratio decreased after eating. Similarly, PI was the lowest at the longest time of fasting, whereas PI increased after eating. [ABSTRACT FROM AUTHOR]

Hemorrhage in multiple trauma causes activation of a number of compensatory mechanisms, one of which is centralization of blood circulation and peripheral tissue hypoperfusion, which is accompanied by decrease in perfusion index (PI). PI is an indicator of volumetric peripheral blood flow and is measured with photoplethysmography method. This study was conducted to assess the relationship between the perfusion index, the degree of hypovolemia and its compensation after treatment with infusion-transfusion therapy in patients with multiple trauma in ICU settings. 32 patients (20 men and 12 women) aged from 32 to 46 years were examined. For the analysis were selected patients with multiple trauma - spleen rupture in combination with damage of one of the large tubular bone (femur, brachial or tibial bone). The obligatory inclusion criterion was the presence of clinical signs of compensated hypovolemic shock (arterial pressure lesser than 90, heart rate more than 100), a quick response to volemic resuscitation, without the use of additional inotropic support. As a result of the study, an increase in the perfusion index was noted already after 6 hours after damage control surgery and traumatology intervention with ongoing infusion-transfusion therapy in ICU, which indicates that perfusion of the peripheral pool of the bloodstream was improved and correlated with an increase in central venous pressure values, central hemodynamic parameters. It is advisable to use PI as one of the indicators of the degree of volemic status compensation in patients with multiple trauma. The growth of PI corresponds to the improvement of hemodynamic parameters. In some cases, the rapid recovery of volemic status after therapy according to continuous arterial pressure measurement, pulseoximetry, CVP, PI exacerbated anemia, caused by infusion associated hemodilution. This should be taken into account, because prolonged anemia can lead to diminished mental status of the patient. Also, an excessive increase in PI may indicate an over-activation of the sympathetic system due to exacerbated pain syndrome, which apparently can serve as an indicator of insufficient analgesia.

Abstract Background A passive leg raising (PLR) test is positive if the cardiac index (CI) increased by > 10%, but it requires a direct measurement of CI. On the oxygen saturation plethysmographic signal, the perfusion index (PI) is the ratio between the pulsatile and the non-pulsatile portions. We hypothesised that the changes in PI could predict a positive PLR test and thus preload responsiveness in a totally non-invasive way. Methods In patients with acute circulatory failure, we measured PI (Radical-7) and CI (PiCCO2) before and during a PLR test and, if decided, before and after volume expansion (500-mL saline). Results Three patients were excluded because the plethysmography signal was absent and 3 other ones because it was unstable. Eventually, 72 patients were analysed. In 34 patients with a positive PLR test (increase in CI ≥ 10%), CI and PI increased during PLR by 21 ± 10% and 54 ± 53%, respectively. In the 38 patients with a negative PLR test, PI did not significantly change during PLR. In 26 patients in whom volume expansion was performed, CI and PI increased by 28 ± 14% and 53 ± 63%, respectively. The correlation between the PI and CI changes for all interventions was significant (r = 0.64, p 9%, a positive response of CI (≥ 10%) was diagnosed with a sensitivity of 91 (76–98%) and a specificity of 79 (63–90%) (area under the receiver operating characteristics curve 0.89 (0.80–0.95), p

Context: Propofol induction is associated with hypotension due to changes in intravascular volume, tone of vessels and cardiac output. Plethysmograph variability index (PVI) and perfusion index (PI) are derived indices from pulse oximeter, used for assessing fluid responsiveness and vessel tone, respectively. We studied the utility of these indices in predicting hypotension due to propofol. Aims: The aim of the study is to test the baseline cutoff values of PVI > 15% and PI <1.05 in predicting hypotension with propofol induction. Settings and Design: This is a prospective double-blind observational study in tertiary care hospital. Methods: Institutional ethical committee approval was obtained. 106 surgical in-patients as per inclusion and exclusion criteria were randomly allotted by computer-generated random numbers. All patients were nil by mouth for 6 h. Injection midazolam and fentanyl were used as premedicants. Propofol at dose of 2 mg.kg−1 was used for induction. Masimo Radical 7® monitor was used for recording of PVI and PI from the upper limb. Baseline values of PVI and PI were recorded every minute from preinduction period till intubation. Standard monitors of noninvasive blood pressure, pulse oximeter, and electrocardiography were used. As per the occurrence of hypotension, patients were grouped as Group H (hypotension) and Group NH (no hypotension). Statistical Analysis: Data were analyzed with SPSS version 20. Quantitative data were analyzed using mean, standard deviation, interquartile range as per distribution. Shapiro–Wilk test with P < 0001 was used descriptive parameters. Scatter plot and Spearman correlation were used to find correlation between the two variables. Mann–Whitney U test was used to compare the two groups in terms of PVI and PI at different time points. Receiver operator characteristic curve was plotted for PI and PVI against hypotension, and cutoff value was calculated. Sensitivity, specificity, positive predictive value, negative value, and diagnostic accuracy of PI and PVI were calculated. P <0.05 was considered statistically significant. Results: Eighty-one patients (76.4%) who had hypotension were grouped into Group H and 25 patients (23.6%) without hypotension as Group NH. There was no difference between groups with respect to doses of midazolam (P = 0.28), fentanyl (P = 0.54), and propofol (P = 0.28). Baseline cutoff of PVI >15 had sensitivity of 58% and specificity of 56%, respectively. PI cutoff value of < 1.05 had sensitivity of 30.9% and specificity of 48%. The risk ratio of PVI cutoff and PI cutoff were 1.41 and 0.43, respectively. There was poor agreement between mean arterial blood pressure (MAP) estimation and prediction of hypotension by PVI (Cohen's kappa = 0.106, P = 0.218) and PI values (Cohen's kappa = −0.133, P = 0.054). Area under the receiver operator curve was 0.596 and 0.511 for PVI >15% and PI < 1.05, respectively. New cutoff values PVI >17.5% and PI > 0.76 were found. PVI and PI had poor diagnostic performance. There was no significant correlation of PVI and PI with hemodynamic variables such as heart rate, MAP, SBP, DBP, and PP. Conclusion: Baseline values of PVI >15% and PI < 1.05 are not good tools for predicting hypotension with propofol induction. New values of baseline cutoff of PVI >17.5% have high specificity, and PI > 0.76 has high sensitivity and positive predictive value. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to investigate the effect of breast milk and sucrose on pain scores and perfusion index (PI) and to evaluate the alteration in pain and PI during retinopathy of prematurity (ROP) examination.Methods: This prospective randomized controlled study was conducted with preterm infants who were born in our hospital, hospitalized in the neonatal intensive care unit and whose gestational week was <32 weeks and birth weight was <1500 g. The preterm infants who would undergo ROP examination were allocated to three groups according to simple randomization method as follows: group 1: only local anesthetic eye drops, proparacaine HCl ophthalmic solution 0.5%, group 2: proparacaine HCl ophthalmic solution 0.5% plus breast milk, and group 3: proparacaine HCl ophthalmic solution 0.5% plus sucrose 24%. Postductal PI, transcutaneous oxygen saturation and heart rate (HR) values were measured before the eye examination (0), at the 30th, 60th, and 90th seconds (s) of the eye examination and 30 s after lasting of the examination in all infants. Pain was evaluated using Neonatal Infant Pain Scale (NIPS) during the examination.Results: Fifty-one preterm neonates were prospectively enrolled into the study. The HR was higher during and after the examination in all infants according to before the examination (p < .001). Transcutaneous oxygen saturation values significantly decreased during the examination in breast milk and sucrose groups (p = .001 and <.001, respectively). While PI was found to be lower at the 60th s compared to the 30th s of the examination in the proparacaine HCl group, no difference was found between the values before and after the examination. Perfusion index was found to significantly decrease during and after the examination compared to the values before the examination in the breast milk group. Perfusion index values were determined to significantly decrease at the 30th and 60th s of the examination in the sucrose group. The NIPS scores during the examination were determined to be higher compared to the NIPS scores before the examination in all groups (p< .001). In the intergroup comparisons, the NIPS scores were found to be higher in the sucrose group compared to the proparacaine HCl group at the 60th s of the examination and higher than that in the breast milk group at the 90th s of the examination (p = .02 and p = .01, respectively).Conclusions: The present study indicates that alterations may be seen in PI during the ROP examination; in other words, peripheral tissue perfusion could be affected. We consider that eye examination is a very painful procedure, and administering breast milk, sucrose or local anesthetic is not sufficient for reducing pain. [ABSTRACT FROM AUTHOR]

RESPIRATORY CHANGES IN PI OR PLETH VARIABILITY INDEX In mechanically ventilated patients, the respiratory changes in left ventricular stroke volume induce proportional changes in arterial pulse pressure (also known as pulse pressure variation [PPV]) and in PI (pleth variability index [PVI]) (10). When assessing the predictive value of absolute PI changes, because pulse oximeters display PI values with only one decimal, Beurton et al (1) showed that the sensitivity dropped to 63%. THE PI AS A MARKER OF TISSUE PERFUSION The PI is the ratio of the pulsatile component of the photoplethysmographic waveform to the total amplitude of the signal (Fig. Other variables, including the peripheral perfusion index (PI), can be measured by pulse oximeters and may have value for hemodynamic monitoring and management, as illustrated by the study from Beurton et al (1) published in this issue in Critical Care Medicine. [Extracted from the article]

Introduction: Laryngoscopy and intubation is always associated with a short term reflex sympathetic pressor response. The perfusion index is an indirect, non-invasive, and continuous measure of peripheral perfusion by pulse oximeter which can detect the stress response to intubation similar to heart rate, systolic blood pressure and diastolic blood pressure. Methods: This prospective observational study enrolled sixty-five normotensive patients of American society of anesthesiologists physical status grade I and II scheduled for elective surgery under general anaesthesia. Tracheal intubation was performed after induction with intravenous fentanyl, propofol and vecuronium. Heart rate, Systolic and Diastolic Blood Pressure and Perfusion Index were measured before induction of anesthesia, before intubation and one minute, three minutes, five minutes after the insertion of the endotracheal tube. Increase in heart rate by ?10 beats per minute, systolic and diastolic blood pressure by ?15 millimeters of mercury and decrease in Perfusion index ?10% after endotracheal intubation as compared to preintubation value were considered positive haemodynamic changes. Results: Endotracheal intubation produced a significant increase in heart rate and blood pressure whereas perfusion index decreased significantly. Our study showed that perfusion index response criterion achieved 97.7% (Confidence interval 97.58-97.86) sensitivity in detecting the stress response to insertion of endotracheal tube whereas systolic and diastolic blood pressure achieved sensitivity of 90% and 92% respectively. Conclusion: Perfusion Index is easier, reliable and non-invasive alternative to conventional haemodynamic criteria for detection of stress response to endotracheal intubation.

Background/Aim: The aim of the study was to compare echocardiographic parameters and the perfusion index (PI) and plethysmographic variability index (PVI) values obtained by routine pulse oximetry in the diagnosis of hemodynamically significant patent ductus arteriosus (hsPDA). Materials and Methods: This prospective study was conducted between 2016 and 2017 at the HacettepeUniversity Neonatal Intensive Care Unit. The study included premature neonates who had a birth weight below 1500 g. Patients were routinely monitored from the right wrist and right foot using a pulse oximeter (Masimo Radical-7® Pulse CO-Oximetry), and PI and PVI values were recorded. The difference between right-hand and right-leg PI values was calculated as the delta PI (ΔPI). A cardiologist blinded to the results evaluated the presence of patent ductus arteriosus (PDA) with echocardiography on postnatal days 1th, 3rd, and 7th. Results: Of the 66 preterm neonates included in the study, 23 had hsPDA. On postnatal day 1, the hsPDA group had a significantly greater ductal diameter, PDA/left pulmonary artery (LPA) ratio, and left ventricle (LA)/aortic (Ao) ratio (P < 0.05). On day 7, the hsPDA group had a significantly higher ductal velocity, PDA/LPA ratio, LA/Ao ratio, antegrade PA and LPA diastolic flow, and LV/Ao ratio (P < 0.05). In hsPDA group, the median ΔPI values were 0.85 (25–75 interquartile range [IQR]; 0.62–1.15) on day 1; 1.03 (25–75 IQR; 0.85–1.26) on day 3; and 0.89 (25–75 IQR; 0.64–1.22) on day 7. The median (25–75 IQR) ΔPI values were higher in the hsPDA group than in the non-hsPDA group on postnatal days 1, 3, and 7 (P < 0.001, P < 0.001, and P < 0.001, respectively). The ΔPI cutoff values for the diagnosis of hsPDA were 0.47 on day 1 (91.3% specificity; 90.5% sensitivity), 0.41 on day 3 (100% specificity; 97.3% sensitivity), and 0.47 on day 7 (90% specificity; 100% sensitivity). Conclusions: Our study shows that the difference between PI values (ΔPI) in the right hand and right leg obtained by pulse oximetry has diagnostic value in hsPDA and can assist diagnosis when echocardiography is not available. [ABSTRACT FROM AUTHOR]

Background: While providing various benefits, concerns about the potential risks of kangaroo mother care, or skin‐to‐skin contact (SSC), between mother and her preterm infant hinder its widespread implementation in some resource‐ rich countries. In neonates, salivary chromogranin A (s‐CgA) is elevated upon exposure to stress, whereas the perfusion index (PI) is associated with hemodynamics and peripheral perfusion. Here, we investigated the effects of SSC on s‐CgA and the PI in preterm infants. Methods: Twelve infants were enrolled in the study. Factors associated with baseline s‐CgA were analyzed. Baseline s‐CgA and the level after SSC were compared. Secreted IgA in the saliva was compared as the control. The PI before, throughout, and after SSC were compared. Results: Baseline s‐CgA was significantly lower in infants who were supplemented with baby formula milk in addition to breast milk before SSC (n = 2) compared with those fed with their mother's breast milk alone (n = 10, P = 0.03). SSC significantly decreased s‐CgA in babies who were fed breast milk only before SSC (n = 10, P = 0.01) but not in those supplemented with formula milk before SSC (n = 2). Secreted IgA in saliva was not affected by SSC. The PI was significantly elevated during SSC (P =.01). Conclusion: Our data indicate that SSC can reduce s‐CgA levels when combined with mother's breast milk and increase the PI in preterm infants, thereby providing additional evidence of the benefit of SSC. [ABSTRACT FROM AUTHOR]

Background: The peripheral perfusion index is the ratio of pulsatile to nonpulsatile static blood flow obtained by photoplethysmography and reflects peripheral tissue perfusion. We investigated the association between intraoperative perfusion index and postoperative acute kidney injury in patients undergoing major noncardiac surgery and receiving continuous vasopressor infusions., Methods: In this exploratory post hoc analysis of a pragmatic, cluster-randomised, multicentre trial, we obtained areas and cumulative times under various thresholds of perfusion index and investigated their association with acute kidney injury in multivariable logistic regression analyses. In secondary analyses, we investigated the association of time-weighted average perfusion index with acute kidney injury. The 30-day mortality was a secondary outcome., Results: Of 2534 cases included, 8.9% developed postoperative acute kidney injury. Areas and cumulative times under a perfusion index of 3% and 2% were associated with an increased risk of acute kidney injury; the strongest association was observed for area under a perfusion index of 1% (adjusted odds ratio [aOR] 1.32, 95% confidence interval [CI] 1.00-1.74, P=0.050, per 100%∗min increase). Additionally, time-weighted average perfusion index was associated with acute kidney injury (aOR 0.82, 95% CI 0.74-0.91, P<0.001) and 30-day mortality (aOR 0.68, 95% CI 0.49-0.95, P=0.024)., Conclusions: Larger areas and longer cumulative times under thresholds of perfusion index and lower time-weighted average perfusion index were associated with postoperative acute kidney injury in patients undergoing major noncardiac surgery and receiving continuous vasopressor infusions., Clinical Trial Registration: NCT04789330., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Nerve block success is commonly assessed through a variety of techniques, including testing sensations for temperature over the relevant dermatomes and evaluating pain response (e.g., pin-prick). This meta-analysis aimed to investigate the diagnostic efficacy of Perfusion Index (PI) in identifying failed nerve blocks in patients undergoing upper extremity surgery., Evidence Acquisition: A literature search was conducted using four databases, including Medline (OVID), Google Scholar, EMBASE (OVID), and the Cochrane Database of Systematic Reviews, to identify relevant studies from the inception of the databases until June 2023. The main purpose of this study was to evaluate the diagnostic accuracy of PI values and PI ratios in identifying failed nerve blocks., Evidence Synthesis: Nine studies (published from 2006 to 2022) involving 533 participants (age ranged from 31 to 52 years) were included. The failure rate of nerve blocks ranged from 0% to 18.9%. Pooled results demonstrated promising diagnostic accuracy when using PI values as a predictor of failed nerve block (sensitivity, 77%; specificity, 88.1%; diagnostic odds ratio [DOR], 30.585). Additionally, the analysis of PI ratios as a diagnostic measure showed even higher diagnostic efficacy than using PI values alone, with a sensitivity of 82.9%, specificity of 93.1%, and DOR of 74.543., Conclusions: Our meta-analysis confirmed that the PI values and ratios are promising objective predictors of nerve block failure. The simplicity of these techniques supports their feasibility for routine clinical practice. Further studies focusing on different patient populations, such as pregnant women or the elderly, are needed to validate and expand upon our findings.

Purpose:  Evaluate the SpO 2 -SaO 2 difference between Black and White volunteer subjects having a low perfusion index (Pi) compared to those having a normal Pi., Methods:  The Pi data were abstracted from electronic files collected on 7183 paired SpO 2 -SaO 2 samples (3201 Black and 3982 White) from a recently reported desaturation study of 75 subjects (39 Black and 36 White) where SaO 2 values were sequentially decreased from 100 to 70%. The Pi values from that dataset were divided into two groups (Pi ≤ 1 or Pi > 1) for analysis. A Pi value ≤ 1 was considered "low perfusion" and a Pi value > 1 was considered "normal perfusion". Statistical calculations included values of bias (mean difference of SpO 2 -SaO 2 ), precision (standard deviation of the difference), and accuracy (root-mean-square error [A RMS ]). During conditions of low perfusion (Pi ≤ 1, range [0.1 to 1]), overall bias and precision were + 0.48% ± 1.59%, while bias and precision were + 0.19 ± 1.53%, and + 0.91 ± 1.57%, for Black and White subjects, respectively., Results:  During normal perfusion (Pi > 1, range [1 to 12]), overall bias and precision were + 0.18% ± 1.34%, while bias and precision were -0.26 ± 1.37%, and - 0.12 ± 1.31%, for Black and White subjects, respectively. A RMS was 1.37% in all subjects with normal perfusion and 1.64% in all subjects with low perfusion., Conclusion:  Masimo SET® pulse oximeters with RD SET® sensors are accurate for individuals of both Black and White races when Pi is normal, as well as during conditions when Pi is low. The A RMS for all conditions studied is well within FDA standards. This study was conducted in healthy volunteers during well-controlled laboratory desaturations, and results could vary under certain challenging clinical conditions., (© 2024. The Author(s).)

Background: Effective pain assessment is crucial to tailor the analgesic regimen post-operatively. Perfusion index (PI) has been reported to be a useful objective assessment tool for monitoring pain. This study aimed to explore the utility of PI in assessing postoperative pain in upper limb surgeries under supraclavicular block and its correlation with visual analogue scale (VAS) scores., Methods: This prospective, observational study included 140 patients scheduled for elective upper limb surgeries. PI, VAS scores, heart rate (HR), mean arterial pressure (MAP) and physiological parameters were recorded at baseline and postoperatively. Inj. tramadol was administered when the VAS score exceeded ≥ 4 and the VAS score, PI, HR and MAP were recorded at 5, 10, 15 and 20 minutes after administration. Comparison of normally and non-normally distributed data was done using t-statistics and Mann-Whitney U-test respectively. Pearson correlation was used to establish a correlation between variables and the receiver operating characteristic (ROC) curve was used to calculate the cut-off value of PI to determine the onset of pain., Results: There was a significant and moderate correlation between pre-analgesic and post-analgesic PI and VAS score (r = -0.425 and -0.448 respectively, p<0.001), while PI and MAP or PI and HR showed only a weak correlation. A cut-off value of 14.7 for PI showed 76.3% sensitivity and 100% specificity in predicting rescue analgesia requirements., Conclusion: The study supports the use of PI as an objective measure for postoperative pain assessment, with a notable correlation with VAS scores. The identified cut-off value for PI adds to its clinical utility in predicting the need for rescue analgesia., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Bihani et al.)

Background: Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency., Methods: We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency., Results: Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency., Conclusion: The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency., Trial Registration: University Hospital Medical Information Network (UMIN000049994 on 9/01/2023)., (© 2024. The Author(s).)

Background: Passive leg raising (PLR) reliably predicts fluid responsiveness but requires a real-time cardiac index (CI) measurement or the presence of an invasive arterial line to achieve this effect. The plethysmographic variability index (PVI), an automatic measurement of the respiratory variation of the perfusion index, is non-invasive and continuously displayed on the pulse oximeter device. We tested whether PLR-induced changes in PVI (ΔPVI PLR ) could accurately predict fluid responsiveness in mechanically ventilated patients with acute circulatory failure., Methods: This was a secondary analysis of an observational prospective study. We included 29 mechanically ventilated patients with acute circulatory failure in this study. We measured PVI (Radical-7 device; Masimo Corp., Irvine, CA) and CI (Echocardiography) before and during a PLR test and before and after volume expansion of 500 mL of crystalloid solution. A volume expansion-induced increase in CI of >15% defined fluid responsiveness. To investigate whether ΔPVI PLR can predict fluid responsiveness, we determined areas under the receiver operating characteristic curves (AUROCs) and gray zones for ΔPVI PLR ., Results: Of the 29 patients, 27 (93.1%) received norepinephrine. The median tidal volume was 7.0 [IQR: 6.6-7.6] mL/kg ideal body weight. Nineteen patients (65.5%) were classified as fluid responders (increase in CI > 15% after volume expansion). Relative ΔPVI PLR accurately predicted fluid responsiveness with an AUROC of 0.89 (95%CI: 0.72-0.98, p < 0.001). A decrease in PVI ≤ -24.1% induced by PLR detected fluid responsiveness with a sensitivity of 95% (95%CI: 74-100%) and a specificity of 80% (95%CI: 44-97%). Gray zone was acceptable, including 13.8% of patients. The correlations between the relative ΔPVI PLR and changes in CI induced by PLR and by volume expansion were significant (r = -0.58, p < 0.001, and r = -0.65, p < 0.001; respectively)., Conclusions: In sedated and mechanically ventilated ICU patients with acute circulatory failure, PLR-induced changes in PVI accurately predict fluid responsiveness with an acceptable gray zone., Trial Registration: ClinicalTrials.govNCT03225378., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Significance: Diffuse correlation spectroscopy (DCS) permits non-invasive assessment of skeletal muscle blood flow but may misestimate changes in muscle perfusion., Aim: We aimed to highlight recent evidence that DCS blood flow index (BFI) misestimates changes in muscle blood flow during physiological perturbation and to introduce a novel approach that adjusts BFI for estimated changes in vasodilation., Approach: We measured changes in muscle BFI during quadriceps and forearm exercises using DCS, the latter of which were adjusted for estimated changes in microvascular flow area and then compared to Doppler ultrasound in the brachial artery. Then, we compared adjusted BFI- and arterial spin labeling (ASL) MRI measures of gastrocnemius blood flow during reactive hyperemia and plantar flexion exercise., Results: We observed little-to-no change in quadriceps BFI during maximal-effort exercise. Similarly, forearm BFI was modestly increased during handgrip exercise, but the magnitude was significantly lower than measured by Doppler ultrasound in the brachial artery. However, this difference was ameliorated after adjusting BFI for estimated changes in microvascular flow area. Similar observations were also observed in the gastrocnemius when directly comparing the adjusted BFI values to ASL-MRI., Conclusions: Adjusting BFI for estimated changes in microvascular flow area may improve DCS estimates of muscle blood flow, but further study is needed to validate these methods moving forward., (© 2024 The Authors.)

Background: Several retrospective studies have reported an increase in necrotizing enterocolitis (NEC) during the 48 h following red blood cell (RBC) transfusion. Whether withholding enteral feeding during transfusion decreases the risk of transfusion-associated acute gut injury (TRAGI) in preterm infants is unclear. Study design and methods: In this pilot study, 112 preterm infants with gestational age ≤32 weeks and/or birth weight ≤1500 g were randomly assigned to withholding (NPO) or continuance of feeding (FED) during RBC transfusion. Primary outcome measure was development of NEC (stage ≥ 2) within 72 h of a transfusion and the change in abdominal circumference. Results: One hundred fifty-four transfusion episodes (74 NPO and 80 FED) were analyzed. Demographic characteristics were found to be similar in both groups. There was no difference in rates of NEC (0 versus 3.4%; p =.49) between the NPO and FED groups. The incidence of feeding intolerance was higher in the FED group; however, it was statistically insignificant (1.9 versus 6.8%, p =.36). Abdominal circumference remained similar in both groups in all three consecutive days following transfusion (p>.05). Conclusion: This pilot study does not support withholding feedings during transfusion but is not adequately powered to test the hypothesis that NPO decreases NEC rates. Adequately powered well-designed multicenter trials are still required. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to examine the prognostic significance of the perfusion index (PI) in mechanically ventilated patients.Methods: Study included sixty patients who had the risk factors for the development of acute respiratory distress syndrome and received mechanical ventilator (MV) support in intensive care unit (ICU) unit between January 2017/January 2018. The demographic characteristics, vital signs, blood gas parameters, lactate levels, prognostic scores, and use of inotropic drugs were recorded. Arterial blood gas and PI measurements at the frontal region were performed at the time of and 12th and 24th hours of admission to the ICU. The patients were followed up for 60 days, and the outcome was recorded.Results: Twelve patients (20%) died during the first 7 days, and 27 patients (45%) died within 60 days of the admission. Multivariate analyses to determine potential predictors of 7 and 30-day mortality showed that only 24th-hour lactate level was independent predictor of 60-day mortality, and the PI at 24th was the sole independent predictor of 7-day mortality.Conclusion: The PI did not predict 60-day mortality in MV patients who had risk factors for the development of Acute Respiratory Distress Syndrome (ARDS). However, the PI at 24th may be a significant predictor of 7-day mortality. [ABSTRACT FROM AUTHOR]

Background: Healthcare workers (HCWs) are at increased risk of exposure to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Personal protective equipment (PPE) is mandated for HCWs. However, the physiological effects on the HCWs while working in the protective gear remains unexplored. This study aimed to assess the physiological effects of the prolonged use of PPE on HCWs. Materials and methods: Seventy-five HCWs, aged 18-50 years were enrolled in this prospective, observational, cohort study. The physiological variables [heart rate, oxygen saturation, and perfusion index (PI)] were recorded at the start of duty, 4 hours after wearing N95 filtering facepiece respirator (FFR), pre-donning, and post-doffing. The rating of perceived exertion (RPE) score and modified Borg scale for dyspnea was evaluated. The physiological variables were represented as the mean ± standard deviation. Wilcoxon signed-rank test was used to show any difference in RPE and modified Borg scale for dyspnea. A p value of <0.05 was considered significant. Results: There is a statistically significant difference in the physiological parameters post-doffing compared with baseline: Heart rate (p < 0.001); oxygen saturation (p < 0.001); PI (p < 0.001). RPE score showed increased discomfort with continuous use of N95 FFR. However, exertion increased only marginally. The major adverse effects noted with PPE use were fogging, headache, tiredness, difficulty in breathing, and mask soakage, with a resultant mean duration of donning to be 3.1 hours. Conclusion: The use of PPE can result in considerable changes in the physiological variables of healthy HCWs. The side effects may lead to excessive exhaustion and increased tiredness after prolonged shifts in the intensive care unit (ICU) while wearing PPE. [ABSTRACT FROM AUTHOR]

Background: The perfusion index (PI), calculated from the photoplethysmographic waveform, reflects peripheral vasomotor tone. As such, the PI serves as a surrogate for quantitative measures of drug-induced vasoconstriction or vasodilation. This study aimed to compare the effect on the PI of desflurane and sevoflurane at equi-anaesthetic concentrations in patients undergoing single-agent inhalation anaesthesia, where equi-anaesthetic dose was based on the known minimum alveolar concentration of these agents.Methods: We randomly allocated patients scheduled for arthroscopic knee surgery to receive either desflurane or sevoflurane general anaesthesia after target-controlled induction of anaesthesia with propofol. Anaesthesia was maintained at age-corrected minimum alveolar concentration 1.0, under neuromuscular block (rocuronium). The PI and haemodynamic data were recorded every minute for 35 min after induction of anaesthesia and after standardised nociceptive stimulation. The primary outcome was PI, compared between the groups over time (repeated-measures analysis of variance). Secondary outcomes included MAP and HR.Results: Sixty-nine participants (mean [range] age: 42 yr [19-65 yr]; 49% females) were assigned to either desflurane (n=34) or sevoflurane (n=35). The PI remained higher under desflurane compared with sevoflurane, both before (mean difference [MD]: 3.3; 95% confidence intervals [CIs]: 2.0-4.7; P<0.001) and after tetanic stimulation (MD: 2.8; 95% CI: 2.0-3.7; P<0.001). Higher PI paralleled lower MAP in participants assigned to desflurane anaesthesia (P<0.001), both before (MD: 8 mm Hg; 95% CI: 4-12) and after nociceptive stimulation (MD: 14 mm Hg; 95% CI: 7-22). HR was similar throughout.Conclusions: These findings suggest that at equipotent doses, desflurane exerts more potent vasodilatory properties and lowers blood pressure by a magnitude potentially associated with harm.Clinical Trial Registration: NCT03570164. [ABSTRACT FROM AUTHOR]

Changes in stroke volume (deltaSV) induced by a lung recruitment manoeuvre (LRM) have been shown to accurately predict fluid responsiveness during protective mechanical ventilation. Cardiac output monitors are used in a limited number of surgical patients. In contrast, all patients are monitored with a pulse oximeter, that may enable the continuous monitoring of a peripheral perfusion index (PI). We postulated that changes in PI (deltaPI) may reflect deltaSV during brief modifications of cardiac preload. We studied 47 patients undergoing neurosurgery and ventilated with a tidal volume of 6-8 ml/kg. All patients were monitored with a pulse contour system enabling the continuous monitoring of SV and with a pulse oximeter enabling the continuous monitoring of PI. LRMs were performed by increasing airway pressure up to 30 cmH20 for 30 s. Fluid loads (250 ml of saline 0.9% in 10 min) were performed only in patients who experienced a deltaSV > 30% during LRMs (potential fluid responders). LRMs induced a 26% decrease in SV (p < 0.05) and a 27% decrease in PI (p < 0.05). We observed a fair relationship between deltaPI and deltaSV (r2 = 0.34). A deltaPI ≥ 26% predicted a deltaSV > 30% with a sensitivity of 83% and a specificity of 78%  (AUC  =  0.84, 95%CI 0.71-0.93). 24 patients experienced a deltaSV > 30% and subsequently received fluid. Fluid loads induced a 16% increase in SV and a 17% increase in PI, but fluid-induced deltaPI and deltaSV were weakly correlated (r2 = 0.19). In neurosurgical patients, we conclude that deltaPI may be used as a surrogate for deltaSV during LRMs but not during fluid loading. [ABSTRACT FROM AUTHOR]

Supraclavicular nerve block (SCB) is a commonly used regional block for upper extremity surgery. The most common form of failure of SCB is ulnar segmental sparing. We aimed to evaluate the accuracy of perfusion index (PI) in early detection of segmental sparing of the ulnar component of SCB. A prospective observational study included adult patients scheduled for surgery under ultrasound-guided SCB. PI was simultaneously measured at the index finger and little finger. PI was recorded every minute for the first 10 min after SCB. PI ratio was calculated at every measurement point as PI/baseline PI. The area under the receiver operating characteristic (AUROC) curve was calculated for the ability of PI ratio to detect segmental ulnar sparing with comparison of little finger readings to the index finger readings. Forty-nine patients were available for the final analysis. Nine patients (18%) had segmental ulnar sparing. PI ratio at the little finger showed excellent predictive ability for ulnar sparing starting from the fifth minute (AUROC 0.92 [0.8-0.98], cutoff value ≤ 1.71) and reached the highest value at the seventh minute (AUROC 0.96 [0.86-1], cutoff value ≤ 1.35), whereas PI ratio at the index finger showed poor predictive ability. When using the PI for evaluation of successful SCB, segmental ulnar sparing could be accurately detected when the PI was measured at the little finger and not at the index finger. An increase of 71% in PI at the little finger 5 min after SCB could accurately rule out ulnar sparing.Clinical trial identifier NCT03880201. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT03880201?term=NCT03880201&draw=2&rank=1 . [ABSTRACT FROM AUTHOR]

Continuous monitoring of tissue perfusion in patients with hemodynamic instability remains challenging because of the lack of tools available. Through using urethral photoplethysmography, the urethral perfusion index (uPI) could allow tissue perfusion monitoring through a modified urinary catheter. The first objective of our study was to evaluate the feasibility and safety of the IKORUS UP (Advanced Perfusion Diagnostics, Villeurbanne, France), a new device in the field. The secondary objectives were to evaluate the performance (duration and signal quality) of the IKORUS UP probe and to assess the uPI variations during hemodynamic events during major abdominal surgery. "STEP UP" was a prospective, multicenter, observational study. The inclusion criteria were age 18 years or older with signed informed consent and admitted to intensive care unit (ICU) with hemodynamic instability or high-risk surgical patient. Thirty patients were included in the study, 26 in the operating room, and four in the ICU. Of these patients, 28 were analyzed. For the primary outcome, six (21%) patients had pain scores assessed at insertion of and 22 (79%) at withdrawal of the catheter. The mean EVA score was 1.5 (IQ 1-2) and 0.7 (IQ 0-1), respectively, with the highest score being 3. One (4%) minor urethral bleeding and one (4%) catheter-associated urinary tract infection were reported. The IKORUS UP probe remained in the urethra for an average of 172 h (IQ40-328). The median signal measurement time was 33 h (IQ 5.2-46). The signal quality was recorded as good or excellent for 99% (IQ 82-100) of the insertion duration. The signal quality index was 93% (IQ 87-96) with a signal-to-noise ratio of 26 (IQ 21-36). We observed clinically relevant variations in the uPI over time during hemodynamic events or therapeutic interventions, with a strong cross-correlation with macrohemodynamic variables in some patients, while others did not display macrohemodynamic changes. The IKORUS UP probe was well tolerated and allowed urethral perfusion monitoring. Clinically relevant changes in tissue perfusion could be recorded during the observational period. Trial Registration: ( www.clinicaltrials.gov NCT03410069) registered January 25, 2018. [ABSTRACT FROM AUTHOR]

Objective: The perfusion index (PI) derived from plethysmographic signals provides a noninvasive indication of peripheral perfusion. This study aimed to investigate changes in PI and other hemodynamic variables in pigs subjected to endotoxemia. Design: Prospective experimental study. Setting: University teaching hospital. Animals: Twelve healthy pigs weighing a mean (± standard deviation [SD]) of 31.7 ± 2.0 kg. Interventions: Pigs were divided into control and endotoxin groups (n = 6 each). Endotoxemia was induced by IV infusion of lipopolysaccharide. Heart rate, mean arterial pressure, cardiac index (CI), central venous pressure, systemic vascular resistance index (SVRI), extravascular lung water index (ELWI), Global end‐diastolic volume (GEDV) index, and pulmonary permeability index were measured using a transpulmonary thermodilution monitor in all pigs. PI was measured using a pulse oximeter probe attached to the tail. Pao2, Paco2, and plasma lactate concentration were measured by blood gas analysis. Measurements were taken at baseline (T0). Saline or lipopolysaccharide was then administered for 30 min to all pigs (control or endotoxemia group, respectively), and each parameter was measured every 30 min up to 270 min. Data were analyzed by analysis of variance and Student's t‐tests. Measurements and Main Results: There were no significant changes in any variables in the control group, but CI, SVRI, PI, ELWI, blood lactate concentration, and Pao2 changed significantly from baseline in the endotoxin group (P < 0.001, P = 0.0048, P < 0.001, P = 0.0064, P < 0.001, and P = 0.0220, respectively). In the endotoxin group, mean (± SD) %PI increased from T0 to 154 ± 34% at T60 (P =.001) and 135 ± 50% at T90 (P =0.004), which mirrored significant changes in %CI and %SVRI. Conclusion: The PI may be useful to detect changes in CI and SVRI. [ABSTRACT FROM AUTHOR]

Background: Perfusion index (PI) derived from pulse oximeter shows the ratio of the pulsatile blood flow to the nonpulsatile blood flow or static blood in peripheral tissue.Objectives: The aim of this study was to investigate the relationship between PI and blood transfusion necessity in 24 h and stage of hemorrhagic shock, as well as the utility of PI according to laboratory and clinical parameters, and determining the major risk of hemorrhage.Methods: PI was measured with a pulse oximeter in 338 patients (235 males, average age 41.8 ± 17.94 years). Laboratory parameters (hemoglobin, hematocrit, lactate, base deficits, pH) and clinical parameters (pulse rate, respiratory rate, SpO2, systolic blood pressure [SBP] and diastolic blood pressure [DBP]), shock index (SI) and revised trauma score (RTS) were recorded. Univariate analysis was used to determine major risk for bleeding, and the receiver operating characteristic curves were performed to compare parameters.Results: PI was < 1 in 39 (11.5%) patients. Positive correlation between PI and hemoglobin (p < 0.001; r: 0.320), hematocrit (p < 0.001; r: 0.294), base deficit (p < 0.001; r: 0.315), pH (p < 0.05; r: 0.235), SBP (p < 0.001; r: 0.146), DBP (p < 0.001; r: 0.259), SpO2 (p < 0.001; r: 0.197), RTS (p < 0.001; r: 0.344), and negative correlation with lactate (p < 0.05; r: -0.117), pulse (p < 0.001; r: -0.326), respiratory rate (p < 0.001; r: -0.231), and SI (p < 0.001; r: -0.257) were detected. A difference was detected between class 1 and 2, and class 1 and 3 (both p < 0.05) in hemorrhagic shock. Thirty-one with PI < 1 had blood transfusion within 24 h (p < 0.001; odds ratio 111.98, sensitivity 75.6%, specificity 97.3, positive predictive value 79.5%, negative predictive value 96.7%). The main risk factors of the need for blood transfusions were PI, pulse rate, and SpO2. PI was more significant than lactate, base deficit, RTS, and SI measurements.Conclusion: PI might be beneficial in the detection and exclusion of critical patients and blood transfusion needs in the emergency department. PI can be used with vital signs and shock parameters in the early diagnosis of hemorrhage. [ABSTRACT FROM AUTHOR]

Peripheral oxygen saturation (SpO2) measured by pulse oximetry is an unreliable surrogate marker for arterial oxygenation (SaO2) in critically ill patients. We hypothesized that a higher perfusion index (PFI) would be associated with better accuracy of SpO2 measurement. We retrospectively collected SaO2, SpO2, and PFI data for each arterial blood gas (ABG) analysis in a cohort of intensive care unit patients. PFI was categorised as low (PFI < 1.0), intermediate (1.0 ≤ PFI ≤ 2.5), or high (PFI > 2.5). The correlation between SpO2 and SaO2 was studied using Pearson's correlation. The Bland–Altman plot was used to analyse the agreement between SpO2 and SaO2. Furthermore, the correlation between the (SpO2–SaO2) difference and PFI was assessed. The level of (dis)agreement was calculated for the three PFI categories separately. Overall, 281 patients and 1281 data points were analysed. There was a significant correlation between SaO2 and SpO2 (r = 0.69, p < 0.01). The Bland–Altman analysis revealed a mean difference between SaO2 and SpO2 of 0.2% with limits of agreement of ± 6% (SD ± 2%). The correlation between the PFI and the (SpO2–SaO2) difference was low; the (SpO2–SaO2) difference improved only marginally with higher PFI values. The accuracy of pulse oximetry for estimating arterial oxygenation was moderate and improved little with increasing PFI values. Thus, the additive value of PFI in clinical decision making is limited. Therefore, we advise performing an ABG before adjusting fraction of inspired oxygen (FiO2) settings. [ABSTRACT FROM AUTHOR]

Background: The importance of microcirculation for adverse outcomes in the early phase of critical illnesses has been reported. Microcirculatory function is assessed using the perfusion index (PI), which represents the level of circulation through peripheral tissues. We investigated the correlation between PI and cardiovascular death to explore whether it can serve as a predictor of cardiovascular death. Methods and results: This retrospective study included 2171 patients admitted to Matsushita Memorial Hospital in Osaka, Japan, for medical treatment. We measured PI for all patients. To examine the effects of PI on cardiovascular death, a Cox proportional hazard model was used. The median age and PI values were 72 years (range 63–79 years) and 2.7% (range 1.4–4.6%), respectively. During the 3927.7 person-years follow-up period, a total of 54 patients died due to cardiovascular disease. PI was positively correlated with BMI (P < 0.0001) and total cholesterol levels (P = 0.004). PI was negatively correlated with age (P < 0.0001), heart rate (P < 0.0001), and creatinine levels (P < 0.0001). Adjusted Cox regression analyses demonstrated that PI was associated with an increased hazard of cardiovascular death (hazard ratio 0.84; 95% CI; range 0.72–0.99). In addition, compared with patients with a high PI (> 3.7%), those with a low PI (≤ 2.0%) had a significantly increased risk of cardiovascular death. This low PI group had a hazard ratio of 3.49 (95% CI 1.73–7.82). Conclusions: The PI is a valuable predictor for cardiovascular death in a clinical setting. [ABSTRACT FROM AUTHOR]

Aims: To correlate the relation between perfusion index and the prediction of hypotension in lower segment caesarean section. Methods: This is a prospective observational study of parturients undergoing caesarean section from 4th February to 2nd June 2020 at Paropakar Maternity and Women's Hospital in Kathmandu. Cases were studied by their Perfusion Index (PI) value of 3.5 as cut-off. parturients undergoing caesarean section. Hemodynamic effects and PI values were monitored recorded and compared between low and high PI groups. Statistical analysis was done using independent sample T test and Pearson correlation. Results: Total 106 cases were studied with 52 with low PI value and 54 cases with high PI value. The incidence of hypotension in low PI was 26% whereas it was 48% in high PI group and mean consumption of phenylephrine was more in high PI group. Conclusions: Parturients with a higher baseline PI index of more than 3.5 have more incidence of hypotension and require vasopressors support following spinal anesthesia in elective LSCS [ABSTRACT FROM AUTHOR]

Aim: We tested a hypothesis that postoperative active warming and/or arm leg stretches reduce the difference between core and skin temperatures (primary variable) improving the peripheral circulation immediately after major abdominal surgery. Methods: Fifty‐one patients undergoing major abdominal surgeries were randomly assigned to receive one of three interventions immediately after surgery; routine care (control group), mild intermittent exercise on the bed (exercise group), and forced‐air warming (warming group). Core and skin temperatures and perfusion index were continuously measured from anesthesia induction to 12 h after arrival at the ward. Results: Core body temperature was maintained over 37°C with a relatively greater gap between core and skin temperatures over 1°C and reduced perfusion index in the early postoperative period in the control group. In the warming group, the reduced skin temperature at arrival at the ward approximated to the core temperature leading to significant reduction of the temperature gap and increasing the perfusion index to the preoperative level. Although less evident, both the temperature gap and peripheral perfusion significantly improved in the exercise group after 6 and 8 h after arrival at the ward, respectively. Conclusions: Vasoconstriction in response to cessation after anesthesia and surgery serves to maintain core temperature, but impairs peripheral circulation. Active warming and intermittent mild exercise immediately after arrival at the ward reduces the temperature gap and improves peripheral circulation during the early postoperative period. While cost‐effectiveness needs to be considered before clinical application of the intervention, the cost‐free mild exercise may be a feasible option for improving postoperative patient care. [ABSTRACT FROM AUTHOR]

Aims/Introduction: Diabetic kidney disease has been considered as an important risk factor of cardiovascular disease. Chronic hypoxia is considered to be the main cause of renal injury. Diminished microcirculatory blood flow could be associated with hypoxia in the kidney. Whether diminished microcirculation is associated with diabetic kidney disease has not yet been reported. Here, we investigated the correlation between microcirculatory function and diabetic kidney disease in patients with type 2 diabetes. Materials and Methods: Our cross‐sectional study included 574 patients who were admitted to Matsushita Memorial Hospital in Moriguchi, Japan, for type 2 diabetes. Microcirculatory function was assessed using the perfusion index (PI), which represents the level of circulation through peripheral tissues. We measured the PI for all patients. Results: The median age and PI values were 70 years (range 60–77 years) and 2.8% (range 1.6–4.8%). Multiple regression analyses showed that the PI independently correlated with the logarithm of urinary albumin excretion (P = 0.009) and estimated glomerular filtration rate (P = 0.005), respectively. Multiple logistic regression analyses showed that patients with systolic blood pressure (SBP) greater than the median and PI less than or equal to the median (high‐low group) had a significantly increased odds of albuminuria compared with those with SBP less than or equal to the median and PI greater than the median (low‐high group), and patients with SBP greater than the median and PI less than or equal to the median (high‐low group) had a significantly increased odds of estimated glomerular filtration rate <60 mL/min per 1.73 m2 compared with those with SBP less than or equal to the median and PI greater than the median (low‐high group) or SBP greater than the median and PI greater than the median (high‐high group). Conclusions: PI could be a novel indicator of diabetic kidney disease in patients with type 2 diabetes. [ABSTRACT FROM AUTHOR]

Background: To evaluate an association between vehicle exhaust and its effect on pulmonary functions of traffic police personnel and to assess the extent of impairment in the lung function of traffic police personnel compared to unexposed healthy control group. Material And Methods: In this comparative, observational study pulmonary function parameters were recorded in age- and BMI - matched 60 traffic police personnel (active in the field as study group) and 30 traffic police personnel (performing back office work as control group) of both genders. PFT parameters were compared between the study group and control group by using electronic (computerized) spirometer available in Department of Medicine, Smt.NHLMMC & VSGH. Blood oxygen saturation levels (b) and Perfusion Index (PI) were recorded using Dr.Trust Professional series Fingertip Pulse Oximeter. Result: No difference was found in case of Systolic Blood Pressure, Blood oxygen saturation levels (SpO2) and Perfusion Index (PI) in both groups. Diastolic Blood Pressure was significantly (P<0.05) higher in study group (75.4 ± 8.03) in compare to control group (72.13 ± 6.02). There was a significant decrease in FVC (P<0.0001), FEV1 (P<0.00001), FEF25-75% (P<0.0001), PEF (P<0.001), FEF0.2-1.2 (P<0.001), FEF25% (P<0.001), FEF50% (P<0.0001) and Inspiratory capacity (P<0.05) in study group compared to the control group. Conclusion: These changes suggest obstruction and narrowing of the airways in study group traffic police personnel compared to the control group. It may be due to exposure to vehicle emission for several hours in a day, which decreases their lung capacity. Abbreviations: BMI: Body Mass Index (Kg/m²), PFT: Pulmonary function test, FVC: Forced Vital Capacity, FEV1: Forced Expiratory Volume in first second, FEF25-75%: Forced Expiratory Flow at 25-75% of FVC in litres per second, PEF: Peak Expiratory Flow in litres per second, FEF0.2-1.2: Forced Expiratory Flow between 200 and 1200 ml of FVC, FEF25%: Forced Expiratory Flow at 25% of FVC in litres per second, FEF50%; Forced Expiratory Flow at 50% of FVC in litres per second, FEF75%: Forced Expiratory Flow at 75% of FVC in litres per second. [ABSTRACT FROM AUTHOR]

Objective: Limited data are available on the use of the perfusion index (PI) and the pleth variability index (PVI) during laparoscopic bariatric surgery. We investigated the effects of pneumoperitoneum and the reverse Trendelenburg position on these indices. Materials and Methods: PI, PVI, heart rate (HR), blood pressure, SpO2 and ventilation parameters were recorded before anaesthesia induction (T0), 5 min after endotracheal intubation (T1), immediately before surgery, after the patient had been in the reverse Trendelenburg position for 5 min (T2), after inflating the abdomen with CO2 in reverse Trendelenburg (T3), after the abdomen had been deflated (T4) and 5 min after extubation (T5). Results: General anaesthesia induced an increase in the PI (P<.001), and a decrease in the PVI (P=.002). The PI and PVI values were not affected during T2 or T3. Pneumoperitoneum caused an increase in mean arterial pressure (MAP) and a decrease in HR. PVI and MAP decreased during T4, but the PI and HR remained unchanged. PVI, HR and MAP increased during T5. Conclusion: Our data suggest that the reverse Trendelenburg position and pneumoperitoneum did not affect the PI or PVI values, whereas deflation decreased the PVI in morbidly obese patients under general anaesthesia. [ABSTRACT FROM AUTHOR]