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Background: Early identification of sepsis in the emergency department (ED) triage is both valuable and challenging. Numerous studies have endeavored to pinpoint clinical and biochemical criteria to assist clinicians in the prompt diagnosis of sepsis, but few studies have assessed the efficacy of these criteria in the ED triage setting. The aim of the study was to explore the accuracy of clinical and laboratory markers evaluated at the triage level in identifying patients with sepsis. Methods: A prospective study was conducted in a large academic urban hospital, implementing a triage protocol aimed at early identification of septic patients based on clinical and laboratory markers. A multidisciplinary panel of experts reviewed cases to ensure accurate identification of septic patients. Variables analyzed included: Charlson comorbidity index, mean arterial pressure (MAP), partial pressure of carbon dioxide (PetCO2), white cell count, eosinophil count, C‐reactive protein to albumin ratio, procalcitonin, and lactate. Results: A total of 235 patients were included. Multivariable analysis identified procalcitonin ≥1 ng/mL (OR 5.2; p < 0.001); CRP‐to‐albumin ratio ≥32 (OR 6.6; p < 0.001); PetCO2 ≤ 28 mmHg (OR 2.7; p = 0.031), and MAP <85 mmHg (OR 7.5; p < 0.001) as independent predictors for sepsis. MAP ≥85 mmHg, CRP/albumin ratio <32, and procalcitonin <1 ng/mL demonstrated negative predictive values for sepsis of 90%, 89%, and 88%, respectively. Conclusions: Our study underscores the significance of procalcitonin and mean arterial pressure, while introducing CRP/albumin ratio and PetCO2 as important variables to consider in the very initial assessment of patients with suspected sepsis in the ED. Clinical Relevance: Early identification of sepsis since the emergency department (ED) triage is challengingImplementing the ED triage protocol with simple clinical and laboratory markers allows to recognize patients with sepsis with a very good discriminatory power (AUC 0.88) [ABSTRACT FROM AUTHOR]

Dyspnea is a common yet poorly understood symptom of long COVID, affecting many patients. This brief report examines the role of dysfunctional breathing in persistent dyspnea among patients with mild post-COVID-19 using hyperventilation provocation tests (HVPT). In this case series, six patients with unexplained dyspnea and normal cardiopulmonary function underwent HVPT. Despite normal exercise testing results, all patients exhibited delayed PETCO2 recovery, indicative of a hyperventilation pattern consistent with chronic hyperventilation syndrome, without typical symptomatic manifestations. These findings suggest underlying post-COVID respiratory dysregulation, emphasizing the importance of targeted diagnostic and therapeutic approaches for persistent respiratory symptoms in long COVID patients. [ABSTRACT FROM AUTHOR]

Dyspnea is a common yet poorly understood symptom of long COVID, affecting many patients. This brief report examines the role of dysfunctional breathing in persistent dyspnea among patients with mild post-COVID-19 using hyperventilation provocation tests (HVPT). In this case series, six patients with unexplained dyspnea and normal cardiopulmonary function underwent HVPT. Despite normal exercise testing results, all patients exhibited delayed PETCO2 recovery, indicative of a hyperventilation pattern consistent with chronic hyperventilation syndrome, without typical symptomatic manifestations. These findings suggest underlying post-COVID respiratory dysregulation, emphasizing the importance of targeted diagnostic and therapeutic approaches for persistent respiratory symptoms in long COVID patients.

A dysregulated autonomic stress physiology is hypothesized to play an important role in the etiology and perpetuation of somatic symptoms that cannot be (fully) explained by an organic disease. The aim of this study was to focus on the role of the respiratory system. We examined end-tidal CO2 concentration (PetCO2) in healthy controls (n = 30), patients with panic disorder (n = 36), and patients with stress-related (overstrain; n = 35, burnout; n = 44) or functional syndromes [fibromyalgia (FM) and/or chronic fatigue syndrome (CFS); n = 36]. Participants went through a rest period and a respiratory challenge with recovery, whilst PetCO2 was continuously monitored by a capnograph. Taken together, our results suggest: (1) an overactive respiratory system to be a possible transdiagnostic underlying factor of overstrain, burnout, and panic disorder, and (2) the presence of a less active respiratory fight-flight response in the more chronic and severe functional syndromes (FM/CFS). [ABSTRACT FROM AUTHOR]

Background: The current study aimed to assess some parameters of the cardiopulmonary exercise test (CPET) among end-stage renal disease patients who underwent dialysis. The ultimate goal is to improve disease management to achieve optimal quality of life and exercise capacity in this group of patients. Materials and Methods: Through a cross-sectional design, the current study enrolled 46 dialysis patients by simple sampling between Jan 2019 and Jan 2020. Some CPET parameters such as AT, VO2, VO2/kg, SPO2, minute ventilation CO2 production/O2 consumption ratios (VE/VCO2 and VE/VO2, respectively), O2 pulse, heart rate reserve (HRR), breathing reserve (BR) and end-tidal carbon dioxide pressure (PETCO2) were focused. Results: Although a limited sample size, the current study showed that VO2/Kg, VE/VCO2, PETCO2, and SPO2 are the main parameters affected by dialysis as expected. Conclusion: The current study suggests using cardiopulmonary rehabilitation for all chronic medical conditions such as chronic kidney disease and end-stage renal disease that increase the rate of metabolic acidosis. [ABSTRACT FROM AUTHOR]

Background: Wearing face shields and masks, which used to have very limited public use before the COVID-19 outbreak, has been highly recommended by organizations, such as CDC and WHO, during this pandemic period. Aims: The aim of this prospective study is to scrutinize the dynamic changes in vital parameters, change in end tidal CO2 (PETCO2) levels, the relationship of these changes with taking a break, and the subjective complaints caused by respiratory protection, while healthcare providers are performing their duties with the N95 mask. Methods: The prospective cohort included 54 healthcare workers (doctors, nurses, paramedics) who worked in the respiratory unit of the emergency department (ED) and performed their duties by wearing valved N95 masks and face shields. The vital parameters and PETCO2 levels were measured at 0–4th–5th and 9th hours of the work-shift. Results: Only the decrease in diastolic BP between 0 and 9 h was statistically significant (p = 0.038). Besides, mean arterial pressure (MAP) values indicated a significant decrease between 0–9 h and 5–9 h (p = 0.024 and p = 0.049, respectively). In terms of the vital parameters of the subjects working with and without breaks, only PETCO2 levels of those working uninterruptedly increased significantly at the 4th hour in comparison to the beginning-of-shift baseline levels (p = 0.003). Conclusion: Although the decrease in systolic blood pressure (SBP) and MAP values is assumed to be caused by increased fatigue due to workload and work pace as well as increase in muscle activity, the increase in PETCO2 levels in the ED healthcare staff working with no breaks between 0 and 4 h should be noted in terms of PPE-induced hypoventilation. [ABSTRACT FROM AUTHOR]

Background: Underwater rugby is a team sport where players try to score points with a negatively buoyant ball while submerged in a swimming pool. Reports of syncope incidents at the Swedish Championships led to us to investigate end-tidal oxygen and carbon dioxide levels during simulated match play. Methods: Eight male underwater rugby club players of varying experience participated. Repetitive measurements were made while players were defending during simulated match play. Each time a player surfaced they exhaled through a mouthpiece connected to a flow meter and a gas analyzer to measure tidal volume, PETO2 and PETCO2. Results: Measurements were made over 12 dives, with an average dive duration of 18.5 seconds. The mean maximal PETCO2 across the eight participants was 10.0 kPa (~75 mmHg) (range, 9.1-11.7 [~68-88]). The corresponding mean minimum PETO2 was 7.6 kPa (~57 mmHg) (6.3-10.4 [~47-78)). PETCO2 drifted upward, with the mean upward change from the first to last dive for each participant being +1.8 (~13.5 mmHg) (SD 1.74) kPa. A similar trend for PETO2 was not detected, with a mean change of -0.1 (~0.75 mmHg) (SD 3.79) kPa. Conclusion: Despite high PETCO2 values that were close to narcotic being recorded, these players seemed to regulate their urge to breathe based on hypoxia rather than hypercapnia. [ABSTRACT FROM AUTHOR]

Abstract Background The physiological dead space is a strong indicator of severity and outcome of acute respiratory distress syndrome (ARDS). The “ideal” alveolar PCO2, in equilibrium with pulmonary capillary PCO2, is a central concept in the physiological dead space measurement. As it cannot be measured, it is surrogated by arterial PCO2 which, unfortunately, may be far higher than ideal alveolar PCO2, when the right-to-left venous admixture is present. The “ideal” alveolar PCO2 equals the end-tidal PCO2 (PETCO2) only in absence of alveolar dead space. Therefore, in the perfect gas exchanger (alveolar dead space = 0, venous admixture = 0), the PETCO2/PaCO2 is 1, as PETCO2, PACO2 and PaCO2 are equal. Our aim is to investigate if and at which extent the PETCO2/PaCO2, a comprehensive meter of the “gas exchanger” performance, is related to the anatomo physiological characteristics in ARDS. Results We retrospectively studied 200 patients with ARDS. The source was a database in which we collected since 2003 all the patients enrolled in different CT scan studies. The PETCO2/PaCO2, measured at 5 cmH2O airway pressure, significantly decreased from mild to mild–moderate moderate–severe and severe ARDS. The overall populations was divided into four groups (~ 50 patients each) according to the quartiles of the PETCO2/PaCO2 (lowest ratio, the worst = group 1, highest ratio, the best = group 4). The progressive increase PETCO2/PaCO2 from quartile 1 to 4 (i.e., the progressive approach to the “perfect” gas exchanger value of 1.0) was associated with a significant decrease of non-aerated tissue, inohomogeneity index and increase of well-aerated tissue. The respiratory system elastance significantly improved from quartile 1 to 4, as well as the PaO2/FiO2 and PaCO2. The improvement of PETCO2/PaCO2 was also associated with a significant decrease of physiological dead space and venous admixture. When PEEP was increased from 5 to 15 cmH2O, the greatest improvement of non-aerated tissue, PaO2 and venous admixture were observed in quartile 1 of PETCO2/PaCO2 and the worst deterioration of dead space in quartile 4. Conclusion The ratio PETCO2/PaCO2 is highly correlated with CT scan, physiological and clinical variables. It appears as an excellent measure of the overall “gas exchanger” status.

Hyperventilation is an intense breathing that exceeds the needs of the body and causes hypocapnia. There are insufficient studies of the individual features of haemodynamic parameter changes when testing for hyperventilation and after it; therefore, the changes of the central haemodynamics are analyzed while testing the regulated respiration at a rate of 30 cycles per minute in healthy young men.PetCO2 level was determined in 81 men on Datex Normocap capnograph; haemodynamic indicators were found with KHAI-medica rheography (Ukraine) for 5 minutes at rest, for 10 minutes of the regulated respiration at a rate of 30 cycles per minute and 40 minutes of recovery period after the test. The reactivity of most haemodynamics features with the regulated respiration were characterized with significant individual features and depended on baseline PetCO2 . The highest values of central hemodynamics in the background were observed in the men with baseline РеtСО2 from 38.5 to 41.74 mm Hg. Thus, the duration of the R-R intervals was 910 ± 30.7 ms, the stroke index was 37.34 ± 2.89 ml·m-2, the cardiac index corresponded to 2.4 ± 0.15 l·m-2·min-1, total peripheral resistance was 1944 ± 166.6 dy·s-1·cm-5 and volumetric emission rate was 257.1 ± 12.1 ml∙s-1. At the end of the test with hyperventilation, the persons of this group had the highest reactivity of the parameters of the cardiac index (0.42 ± 0.10 l·m-2·min-1, p

Aim: to assess the dynamic and prognostic significance of the end-tidal carbon dioxide pressure (PetCO2) during cardiopulmonary exercise testing in recipients before and after heart transplantation (HT).Materials and methods. The study included 55 patients with severe chronic heart failure (CHF) from the HT waiting list. All patients underwent cardiopulmonary exercise testing before and in the long-term follow-up after TS, including determination of PetCO2 at rest and during exercise.Results. Physical capacity, the efficiency of pulmonary ventilation and gas exchange in the long-term after the HT significantly improved compared with the preoperative data. Peak oxygen consumption before and after HT was 10.8 (9.4-11.7) ml/min/kg and 18.9 (18.2-21.0) ml/in/kg (p = 0.020), respectively, the value of the VE/VCO2 slope decreased from 38 (34-45) to 32 (30-36), p = 0.017. PetCO2 at rest before the HT was below the norm, amounted to 30 (28-32) mm Hg, increased to the anaerobic threshold by an average of 3.6 (0.2-5.2)%. After the HT, the level of PetCO2 at rest did not change significantly, but the increase during exercise was 7.6 (3.2-9.4)% (p = 0.001). It was shown that a low baseline PetCO2 value and the absence of its increase during cardiopulmonary exercise test significantly increase the risk of adverse outcome in patients with severe CHF before and after HT (OR 0.62 (0.35-0.87), p = 0.035 and, 16 (0.10-0.24), p = 0.002, respectively).Conclusion. Heart transplantation in patients with severe CHF leads to a significant improvement in the efficiency of pulmonary ventilation and gas exchange in the long-term follow-up. Estimation of the PetCO2 level at rest and during exercise is a promising predictor of adverse outcomes risk stratification in patients with severe CHF before and after HT.

Noninvasive monitoring of partial pressure of carbon dioxide can be accomplished indirectly with capnography (P ET CO 2) or with transcutaneous carbon dioxide monitoring (P TC CO 2). The use of capnography has been shown to offer an advantage over pulse oximetry alone in the early detection of adverse respiratory events when supplemental oxygen is administered. Furthermore, capnography allows for the monitoring of various respiratory measures, including end-tidal carbon dioxide, respiratory rate, tidal volume, and changes in breathing patterns. Transcutaneous CO 2 also closely approximates arterial CO 2 values, but is not as easy to monitor for prolonged periods. The purpose of this study was to examine the usefulness of capnography and of transcutaneous carbon dioxide monitoring in patients recovering from obesity surgery at high risk of developing postoperative obstructive sleep apnea. In a prospective observational study, 64 bariatric surgery patients at risk of developing obstructive sleep apnea were monitored in the postanesthesia care unit (PACU) with either capnography alone (31 patients) or capnography plus transcutaneous carbon dioxide monitoring (33 additional patients) every 3–5 minutes for the duration of their recovery. Primary endpoints included end-tidal and transcutaneous carbon dioxide, peripheral oxygen saturation, respiratory rate, pain scores, and incidence of adverse respiratory events. Although no adverse pulmonary events were observed, capnography detected several patients who experienced short periods of respiratory apnea while maintaining pulse oximetry readings within normal limits. Transcutaneous values were slow to change and averaged 4.5 ± 5.5 mm Hg (P <.05) higher than corresponding end-tidal measurements. These results indicate the capabilities of both these noninvasive techniques for postoperative monitoring. Capnography acutely monitors changes in respiration, whereas transcutaneous monitoring more accurately reflects arterial CO 2 levels. • Comparison of two patient groups after obesity surgery with opioid sparing anesthesia • Respiratory CO2 and transcutaneous CO2 were analyzed to detect hypoventilation • Transcutaneous values approximate arterial CO2 and are non-invasive • None of these patients showed respiratory depression during recovery [ABSTRACT FROM AUTHOR]

Aim. To assess the influence of resting partial pressure of end-tidal carbon dioxide (PetCO2) levels on the long-term results of cardiac surgery.Materials and methods. This prospective cohort study included 454 patients with coronary artery disease who underwent elective coronary artery bypass graft surgery. Before surgery, all patients underwent pulmonary function tests, including body plethysmography, lung diffusion capacity assessment and cardiopulmonary exercise testing with the determination of ventilatory and gas exchange parameters, including PetCO2 at rest. The endpoint was the 2-year survival rate after surgery.Results. Parameters characterizing the obstructive breathing pattern, the lung diffusion capacity, and resting PetCO2 levels had a significant predictor value in relation to long-term survival after cardiac surgery. Among the baseline clinical and functional characteristics, a significant influence on long-term results was shown by the EuroSCORE II (OR 1,69 (1,26-2,27), p=0,001). The highest sensitivity and specificity in relation to long-term mortality risk after coronary artery bypass grafting was shown by resting PetCO2 value equal to 31 mm Hg (area under the ROC curve 0,74 (0,64-0,86), p

Pasien dengan ventilasi mekanik perlu dilakukan pemantauan CO2 karena berperan penting pada regulasi pernapasan dan keseimbangan asam-basa tubuh. Pemantauan CO2 dapat dilakukan dengan mengukur PaCO2 melalui analisis gas darah arteri. Pengukuran PaCO2 tidak dapat dilakukan secara kontinu sehingga perlu sering dilakukan pengambilan darah arteri yang dapat menimbulkan komplikasi. Pengukuran PETCO2 dapat memantau CO2 secara kontinu dan non invasif. PETCO2 adalah tekanan parsial CO2 ekspirasi yang diukur pada saat akhir volume tidal pernapasan. Penelitian ini bertujuan membandingkan nilai PETCO2 dan PaCO2 pada pasien dengan ventilasi mekanik di ruang GICU RSUP Dr. Hasan Sadikin Bandung. Rancangan penelitian yang digunakan adalah prospective cross sectional. Pemilihan sampel dilakukan secara consecutive sampling. Penelitian dilakukan terhadap 21 pasien yang menggunakan ventilasi mekanik di ruang GICU RSUP Dr. Hasan Sadikin Bandung. Data PETCO2 dicatat pada saat perawat mengambil sampel darah arteri untuk pemeriksaan analisis gas darah. Didapatkan 122 pasang data nilai PETCO2 dan PaCO2. Data yang diperoleh dianalisis dengan Bland-Altman plot. Hasil penelitian nilai PETCO2 berada pada rentang 14-67 mmHg dan nilai PaCO2 berada pada rentang 17-77 mmHg. Bias nilai PETCO2 dan PaCO2 adalah -4,6475 mmHg lebih rendah daripada estimasi nilai bias ±5 mmHg sehingga bisa diterima secara klinik. Presisi nilai PETCO2 adalah 12,7969 mmHg (limit of agreement= 1,7509; -11,0460) lebih tinggi daripada estimasi nilai presisi ±5 mmHg sehingga tidak bisa diterima secara klinik. Kesimpulan dari penelitian ini adalah pengukuran PETCO2 tidak dapat menggantikan pengukuran PaCO2, tetapi pengukuran PETCO2 dapat digunakan untuk memperkirakan nilai PaCO2 pasien dengan ventilasi mekanik.

Breathing at a frequency of around 0.1 Hz is widely used in basic research and in applied psychophysiology because it strongly increases fluctuations in the cardiovascular system and affects psychological functioning. Volitional control of breathing often leads to hyperventilation among untrained individuals, which may produce aversive symptoms and alter the psychological and physiological effects of the paced breathing. The present study investigated the effectiveness of a brief anti-hyperventilation instruction during paced breathing at a frequency of 0.1 Hz. Forty-six participants were randomly assigned to one of two groups: a group given an anti-hyperventilation instruction and a control group without such an instruction. The instruction asked participants to avoid excessively deep breathing and to breathe shallowly and naturally. Participants performed the breathing task for 10 min. Hyperventilation was measured by partial pressure of end-tidal CO2 (PetCO2); furthermore, symptoms of hyperventilation, feeling of air hunger, task difficulty, and affective state were measured by self-report. The results showed that paced breathing without instruction decreased PetCO2 by 5.21 mmHg and that the use of the anti-hyperventilation instruction reduced the drop in PetCO2 to 2.7 mmHg. Symptoms of hyperventilation were lower in the group with the anti-hyperventilation instruction. Neither the feeling of air hunger nor task difficulty were affected by the instruction. There were no significant effects of the instruction on affective state. The present study indicates that a brief anti-hyperventilation instruction may be used to decrease drop in PetCO2 and symptoms of hyperventilation during breathing at 0.1 Hz and that the instruction is well tolerated. [ABSTRACT FROM AUTHOR]

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Exercise has been shown to induce cerebrovascular adaptations. However, the underlying temporal dynamics are poorly understood, and regional variation in the vascular response to exercise has been observed in the large cerebral arteries. Here, we sought to measure the cerebrovascular effects of a single 20-min session of moderate-intensity exercise in the one hour period immediately following exercise cessation. We employed transcranial Doppler (TCD) ultrasonography to measure cerebral blood flow velocity (CBFV) in the middle cerebral artery (MCAv) and posterior cerebral artery (PCAv) before, during, and following exercise. Additionally, we simultaneously measured cerebral blood flow (CBF) in the internal carotid artery (ICA) and vertebral artery (VA) before and up to one hour following exercise cessation using Duplex ultrasound. A hypercapnia challenge was used before and after exercise to examine exercise-induced changes in cerebrovascular reactivity (CVR). We found that MCAv and PCAv were significantly elevated during exercise (p = 4.81 × 10-5 and 2.40 × 10-4, respectively). A general linear model revealed that these changes were largely explained by the partial pressure of end-tidal CO2 and not a direct vascular effect of exercise. After exercise cessation, there was no effect of exercise on CBFV or CVR in the intracranial or extracranial arteries (all p > 0.05). Taken together, these data confirm that CBF is rapidly and uniformly regulated following exercise cessation in healthy young males.

Introduction: A dysregulated autonomic stress physiology is hypothesized to play an important role in the etiology and perpetuation of somatic symptoms that cannot be (fully) medically explained. Methods: The aim of this study was to focus on the role of the respiratory system. We examined end-tidal CO2 concentration (PetCO2) in healthy controls (HC; n = 30), and in patient groups experiencing panic (n = 36), stress-related (overstrain; n = 35, burnout; n = 44) or persistent somatic symptoms in daily life [fibromyalgia (FM) and/or chronic fatigue syndrome (CFS); n = 36]. Further, we explored perfectionism, experiential avoidance, and self-reported trauma in the different groups. Participants filled out questionnaires and went through a rest period and a respiratory challenge with recovery, whilst PetCO2 was continuously monitored. Results: Our results suggest: (1) an overactive respiratory system to be a transdiagnostic underlying factor of panic disorder, overstrain, and burnout, and (2) the presence of a more active fight-flight response in less chronic and severe disorders (overstrain), which gradually becomes more passive as symptoms become more chronic and severe (FM/CFS). Finally, our data show higher perfectionism and experiential avoidance in all patients, and higher self-reported trauma in FM/CFS patients compared to HC. Discussion: Although respiratory dysfunctions are often seen as a specific characteristic of panic disorder, the present study found evidence for an overactive respiratory system be a transdiagnostic underlying factor of both panic and stress-related disorders. Process evaluation: A limitation is that we only studied one respiratory parameter. Research including multiple psychophysiological parameters is needed to confirm the specificity of the current findings. [ABSTRACT FROM AUTHOR]

Heart failure (HF) is characterized by an increase in ventilatory response to exercise of multifactorial aetiology and by a dysregulation in the ventilatory control during sleep with the occurrence of both central and obstructive apnoeas. In this setting, the study of the ventilatory behaviour during exercise, by cardiopulmonary exercise testing, or during sleep, by complete polysomnography or simplified nocturnal cardiorespiratory monitoring, is of paramount importance because of its prognostic value and of the possible effects of sleep-disordered breathing on the progression of the disease. Moreover, several therapeutic interventions can significantly influence ventilatory control in HF. Also, rest daytime monitoring of cardiac, metabolic, and respiratory activities through specific wearable devices could provide useful information for HF management. The aim of the review is to summarize the main studies conducted at Centro Cardiologico Monzino on these topics., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: To measure end-tidal carbon dioxide pressure (PetCO2) in preset interval in order to evaluate the efficiency of cardiopulmonary resuscitation (CPR) performed on patients in cardiopulmonary arrest, evaluate the validity of PetCO2 in predicting the mortality and finally assess the PetCO2 levels of the patients in cardiopulmonary arrest based on the initial presenting rhythm. Methods: This prospective study was conducted at the Ankara Training and Research Hospital on patients who presented with cardiopulmonary arrest. Standard ACLS (Advanced Cardiac Life Support) protocols were performed. Patients were categorized in two groups based on their rhythms as Ventricular Fibrillation and Asystole. Patients' PetCO2 values were recorded. Results: PetCO2 levels of the Return of Spontaneous Circulation (ROSC) group in the 5th, 10th, 15th and 20th minutes were significantly higher compared to the exitus group (p < 0.001). In distinguishing ROSC and exitus, PetCO2 measurements within 5-20 minute intervals showed highest performance on the 20th and lowest on the 5th minutes. Conclusion: PetCO2 values are higher in the ROSC group. During the CPR, the most reliable time for ROSC estimation according to PetCO2 values is 20th minute. None of the patients who had PetCO2 levels less than 14 mmHg survived. [ABSTRACT FROM AUTHOR]

Abstract: The aim was to investigate the effect of different speech tasks, i.e. recitation of prose (PR), alliteration (AR) and hexameter (HR) verses and a control task (mental arithmetic (MA) with voicing of the result on end-tidal CO2 (PETCO2), cerebral hemodynamics and oxygenation. CO2 levels in the blood are known to strongly affect cerebral blood flow. Speech changes breathing pattern and may affect CO2 levels. Measurements were performed on 24 healthy adult volunteers during the performance of the 4 tasks. Tissue oxygen saturation (StO2) and absolute concentrations of oxyhemoglobin ([O2Hb]), deoxyhemoglobin ([HHb]) and total hemoglobin ([tHb]) were measured by functional near-infrared spectroscopy (fNIRS) and PETCO2 by a gas analyzer. Statistical analysis was applied to the difference between baseline before the task, 2 recitation and 5 baseline periods after the task. The 2 brain hemispheres and 4 tasks were tested separately. A significant decrease in PETCO2 was found during all 4 tasks with the smallest decrease during the MA task. During the recitation tasks (PR, AR and HR) a statistically significant (p <0.05) decrease occurred for StO2 during PR and AR in the right prefrontal cortex (PFC) and during AR and HR in the left PFC. [O2Hb] decreased significantly during PR, AR and HR in both hemispheres. [HHb] increased significantly during the AR task in the right PFC. [tHb] decreased significantly during HR in the right PFC and during PR, AR and HR in the left PFC. During the MA task, StO2 increased and [HHb] decreased significantly during the MA task. We conclude that changes in breathing (hyperventilation) during the tasks led to lower CO2 pressure in the blood (hypocapnia), predominantly responsible for the measured changes in cerebral hemodynamics and oxygenation. In conclusion, our findings demonstrate that PETCO2 should be monitored during functional brain studies investigating speech using neuroimaging modalities, such as fNIRS, fMRI to ensure a correct interpretation of changes in hemodynamics and oxygenation. [Copyright &y& Elsevier]

Abstract: We hypothesized that administration of clonidine would decrease the hypocapnic apnoeic threshold (HAT) and widen the CO2 reserve during non-REM sleep. Methods: Ten healthy subjects (4 females) (age 22.3±3.0 years; BMI 25.5±3.4kg/m2) were randomized to receive placebo or 0.1mg/45kg of clonidine on 2 separate nights. Ventilation and upper airway resistance were monitored during wakefulness and sleep. Two separate experiments were performed: Protocol 1 (n =8), CO2 reserve, HAT and HcVR were determined using non-invasive hyperventilation (NIV) to induce hypocapnia for at least 3min; Protocol 2 (n =6), peripheral hypocapnic ventilatory response (HcVR) was determined by NIV using short (3 breaths) hyperventilation. Results: Clonidine decreased the systolic blood pressure by 12±10mmHg but did not affect baseline ventilation or upper airway resistance during wakefulness or sleep. Protocol (1), clonidine was associated with decreased HAT relative to placebo (37.3±3.3mmHg vs. 39.7±3.4mmHg, P <0.05), increased CO2 reserve (−3.8±1.3mmHg vs. −2.8±1.2mmHg, P <0.05), and decreased HcVR (1.6±0.6L/min/mmHg vs. 2.5±1.3L/min/mmHg, P <0.05). Protocol (2), administration of clonidine did not decrease peripheral HcVR compared to placebo (0.5±0.3L/min/mmHg vs. 0.7±0.3L/min/mmHg, P =NS). Conclusion: Clonidine is associated with diminished susceptibility to hypocapnic central apnoea without significant effect on ventilation or upper airway mechanics. Reduced susceptibility to hypocapnic central apnoea is not explained by the peripheral chemoreceptor pathway. This suggests a central rather than a peripheral effect of clonidine on the susceptibility to hypocapnic central apnoea. [Copyright &y& Elsevier]

Abstract: Objective: To compare the PaCO2 with the ETCO2 obtained with the Smart Capnoline™ in the postoperative setting of cardiac surgery during ventilation and after extubation Type of study: Prospective, observational. Patients: Twenty patients after cardiac surgery. Methods: In the intensive care unit, arterial blood gases were measured concomitantly with ETCO2, and difference between PaCO2 and ETCO2 were calculated. Three CO2 sensors were utilized: Filterline H set for intubated patients, Smart Capnoline HO2 (nasal version) and Smart Capnoline O2 (bucconasal version) after extubation. Data were compared with Wilconson test and the intraclass correlation coefficient was calculated. Results: The difference PaCO2 – ETCO2 was significantly larger in extubated patients compared to intubated patients, which is also confirmed for the bucconasal sensor (intubated patients: 6.6±4.3mmHg, nasal sensor: 9.3±3.5mmHg, bucconasal sensor: 15,4±12.9mmHg). Conclusion: In the postoperative setting of cardiac surgery, ETCO2 measurements allow a reliable estimation of PaCO2 in intubated patients in contrast to measurements in extubated patients. The bucconasal CO2 sensor does not show more reliable measurements compared to nasal sensors in the postoperative setting of cardiac surgery. [Copyright &y& Elsevier]

Objective: Methods: To compare the influence of cis atracurium and atracurium on the airway function in pediatric anesthesia. A total of 72 patients (42 male and 30 female) were divided into the observation group and control group randomly, 36 cases in each group. Anesthesia induction adopted propofol, fentanyl and midazolamin two groups. The cis atracurium (0.15 mg/kg) was used in observation group while atracurium (0.5 mg/kg) was used in control group. Then comparison of the PETCO2, P-PEAK, auscultation breath sounds, SPO2were conducted between two groups of children at 5, 10, 15, 20 min after intubation on the respiratory system. Results: The changing trend of ETCO2 and P-PEAK was not obvious in observation group at 5, 10, 15, 20 min after intubation, and the auscultation breath sounds and SPO2 also had no significant change (P>0.05). However, ETCO2, P-PEAK, auscultation breath sounds and SPO2 had great changes at 5, 10, 15, 20 min after intubation in control group (P<0.05). As time increasing, the ETCO2 and P-PEAK increased markedly, and SPO2 declined gradually in the control group (P <0.05). At each time point, the SPO2 in observation group was higher than in the control group; ETCO2, P-PEAK and the rale occurrence rate in observation group were significantly lower than in the control group, and the differences were statistically significant (P<0.05). Conclusion: The cis atracurium has less impact on the airway function and ideal muscle relaxant effect, so it could be widely used in clinical general anesthesia. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the study was to compare the magnitude of vascular reactivity of the retinal arterioles in terms of percentage change to that of the retinal capillaries using a novel, standardized methodology to provoke isoxic hypercapnia. Ten healthy subjects (mean age 25 years, range 21–31) were recruited. Subjects attended a single visit comprising two study sessions separated by 30min. Subjects were fitted with a sequential re-breathing circuit connected to a computer-controlled gas blender. Each session consisted of breathing at rest for 10min (baseline), increase of PETCO2 (maximum partial pressure of CO2 during expiration) by 15% above baseline whilst maintaining isoxia for 20min, and returning to baseline conditions for 10min. Retinal hemodynamic measurements were performed using the Canon Laser Blood Flowmeter and the Heidelberg Retina Flowmeter in random order across sessions. Retinal arteriolar diameter, blood velocity and flow increased by 3.3%, 16.9% and 24.9% (p <0.001), respectively, during isoxic hypercapnia. There was also an increase of capillary blood flow of 34.8%, 21.6%, 24.9% (p ≤0.006) at the optic nerve head neuroretinal rim, nasal macula and fovea, respectively. The coefficient of repeatability (COR) was 5% of the average PETCO2 both at baseline and during isoxic hypercapnia and was 10% and 7% of the average PETO2 (minimum partial pressure of oxygen at end exhalation), respectively. The overall magnitude of retinal capillary vascular reactivity was equivalent to the arteriolar vascular reactivity with respect to percentage change of flow. The magnitude of isoxic hypercapnia was repeatable. [Copyright &y& Elsevier]

The article talks about the use of noninvasive monitoring of end-tidal carbon dioxide (ETCO2) in the emergency department (ED). This technology, which has been used to evaluate endotracheal tube placement, is considered as a better tool to evaluate ventilation compared to oximetry. EDs can now use ETCO2 in a variety of situations due to the side stream and mainstream monitoring available in the technology.

The relationship between psychosocial factors and psychophysiological reactions to a situation including stressors and relaxation in a working population was examined. A sample of 115 working men and women aged 26–65 was used. Each participant was examined at baseline, during deep breathing, experimentally induced stress and relaxation. Heart rate, exhalation carbon dioxide, oxygen saturation and blood pressure were monitored. Significant variations across experimental conditions were observed for all physiological variables. There was a pronounced lowering of blood pressure during deep breathing. Women showed significantly more pronounced physiological variation than men. Participants with low education reacted with significantly more systolic blood pressure elevation during the stressful conditions than others. The implication of the results for therapeutic and preventive exercises with deep breathing are discussed. [ABSTRACT FROM AUTHOR]

Background: Noninvasive monitoring of partial pressure of carbon dioxide can be accomplished indirectly with capnography (P ET CO 2 ) or with transcutaneous carbon dioxide monitoring (P TC CO 2 ). The use of capnography has been shown to offer an advantage over pulse oximetry alone in the early detection of adverse respiratory events when supplemental oxygen is administered. Furthermore, capnography allows for the monitoring of various respiratory measures, including end-tidal carbon dioxide, respiratory rate, tidal volume, and changes in breathing patterns. Transcutaneous CO 2 also closely approximates arterial CO 2 values, but is not as easy to monitor for prolonged periods. The purpose of this study was to examine the usefulness of capnography and of transcutaneous carbon dioxide monitoring in patients recovering from obesity surgery at high risk of developing postoperative obstructive sleep apnea., Methods: In a prospective observational study, 64 bariatric surgery patients at risk of developing obstructive sleep apnea were monitored in the postanesthesia care unit (PACU) with either capnography alone (31 patients) or capnography plus transcutaneous carbon dioxide monitoring (33 additional patients) every 3-5 minutes for the duration of their recovery. Primary endpoints included end-tidal and transcutaneous carbon dioxide, peripheral oxygen saturation, respiratory rate, pain scores, and incidence of adverse respiratory events., Results: Although no adverse pulmonary events were observed, capnography detected several patients who experienced short periods of respiratory apnea while maintaining pulse oximetry readings within normal limits. Transcutaneous values were slow to change and averaged 4.5 ± 5.5 mm Hg (P < .05) higher than corresponding end-tidal measurements., Conclusions: These results indicate the capabilities of both these noninvasive techniques for postoperative monitoring. Capnography acutely monitors changes in respiration, whereas transcutaneous monitoring more accurately reflects arterial CO 2 levels., (Copyright © 2021 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: Using different techniques, reduction of cerebral blood flow (CBF) during orthostatic stress were demonstrated. One study reported flow reduction of the right internal carotid (ICA) and vertebral (VA) artery during orthostatic stress by Doppler imaging, with different effects on the 2 vessels. Global CBF changes, using this technique, have not been reported. Therefore, flow of the ICA, VA and global CBF were measured during head-up tilt testing., Methods: 33 healthy volunteers underwent tilt testing. At three time points (supine, half way and at the end of the test) Doppler imaging of the ICA and VA was performed, as well as PetCO2 measurements., Results: Global CBF was significantly reduced by 4.5 ± 2.8% halfway the test and by 6.0 ± 3.4% at the end. All 4 artery flows were significantly reduced during the tilt, without differences between them. Despite small changes in PetCO2 there was a significant relation between de CBF decrease and PetCO2 decrease (p < 0.05)., Conclusions: Orthostatic stress in HV results in a small but significant reduction of CBF by a homogenous reduction in the four cerebral vessels and is modulated by PetCO2 changes., Significance: CBF changes can be measured during tilt testing using Doppler VA and ICA imaging.

Unlabelled: There is some disagreement about whether the PetCO2 is reliable in predicting the PaCO2 in laparoscopic procedures with CO2 inflation. The aim of the present study is to measure the Pa-etCO2 differences over time in healthy patients undergoing gynecological laparoscopic surgery with different ventilation methods., Methods: After intubation, patients were randomized into three groups. The patients in group A were ventilated with air/O2 (FiO2 = 50%) and supplied with PEEP (5cmH2O). The patients in group B were ventilated with 50% oxygen while the patients in group C were ventilated with 100% oxygen. All patients were conducted with volume-controlled ventilation. PetCO2 and PaCO2 were measured at baseline, one minute after intubation, every 30 min thereafter and 5 minutes after deflation of pneumoperitoneum., Results: The differences in Pa-etCO2 between groups A, B and C were insignificant one minute after intubation. The Pa-etCO2 in group B and C significantly increased compared with that in group A at other time points after intubation., Conclusion: Oxygen concentration and positive end-expiratory pressure could affect Pa-etCO2 in laparoscopic surgery patients.

Background: The use of CO2 for pneumoperitoneum during laparoscopic surgery provokes a decrement in the gastric pH. Since the incidence rate of PONV increases after laparoscopic surgery, the possibility of lung aspiration of gastric juice with a low pH during a postanesthetic emergence may increase and this could be fatal for the patient. We conducted this study to determine the effects of esomeprazole premedication on inhibiting the decrement of the gastric pH during laparoscopic surgery., Methods: 40 adult patients with no underlying diseases were chosen and 20 patients each were grouped as C (the control group) and E (the esomeprazole group). In both group, 0.2 mg glycopyrrolate was given intramuscularly 30 minutes prior to the surgery. In group E, esomeprazole was given orally 2 hours prior to the surgery. The pH, PaCO2, and PETCO2 were measured via pH probe, an ABGA and an capnogram at preinsufflation and 15, 30 and 60 minutes after the CO2 insufflation and right before CO2 exhaustion (predeflation)., Results: Comparing the measurements of the gastric pH between group E and group C, all the results showed a significant increase in group E (P < 0.05). The difference of the PaCO2 and PETCO2 in the two groups was not significance., Conclusions: In contrast to the decrease in the gastric pH as the PaCO2 and PETCO2 increased in group C, the gastric pH in group E remained high until the end of the surgery despite the increase in the PaCO2 and PETCO2. Esomeprazole premedication seem to have an effect for inhibiting the gastric pH decrement regardless of the increase in the PaCO2 and PETCO2 during laparoscopic surgery.