End-tidal Carbon Dioxide Levels Research Articles

Management and monitoring of anesthesia during the perioperative period in a Tertiary Hospital in Bangladesh

Background: Anesthesia management is crucial for ensuring patient safety and optimal surgical outcomes during the perioperative period. In Bangladesh, the challenges faced in managing and monitoring anesthesia in tertiary care hospitals necessitate a comprehensive evaluation of current practices. This study aims to assess the anesthetic management protocols and monitoring strategies employed in a tertiary hospital in Bangladesh. Methods: This observational study was conducted in Islami Bank Medical College Hospital, Rajshahi, Bangladesh from July to December 2023. Data were collected from patients undergoing various surgical procedures requiring anesthesia. The anesthetic techniques used, intraoperative monitoring parameters, and any complications encountered were recorded. The study included a review of anesthesia charts, patient records, and interviews with anesthesia providers. Statistical analysis was performed to identify trends and correlations. Results: A total of 200 patients were included in the study. The most commonly used anesthetic technique was general anesthesia (65%), followed by regional anesthesia (30%) and local anesthesia (5%). Intraoperative monitoring parameters included heart rate, blood pressure, oxygen saturation, and end-tidal carbon dioxide levels, which were consistently documented in 95% of cases. Complications occurred in 10% of patients, primarily involving respiratory issues and cardiovascular instability. Proper adherence to monitoring protocols significantly reduced the incidence of complications. Conclusion: Effective management and monitoring of anesthesia during the perioperative period are vital for patient safety in a tertiary hospital setting. The study highlights the importance of standardized protocols and continuous monitoring to minimize complications. Recommendations for improving anesthetic practices include regular training for anesthesia providers and enhancing monitoring infrastructure to ensure optimal patient care.

Development of artificial intelligence-driven biosignal-sensitive cardiopulmonary resuscitation robot

Aim of the studyWe evaluated whether an artificial intelligence (AI)-driven robot cardiopulmonary resuscitation (CPR) could improve hemodynamic parameters and clinical outcomes. MethodsWe developed an AI-driven CPR robot which utilizes an integrated feedback system with an AI model predicting carotid blood flow (CBF). Twelve pigs were assigned to the AI robot group (n = 6) and the LUCAS 3 group (n = 6). They underwent 6 min of CPR after 7 min of ventricular fibrillation. In the AI robot group, the robot explored for the optimal compression position, depth and rate during the first 270-second period, and continued CPR with the optimal setup during the next 90-second period and beyond. The primary outcome was CBF during the last 90-second period. The secondary outcomes were coronary perfusion pressure (CPP), end-tidal carbon dioxide level (ETCO2) and return of spontaneous circulation (ROSC). ResultsThe AI model’s prediction performance was excellent (Pearson correlation coefficient = 0.98). CBF did not differ between the two groups [estimate and standard error (SE), −23.210 ± 20.193, P = 0.250]. CPP, ETCO2 level and rate of ROSC also did not show difference [estimate and SE, −0.214 ± 7.245, P = 0.976 for CPP; estimate and SE, 1.745 ± 3.199, P = 0.585 for ETCO2; 5/6 (83.3%) vs. 4/6 (66.7%), P = 1.000 for ROSC). ConclusionThis study provides proof of concept that an AI-driven CPR robot in porcine cardiac arrest is feasible. Compared to a LUCAS 3, an AI-driven CPR robot produced comparable hemodynamic and clinical outcomes.

A systematic review and meta-analysis compared the safety and effectiveness of the AirSeal system with traditional pneumoperitoneum systems in robot-assisted laparoscopic urologic surgery.

This study aimed to analyze perioperative results in robot-assisted laparoscopic urological surgeries, comparing the AirSeal system with traditional pneumoperitoneum systems. This study adhered to the PRISMA guidelines for conducting systematic reviews and meta-analyses. Extensive searches were conducted in PubMed, EMBASE, and Google Scholar, including randomized controlled trials (RCTs) and cohort studies up to June 15, 2024. A combined examination of the studies found that the AirSeal system had superior results in terms of surgery duration, end-tidal carbon dioxide levels, and tidal volume compared to the traditional pneumoperitoneum system. During robotic-assisted partial nephrectomy, the AirSeal team experienced a notable decrease in surgical time, ETCO2, and VT. In addition, the occurrence of SCE was lower in the AirSeal group. However, there were no significant differences observed between the groups regarding EBL, LOHS, overall complications, and major complications. Compared to conventional pneumoperitoneum systems, the AirSeal system offers several advantages in robot-assisted laparoscopic urological surgery: reduced operative time, lower end-tidal CO2 pressure, and decreased tidal volume. Furthermore, implementing the AirSeal system does not lead to higher rates of complications, estimated blood loss, or lengthier hospital stays.

Does exercise modality and posture influence cerebrovascular and cardiovascular systems similarly?

Cerebral hemodynamics have been quantified during exercise via transcranial Doppler ultrasound, as it has high-sensitivity to movement artifacts and displays temporal superiority. Currently, limited research exists regarding how different exercise modalities and postural changes impact the cerebrovasculature across the cardiac cycle. Ten participants (4 females and 6 males) ages 20-29 completed three exercise tests (treadmill, supine, and upright cycling) to volitional fatigue. Physiological data collected included middle cerebral artery velocity (MCAv), blood pressure (BP), heart rate, and respiratory parameters. Normalized data were analyzed for variance and effect sizes were calculated to examine differences between physiological measures across the three exercise modalities. Systolic MCAv was greater during treadmill compared to supine and upright cycling (p<0.001, (large) effect size), and greater during upright versus supine cycling (p<0.017, (large)). Diastolic MCAv was lower during treadmill versus cycling exercise only at 60% maximal effort (p<0.005, (moderate)) and no differences were observed between upright and supine cycling. No main effect was found for mean and diastolic BP (p>0.05, (negligible)). Systolic BP was lower during treadmill versus supine cycling at 40% and 60% intensity (p<0.05, (moderate-large)) and greater during supine versus upright at only 60% intensity (p<0.003, (moderate)). The above differences were not explained by partial pressure of end-tidal carbon dioxide levels (main effect: p=0.432). The current study demonstrates the cerebrovascular and cardiovascular systems respond heterogeneously to different exercise modalities and aspects of the cardiac cycle. As physiological data were largely similar between tests, differences associated with posture and modality are likely contributors.

Low intraoperative end-tidal carbon dioxide levels are associated with improved recurrence-free survival after elective colorectal cancer surgery

Study objectiveHigher levels of carbon dioxide (CO2) increase the invasive abilities of colon cancer cells in vitro. Studies assessing target values for end-tidal CO2 concentrations (EtCO2) to improve surgical outcome after colorectal cancer surgery are lacking. Therefore, we evaluated whether intraoperative EtCO2 was associated with differences in recurrence-free survival after elective colorectal cancer (CRC) surgery. DesignSingle center, retrospective analysis. SettingAnesthesia records, surgical databases and hospital information system of a tertiary university hospital. PatientsWe analyzed 528 patients undergoing elective resection of colorectal cancer at Heidelberg University Hospital between 2009 and 2018. InterventionsNone. MeasurementsIntraoperative mean EtCO2 values were calculated. The study cohort was equally stratified into low-and high-EtCO2 groups. The primary endpoint measure was recurrence-free survival until last known follow-up. Groups were compared using Kaplan-Meier analysis. Cox-regression analysis was used to control for covariates. Sepsis, reoperations, surgical site infections and cardiovascular events during hospital stay, and overall survival were secondary outcomes. Main resultsMean EtCO2 was 33.8 mmHg ±1.2 in the low- EtCO2 group vs. 37.3 mmHg ±1.6 in the high-EtCO2 group. Median follow-up was 3.8 (Q1-Q3, 2.5–5.1) years. Recurrence-free survival was higher in the low-EtCO2 group (log-rank-test: p = .024). After correction for confounding factors, lower EtCO2 was associated with increased recurrence-free survival (HR = 1.138, 95%-CI:1.015–1.276, p = .027); the hazard for the primary outcome decreased by 12.1% per 1 mmHg decrease in mean EtCO2. 1-year and 5-year survival was also higher in the low-EtCO2 group. We did not find differences in the other secondary endpoints. ConclusionsLower intraoperative EtCO2 target values in CRC surgery might benefit oncological outcome and should be evaluated in confirmative studies.

A comparative study between serum lactate level versus change in end tidal carbon dioxide level regarding assessment of hemodynamic instability in intensive care unit patients after cardiac surgeries

ABSTRACT Background After cardiac surgeries, elevated lactate level is used as a marker of tissue hypoperfusion. Still, there is a search for other helpful markers of hemodynamic instability. Exhaled carbon dioxide has been recently studied as marker of cardiac output and tissue perfusion and may be considered a reliable alternative which is more convenient and real time. Objectives The main aim is to correlate between end tidal carbon dioxide (ETCO2) and serum lactate level as indicators of hemodynamic instability in intensive care unit (ICU) patients after cardiac surgeries. The secondary objective is to correlate the measured parameters to the changes in the vital data and the resuscitation efforts. Methods A prospective cohort study that enrolled 51 adult patients admitted to ICU after cardiac surgeries. The serum lactate and ETCO2 values as well as vital data and vasopressor doses were recorded on admission to ICU, after 2 hours and after 6 hours. Results The study shows insignificant weak positive correlation between Lactate and ETCO2 levels at admission (r = 0.172, p value = 0.229), and insignificant negative weak correlation after 2 hours (r = -0.148, p value = 0.300) and after 6 hours (r = -0.235, p value = 0.096). Moreover, lactate level showed significant direct relation with the doses of vasopressors at admission, after 2 hours and after 6 hours postoperative (p value < 0.001 at all intervals). Whereas there was insignificant relation between ETCO2 and doses of vasopressors at all intervals (p value = 0.23, 0.4 and 0.18 respectively). Conclusion In post-cardiac surgery ICU patients we detected no statistically significant relation between serum lactate and ETCO2 as indicators of hemodynamic instability. The change in ETCO2 over a period of time has failed so far to be of a beneficial value as a non-invasive real-time cardiac output monitoring parameter. In addition, serum lactate had strong correlation with changes in vital signs and resuscitation efforts.

Tracheal injury diagnosed by a sudden increase in end-tidal carbon dioxide levels during mediastinoscopic subtotal esophagectomy: a case report

BackgroundMediastinoscopic surgery for esophageal cancer facilitates early postoperative recovery. However, it can occasionally cause serious complications. Here, we present the case of a patient with a tracheal injury diagnosed by a sudden increase in end-tidal carbon dioxide (EtCO2) during mediastinoscopic subtotal esophagectomy.Case presentationA 52-year-old man diagnosed with esophageal cancer was scheduled to undergo mediastinoscopic subtotal esophagectomy. During the mediastinoscopic procedure, the EtCO2 level suddenly increased above 200 mmHg, and the blood pressure dropped below 80 mmHg. We immediately asked the operator to stop insufflation and found a tracheal injury on the right side of the trachea near the carina by bronchoscopy. The endotracheal tube was replaced with a double-lumen tube, and the trachea was repaired via right thoracotomy. There were no further intraoperative complications. After surgery, the patient was extubated and admitted to the intensive care unit.ConclusionsMonitoring EtCO2 levels and close communication with the operator is important for safely managing sudden tracheal injury during mediastinoscopic esophagectomy.

End-Tidal Carbon Dioxide Measurement in Out-of-Hospital Cardiac Arrest as a Predictor of Return of Spontaneous Circulation: A Literature Review.

One of the leading causes of morbidity and mortality worldwide is out-of-hospital cardiac arrest. Early defibrillation and high-quality cardiopulmonary resuscitation (CPR) have improved survival. The main goal of CPR is to achieve return of spontaneous circulation (ROSC), which is assessed by looking for a pulse, analyzing the heart rhythm, and assessing carbon dioxide levels. The use of cartography during CPR to confirm the correct position of the endotracheal tube during intubation or to assess the effectiveness of chest compressions has increased significantly in the last years. The aim of this review was to identify correlations between end-tidal carbon dioxide levels and the likelihood of ROSC in patients with out-of-hospital cardiac arrest. A literature search was performed in MEDLINE (via Pubmed), Scopus, Web of Science, and Google Scholar databases from September to November 2022. Keywords combined with the Boolean operators (AND/OR) were used in both free text and Medical Subject Headings. Studies on adult patients published between 01/01/2016 and 28/09/2022 were searched, with no geographical restrictions. At the end of the selection process, 14 studies were included that investigated capnography in out-of-hospital CPR and reported at least 1 outcome between end-tidal carbon dioxide and ROSC or survival. Capnography is an advantageous tool due to its noninvasive characteristics, ease of use, and immediacy of data. In out-of-hospital cardiac arrest, the use of the end-tidal carbon dioxide appears to be an appropriate complementary tool to support clinical decisions, such as correct positioning of the endotracheal tube, optimizing ventilation in CPR, and as a predictor of ROSC.

Evaluation of the relationship between end-tidal carbon dioxide level and heart failure classification.

Heart failure is a disease with cardiac dysfunction, and its morbidity and mortality are associated with the degree of dysfunction. The New York Heart Association classifies the heart failure stages based on the severity of symptoms and physical activity. End-tidal carbon dioxide refers to the level of carbon dioxide that a person exhales with each breath. End-tidal carbon dioxide levels can be used in many clinical conditions such as heart failure, asthma, and chronic obstructive pulmonary disease. The aim of the study was to reveal the relationship between end-tidal carbon dioxide levels and the New York Heart Association classification of heart failure stages. This study was conducted at Kahramanmaraş Sütçü İmam University Faculty of Medicine Adult Emergency Department between 01/03/2019 and 01/09/2019. A total of 80 patients who presented to the emergency department with a history of heart failure or were diagnosed with heart failure during admission were grouped according to the New York Heart Association classification of heart failure stages. The laboratory parameters, ejection fraction values, and end-tidal carbon dioxide levels of the patients were measured and recorded in the study forms. End-tidal carbon dioxide levels and ejection fraction values were found to be significantly lower in the stage 4 group compared to the other groups. Furthermore, pro-B-type natriuretic peptide (BNP) values were found to be significantly higher in stage 4 group compared to the other groups. It was concluded that end-tidal carbon dioxide levels could be used together with pro-BNP and ejection fraction values in determining the severity of heart failure.

Comparing the Efficiency of Laryngeal Mask Airway and Endotracheal Tube Insertion in Airway Management in Patients Planning for Elective Orthopedic Surgery under General Anesthesia: A Randomized Clinical Trial.

The present study compared respiratory parameters between the two methods of airway establishment, ETT and LMA, for patients scheduled for orthopedic surgery with general anesthesia. This randomized double-blinded clinical trial was conducted on patients scheduled for elective orthopedic surgery under general anesthesia, in Bandar Abbas, Iran, from January 2021 to December 2021. Using a random allocation table, the study participants were randomly divided into two groups, to employ either ETT (n=48) or LMA insertion (n=48). The study's ultimate goal was to assess the respiratory parameters in 1, 3, 5, 10, and 15 minutes following intubation. At all-time points, the average of peak airway pressure (P peak) and P plateau parameters in the ETT group was much higher than the EMA group (p<0.001 in all comparisons). The value of dynamic lung compliance in the LMA group was significantly higher than the ETT group in all considered time periods (p<0.001 in all comparisons). The upward trend in the value of this index was significant only in the LMA group (p=0.030). There were no significant differences in arterial oxygen saturation and end-tidal carbon dioxide levels between the two groups (p>0.05). In terms of arterial oxygen saturation stability and at the same time providing respiratory dynamic compliance, the LMA device outperformed the ETT.

Comparative Analysis of Haemodynamic and Capnographic Changes in Laparoscopic Cholecystectomy and Open Cholecystectomy: A Randomised Clinical Study

Introduction: Laparoscopic cholecystectomy is now preferred over the open procedure due to advantages such as reduced blood loss and shorter hospital stays. However, concerns have been raised regarding the potential for increased Intra-abdominal Pressure (IAP) during laparoscopic procedures, which may impact haemodynamic stability and respiratory parameters. However, there is a lack of comprehensive analysis directly comparing both surgical approaches from both haemodynamic and capnographic perspectives. Aim: To compare the haemodynamic and capnographic changes between laparoscopic and open cholecystectomy. Materials and Methods: This randomised clinical study was conducted at Department of Anaesthesiology, Assam Medical College and Hospital, Dibrugarh, Assam, India from May 2021 to June 2022. The study included 300 patients scheduled for cholecystectomy, divided into two groups: Laparoscopic Cholecystectomy (LC) Group I (n=150) and Open Cholecystectomy (OC) Group II (n=150). Haemodynamic parameters, including Pulse Rate (PR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), and Oxygen Saturation (SpO2 ), were recorded. Capnographic parameters, such as End-Tidal Carbon Dioxide (EtCO2 ) levels, were also measured at regular intervals. Data analysis was performed using the student’s t-test and Chi-square test with Statistical Package for Social Sciences (SPSS) version 21.0 software and Microsoft excel. Results: There were no significant differences in age, body weight, and sex distribution between Group I and Group II. However, significant differences were observed in PR and SBP at 15 minutes (PR: 101.46 and 95.86; SBP: 148.57 and 140.97), 30 minutes (PR: 104.52 and 99.82; SBP: 141.28 and 136.07), and 45 minutes (PR: 102.52 and 97.70; SBP: 140.59 and 133.95) (p-value &lt;0.01). Highly significant differences were observed in MAP and EtCO2 postinsufflation at 15 minutes (MAP: 118.38 and 108.61; EtCO2: 36.48 and 33.89), 30 minutes (MAP: 111.11 and 106.01; EtCO2: 41.02 and 36.15), 45 minutes (MAP: 110.73 and 103.48; EtCO2: 42.65 and 38.36), and 60 minutes (MAP: 106.08 and 101.45; EtCO2: 41.10 and 38.21) (p-value &lt;0.01). DBP showed high significance at 15 minutes (103.21 and 93.23), 30 minutes (96.74 and 92.57), and 60 minutes (93.14 and 86.92) (p-value &lt;0.01), and significant (p-value=0.01) at 45 minutes (95.53 and 87.59). Oxygen saturation showed significance (p-value &lt;0.05) at 15 minutes (99.93 and 100). Conclusion: The present study demonstrated a significant increase in both haemodynamic and capnographic parameters, even in American Society of Anaesthesiologists (ASA) Grade-I and Grade-II patients undergoing laparoscopic cholecystectomy compared to the open surgical technique. These findings emphasise the need for careful monitoring during laparoscopic procedures.

Intraoperative end-tidal carbon dioxide levels are not associated with recurrence-free survival after elective pancreatic cancer surgery: a retrospective cohort study.

Intraoperative end-tidal carbon dioxide concentrations (EtCO2) values are associated with recurrence-free survival after colorectal cancer surgery. However, it is unknown if similar effects can be observed after other surgical procedures. There is now evidence available for target EtCO2 and its relation to surgical outcomes following pancreatic cancer surgery. In this single-center, retrospective cohort study, we analyzed 652 patients undergoing elective resection of pancreatic cancer at Heidelberg University Hospital between 2009 and 2016. The entire patient cohort was sorted in ascending order based on mean intraoperative EtCO2 values and then divided into two groups: the high-EtCO2 group and the low-EtCO2 group. The pre-specified primary endpoint was the assessment of recurrence-free survival up to the last known follow-up. Cardiovascular events, surgical site infections, sepsis, and reoperations during the hospital stay, as well as overall survival were pre-specified secondary outcomes. Mean EtCO2 was 33.8 mmHg ±1.1 in the low-EtCO2 group vs. 36.8 mmHg ±1.9 in the high-EtCO2 group. Median follow-up was 2.6 (Q1:1.4; Q3:4.4) years. Recurrence-free survival did not differ among the high and low-EtCO2 groups [HR = 1.043 (95% CI: 0.875-1.243), log rank test: p = 0.909]. Factors affecting the primary endpoint were studied via Cox analysis, which indicated no correlation between mean EtCO2 levels and recurrence-free survival [Coefficient -0.004, HR = 0.996 (95% CI:0.95-1.04); p = 0.871]. We did not identify any differences in the secondary endpoints, either. During elective pancreatic cancer surgery, anesthesiologists should set EtCO2 targets for reasons other than oncological outcome until conclusive evidence from prospective, multicenter randomized controlled trials is available.

A neonatal in-vitro study on the effect of the inflation pressure on end-tidal carbon dioxide levels.

Describing the association of the peak inflation pressure (PIP) with end-tidal carbon dioxide (ETCO2) is a prerequisite for the development of closed loop ventilation in neonatal intensive care. We aimed to develop an in-vitro system to study this relationship. A ventilator was connected to a test lung, supplied with a stable CO2 concentration from a cylinder. The PIP was altered and the change in ETCO2 per unit of PIP was calculated in three models mimicking respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD) and viral bronchiolitis. The median (IQR) change in ETCO2 per unit of PIP was 0.23(0.13-0.38) kPa/cmH2O, using 138 paired measurements of PIP and ETCO2. The median (IQR) change in ETCO2 per unit of PIP, was higher when starting at an ETCO2>6kPa [0.43(0.33-0.58) kPa/cmH2O] compared to starting at an ETCO2<6kPa [0.14(0.08-0.20) kPa/cmH2O, p<0.001]. The median (IQR) change in ETCO2 per unit of PIP, was larger in the model of RDS [0.33(0.13-0.51) kPa/cmH2O] compared to the BPD [0.23(0.13-0.33) kPa/cmH2O, p=0.043] and the bronchiolitis models [0.15(0.10-0.31) kPa/cmH2O, p=0.017]. The change in ETCO2 in response to increasing PIP was larger for higher ETCO2 values and in a model simulating neonatal RDS, compared to BPD and bronchiolitis.

EtCO2 Levels in Medical Students Wearing N95 Masks

Introduction: N95 masks are very popular for daily use and can actively filter microparticles such as viruses. However, there are concerns that prolonged wearing of the mask may result in exhaled CO2 accumulation between the face and the mask, which may cause increased end-tidal carbon dioxide (EtCO2) levels and physiological changes. This study aimed to determine EtCO2 levels in students wearing the N95 mask. Methods: This was an experimental study with a case-control design. The subjects were divided into a treatment and a control group and were subjected to five measurements in 120 minutes. The data were analyzed using the independent samples T-test (normally distributed data) and the Mann-Whitney U test (not normally distributed data). Results: Mann-Whitney test at minute 0 showed that p = 0.010, independent sample T-test at minute 30 showed that the control group p = 0.016, while in the treatment group p = 0.019. Independent sample T-test at minute 60 for the control group p = 0.034, while the treatment group p = 0.037. Independent sample T-test at minute 90 for the control group and treatment p = 0.001, and independent sample T-test showed that at minute 120 in the control and treatment groups p = 0.000. Conclusion: The EtCO2 measurements at each of the five time points showed a statistical difference (p &lt; 0.05). However, medical students who wore an N95 mask did not suffer adverse effects because the EtCO2 values in the control group were higher than in the treatment group.

Pitfalls in the Diagnosis of Peri-Operative Acute Pulmonary Embolism: A Case Report

An 80 years-old man with hypertension, atrial fibrillation, and coronary artery occlusion disease presented for an elective right femur bipolar hip arthroplasty under general anesthesia. Preoperative transthoracic echocardiography (TTE) showed only preexisting regional wall motion abnormality. During the reversal of muscular relaxation following surgery, there was a sudden decrease in blood pressure associated with rapid ventricular response, which was successfully treated by cardioversion. No decrease in end-tidal carbon dioxide level was observed during the hypotensive episode. However, despite fluid and blood resuscitation and vasopressor treatment, there was a repeated hemodynamic collapse postoperatively. A portable TTE showed dilated right atrium and right ventricle (RV), D-shaped left ventricle, and septal wall motion abnormalities consistent with RV pressure overload (McConnell’s sign). Computed tomography pulmonary angiography revealed multifocal PE (pulmonary embolism). Anticoagulation therapy was continued to avoid PE recurrence. The patient discharged uneventfully 30 days later. Perioperative PE is a rare and perhaps dangerous circumstance that can be challenging to diagnose when it happens under anesthesia. The likelihood of PE should always be suspected at the time of perioperative hemodynamic collapse.

Capnography as a tool for triaging and diagnosis of diabetic ketoacidosis in the emergency department: A prospective observational study.

The cornerstone of management of acidosis in a patient with diabetic ketoacidosis (DKA) has traditionally been carried out by blood gas analysis, which is expensive and associated with significant risk. It is against this background that the correlation between end-tidal carbon dioxide (EtCO2), blood pH, and EtCO2 bicarbonate levels was analyzed. The predictive value of EtCO2 was also analyzed in the diagnosis of DKA. Finally, we aimed to determine the value of EtCO2 as a screening test for the exclusion of DKA. This was a prospective cohort study carried out in the emergency department of a tertiary care teaching hospital from September 2020 to September 2021. Patients with suspected DKA underwent simultaneous blood gas collection and EtCO2 analysis. A total of 123 patients with blood sugar levels >250 mg/dl and moderate-to-large (≥2+) urine ketones were studied. A cut-off value of EtCO2 ≤24 was determined to rule in DKA with a sensitivity of 93.02% and specificity of 91.9%. EtCO2 >26 could effectively rule out the diagnosis of DKA with sensitivity of 98.8% and specificity of 75.7%. A significant linear correlation between pH and EtCO2 (P < 0.0001, r = 0.82) and HCO3 and EtCO2 (r = 0.896, P < 0.0001) was found. EtCO2 values ≤24 can accurately identify patients with DKA in the presence of elevated blood sugar and urinary ketones and must be considered a valuable addition to the diagnostic criteria. EtCO2 values >26 can be an effective triaging tool for ruling our DKA. A significant linear correlation between pH and EtCO2 and pH and HCO3 was observed. EtCO2 can be considered a surrogate marker for the degree of response to the treatment in DKA.

Arterial versus end-tidal carbon dioxide levels in children with congenital heart disease: a prospective cohort study in patients undergoing pulmonary catheterization.

Fifty-seven children with congenital heart disease who underwent cardiopulmonary catheterization between March 2018 and April 2019 were included in a prospective cohort study at Children's Medical Center. Arterial and end-tidal CO2, and hemodynamic variables were assessed prior to the catheterization procedure. Then the patients underwent catheterization, and before being extubated, these variables were again assessed and compared to the baseline levels. End-tidal CO2 increased significantly in cyanotic patients following the catheterization procedure, and the difference between arterial and end-tidal CO2 decreased significantly. End-tidal CO2, arterial CO2, and their difference did not significantly change in non-cyanotic patients following the catheterization procedure. End-tidal and arterial CO2 were not significantly correlated in cyanotic patients (r=0.411, P=0.128), but they were correlated after the catheterization procedure (r=0.617, P=0.014). End-tidal CO2 can estimate arterial CO2 in non-cyanotic patients reasonably. End-tidal CO2 cannot be used to estimate arterial CO2 in cyanotic patients since there is no association. After cardiac defect correction, end-tidal CO2 can be a reliable predictor of arterial CO2.

The Effect of Supine Cycling and Progressive Lower Body Negative Pressure on Cerebral Blood Velocity Responses.

Moderate-intensity aerobic exercise increases cerebral blood velocity (CBv) primarily due to hyperpnea-induced vasodilation; however, the integrative control of cerebral blood flow (CBF) allows other factors to contribute to vasodilation. Lower body negative pressure (LBNP) can reduce CBv, the exact LBNP-intensity required to blunt the aforementioned exercise-induced CBv response is unknown. This could hold utility for concussion recovery, allowing individuals to exercise at higher-intensities without symptom exacerbation. Thirty-two healthy adults (age: 20-33 years; 19 females) completed a stepwise maximal-exercise test to determine each participant's wattage associated with their exercise-induced maximal CBv increase. During the second visit, participants completed moderate-intensity exercise at their determined threshold, while progressive LBNP was applied at 0, -20, -40, -60, -70, -80, and ~88 Torr. Bilateral middle cerebral artery blood velocities (MCAv), mean arterial pressure (MAP), heart rate, respiratory rate, and end-tidal carbon dioxide levels were measured continuously. Two-way analysis of variance with effect sizes compared between sexes and stages. Compared to resting-supine baseline, averaged MCAv was elevated during 0 and -20 Torr LBNP (q-value>7.73; p<0.001); no differences were noted between baseline and -40 to -70 Torr (q-value<|4.24|; p>0.262). Differences were present between females and males for absolute MCAv measures (q-value>11.2; p<0.001), but not when normalized to baseline (q-value<0.03; p>0.951). Supine cycling-elicited increases in MCAv were blunted during the application of LBNP ranging from -40 to -70 Torr. The blunted CBv response demonstrates the potential benefit of allowing individuals to aerobically train (moderate-intensity supine cycling with LBNP) without exacerbating symptoms during concussion recovery.

Does a change in end-tidal carbon dioxide level predict high altitude mountain sickness?

BackgroundIt is postulated that lack of hypoxic ventilatory response is a predictor for AMS. End-tidal carbon dioxide (ETCO2) is an accurate, noninvasive surrogate measure of ventilation. ObjectivesWe sought to determine if changes in baseline ETCO2 predicts the development of AMS. MethodsThis prospective cohort study took place in three separate high-altitude hiking treks. Subjects included a convenience sample of hikers. Predictor variable was change in ETCO2 levels and outcome variable was AMS. Measurements of ETCO2 levels were obtained at the base and repeated daily at various elevations and the summit of each hike. Concurrently, hikers were scored for AMS by a trained investigator. We utilized correlation coefficients and developed a linear regression model for analysis. Results21 subjects in 3 separate hikes participated: 10 ascended to 19,341 ft over 7 days, 6 ascended to 8900 ft in 1 day, and 4 ascended to 11,006 ft in 1 day. Mean age was 40 years, 67% were males, mean daily elevation gain was 2150 ft, and 5 hikers developed AMS. The correlation coefficients for ETCO2 and development of AMS were −0.46 (95%CI -0.33 to −0.57), and −0.77 (95%CI -0.71 to −0.83) for ETCO2 and altitude. ETCO2 predicted the development of symptoms better than the elevation with AUCs of 0.90 (95%CI 0.81–0.99) versus 0.64 (95%CI 0.45–0.83). An ETCO2 measurement of ≤22 mmHg was 100% sensitive and 60% specific for predicting AMS. ConclusionsETCO2 was strongly correlated with altitude and moderately correlated with AMS and it was a better predictor than altitude.

Association between prehospital end-tidal carbon dioxide levels and mortality in patients with suspected severe traumatic brain injury

PurposeSevere traumatic brain injury is a leading cause of mortality and morbidity, and these patients are frequently intubated in the prehospital setting. Cerebral perfusion and intracranial pressure are influenced by the arterial partial pressure of CO2 and derangements might induce further brain damage. We investigated which lower and upper limits of prehospital end-tidal CO2 levels are associated with increased mortality in patients with severe traumatic brain injury.MethodsThe BRAIN-PROTECT study is an observational multicenter study. Patients with severe traumatic brain injury, treated by Dutch Helicopter Emergency Medical Services between February 2012 and December 2017, were included. Follow-up continued for 1 year after inclusion. End-tidal CO2 levels were measured during prehospital care and their association with 30-day mortality was analyzed with multivariable logistic regression.ResultsA total of 1776 patients were eligible for analysis. An L-shaped association between end-tidal CO2 levels and 30-day mortality was observed (p = 0.01), with a sharp increase in mortality with values below 35 mmHg. End-tidal CO2 values between 35 and 45 mmHg were associated with better survival rates compared to < 35 mmHg. No association between hypercapnia and mortality was observed. The odds ratio for the association between hypocapnia (< 35 mmHg) and mortality was 1.89 (95% CI 1.53–2.34, p < 0.001) and for hypercapnia (≥ 45 mmHg) 0.83 (0.62–1.11, p = 0.212).ConclusionA safe zone of 35–45 mmHg for end-tidal CO2 guidance seems reasonable during prehospital care. Particularly, end-tidal partial pressures of less than 35 mmHg were associated with a significantly increased mortality.