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The incidence of aortic valve stenosis (AoS) increases with age, and once diagnosed, symptomatic severe AoS has a yearly mortality rate of 25%. AoS is diagnosed with transthoracic echocardiography (TTE), however, this gold standard is time consuming and operator and acoustic window dependent. As AoS affects the arterial blood pressure waveform, AoS-specific waveform features might serve as a diagnostic tool. Aim of the present study was to develop a novel, non-invasive, AoS detection model based on blood pressures waveforms. This cross-sectional study included patients with AoS undergoing elective transcatheter or surgical aortic valve replacement. AoS was determined using TTE, and patients with no or mild AoS were labelled as patients without AoS, while patients with moderate or severe AoS were labelled as patients with AoS. Non-invasive blood pressure measurements were performed in awake patients. Ten minutes of consecutive data was collected. Several blood pressure-based features were derived, and the median, interquartile range, variance, and the 1st and 9th decile of the change of these features were calculated. The primary outcome was the development of a machine-learning model for AoS detection, investigating multiple classifiers and training on the area under the receiver-operating curve (AUROC). In total, 101 patients with AoS and 48 patients without AoS were included. Patients with AoS showed an increase in left ventricular ejection time (0.02 s, p = 0.001), a delayed maximum upstroke in the systolic phase (0.015 s, p < 0.001), and a delayed maximal systolic pressure (0.03 s, p < 0.001) compared to patients without AoS. With the logistic regression model, a sensitivity of 0.81, specificity of 0.67, and AUROC of 0.79 were found. The majority of the population without AoS was male (85%), whereas in the population with AoS this was evenly distributed (54% males). Age was significantly (5 years, p < 0.001) higher in the population with AoS. In the present study, we developed a novel model able to distinguish no to mild AoS from moderate to severe AoS, based on blood pressure features with high accuracy. Clinical registration number: The study entailing patients with TAVR treatment was registered at ClinicalTrials.gov (NCT03088787, https://clinicaltrials.gov/ct2/show/NCT03088787). The study with elective cardiac surgery patients was registered with the Netherland Trial Register (NL7810, https://trialsearch.who.int/Trial2.aspx?TrialID=NL7810). [ABSTRACT FROM AUTHOR]

The quality of remote photoplethysmography (rPPG) signals presents a significant challenge in contactless optical blood pressure measurement. Feature and morphologybased approaches heavily rely on subtle changes in signal characteristics, but rPPG signals are highly susceptible to noise and interference. This study aims to evaluate rPPG signal quality by assessing correlation with a reference PPG and signal-to-noise ratio (SNR) across various color models and rPPG methods. Analyses are performed under different measurement conditions, accounting for common sources of signal artifacts. [ABSTRACT FROM AUTHOR]

Objectives: Systemic arterial hypertension is a common occurrence and can have serious adverse consequences in cats. Therefore, measuring blood pressure is very important. There are many indirect blood pressure measurement devices available. This study compared Doppler, oscillometric (petMAP Graphic II, SunTech Vet20, the Cardell Insight-X0000) and high-definition oscillometry devices for the non-invasive measurement of blood pressure in conscious cats. Methods: In this prospective study, blood pressure was measured in 32 cats using the different devices according to the recommendations of the American College of Veterinary Internal Medicine Consensus Statement. Blood pressures (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), time to complete measurements, number of attempts needed, coefficient of variation (CV) between the blood pressure measurements of the different devices, ease of completing measurements and apparent stress level of the cat were assessed. Results: There was a significant difference between devices in the time taken to obtain blood pressure readings and the number of attempts necessary to obtain six reliable measurements. The CV of the Doppler device was significantly smaller than that of the rest of the devices, but there were no other differences between the devices. The mean SBP, DBP and MAP measured by the petMAP device were significantly higher than the measurements from the other devices. The perceived ease of measurement was not significantly different between the various machines. The perceived level of stress of measurement with the Doppler device was significantly higher compared with the other devices but did not lead to an increased SBP. Conclusions and relevance: Using a Doppler device to measure blood pressure in conscious cats is fast, relatively easy and gives reliable results. A disadvantage is that the Doppler device can only measure SBP, while oscillometric devices also provide DBP and MAP. However, in veterinary medicine, systolic hypertension is considered the most relevant. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the accuracy of oscillometric blood pressure measurement at the ankle in children using invasive blood pressure as reference standard. This prospective observational study included children undergoing noncardiac surgery. Paired radial invasive and ankle non-invasive blood pressure measurements were obtained. Delta blood pressure was calculated as the difference between two consecutive readings. The primary outcome was the mean bias and agreement between the two methods using the Bland-Altman analysis. The ISO standard was fulfilled if the mean bias between the two methods was ≤ 5 ± 8 mmHg. Other outcomes included the trending ability of ankle blood pressure using the four-quadrant plot and the accuracy of ankle measurement to detect hypotension using area under receiver operating characteristic curve (AUC) analysis. We analyzed 683 paired readings from 86 children. The mean bias between the two methods for systolic, diastolic, and mean blood pressure (SBP, DBP, MAP) was − 7.2 ± 10.7, 4.5 ± 12.8, and − 1.8 ± 8.2 mmHg, respectively. The concordance rate of ankle blood pressure was 72%, 71%, and 77% for delta SBP, DBP and MAP, respectively. The AUC (95% confidence interval) for ankle MAP ability to detect hypotension was 0.91 (0.89–0.93) with negative predictive value of 100% at cut-off value ≤ 70 mmHg, We concluded that in pediatric population undergoing noncardiac surgery, ankle blood pressure was not interchangeable with the corresponding invasive readings with the ankle MAP having the least bias compared to SBP and DBP. An ankle MAP > 70 mmHg can exclude hypotension with negative predictive value of 100%. [ABSTRACT FROM AUTHOR]

BACKGROUND: Blood pressure (BP) monitoring is essential for patient care. Invasive arterial BP (IABP) is more accurate than non-invasive BP (NIBP), although the clinical significance of this difference is unknown. We hypothesized that IABP would result in a change of management (COM) among patients with non-hypertensive diseases in the acute phase of resuscitation. METHODS: This prospective study included adults admitted to the Critical Care Resuscitation Unit (CCRU) with non-hypertensive disease from February 1, 2019, to May 31, 2021. Management plans to maintain a mean arterial pressure >65 mmHg (1 mmHg=0.133 kPa) were recorded in real time for both NIBP and IABP measurements. A COM was defined as a discrepancy between IABP and NIBP that resulted in an increase/decrease or addition/discontinuation of a medication/infusion. Classification and regression tree analysis identified significant variables associated with a COM and assigned relative variable importance (RVI) values. RESULTS: Among the 206 patients analyzed, a COM occurred in 94 (45.6% [94/206]) patients. The most common COM was an increase in current infusion dosages (40 patients, 19.4%). Patients receiving norepinephrine at arterial cannulation were more likely to have a COM compared with those without (45 [47.9%] vs. 32 [28.6%], P=0.004). Receiving norepinephrine (relative variable importance [RVI] 100%) was the most significant factor associated with a COM. No complications were identified with IABP use. CONCLUSION: A COM occurred in 94 (45.6%) non-hypertensive patients in the CCRU. Receiving vasopressors was the greatest factor associated with COM. Clinicians should consider IABP monitoring more often in non-hypertensive patients requiring norepinephrine in the acute resuscitation phase. Further studies are necessary to confirm the risk-to-benefit ratios of IABP among these high-risk patients. [ABSTRACT FROM AUTHOR]

Background: The multiparameter monitor (MPM) is replacing mercury column sphygmomanometers (MCS) in acute care settings. However, data on the former's accuracy in critically ill children are scarce and mostly extrapolated from adults. We compared non-invasive blood pressure (NIBP) measurements by MPMs with MCS in pediatric intensive care unit (PICU). Patients: Adequately sedated and hemodynamically stabilized children (age, 1-144 months) were prospectively enrolled. Materials and methods: Three NIBP measurements were obtained from MCS (Diamond®, India) and MPM (Intellivue MX800® or Ultraview SL®) in rapid succession in the upper limb resting in supine position. Respective three measurements were averaged to obtain a paired set of NIBP readings, one each from MCS and MPM. Such readings were obtained thrice a day. NIBP readings were then compared, and agreement was assessed. Results: From 39 children [median age (IQR), 30 (10-72) months], 1,690 sets of NIBP readings were obtained. A-third of readings were from infants and children >96 months, while 383 (22.6%) readings were from patients on inotropes. Multiparameter monitors gave significantly higher NIBP readings compared to MCS [median systolic blood pressure (SBP), 6.5 (6.4-6.7 mm Hg); diastolic blood pressure (DBP), 4.5 (4.3-4.6 mm Hg); mean arterial pressure (MAP), 5.3 (5.1-5.4 mm Hg); p < 0.05]. It was consistent across age, gender, and critical care characteristics. Multiparameter monitors overestimated SBP in 80% of readings beyond the maximal clinically acceptable difference (MCAD). Conclusions: Non-invasive blood pressure readings from MCS and MPMs are not interchangeable; SBP was 6-7 mm Hg higher with the latter. Overestimation beyond MCAD was overwhelming. Caution is required while classifying systolic hypotension with MPMs. Confirmation with auscultatory methods is advisable. More studies are required to evaluate currently available MPMs in different pediatric age groups. [ABSTRACT FROM AUTHOR]

A six month old cross bred calf was presented with a swelling on lateral abdomen and diagnosed with lateral abdominal hernia, which underwent herniorrhaphy under general anaesthesia formed the subject of the study. The animal was administered with meloxicam @ 0.5 mg/kg body weight intravenously for pre-emptive analgesia. Thirty minutes later, xylazine @ 0.02 mg/kg and butorphanol @ 0.05 mg/kg, were administered intravenously. Upon sedation, the animal was administered with a loading dose of lignocaine @ 1 mg/kg body weight intravenously. Immediately following the loading dose of lignocaine, anaesthesia was induced using guaiphenesin @ 50 mg/kg and ketamine @ 2mg/kg intravenously. Following induction, anaesthesia was maintained using the prepared guaiphenesin-ketamine-lignocaine-butorphanol anaesthetic mixture as continuous rate infusion @ 3 ml/kg/hr. Indirect and direct blood pressure measurements were monitored and recorded. The non-invasive blood pressure values for systolic, diastolic and mean blood pressures did not differ significantly (p > 0.05) from those monitored invasively

Abstract Background Measuring blood pressure in patients with obesity is challenging. The ClearSight™ finger cuff (FC) uses the vascular unloading technique to provide continuous non-invasive blood pressure measurements. We aimed to test the agreement of the FC with invasive radial arterial monitoring (INV) in patients with obesity. Methods Participants had a body mass index (BMI) ≥45 kg/m2 and underwent laparoscopic bariatric surgery. FC and INV measurements were obtained simultaneously every 5 min on each patient, following induction of anesthesia. Agreement over time was assessed using modified Bland-Altman plots and error grid analysis permitted clinical interpretation of the results. Four-quadrant plots allowed assessment of concordance in blood pressure changes. Results The 30 participants had a median (IQR) BMI of 50.2 kg/m2 (IQR 48.3–55.3). The observed bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 14.3 mmHg (14.1, -13.4 – 42.0), 5.2 mmHg (10.9, -16.0 – 26.5) for mean arterial pressure (MAP) and 2.6 mmHg (10.8, -18.6 – 23.8) for diastolic blood pressure (DBP). Error grid analysis showed that the proportion of readings in risk zones A-E were 90.8, 6.5, 2.7, 0 and 0% for SBP and 91.4, 4.3, 4.3, 0 and 0% for MAP, respectively. Discordance occurred in ≤8% of pairs for consecutive change in SBP, MAP and DBP. Conclusions The vascular unloading technique was not adequately in agreement with radial arterial monitoring. Evaluation in a larger sample is required before recommending this technique for intraoperative monitoring of patients with BMI ≥45 kg/m2.

Background: Accurate measurement of blood pressure (BP) is extremely important in the management of sick preterm newborns. The primary objective of this study was to compare non-invasive blood pressure measurement (NIBP) with invasive blood pressure measurement (IBP) using peripheral arterial cannulation (PAC) in preterm neonates < 37 weeks in the neonatal intensive care unit.Methods: Preterm neonates needing PAC were prospectively enrolled in the study. NIBP measurements were taken in the same limb as that of peripheral arterial line. Initially IBP was recorded followed by NIBP within 1 min using the same monitor. These were called as paired measurements since they are taken within 1 min of each other.Results: Seventy-three preterm infants with 1703 paired measurements were included in the final analysis (median gestational age 32 weeks, IQR 30-34 weeks, median birth weight 1540 g, IQR 1160-2100 g). In preterm infants not receiving vasoactive agents (n = 51, 1428 paired measurements, Bland-Altman analysis for agreement between invasive mean blood pressure (MBP) and non-invasive mean BP revealed a bias of -2.9123 mmHg (SD 7.8074). The 95% limits of agreement were from -18.2157 to 12.3893 mmHg. In preterm infants with hypotension, we detected a bias of -3.9176 mmHg (SD 5.1135) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -13.9401 to 6.1048 mmHg. In normotensive preterm infants receiving vasoactive agents, we detected a bias of -0.7629 mmHg (SD 8.0539) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -16.5485 to 15.02274 mmHg.Conclusions: There is poor level of agreement between IBP and NIBP measurements in sick preterm neonates, leading to overestimation or underestimation of blood pressure. The bias was less for mean BP measurements as compared with systolic BP measurements and also for normotensive neonates as compared with hypotensive neonates. Hence, NIBP may be used as a screening method in haemodynamically stable preterm infants, but infants who are haemodynamically unstable and need to be commenced on vasoactive agents should have IBP monitoring. [ABSTRACT FROM AUTHOR]

Background and Aims: Non-invasive blood pressure (NiBP) varies with the arm and body position. In the lateral decubitus position (LDP), the non-dependent arm reads lower, and the dependent arm reads higher pressure. We aimed to study the correlation between the NiBP and invasive arterial blood pressure (ABP) as anaesthesia progressed and its correlation in different BP ranges. Methods: American Society of Anesthesiologists (ASA I–III) patients, between 18–70 years undergoing neurosurgical procedures in the LDP were studied. All were anaesthetised using a standard protocol, positioned in the LDP. NiBP was measured every 15 min in both dependent and non-dependent arms and correlated with the ABP. Results: Intra-class correlation (ICC) done between the dependent arm NiBP and ABP showed good correlation for mean and systolic BP and moderate correlation for diastolic BP. ICC was 0.800, 0.846 and 0.818 for mean and 0.771, 0.782, 0.792 for systolic BP at 15 min, 1 h, and 2 h, respectively. The ICC between the non-dependent arm NiBP and the invasive ABP showed poor correlation for all BP (systolic, diastolic and mean). As anaesthesia progressed, the mean difference between the NiBP and the ABP decreased in the dependent arm and increased in the non-dependent arm. The strength of agreement between the NiBP and the ABP in various BP ranges showed moderate correlation for the dependent arm NiBP (0.45–0.54) and poor correlation (0.21–0.38) for the non-dependent arm. Conclusion: The NiBP of the dependent arm correlated well with ABP in LDP under general anaesthesia (GA). It is better to defer measuring NiBP in the non-dependent arm as the correlation with ABP is poor.

Seth Hayes,1 Rebecca Miller,1 Ambrish Patel,2,3 Dmitry Tumin,1,2 Hina Walia,1 Mohammed Hakim,1 Faizaan Syed,1 Joseph D Tobias1,2,41Department of Anesthesiology and Pain Medicine, Nationwide Children’s Hospital, Columbus, OH 43205, USA; 2Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA; 3Division of Pediatric Critical Care, Nationwide Children’s Hospital, Columbus, OH 43205, USA; 4Department of Anesthesiology and Pain Medicine, The Ohio State University, Columbus, OH 43210, USACorrespondence: Seth HayesDepartment of Anesthesiology and Pain Medicine, Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205, USATel +1 614 722 4200Fax +1 614 722 4203Email seth.hayes@nationwidechildrens.orgPurpose: To compare invasive blood pressure (IBP) readings obtained from an arterial cannula with non-invasive blood pressure (NIBP) measurements from oscillometric cuffs on the upper and lower extremities of infants and children under general anesthesia.Patients and methods: Patients under 10 years of age were enrolled in our study if they were to receive general anesthesia with planned placement of a radial arterial cannula. At 5 mins intervals, IBP was measured using a fluid-coupled pressure transducer and NIBP was measured with two oscillometers with appropriately sized cuffs placed on the upper arm and lower leg, for 10 readings per patient.Results: The study enrolled 18 boys and 12 girls, ranging in age from 0 to 8 years. Across 300 data points, the absolute difference between the arm and invasive mean arterial pressure (MAP) measurements was 7±7 mmHg (range: 0–52 mmHg). The absolute difference between the leg and invasive MAP measurements was 8±8 mmHg (range: 0–52 mmHg). Although both non-invasive measurement sites demonstrated frequent deviation from invasive measurement, large deviations were more common when BP was measured at the leg (81 of 298 observations (27%) deviating by >10 mmHg) compared to the arm (60 of 300 observations (20%) deviating by >10 mmHg).Conclusion: The frequency of clinically significant NIBP deviation in children under general anesthesia supports the importance of IBP monitoring when hemodynamic fluctuations are likely and would be particularly detrimental. NIBP measured at the lower leg is more likely to result in clinically significant deviation from invasively measured MAP than NIBP values obtained from an upper arm.Keywords: invasive blood pressure, non-invasive blood pressure, blood pressure cuff

Background: Measuring blood pressure in patients with obesity is challenging. The ClearSight™ finger cuff (FC) uses the vascular unloading technique to provide continuous non-invasive blood pressure measurements. We aimed to test the agreement of the FC with invasive radial arterial monitoring (INV) in patients with obesity. Methods: Participants had a body mass index (BMI) ≥45 kg/m2 and underwent laparoscopic bariatric surgery. FC and INV measurements were obtained simultaneously every 5 min on each patient, following induction of anesthesia. Agreement over time was assessed using modified Bland-Altman plots and error grid analysis permitted clinical interpretation of the results. Four-quadrant plots allowed assessment of concordance in blood pressure changes. Results: The 30 participants had a median (IQR) BMI of 50.2 kg/m2 (IQR 48.3–55.3). The observed bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 14.3 mmHg (14.1, -13.4 – 42.0), 5.2 mmHg (10.9, -16.0 – 26.5) for mean arterial pressure (MAP) and 2.6 mmHg (10.8, -18.6 – 23.8) for diastolic blood pressure (DBP). Error grid analysis showed that the proportion of readings in risk zones A-E were 90.8, 6.5, 2.7, 0 and 0% for SBP and 91.4, 4.3, 4.3, 0 and 0% for MAP, respectively. Discordance occurred in ≤8% of pairs for consecutive change in SBP, MAP and DBP. Conclusions: The vascular unloading technique was not adequately in agreement with radial arterial monitoring. Evaluation in a larger sample is required before recommending this technique for intraoperative monitoring of patients with BMI ≥45 kg/m2. [ABSTRACT FROM AUTHOR]

An algorithm derived from machine learning uses the arterial waveform to predict intraoperative hypotension some minutes before episodes, possibly giving clinician's time to intervene and prevent hypotension. Whether the Hypotension Prediction Index works well with noninvasive arterial pressure waveforms remains unknown. We therefore evaluated sensitivity, specificity, and positive predictive value of the Index based on non-invasive arterial waveform estimates. We used continuous hemodynamic data measured from ClearSight (formerly Nexfin) noninvasive finger blood pressure monitors in surgical patients. We re-evaluated data from a trial that included 320 adults ≥ 45 years old designated ASA physical status 3 or 4 who had moderate-to-high-risk non-cardiac surgery with general anesthesia. We calculated sensitivity and specificity for predicting hypotension, defined as mean arterial pressure ≤ 65 mmHg for at least 1 min, and characterized the relationship with receiver operating characteristics curves. We also evaluated the number of hypotensive events at various ranges of the Hypotension Prediction Index. And finally, we calculated the positive predictive value for hypotension episodes when the Prediction Index threshold was 85. The algorithm predicted hypotension 5 min in advance, with a sensitivity of 0.86 [95% confidence interval 0.82, 0.89] and specificity 0.86 [0.82, 0.89]. At 10 min, the sensitivity was 0.83 [0.79, 0.86] and the specificity was 0.83 [0.79, 0.86]. And at 15 min, the sensitivity was 0.75 [0.71, 0.80] and the specificity was 0.75 [0.71, 0.80]. The positive predictive value of the algorithm prediction at an Index threshold of 85 was 0.83 [0.79, 0.87]. A Hypotension Prediction Index of 80–89 provided a median of 6.0 [95% confidence interval 5.3, 6.7] minutes warning before mean arterial pressure decreased to < 65 mmHg. The Hypotension Prediction Index, which was developed and validated with invasive arterial waveforms, predicts intraoperative hypotension reasonably well from non-invasive estimates of the arterial waveform. Hypotension prediction, along with appropriate management, can potentially reduce intraoperative hypotension. Being able to use the non-invasive pressure waveform will widen the range of patients who might benefit. Clinical Trial Number: ClinicalTrials.gov NCT02872896. [ABSTRACT FROM AUTHOR]

Background and Aims: Non-invasive blood pressure (NiBP) varies with the arm and body position. In the lateral decubitus position (LDP), the non-dependent arm reads lower, and the dependent arm reads higher pressure. We aimed to study the correlation between the NiBP and invasive arterial blood pressure (ABP) as anaesthesia progressed and its correlation in different BP ranges. Methods: American Society of Anesthesiologists (ASA I–III) patients, between 18–70 years undergoing neurosurgical procedures in the LDP were studied. All were anaesthetised using a standard protocol, positioned in the LDP. NiBP was measured every 15 min in both dependent and non-dependent arms and correlated with the ABP. Results: Intra-class correlation (ICC) done between the dependent arm NiBP and ABP showed good correlation for mean and systolic BP and moderate correlation for diastolic BP. ICC was 0.800, 0.846 and 0.818 for mean and 0.771, 0.782, 0.792 for systolic BP at 15 min, 1 h, and 2 h, respectively. The ICC between the non-dependent arm NiBP and the invasive ABP showed poor correlation for all BP (systolic, diastolic and mean). As anaesthesia progressed, the mean difference between the NiBP and the ABP decreased in the dependent arm and increased in the non-dependent arm. The strength of agreement between the NiBP and the ABP in various BP ranges showed moderate correlation for the dependent arm NiBP (0.45–0.54) and poor correlation (0.21–0.38) for the non-dependent arm. Conclusion: The NiBP of the dependent arm correlated well with ABP in LDP under general anaesthesia (GA). It is better to defer measuring NiBP in the non-dependent arm as the correlation with ABP is poor. [ABSTRACT FROM AUTHOR]

• Non-invasive blood pressure monitoring in obese patients is challenging. • Arm, forearm and wrist non-invasive readings were compared to invasive pressure. • Wrist measurement had the highest correlation and least bias with invasive pressure. • Wrist cuff inflation time was the shortest followed by forearm, then arm. In obese patients, non-invasive blood pressure monitoring in the arm is difficult due to the arm size and morphology. We compared the non-invasive oscillometric wrist blood pressure measurement with the arm and forearm in obese patients monitored with invasive radial blood pressure (reference standard). This prospective observational study included adult obese patients scheduled for bariatric surgery. Non-invasive blood pressure was measured at the arm, upper forearm and wrist of one upper extremity, while invasive blood pressure was simultaneously measured through a radial arterial catheter in the contralateral upper extremity. The accuracy of non-invasive blood pressure reading at each site was evaluated for absolute and trending values using the Bland–Altman analysis and Spearman's correlation coefficient. In 40 patients, 262, 259, and 263 pairs of non-invasive blood pressure readings were obtained from the arm, forearm, and wrist sites, respectively. As primary outcome, the correlation coefficient for systolic blood pressure was higher for the wrist (0.92, 95% confidence interval (CI) [0.9–0.94]) than for the arm (0.74, 95% CI [0.68–0.79]) and the forearm (0.71, 95% CI [0.64–0.76]) (P < 0.05). The non-invasive systolic wrist blood pressure showed the least mean bias and the narrowest limits of agreement (−0.3 ± 7.6 mmHg) when compared with forearm (4.3 ± 16) and arm measurements (14.2 ± 13.6) (P < 0.05). For trending values, the correlation coefficient was the highest at the wrist. In obese patients undergoing bariatric surgery, non-invasive blood pressure measured at the wrist showed the highest accuracy in comparison with the arm and forearm. [ABSTRACT FROM AUTHOR]

Background: Indirect blood pressure measurements are often used to guide clinical decisions, but few studies have verified their agreement with direct arterial blood pressure in nonhuman primates. Here, the accuracy and precision of Doppler (DOP) and oscillometric (OS) [systolic (OSsys), mean (OSmean), and diastolic (OSdias)] blood pressure readings were assessed in rhesus macaques. Methods: DOP and OS were utilized to measure blood pressure values in nine anesthetized rhesus macaques, which were compared to direct measurements via a saphenous arterial catheter. All measurements were taken simultaneously every 5 min for 60‐240 min. Results: DOP and OSsys underestimated direct systolic arterial pressure with a bias ± precision of 10.21 ± 6.37 mmHg and 11.67 ± 11.55 mmHg, respectively. OSmean correlated well with direct mean arterial pressure with a bias ± precision of 7.25 ± 7.35 mmHg. Conclusions: DOP provided the better representation of systolic blood pressure, and OSmean provided a useful representation of mean arterial pressure in anesthetized rhesus macaques. [ABSTRACT FROM AUTHOR]

The American Society of Anesthesiologists Standards for Basic Monitoring recommends blood pressure (BP) measurement every 5 min. Research has shown distractions or technical factors can cause prolonged measurement intervals exceeding 5 min. We investigated the relationship between prolonged non-invasive BP (NIBP) measurement interval and the incidence of hypotension, detected post-interval. Our secondary outcome was to determine independent predictors of these prolonged NIBP measurement intervals. Retrospective data were analyzed from 139,509 general anesthesia cases from our institution's Anesthesia Information Management System (AIMS). Absolute hypotension (AH) was defined a priori as a systolic BP < 80 mmHg and relative hypotension (RH) was defined as a 40% decrease in systolic BP from the preoperative baseline. Odds ratios (OR) with 95% confidence intervals and Pearson's Chi square Test reported the association of prolonged NIBP measurement intervals on hypotension detected post-NIBP measurement interval. Logistic regression models were developed to determine independent predictors of NIBP measurement intervals. The analysis revealed that NIBP measurement intervals greater than 6 and 10 min are associated with an approximately four times higher incidence of a patient transitioning into hypotension (AH/RH > 6 min OR 4.0 / 3.6; AH/RH > 10 min OR 4.3 / 3.9; p < 0.001). A key finding was that the "> 10-minute AH model" indicated that age 41-80, increased co-morbidity profile, obesity and turning (repositioning) of the operative room table were significant predictors of prolonged NIBP measurement intervals (p < 0.001). While we do not suggest NIBP measurement intervals cause hypotension, intervals greater than 6 and 10 min are associated with a fourfold increase in the propensity of an undetected transition into both RH or AH. These data support current monitoring guidelines. [ABSTRACT FROM AUTHOR]

Objective To assess the validity and reliability of Doppler ultrasonography (DOP) as compared with invasive arterial blood pressure measurements in anaesthetized dogs weighing less than 5 kg. Study design Controlled, prospective, clinical study. Animals A total of 41 privately owned dogs weighing less than 5 kg. Methods The dogs were anaesthetized, and an intra-arterial catheter was placed aseptically in the dorsal pedal artery of the pelvic limb to perform invasive blood pressure (IBP) measurement. The contralateral metatarsal surface of the foot was clipped in order to perform DOP. Both techniques were used to record blood pressure measurements every 5 minutes during surgical procedures. The blood pressure measurements were categorized into two groups: hypotensive [mean arterial pressure (MAP) < 60 mmHg] and normotensive (MAP between 60 and 120 mmHg). A linear mixed model was used to compare the DOP and IBP values. The results were evaluated according to the requirements of the American College of Veterinary Internal Medicine (ACVIM) guidelines for the validation of devices. Results DOP provided higher values compared to the systolic arterial blood pressure (SAP) and MAP of IBP measurements. The closest agreement between the two techniques was found for SAP; the bias was 8.8, and limits of agreement (LOA) were –32.9 and 50.4. Similar results were observed when the IBP technique was categorized. The closest agreement was for SAP in animals categorized as normotensive; the bias was 8.2, and LOAs were –32.8 and 49.2. The level of agreement between DOP and IBP did not meet the ACVIM recommendations. Conclusions and clinical relevance Our results suggest there is poor agreement between DOP and IBP measurements in anaesthetized dogs weighing less than 5 kg. Hence, the use of DOP in these animals could be misleading. [ABSTRACT FROM AUTHOR]

Since both, hypotension and hypertension, can potentially impair the function of vital organs such as heart, brain, or kidneys, monitoring of arterial blood pressure (BP) is a mainstay of hemodynamic monitoring in acutely or critically ill patients. Arterial BP can either be obtained invasively via an arterial catheter or non-invasively. Non-invasive BP measurement provides either intermittent or continuous readings. Most commonly, an occluding upper arm cuff is used for intermittent non-invasive monitoring. BP values are then obtained either manually (by auscultation of Korotkoff sounds or palpation) or automatically (e.g., by oscillometry). For continuous non-invasive BP monitoring, the volume clamp method or arterial applanation tonometry can be used. Both techniques enable the arterial waveform and BP values to be obtained continuously. This article describes the different techniques for non-invasive BP measurement, their advantages and limitations, and their clinical applicability.

Use of healthcare-related smartphone applications is common. However, there is concern that inaccurate information from these applications may lead patients to make erroneous healthcare decisions. The objective of this study is to study smartphone applications purporting to measure vital sign data using only onboard technology compared with monitors used routinely in clinical practice. This is a prospective trial comparing correlation between a clinically utilized vital sign monitor (Propaq CS, WelchAllyn, Skaneateles Falls, NY, USA) and four smartphone application-based monitors Instant Blood Pressure, Instant Blood Pressure Pro, Pulse Oximeter, and Pulse Oximeter Pro. We performed measurements of heart rate (HR), systolic blood pressures (SBP), diastolic blood pressure (DBP), and oxygen saturation (SpO2) using standard monitor and four smartphone applications. Analysis of variance was used to compare measurements from the applications to the routine monitor. The study was completed on 100 healthy volunteers. Comparison of routine monitor with the smartphone applications shows significant differences in terms of HR, SpO2 and DBP. The SBP values from the applications were not significantly different from those from the routine monitor, but had wide limits of agreement signifying a large degree of variation in the compared values. The degree of correlation between monitors routinely used in clinical practice and the smartphone-based applications studied is insufficient to recommend clinical utilization. This lack of correlation suggests that the applications evaluated do not provide clinically meaningful data. The inaccurate data provided by these applications can potentially contribute to patient harm. [ABSTRACT FROM AUTHOR]

Objective. The auscultatory technique is still considered the most accurate method for non-invasive blood pressure (NIBP) measurement, although its reliability depends on operator's skills. Various methods for automated Korotkoff sounds analysis have been proposed for reliable estimation of systolic (SBP) and diastolic (DBP) blood pressures. To this aim, very complex methodologies have been presented, including some based on artificial intelligence (AI). This study proposes a relatively simple methodology, named B 3 X, to estimate SBP and DBP by processing Korotkoff sounds recordings acquired during an auscultatory NIBP measurement. Approach. The beat-by-beat change in morphology of adjacent Korotkoff sounds is evaluated via their cross-correlation. The time series of the beat-by-beat cross-correlation and its first derivative are analyzed to locate the timings of SBP and DBP values. Extensive tests were performed on a public database of 350 annotated measurements, and the performance was evaluated according to the BHS, AAMI/ANSI, and International Organization for Standardization (ISO) quality standards. Main results. The proposed approach achieved ' A ' scores for SBP and DBP in the BHS grading system, and passed the quality tests of AAMI/ANSI and ISO standards. The B 3 X algorithm outperformed two well-established algorithms for oscillometric NIBP measurement in both SBP and DBP estimation. It also outperformed four AI-based algorithms in DBP estimation, while providing comparable performance for SBP, at the cost of a much lower computational burden. The full code of the B 3 X algorithm is provided in a public repository. Significance. The very good performances ensured by the proposed B 3 X algorithm, at a low computational cost and without the need for parameter training, support its direct implementation into clinical blood pressure (BP) monitoring devices. The results of this study pave the way for solving/overcoming the trade-off between the accuracy of the auscultatory technique and the objectivity of oscillatory measurements, by bringing an automated auscultatory BP measurement method in clinical practice., (Creative Commons Attribution license.)

We aimed to compare simultaneous invasive and non-invasive blood pressure (IBP and NIBP) measurements in young, middle and old age using the data from the Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC II) database. In total, 23,679 blood pressure measurements were extracted from 742 patients, divided into three groups of young, middle and old age. IBP–NIBP differences in systolic/diastolic blood pressure (SBP/DBP) were 0.1 ± 16.5 mmHg/11.0 ± 12.2 mmHg in young age, –2.9 ± 19.8 mmHg/6.9 ± 17.5 mmHg in middle age and –3.2 ± 29.3 mmHg/8.5 ± 19.8 mmHg in old age. The mean and standard deviation (SD) of invasive systolic blood pressure (ISBP)–non-invasive systolic blood pressure (NISBP) differences increased from young to middle then to old age, and the SD of invasive diastolic blood pressure (IDBP)–non-invasive diastolic blood pressure (NIDBP) differences also increased with age. In young, middle and old age, the correlation coefficients were 0.86, 0.79 and 0.53, respectively, between ISBP and NISBP, and 0.78, 0.78 and 0.41 between IDBP and NIDBP. In conclusion, IBP showed good correlation with NIBP in each age category. The agreement between IBP and NIBP measurements was influenced by age category. [ABSTRACT FROM PUBLISHER]

Objective: To compare the simultaneous invasive and non-invasive measurements of blood pressure (IBP and NIBP) based upon the Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC II) database. Methods and results: A total of 986 records and 26,942 blood pressure (BP) measurements were extracted from MIMIC II database. The mean values of invasive systolic and invasive diastolic blood pressure (ISBP and IDBP) were 111.2 ± 33.9 mm Hg and 59.9 ± 22.8 mm Hg respectively, and the values of non-invasive ones were 114.0 ± 23.4 mm Hg and 51.0 ± 14.9 mm Hg. The average differences of systolic and diastolic blood pressure were −2.8 mm Hg and 8.9 mm Hg between IBP and NIBP. The correlation coefficients were 0.60 between ISBP and NISBP and 0.45 between IDBP and NIDBP. The robust regression equations between IBP (y) and NIBP (x) showed y = 1.02x − 2.95 for SBP (R2 = 0.60) and y = 0.77x + 18.43 for DBP (R2 = 0.82). At the higher part of BP, IBP is larger than NIBP, and at the lower part of BP, IBP is less than NIBP. Conclusion: Average invasive systolic blood pressure is lower than the non-invasive one and average invasive diastolic blood pressure is higher than the non-invasive one. The IBP shows good correlation with the NIBP. The invasive blood pressures can be estimated from non-invasive ones by the regression equations.

Monitoring blood pressure under general anesthesia in animals is important to prevent hypotension and poor tissue perfusion. Thirteen sheep were enrolled to evaluate the accuracy of the petMAP, a portable non-invasive blood pressure (NIBP) monitor. Animals were anesthetized with midazolam, fentanyl, ketamine, propofol and maintained with isoflurane in oxygen for ovariectomy. Invasive and non-invasive (petMAP) blood pressure measurements were recorded simultaneously every 5 minutes. Agreement between IBP and NIBP was assessed by evaluation of bias and 95% limits of agreement (LOA) using the Bland-Altman method and correlation coefficient. None of the measurements met the criteria for good agreement between invasive and non-invasive readings established by the Association for the Advancement of Medical In-strumentation. Systolic blood pressure readings obtained at the left thoracic limb site and mean blood pressure at the right pelvic limb site met the bias and LOA criteria established by the American College of Veterinary Internal Medicine. [ABSTRACT FROM AUTHOR]

Objective To compare the simultaneous invasive and non-invasive measurements of blood pressure (IBP and NIBP) based upon the Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC II) database. Methods and results A total of 986 records and 26,942 blood pressure (BP) measurements were extracted from MIMIC II database. The mean values of invasive systolic and invasive diastolic blood pressure (ISBP and IDBP) were 111.2 ± 33.9 mm Hg and 59.9 ± 22.8 mm Hg respectively, and the values of non-invasive ones were 114.0 ± 23.4 mm Hg and 51.0 ± 14.9 mm Hg. The average differences of systolic and diastolic blood pressure were −2.8 mm Hg and 8.9 mm Hg between IBP and NIBP. The correlation coefficients were 0.60 between ISBP and NISBP and 0.45 between IDBP and NIDBP. The robust regression equations between IBP ( y ) and NIBP ( x ) showed y = 1.02 x − 2.95 for SBP ( R 2 = 0.60) and y = 0.77 x + 18.43 for DBP ( R 2 = 0.82). At the higher part of BP, IBP is larger than NIBP, and at the lower part of BP, IBP is less than NIBP. Conclusion Average invasive systolic blood pressure is lower than the non-invasive one and average invasive diastolic blood pressure is higher than the non-invasive one. The IBP shows good correlation with the NIBP. The invasive blood pressures can be estimated from non-invasive ones by the regression equations. [ABSTRACT FROM AUTHOR]

Objective To determine the level of agreement between an oscillometric (O- NIBP) and an invasive method ( IBP) of monitoring arterial blood pressure ( ABP) in anesthetized sheep, goats, and cattle. Study design Prospective clinical study. Animals Twenty sheep and goats, 20 cattle weighing <150 kg body weight, and 20 cattle weighing >150 kg body weight. Methods Animals were anesthetized and systolic ABP ( SABP), mean ABP ( MABP), and diastolic ABP ( DABP) were measured using IBP and O- NIBP. Differences between IBP and O- NIBP, and 95% limits of agreement ( LOA) between SABP, MABP, and DABP values were assessed by the Bland-Altman method. Results Mean difference ± standard deviation (range) between SABP, DABP, and MABP measurements in sheep and goats was 0 ± 16 (−57 to 38) mmHg, 13 ± 16 (−37 to 70) mmHg, and 8 ± 13 (−34 to 54) mmHg, respectively. Mean difference between SABP, DABP, and MABP measurements in small cattle was 0 ± 19 (−37 to 37) mmHg, 6 ± 18 (−77 to 48) mmHg, and 4 ± 16 (−73 to 48) mmHg, respectively. Mean difference between SABP, DABP, and MABP measurements in large cattle was −18 ± 32 (−107 to 71) mmHg, 7 ± 29 (−112 to 63) mmHg, and −5 ± 28 (−110 to 60) mmHg, respectively. The 95% LOAs for SABP, DABP, and MABP were −31 to +31, −19 to +44, and −19 to +34 mmHg, respectively in sheep and goats; were −37 to +37, −19 to +44, and −19 to +34 mmHg, respectively in small cattle; and were −81 to +45, −50 to +63, and −59 to +50 mmHg, respectively in large cattle. Conclusions Agreement was poor between O- NIBP and IBP monitoring techniques. Clinical relevance Arterial BP should be monitored in anesthetized sheep, goats, and cattle using IBP. [ABSTRACT FROM AUTHOR]

Abstract: Conflicting data exist regarding the accuracy of the oscillometric method of blood pressure (BP) measurement in neonates. There is limited data regarding intra-arterial BP trends in neonates. We aimed to determine the accuracy of oscillometric BP measurements and to evaluate the BP distributions in ill neonates. A total of 1492 simultaneously obtained oscillometric and intra-arterial (umbilical arterial [UAC] or radial arterial) BP measurements were used for comparisons and 125,580 intra-arterial BP readings were used to the evaluate BP distribution. There was a statistically significant difference (P < .0001) between the oscillometric and radial mean arterial BP (MAP) 4.8 ± 9.8 mm Hg, systolic BP 8.3 ± 11.6 mm Hg, diastolic BP 4.3 ± 9.3 mm Hg and between the oscillometric and UAC systolic BP 5.2 ± 11.9 mm Hg and diastolic BP −0.8 ± 10.4 mm Hg. The MAP increased with increases in weight (35.3 ± 4.92 mm Hg/kg), post-menstrual age (−0.29 ± 1.41 mm Hg/week) and advanced gestational age at birth (13.12 ± 0.90 mm Hg/week). Oscillometric BP measurements are not equivalent to the intra-arterial (UAC or radial arterial) BP in ill neonates. The BP increases with increase in weight, gestational age at birth, and post-menstrual age in ill neonates. [Copyright &y& Elsevier]

Objective To evaluate the agreement between invasive blood pressure (IBP) and Doppler ultrasound blood pressure (DUBP) using three cuff positions and oscillometric blood pressure (OBP) in anesthetized dogs. Study design Prospective study. Animals Nine adult dogs weighing 14.5-29.5 kg. Methods The cuff was placed above and below the tarsus, and above the carpus with the DUBP and above the carpus with the OBP monitor. Based on IBP recorded via a dorsal pedal artery catheter, conditions of low, normal, and high systolic arterial pressures [SAP (mmHg) <90, between 90 and 140, and >140, respectively] were induced by changes in isoflurane concentrations and/or dopamine administration. Mean biases ± 2 SD (limits of agreement) were determined. Results At high blood pressures, regardless of cuff position, SAP determinations with the DUBP underestimated invasive SAP values by more than 20 mmHg in most instances. With the DUBP, cuff placement above the tarsus yielded better agreement with invasive SAP during low blood pressures (0.2 ± 16 mmHg). The OBP underestimated SAP during high blood pressures (−42 ± 42 mmHg) and yielded better agreement with IBP for mean (MAP) and diastolic (DAP) arterial pressure measurements [overall bias: 2 ± 15 mmHg (MAP) and 0.2 ± 16 mmHg (DAP)]. Conclusions Agreement of SAP determinations with the DUBP is poor at SAP > 140 mmHg, regardless of cuff placement. Measurement error of the DUBP with the cuff placed above the tarsus is clinically acceptable during low blood pressures. Agreement of MAP and DAP measurements with this OBP monitor compared with IBP was clinically acceptable over a wide pressure range. Clinical relevance With the DUBP device, placing the cuff above the tarsus allows reasonable agreement with IBP obtained via dorsal pedal artery catheterization. Only MAP and DAP provide reasonable estimates of direct blood pressure with the OBP monitor evaluated. [ABSTRACT FROM AUTHOR]

There has been increasing pressure to remove medical devices containing mercury from clinical areas, which is leading to the demise of the mercury sphygmomanometer. As a result, automated blood pressure devices have been embraced by clinicians for their convenience and ease of use. However, it is essential that clinicians are aware of their limitations and are able to select the correct sphygmomanometer dependent upon the clinical need. It is a recommendation of the Independent Advisory Group that auscultation, as a method of determining blood pressure, should continue to be taught to healthcare professionals. Nevertheless, the reality is that in most clinical areas the automated sphygmomanometer is readily available and appears to be the device of choice. Therefore, where treatment protocols are based on accurate blood pressure readings, the clinician must ensure that the equipment used is appropriate for that application. [ABSTRACT FROM AUTHOR]

Objectives:  Analysis of the contour of the arterial pressure pulse (pulse wave analysis; PWA) adds information about arterial stiffness etc., beyond that obtained from absolute pressures. Peripheral pulses normally show an anterograde systolic peak and two reflected peaks: one in systole and one in diastole. The amplitudes and timings of these were estimated from finger pressure recordings in three study groups. We studied the usefulness of continuous digital pressures for PWA. Methods:  First, PWA from intra-arterial (brachial) and non-invasive finger pressure recordings was compared. Secondly, stress-induced (mental arithmetics and cold pressor test) changes in pressure pulse reflection were compared with blood flow changes in brachial and femoral arteries (ultrasound). Thirdly, the influence of age and gender on digital pulse pressures was investigated at rest and during exercise. Results and conclusion:  Pulse wave analysis results from brachial and digital pressures correlated strongly. Stress induced changes in systolic reflection were associated with changes in brachial artery flow patterns, whereas diastolic reflection was associated with femoral artery flow changes. At rest, age increased systolic reflection without affecting diastolic reflection. Exercise increased systolic reflection and reduced diastolic reflection more in older subjects (>40 years) than in younger (<40 years). In conclusion, PWA from continuous, digital pressure recordings is a convenient technique to study the arterial function at rest and during exposure to stressors in broad populations. The two reflected waves are differently regulated, which may indicate different anatomical origin. [ABSTRACT FROM AUTHOR]

In humans, skin is a primary thermoregulatory organ, with vasodilation leading to rapid body cooling, whereas in Rodentia the tail performs an analogous function. Many thermodetection mechanisms are likely to be involved including transient receptor potential vanilloid-type 4 (TRPV4), an ion channel with thermosensitive properties. Previous studies have shown that TRPV4 is a vasodilator by local action in blood vessels, so here, we investigated whether constitutive TRPV4 activity affects Mus muscularis tail vascular tone and thermoregulation. We measured tail blood flow by pressure plethysmography in lightly sedated M. muscularis (CD1 strain) at a range of ambient temperatures, with and without intraperitoneal administration of the blood-brain barrier crossing TRPV4 antagonist GSK2193874. We also measured heart rate (HR) and blood pressure. As expected for a thermoregulatory organ, we found that tail blood flow increased with temperature. However, unexpectedly, we found that GSK2193874 increased tail blood flow at all temperatures, and we observed changes in HR variability. Since local TRPV4 activation causes vasodilation that would increase tail blood flow, these data suggest that increases in tail blood flow resulting from the TRPV4 antagonist may arise from a site other than the blood vessels themselves, perhaps in central cardiovascular control centres.

• Blood Pressure (BP). • Photoplethysmography (PPG). • Cuff-less and continuous blood pressure monitoring using PPG. • Machine learning models for non-invasive cuff-less blood pressure estimation. • Blood pressure estimation with recurrent neural networks. Blood pressure (BP) is a direct indicator for hypertension, therefore, continuous and non-invasive BP monitoring is essential for reducing future health complications. Most non-invasive blood pressure monitors use the oscillometric technique, which can be cumbersome and impractical. To address this problem, we explore several features extracted from the Photoplethysmogram (PPG) waveform and its first and second derivatives and employ deep learning recurrent models for non-invasive cuffless estimation for systolic and diastolic BP. In this research, three techniques have been considered including statistical and machine learning techniques for reducing the collinearity and redundancy in the input feature vector. The estimation models consist of a one bidirectional recurrent layer, followed by a series of stacked conventional recurrent layers and an attention layer. All models were evaluated on 942 subjects collected from the MIMIC II dataset. The best performing model (consists of one bidirectional layer followed by several Long Short-Term Memory layers and an attention layer) achieved a mean absolute error, and standard deviation of 4.51 ± 7.81 mmHg for systolic BP (SBP), and 2.6 ± 4.41 mmHg for diastolic BP (DBP). The results show that the deep learning model trained on features extracted from one PPG sensor yield good performance for continuous and cuffless BP monitoring. Additionally, the results fulfil the international standard for cuffless BP estimation. [ABSTRACT FROM AUTHOR]

A theoretical analysis is performed to evaluate the effect of arterial mechanical and blood pressure pulse properties on the accuracy of non-invasive oscillometric maximum amplitude algorithm (MAA) estimates of the mean blood pressure obtained using air-filled occlusive cuffs. Invasively recorded blood pressure pulses, selected for their varied shapes, are scaled to simulate a wide range of blood pulse pressures (diastolic blood pressure minus systolic blood pressure). Each scaled blood pressure pulse is transformed through an exponential model of an artery to create a series of blood volume pulses from which a simulated oscillometric waveform is created and the corresponding MAA estimate of the mean blood pressure and error (mean blood pressure minus MAA estimate) are determined. The MAA estimates are found to depend on the arterial blood pressure. The errors are found to depend on the arterial mechanical properties, blood pressure pulse shape and blood pulse pressure. These results suggest that there is no direct relationship between the mean blood pressure and MAA estimate, and that multiple variables may affect the accuracy of MAA estimates of the mean blood pressure obtained using air-filled occlusive cuffs. [ABSTRACT FROM AUTHOR]

The blood pressure waveform is modified on distal propagation by phenomena such as dispersion, reflection and the state of the arterial compliance. The consequent effects are amplification and narrowing of the wave, with an increased systolic, reduced diastolic and essentially unaltered mean blood pressure. The Finapres measures the peripheral pressure using the volume clamp principle; it has not been validated under altered physiological conditions and during pharmacodynamic interventions. We studied simultaneous Finapres and brachial blood pressures (using a conventional oscillometric sphygmomanometer—Vitalmap) in ten normal volunteers at rest, and during dynamic exercise and a cold pressor test. The effects of pharmacodynamic intervention were examined following beta-adrenoceptor blockade with propranolol (160 mg) or beta-adrenoceptor modulation with the beta-adrenoceptor partial agonist celiprolol (400 mg). The Finapres systolic pressure was significantly higher than the brachial value during all three test states. The difference between the systolic pressures measured by the two devices was shown to increase significantly during the cold pressor test, but not during dynamic (supine bicycle) exercise. The Finapres diastolic pressure was significantly higher than the Vitalmap value during exercise and the cold pressor test. The differences between the two methods increased significantly over time. Beta-adrenergic blockade with propranolol or modulation with celiprolol had no significant interaction with the pressure differences between the Finapres and Vitalmap techniques. The results would support the view that the Finapres can provide blood pressure information which is robust under most circumstances. Although this pharmacodynamic intervention did not alter the relationship between the peripheral and central blood pressure, it is important to note that this dynamic relationship is sensitive to circulatory loading conditions and wave transmission characteristics; it is possible that the Finapres could be less reliable in clinical settings where potent vasoactive agents were being administered. [ABSTRACT FROM AUTHOR]

Accurate noninvasive blood pressure (NIBP) measurement requires use of an appropriately sized cuff. We aimed to improve the perioperative allocation of NIBP cuffs in patients with Class II–III obesity. In the baseline evaluation, we measured the mid-arm circumference (MAC) of 40 patients with BMI > 35 kg/m2, documenting the corresponding cuff allocated by pre-operative nurses. The intervention consisted of the introduction of cuff allocation based on MAC measurement and augmented NIBP cuff supplies. We completed a re-evaluation and evaluation of the intervention by staff survey, using 5-point Likert scales and free text comments. At baseline, the correct cuff was allocated in 9 of 40 patients (22.5%). During the intervention, education occurred in 54 (69.2%) peri-operative nursing staff. Upon re-evaluation, the correct cuff was allocated in 30 of 40 patients (75.0%), a statistically significant improvement (χ2 = 22.1, p < 0.001). Ninety-three of 120 staff surveys were returned (78%). Eleven out of 18 preoperative staff surveyed (61.1%) felt confident measuring the arm and selecting the correct cuff. Six (33%) agreed that taking the arm measurement added a lot of extra work. Equipment shortages, accuracy concerns, and clinical workarounds were reported by staff. Our intervention increased the proportion of correct cuffs allocated, but equipment and practical issues persist with NIBP cuff selection in obese patients. [ABSTRACT FROM AUTHOR]

Blood pressure (BP) measurement is very important and crucial parameter for monitoring, controlling and treatment of human health conditions. Measurement of BP is performed using variety of instruments. Out of these, (i) mechanical or mercury manometers and (ii) oscillometric digital sphygmomanometers, are the most commonly used devices. Although, the international recommendations (OIML R16-2) for the automatic BP measuring instrument is available, there is no uniform international standard or method of calibration available. In this paper, a terse review of different types of BP measuring techniques and devices, commercially available is presented along with some related important historical developments. A concise and consolidated report of the several existing methods of BP device calibration being used at various National Metrology Institutes (NMIs) and other leading research groups is also included. This would open new lines for the future researchers to standardise a uniform and acceptable calibration method for these devices which is need of the hour. [ABSTRACT FROM AUTHOR]

Objective: Blood pressure (BP) monitoring in children immediately after kidney transplantation is ideally performed with an arterial line. Accurate measurement of BP is necessary for optimal management. However, during the first days postoperative, the arterial line is removed and BP measurement is switched to a non‐invasive device. The aim of this study was to determine the accuracy and reliability of the automated oscillometric device compared to invasive arterial BP (IBP) monitoring in patients after renal transplantation in pediatric intensive care unit (PICU). Method: We analyzed all simultaneously measured BPs in children with a kidney transplant in the Amalia Children's Hospital Radboud University Medical Center between January 1, 2012, and January 1, 2016. BP measurements were performed according to the hospital protocol. Agreement between invasive and non‐invasive methods was assessed using Bland‐Altman plots. Results: A total of 29 patients were included in this retrospective study. The majority of children were male (59%), and median age was 11 years (range 1‐17 years). Totally, 80 BP measurements were recorded during the first days post‐kidney transplantation. The correlation coefficients (R) of systolic, diastolic, and MAP of non‐invasive (NIBP) and IBP measurements were 0.84, 0.76, and 0.77, respectively (P < 0.01). Overall, the average MAP (7.5 ± 1.2 mm Hg; P < 0.05) NIBP values were lower compared to IBP. In hypertensive patients, MAP (10.4 ± 10.0 mm Hg; P < 0.05) BP values were significantly lower using the NIBP device. Clinically relevant difference of >10 mm Hg was found in 51% (41/80) of measurements and mainly observed in hypertensive measurements. Conclusions: IBP measurement is considered the golden standard for monitoring BP in patients immediately after kidney transplantation. NIBP values showed a good agreement with invasive reading, but the variability of NIBP mainly in hypertensive patients is high as it is the number of clinically relevant differences to IBP. We conclude that IBP remains the golden standard to monitor BP in children directly postoperatively. [ABSTRACT FROM AUTHOR]

The automated oscillometric method is a common method for measuring blood pressure non-invasively and is broadly and confidently used in the veterinary setting. Twenty-one pigs undergoing anesthesia for exploratory laparotomy were enrolled in a study to evaluate the performance of the Surgivet V9203 non-invasive blood pressure (NIBP) monitor. The aim was to compare measurements of arterial blood pressure obtained simultaneously using the Surgivet V9203 oscillometric system and an intra-arterial catheter-transducer system, both at the level of the metatarsus. Invasive blood pressure (IBP) was consistently underestimated by the non-invasive method. Bland-Altman analysis showed poor agreement between the two modalities based on evaluation of mean bias and 95% limits of agreement. The Surgivet V9203 cannot therefore be recommended as a reliable alternative to invasive blood pressure monitoring in anaesthetised pigs. As pulse detection is one of the most important factors affecting NIBP accuracy it is likely that our findings may reflect an anatomical or physiological difference in the species that alters the detection of wall movement by the oscillometric technique and additionally, makes the algorithm used by the Surgivet to determine blood pressure parameters unsuitable for use in pigs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)