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Background: The purpose of this study is to investigate if a laryngeal mask could improve respiratory condition during radiofrequency catheter ablation (RFCA). Methods: Twenty-four consecutive patients who underwent RFCA for atrial fibrillation were divided into two groups (Facemask group; n = 10, Laryngeal mask group; n = 14). All patients were completely sedated under intravenous anesthesia and fitted with artificial respirators during the RFCA. The capnography waveforms and their differential coefficients were analyzed to evaluate the changes of end-tidal CO2 (ETCO2) values, respiratory intervals, expiratory durations, and inspiratory durations. Results: During the RFCA, ETCO2 values of the laryngeal mask group were higher than those of the facemask group (36.0 vs. 29.2 mmHg, p = 0.005). The respiratory interval was significantly longer in the laryngeal mask group than those in the facemask group (4.28 s vs.5.25 s, p < 0.001). In both expiratory and inspiratory phases, the mean of the maximum and minimum values of CO2 was significantly higher when using a laryngeal mask than when using a facemask. The inspiratory-expiratory ratio of the laryngeal mask group was significantly larger than that of the facemask group (1.59 vs. 1.27, p < 0.001). The total procedure duration, fluoroscopic duration and the ablation energy were significantly lower in the laryngeal mask group than in the facemask group. The ETCO2 value is the most influential parameter on the fluoroscopic duration during the RFCA procedure (β = − 0.477, p = 0.029). Conclusions: The use of a laryngeal mask could stabilize respiration during intravenous anesthesia, which could improve the efficiency of RFCA. [ABSTRACT FROM AUTHOR]

Little is known about the impact of tidal volumes delivered by emergency medical services (EMS) to adult patients with out-of-hospital cardiac arrest (OHCA). A large urban EMS system changed from standard adult ventilation bags to small adult bags. We hypothesized that the incidence of return of spontaneous circulation (ROSC) at the end of EMS care would increase after this change. We performed a retrospective analysis evaluating adults treated with advanced airway placement for nontraumatic OHCA between January 1, 2015 and December 31, 2021. We compared rates of ROSC, ventilation rate, and mean end tidal carbon dioxide (ETCO 2) by minute before and after the smaller ventilation bag implementation using linear and logistic regression. Of the 1,994 patients included, 1,331 (67%) were treated with a small adult bag. ROSC at the end of EMS care was lower in the small bag cohort than the large bag cohort, 33% vs 40% (p = 0.003). After adjustment, small bag use was associated with lower odds of ROSC at the end of EMS care [OR 0.74, 95% CI 0.61 – 0.91]. Ventilation rates did not differ between cohorts. ETCO 2 values were lower in the large bag cohort (33.2 ± 17.2 mmHg vs. 36.9 ± 19.2 mmHg, p < 0.01). Use of a small adult bag during OHCA was associated with lower odds of ROSC at the end of EMS care. The effects on acid base status, hemodynamics, and delivered minute ventilation remain unclear and warrant additional study. [ABSTRACT FROM AUTHOR]

Current general anesthesia method through the use of inhalational anesthetics uses the high-flow anesthesia (HFA) approach. This study aimed to compare the SpO2 and EtCO2 in low flow anesthesia and high flow anesthesia. This is a single blind, randomized clinical trial on 54 adult patients, 21–50 years, with physical status ASA 1 who underwent elective surgery under general anesthesia through intubation at H. Adam Malik Medan General Hospital during the period of October 2014 to April 2015. Samples were divided into two groups of 27 subjects. Group A received low flow anesthesia (FGF 1 liter/minute) and group B received high flow anesthesia (FGF 4 liters/minute). The SpO2 and EtCO2 were observed every 10 minutes during anesthesia. Analysis was performed using Mann-Whitney U test and t-test in SPSS 23 software. This study showed that the mean SpO2 during anesthesia for the low flow anesthesia group was 98.63% ± 0.39, and 98.70%±0.37 for the high flow anesthesia. The mean EtCO2 values during anesthesia were 33.73 mmHg± 0.54 and 32.77 mmHg±0.39 for the low flow anesthesia group and high flow anesthesia, respectively. There was no significant difference in SpO2 and EtCO2 values during anesthesia in both groups (p>0.05). Hence, it is concluded that there is no significant difference in SpO2 and EtCO2 values between low flow and high flow anesthesia techniques.

Aim: To determine the end-tidal CO2 (ETCO2) value that predicts a HR > 60 beats per minute (bpm) with the best sensitivity and specificity during neonatal/infant cardiopulmonary resuscitation (CPR) defined as chest compressions ± epinephrine in neonates/infants admitted to a CVICU/PICU. Methods: This was a retrospective cohort study from 1/1/08 to 12/31/12 of all infants ≤6 month of age who received CPR and had ETCO2 documented during serial resuscitations in the pediatric (PICU) or pediatric cardiovascular intensive care units (CVICU) of Children's Medical Center of Dallas. A receiver operator characteristic (ROC) curve was generated to determine the ETCO2 cut-off with the best sensitivity and specificity for predicting HR > 60 bpm. Each ETCO2 value was correlated to the infant's HR at that specific time. Results: CPR was provided for 165 infants of which 49 infants had quantitative ETCO2 documented so only these infants were included. The majority were in the CVICU (81%) and intubated (84%). Mean gestational age was 36 ± 3 weeks and median age (interquartile range) at time of CPR was 30 (16–96) days. An ETCO2 between 17 and 18 mmHg correlated with the highest sensitivity and specificity for return of a HR > 60 bpm. Area under the curve for the ROC is 0.835. Conclusions: This study provides critical clinical information regarding correlation between ETCO2 values and an adequate rise in heart rate in neonates and young infants during CPR. Quantitative ETCO2 monitoring allows CPR to progress uninterrupted without need to pause to check heart rate every 60 seconds until the critical ETCO2 threshold is reached. Quantitative ETCO2 monitoring as an adjunct to cardiac monitoring during infant CPR might enhance perfusion and improve outcomes.

Background: Prehospital identification of shock in trauma patients lacks accurate markers. Low end tidal carbon dioxide (ETCO 2 ) correlates with mortality in intubated patients. The predictive value of ETCO 2 obtained by nasal capnography cannula (NCC) is unknown. We hypothesized that prehospital ETCO 2 values obtained by NCC and in-line ventilator circuit (ILVC) would be predictive of mortality., Methods: This was a prospective, observational, multicenter study. ETCO 2 values were collected by a NCC or through ILVC. AUROCs were compared with prehospital systolic blood pressure (SBP) and shock index (SI). The Youden index defined optimal cutoffs., Results: Of 550 enrolled patients, 487 (88.5%) had ETCO 2 measured through an NCC. Median age was 37 (27-52) years; 76.5% were male; median ISS was 13 (5-22). Mortality was 10.4%. Minimum prehospital ETCO 2 significantly predicted mortality with an AUROC of 0.76 (CI 0.69-0.84; Youden index ​= ​22 ​mmHg), outperforming SBP with an AUROC of 0.68; (CI 0.62-0.74, p ​= ​0.04) and shock index with an AUROC of 0.67 (CI 0.59-0.74, p ​= ​0.03)., Conclusion: Prehospital ETCO 2 measured by non-invasive NCC or ILVC may be predictive of mortality in injured patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Carbon dioxide (CO2) is a by-product of cellular metabolism, which could be considered as a reflection of metabolism, circulation, and ventilation. Arterial blood gas analysis (ABG) is the gold standard of monitoring for CO2. However, is an expensive method leading to blood loss and iatrogenic anemia. In addition, each sample is only a snapshot view of the sampling moment. End-tidal CO2 (ETCO2) measurement gives a non-invasive and continuous monitoring of exhaled CO2. Therefore, this study aimed to validate the non-invasive CO2 measurement performed by nasal cannula and evaluate the correlation with partial pressure of arterial CO2 (PaCO2 ) in neonates. Methods: This single-center observational study was conducted in the Neonatal Intensive Care Unit (NICU), Kasturba Hospital, Manipal, India. PaCO2 was reported on routine ABG within a 15-minute interval of ABG sampling. Moreover, partial pressure of end-tidal carbon dioxide (PetCO2) was noted at continuous 30-sec intervals (i.e., 30, 60, 90, ..., 180) up to 3 minutes. The values of PaCO2 and PetCO2 were found to be correlated with Pearson correlation and were shown by scattered plot. Regression analysis was used to get the prediction equation and the variance. Results: A total of 70 samples were taken in the initial phase to study the correlation between PaCO2 and measured PetCO2. Pearson correlation showed a moderate positive correlation (r= 0.589) between PetCO2 and measured PaCO2. Regression analysis demonstrated a variance of 33.8% between the measured PetCO2 and PaCO2, which was statistically significant (P<0.001). A prediction equation was obtained for PaCO2. In the final phase, 20 samples were recruited to standardize and validate the prediction equation. The PaCO2 was calculated using the predicted equation and a new prediction equation was obtained. Conclusion: According to the findings of this study, there is a good correlation (r=0.681) between the non-invasively measured PetCO2 and PaCO2. [ABSTRACT FROM AUTHOR]

CO2 removal by the lungs depends upon ventilation and pulmonary blood flow, with end tidal CO2 (EtCO2) as surrogate for it. We studied indices based on EtCO2 measured routinely during anesthesia for cardiac catheterization, along with simultaneously calculated Qp:Qs (pulmonary-to-systemic-blood-flow ratio) in children with complex congenital heart disease to assess the relationship between these measures. A retrospective, single-center, correlational cohort study was conducted at a tertiary-care, free-standing children's hospital. All included subjects had Qp:Qs calculated as well as EtCO2 and PaCO2 documented during a single cardiac catheterization. Children with stage-1 single ventricle or complex biventricular repair with highly variable Qp:Qs were defined as Group 1, and Group 2 comprised those with stage 2 or 3 repairs with less variable Qp:Qs. Exclusion criteria were uncuffed artificial airway, EtCO2 > PaCO2, and abnormally high Qp:Qs. EtCO2 indices were defined as EtCO2:PaCO2 (alveolar functional fraction) and EtCO2 gap (PaCO2-EtCO2). Correlation coefficients were obtained between Qp:Qs and EtCO2 indices in both groups. A total of 29 patients in Group 1 and 24 in Group 2 underwent final analysis. Even with highly variable Qp:Qs, Group 1 showed a strong correlation between Qp:Qs and EtCO2:PaCO2 (r = 0.83, p < 0.0001). A similarly strong correlation was maintained in Group 2 (r = 0.79, p < 0.0001) and in both groups combined (r = 0.86, p < 0.0001). A very strong negative correlation was present between Qp:Qs and EtCO2 gap (r = − 0.77, p < 0.0001). EtCO2:PaCO2 has a very strong correlation with Qp:Qs simultaneously calculated during catheterization. It can be an additional parameter to estimate Qp:Qs in critical management of children with congenital heart disease. Our results also provide a basis for future prospective studies to assess dynamic changes in EtCO2-based indices and Qp:Qs. [ABSTRACT FROM AUTHOR]

Capnography allows us to measure the amount of expired (end tidal) carbon dioxide (CO2) and has become a vital monitoring tool when anaesthetising our veterinary patients. Knowledge and understanding of the information it provides is essential to the veterinary nurse (VN) anaesthetist. This article provides a brief history of this technology’s development, the information capnography provides us, the varying waveforms commonly seen and how its use is an important contributor to the safety and stability of the anaesthetised patient. The waveforms encountered on the monitoring screen are also included and a brief description of what they may be demonstrating. [ABSTRACT FROM AUTHOR]

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The holistic self-management plan includes lifelong actions that enable patients to cope with their disease. The present study was designed to evaluate the effect of a holistic self-management plan on asthma control. A 12-month controlled study was conducted. Adult patients with mild-to-moderate asthma (n = 24) who attended the emergency asthma department were randomized to two groups: One group followed four educational sessions and three personal home sessions (n = 12), while a second group received a short manual with asthma information (n = 12). The main measure was the asthma control test (ACT), while secondary outcomes were self-efficacy (general self-efficacy scale, GSE), end-tidal carbon dioxide (ETCO2), respiratory rate (RR), breathing hold time (BHT), the Nijmegen Questionnaire (NQ), and spirometry (FEV1% predicted (forced expiratory volume in 1 second % predicted)) scores. The 2 × 4 ANOVA showed a significant interaction effect between intervention and time in ACT (p = 0.001), GSE (p < 0.001), ETCO2 (p < 0.001), RR (p < 0.001), BHT (p < 0.001), NQ (p = 0.05), and FEV1% predicted (p < 0.001). Predictors of asthma control were self-efficacy and ETCO2. In conclusion, this exploratory study provided support for the effectiveness of holistic self-management in asthma control. Behavioral changes, as indicated by the development of self-efficacy and the reduction of hyperventilation, contributed to the effectiveness of the intervention. [ABSTRACT FROM AUTHOR]

An accurate, non-invasive measure of return of spontaneous circulation (ROSC) is needed to improve management of cardiac arrest patients. During a pulse check in Emergency Department (ED) cardiac arrest patients, we compared the correlation between 1) end tidal carbon dioxide (ETCO 2) and systolic blood pressure (SBP), and 2) Doppler ultrasound peak systolic velocity (PSV) and SBP. Additionally, we assessed the accuracy of PSV ≥ 20 cm/sec in comparison to previously suggested ETCO 2 ≥ 20 or ≥ 25 mmHg thresholds to predict ROSC with SBP ≥ 60 mmHg. This was a secondary analysis of a previously published prospective observational study of ED cardiac arrest patients with an advanced airway and femoral arterial line in place. During each pulse check, highest SBP, highest PSV, and ETCO 2 at the end of the pulse check were recorded. Spearman correlation coefficients were calculated and compared using a Fisher Z-transformation. Accuracy of previously determined PSV and ETCO 2 thresholds for detecting ROSC with SBP ≥ 60 mmHg were compared using McNemar's tests. Based on data from 35 patients with 111 pulse checks, we found a higher correlation between PSV and SBP than ETCO 2 and SBP (0.71 vs 0.31; p < 0.001). Diagnostic accuracy of PSV ≥ 20 cm/sec for detecting ROSC with SBP ≥ 60 mmHg was 89% (95% CI: 82%-94%) versus 59% (95% CI: 49%-68%) and 58% (95% CI: 48%-67%) for ETCO 2 ≥ 20 and ≥ 25 mmHg, respectively. During a pulse check, Doppler ultrasound PSV outperformed ETCO 2 for correlation with SBP and accuracy in detecting ROSC with SBP ≥ 60 mmHg. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the correlation and agreement between end-tidal CO 2 (EtCO 2 ) measured with the novel portable capnometer (CapnoEye®) and partial pressure of arterial carbon dioxide (PaCO 2 ) levels in patients with respiratory diseases and to compare the efficacy of EtCO 2 and PvCO 2 in predicting PaCO 2 levels., Methods: We analyzed the correlation and the agreement between EtCO 2 and PaCO 2 and between PvCO 2 and PaCO 2 using Pearson's moment correlation coefficient in patients with type 1 and type 2 respiratory failure and both groups overall., Results: A total of 100 samples were included that comprised 67 men (67%). The mean age of the subjects was 77 ± 13 years. Chronic obstructive pulmonary disease (COPD) (43%) was the most common disease. There was a high correlation between EtCO 2 and PaCO 2 (r = 0.88; p < 0.0001). Sixty-six PvCO 2 samples were obtained, and there was a high correlation between PvCO 2 and PaCO 2 (r = 0.81; p < 0.0001). Regarding type 2 respiratory failure, there was a high correlation between EtCO 2 and PaCO 2 (r = 0.81). The Bland-Altman analysis between PaCO 2 and EtCO 2 revealed a bias of 5.7 mmHg, with limits of agreement ranging from -5.1 mmHg to 16.5 mmHg. In contrast, the analysis between PaCO 2 and PvCO 2 revealed a bias of -6.8 mmHg, and the limits of agreement ranged from -22.13 mmHg to 8.53 mmHg., Conclusion: EtCO 2 measured by CapnoEye® was significantly correlated to PaCO 2 levels in patients with respiratory diseases. Moreover, CapnoEye® may be more useful for predicting hypercapnia conditions in which respiratory diseases are compared with measure PvCO 2 ., (© 2023 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.)

Background: Atelectasis occurs regularly after induction of general anesthesia in bariatric surgery, persists postoperatively, and may contribute to significant postoperative morbidity. Intraoperative recruitment maneuver improve lung ventilation, oxygenation and lung mechanics. Objectives: The aim of this study was to compare the effects of recruitment maneuver on oxygen saturation, end tidal carbon dioxide and lung mechanics in two Groups; the volume control group and pressure control group with fixed level of PEEP. Patient and Method: Forty patients, BMI >35 kg/ m2, who have no major obstructive or restrictive respiratory disorders where allocated in two groups (volume group and pressure group). In both groups we tested the effect of recruitment maneuver on SpO2, ETCO2 and lung mechanics (The volume group of 20 patients and the pressure group of 20 patients). Results: We found that alveolar recruitment effectively decreased Intraoperative EtCO2 in pressure group ( P.value 0.05 ) for volume group and increase Intraoperative SpO2in BOTH groups ( P.value < 0.05) with more effect seen in pressure group. BUT, soon after extubation SpO2 decreases again and P.value was >0.05 for both groups. Also we found that pulmonary mechanics (PIP, EXPvt) were significantly improved after recruitment (BOTH P.value < 0.05). Conclusions: our data suggest that the use of alveolar recruitment maneuver may be an effective mode of improving intraoperative oxygenation in morbidly obese patients. Our results showed that the effect is to be short lived and end after extubation. with significant improvement in lung mechanics.

Aim of the Study: End tidal carbon dioxide (EtCO2) monitoring is considered to reflect real-time estimation of partial pressure of carbon dioxide in arterial blood (PaCO2) noninvasively. However, knowledge about its relationship with PaCO2 in critically ill pediatric and neonatal patients is limited. The primary objective was to evaluate predictive capability of end tidal carbon dioxide monitoring and secondary objective was to determine the influence of severity of lung disease on EtCO2 and PaCO2 relationship. Materials and Methods: This was a prospective, nonrandomized, consecutive enrollment study carried out in neonatal and pediatric intensive care units of a tertiary care children hospital. It was conducted in 66 neonates and 35 children receiving mechanical ventilation. Severity of lung disease was estimated by ventilation index and PaO2/FiO2 (P/F) ratio. Simultaneous recording of EtCO2 and PaCO2 levels was done and data were analyzed for correlation and agreement. Results: In neonates, 150 EtCO2 and PaCO2 pairs were recorded. The mean weight ± SD of patients was 2.1 ± 0.63 kg. PaCO2 had a positive correlation with EtCO2 (r = 0.836, 95% CI = 0.78-0.88). P/F ratio <200 adversely affected relationship. In infants and children, 96 pairs were recorded. Mean age ± SD of patients was 4.20 ± 4.92 years and mean weight ± SD was 13.1 ± 9.49 kg. PaCO2 had an excellent correlation with EtCO2 (r = 0.914, 95% CI = 0.87 and 0.94). P/F ratio <200 adversely affected relationship. Conclusion: EtCO2 monitoring displayed a good validity to predict PaCO2. Correlation was affected by low P/F ratio (<200); hence, it is recommended that blood gases be measured in these patients until such time that a good relation can be established between end tidal and arterial CO2 values. [ABSTRACT FROM AUTHOR]

Hyperventilation has been linked to emotional distress in adults. This study investigates end-tidal carbon dioxide ( ETCO2), respiratory rate ( RR), and heart rate variability ( HRV) in adolescent girls with emotional disorders and healthy controls. ETCO2, RR, HRV, and ratings of emotional symptom severity were collected in adolescent female psychiatric patients with emotional disorders ( n = 63) and healthy controls ( n = 62). ETCO2 and RR differed significantly between patients and controls. ETCO2, HR, and HRV were significant independent predictors of group status, that is, clinical or healthy, while RR was not. ETCO2 and RR were significantly related to emotional symptom severity and to HRV in the total group. ETCO2 and RR were not affected by use of selective serotonin reuptake inhibitors. It is concluded that emotional dysregulation is related to hyperventilation in adolescent girls. Respiratory-based treatments may be relevant to investigate in future research. [ABSTRACT FROM AUTHOR]

Study objective. To determine if an initial (before treatment) prehospital end-tidal carbon dioxide (EtCO2) measurement in adult, non-chronic obstructive pulmonary disease (COPD), asthmatic patients predicts patient outcomes. Methods. This is a retrospective chart review of EtCO2 assessment data in a convenience sample of adult, asthmatic patients transported via advanced life support (ALS) units to a large, urban, academic hospital. Initial EtCO2 measurements were obtained routinely on all respiratory distress patients in the field, and emergency department physicians were unaware of the results. Data were analyzed using descriptive statistics, including percentages, means, and 95% confidence intervals (CI). Results. We reviewed data for prehospital initial EtCO2 measurements on 299 unique asthma patients (repeat visits by same patient were not included). Mean (SD) age was 43.1 years (12.5) and 142 (47.5%) were male. The mean EtCO2 measurement was 38.8 mmHg (SD ± 9.5; CI: 37.7-39.9; range: 14-82). Examination of initial EtCO2 measurements by deciles revealed that extreme values, in the lowest (14-28 mmHg) and highest (50-82 mmHg) deciles, experienced more markers of poor outcome than less extreme measurements. Patients were thus dichotomized by extreme ( n = 59) or nonextreme ( n = 240) EtCO2 measurements. More extreme patients were ultimately intubated (30.5 vs. 5.8%; p < 0.001; positive predictive value (ppv) = 30.5% ), and/or admitted to the intensive care unit (ICU) (28.8 vs. 6.7%; p <0.001; ppv = 28.8%), and/or died (5.1 vs. 0%; p = 0.007 [Fisher's exact test]; ppv = 5.1%), than nonextreme patients, respectively. Conclusion. Extreme (both low and high) prehospital initial EtCO2 measurements may be associated with markers of poor patient outcomes. Future work will prospectively determine whether the addition of this information improves early recognition of severe asthma episodes beyond clinical assessment. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Cardiac arrest is a common presentation to the emergency care system. The decision to terminate CPR is often challenging to heath care providers. An accurate, early predictor of the outcome of resuscitation is needed. The purpose of this systematic review is to evaluate the prognostic value of ETCO2 during cardiac arrest and to explore whether ETCO2 values could be utilised as a tool to predict the outcome of resuscitation. Method: Literature search was performed using Medline and EMBASE databases to identify studies that evaluated the relationship between ETCO2 during cardiac arrest and outcome. Studies were thoroughly evaluated and appraised. Summary of evidence and conclusions were drawn from this systematic literature review. Results: 23 observational studies were included. The majority of studies showed that ETCO2 values during CPR were significantly higher in patients who later developed ROSC compared to patients who did not. Several studies suggested that initial ETCO2 value of more than 1.33kPa is 100% sensitive for predicting survival making ETCO2 value below 1.33kPa a strong predictor of mortality. These studies however had several limitations and the 100% sensitivity for predicting survival was not consistent among all studies. Conclusion: ETCO2 values during CPR do correlate with the likelihood of ROSC and survival and therefore have prognostic value. Although certain ETCO2 cut-off values appears to be a strong predictor of mortality, the utility of ETCO2 cut-off values during CPR to accurately predict the outcome of resuscitation is not fully established. Therefore, ETCO2 values cannot be used as a mortality predictor in isolation. [Copyright &y& Elsevier]

Background: Among subjects with exercise intolerance and suspected early-stage pulmonary hypertension (PH), early identification of pulmonary vascular disease (PVD) with noninvasive methods is essential for prompt PH management., Hypothesis: Rest gas exchange parameters (minute ventilation to carbon dioxide production ratio: V E /VCO 2 and end-tidal carbon dioxide: ETCO 2 ) can identify PVD in early-stage PH., Methods: We conducted a retrospective review of 55 subjects with early-stage PH (per echocardiogram), undergoing invasive exercise hemodynamics with cardiopulmonary exercise test to distinguish exercise intolerance mechanisms. Based on the rest and exercise hemodynamics, three distinct phenotypes were defined: (1) PVD, (2) pulmonary venous hypertension, and (3) noncardiac dyspnea (no rest or exercise PH). For all tests, *p < .05 was considered statistically significant., Results: The mean age was 63.3 ± 13.4 years (53% female). In the overall cohort, higher rest V E /VCO 2 and lower rest ETCO 2 (mm Hg) correlated with high rest and exercise pulmonary vascular resistance (PVR) (r ~ 0.5-0.6*). On receiver-operating characteristic analysis to predict PVD (vs. non-PVD) subjects with noninvasive metrics, area under the curve for pulmonary artery systolic pressure (echocardiogram) = 0.53, rest V E /VCO 2  = 0.70* and ETCO 2  = 0.73*. Based on this, optimal thresholds of rest V E /VCO 2  > 40 mm Hg and rest ETCO 2  < 30 mm Hg were applied to the overall cohort. Subjects with both abnormal gas exchange parameters (n = 12, vs. both normal parameters, n = 19) had an exercise PVR 5.2 ± 2.6* (vs. 1.9 ± 1.2), mPAP/CO slope with exercise 10.2 ± 6.0* (vs. 2.9 ± 2.0), and none included subjects from the noncardiac dyspnea group., Conclusions: In a broad cohort of subjects with suspected early-stage PH, referred for invasive exercise testing to distinguish mechanisms of exercise intolerance, rest gas exchange parameters (V E /VCO 2  > 40 mm Hg and ETCO 2  < 30 mm Hg) identify PVD., (© 2022 The Authors. Clinical Cardiology published by Wiley Periodicals, LLC.)

Background. The utility of prehospital intubation is controversial, as uncontrolled studies in trauma patients suggest adverse outcomes with prehospital intubation, perhaps secondary to inappropriate ventilation once intubation is accomplished. Objectives. The objectives were 1) to establish, immediately upon arrival to the emergency department (ED), the prevalence of abnormal end-tidal carbon dioxide (ETCO2) levels in patients with prehospital intubation and 2) to describe the relationship between abnormal ETCO2 levels on ED arrival and mortality. Methods. This was a prospective, observational cohort study of patients with prehospital intubation. Patients were excluded if they underwent prehospital cardiopulmonary resuscitation (CPR). On ED arrival, the initial ETCO2 measurement from the patient's endotracheal tube was immediately obtained prior to purposeful intervention in the patient's ventilation by using an Oridion Surestream Sure VentLine H Set with a Welch Allyn Propaq CS monitor. For each patient, the treating physician documented the ETCO2 measurement, patient demographics, and details of the transport. The primary outcome was an abnormal ETCO2 value (<30 mmHg or >45 mmHg). The secondary outcome was mortality. Results. One hundred eligible patients were enrolled, with a median age of 30 years (interquartile range [[IQR]] 15, 48 years). Esophageal intubations were identified in four cases, and those cases were excluded from further analysis. Mechanisms included trauma, 74; medical, 12; and burn, 10. The median ETCO2 value was 32 mmHg (IQR 27, 38 mmHg), range 18-80 mmHg. Forty-six of 96 (48%%, 95%% confidence interval [[CI]] 38%%, 58%%) patients had abnormal ETCO2 values, including 37 (39%%, 95%% CI 29%%, 49%%) with low ETCO2 levels and nine (9%%, 95%% CI 4%%, 17%%) with high ETCO2 levels. Death was higher in those trauma patients with abnormal ETCO2 levels (10/33, 30%%, 95%% CI 16%%, 49%%) than in those with normal ETCO2 levels (2/41, 5%%, 95%% CI 0.6%%, 17%%), relative risk == 6.2 (95%% CI 1.5, 26.4), p == 0.004. Conclusion. Nearly half of all patients transported by prehospital providers had abnormal ETCO2 measurements on initial ED presentation, suggesting an area for potential improvement. Trauma patients with abnormal initial ETCO2 levels were more likely to die. [ABSTRACT FROM AUTHOR]

Background. The mechanism of the breathing retraining effect on asthma control is not adequately based on evidence. Objective. The present study was designed to evaluate the effect of physiotherapy-based breathing retraining on asthma control and on asthma physiological indices across time. Study design. A 6-month controlled study was conducted. Adult patients with stable, mild to moderate asthma (n = 40), under the same specialist's care, were randomized either to be trained as one group receiving 12 individual breathing retraining sessions (n = 20), or to have usual asthma care (n = 20). The main outcome was the Asthma Control Test score, with secondary outcomes the end-tidal carbon dioxide, respiratory rate, spirometry, and the scores of Nijmegen Hyperventilation Questionnaire, Medical Research Council scale, and SF-36v2 quality-of-life questionnaire. Results. The 2 × 4 ANOVA showed significant interaction between intervention and time in asthma control (F = 9.03, p < .001, η2 = 0.19), end-tidal carbon dioxide (p < .001), respiratory rate (p < .001), symptoms of hypocapnia (p = .001), FEV1% predicted (p = .022), and breathlessness disability (p = .023). The 2 × 4 MANOVA showed significant interaction between intervention and time, with respect to the two components of the SF-36v2 (p < .001). Conclusion. Breathing retraining resulted in improvement not only in asthma control but in physiological indices across time as well. Further studies are needed to confirm the benefits of this training in order to help patients with stable asthma achieve the control of their disease. [ABSTRACT FROM AUTHOR]

Objective: To demonstrate correlation and clinical usefulness of the partial pressure of end-tidal CO2 (ETCO2) measurement by nasal catheter placement in sedated dogs with and without concurrent nasal oxygen administration as a substitute for partial pressure of arterial CO2 (PaCO2). Design: Prospective, cross-over trial. Setting: University of Saskatchewan veterinary research laboratory. Animals: Six cross-breed dogs with a mean (±SD) weight of 29.1±4.03 kg. Interventions: All dogs were sedated with 5 μg/kg medetomidine intravenously (IV) and an arterial catheter was placed in a dorsal pedal artery for removal of blood for gas analysis. A nasal catheter was placed in the ventral meatus and connected to a capnometer for ETCO2 measurements in all dogs. Dogs receiving supplemental nasal oxygen had a second nasal catheter placed in the contralateral naris. Measurements and main results: In the group without nasal oxygen supplementation, the ETCO2 measurement underestimated (negative bias) the PaCO2 by −2.20 mmHg with limits of agreement (95% confidence interval) of −5.79, 1.39 mmHg. In the group receiving oxygen supplementation, ETCO2 measurement underestimated (negative bias) the PaCO2 by −2.46 mmHg with limits of agreement (95% confidence interval) of −8.42, 3.50 mmHg. Conclusions: The results of this study demonstrate that ETCO2 monitoring via a nasal catheter provides a clinically acceptable substitute to arterial blood gas analysis as a means of monitoring ventilation in healthy, sedated dogs. The limits of agreement were within acceptable limits with and without concurrent insufflation of oxygen. [ABSTRACT FROM AUTHOR]

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.