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Several noninvasive solutions are available for the assessment of patients at risk of deterioration. Capnography, in the form of end-tidal exhaled CO2 (ETCO2) and perfusion index (PI), could provide relevant information about patient prognosis. The aim of the present project was to determine the association of ETCO2 and PI with mortality of patients admitted to the emergency department (ED). Multicenter, prospective, cohort study of adult patients with acute disease who needed continuous monitoring in the ED. The study included two tertiary hospitals in Spain between October 2022 and June 2023. The primary outcome of the study was in-hospital mortality (all-cause). Demographics, vital signs, ETCO2 and PI were collected. A total of 687 patients were included in the study. The in-hospital mortality rate was 6.8%. The median age was 79 years (IQR: 69–86), and 63.3% were males. The median ETCO2 value was 30 mmHg (26–35) in survivors and 23 mmHg (16–30) in nonsurvivors (p = 0.001). For the PI, the medians were 4.7% (2.8–8.1) for survivors and 2.5% (0.98–4-4) for nonsurvivors (p < 0.001). The model that presented the best AUC was age (odds ratio (OR): 1.02 (1.00–1.05)), the respiratory rate (OR: 1.06 (1.02–1.11)), and the PI (OR: 0.83 (0.75–0.91)), with a result of 0.840 (95% CI: 0.795–0.886); the model with the respiratory rate (OR: 1.05 (1.01–1.10)), the PI (OR: 0.84 (0.76–0.93)), and the ETCO2 (no statistically significant OR), with an AUC of 0.838 (95% CI: 0.787–0.889). The present study showed that the PI and respiratory rate are independently associated with in-hospital mortality. Both the PI and ETCO2 are predictive parameters with improved prognostic performance compared with that of standard vital signs. [ABSTRACT FROM AUTHOR]

To evaluate whether end-tidal carbon dioxide (ETCO2) value at intubation and its early increase (10 min) after intubation predict both the survival to hospital admission and the survival at hospital discharge, including good neurological outcome (CPC 1–2), in patients with out-of-hospital cardiac arrest (OHCA). All consecutive OHCA patients of any etiology between 2015 and 2018 in Pavia Province (Italy) and Ticino Region (Switzerland) were considered. Patients died before ambulance arrival, with a "do-not-resuscitate" order, without ETCO2 value or with incomplete data were excluded. The study population consisted of 668 patients. An ETCO2 value at intubation > 20 mmHg and its increase 10 min after intubation were independent predictors (after correction for known predictors of OHCA outcome) of survival to hospital admission and survival at hospital discharge. Relative to hospital discharge with good neurological outcome, ETCO2 at intubation and its 10-min change were confirmed predictors both individually and in a bivariable analysis (OR 1.83, 95 %CI 1.02–3.3; p = 0.04 and OR 3.9, 95 %CI 1.97–7.74; p < 0.001, respectively). This was confirmed also when accounting for gender, age, etiology and location. After further adjustment for bystander and CPR status, presenting rhythm and EMS arrival time, the ETCO2 change remained an independent predictor. ETCO2 value > 20 mmHg at intubation and its increase during resuscitation improve the prediction of survival at hospital discharge with good neurological outcome of OHCA patients. ETCO2 increase during resuscitation is a more powerful predictor than ETCO2 at intubation. A larger prospective study to confirm this finding appears warranted. [ABSTRACT FROM AUTHOR]

Introduction: In former studies, the arterio-alveolar carbon dioxide gradient (ΔCO2) predicted in-hospital mortality after initially survived cardiac arrest. As early outcome predictors are urgently needed, we evaluated ΔCO2 as predictor for good neurological outcome in our cohort.Methods: We retrospectively analyzed all patients ≥18 years of age after non-traumatic in- and out of hospital cardiac arrest in the year 2018 from our resuscitation database. Patients without advanced airway management, incomplete datasets or without return of spontaneous circulation were excluded. The first arterial pCO2 after admission and the etCO2 in mmHg at the time of blood sampling were recorded from patient's charts. We then calculated ΔCO2 (pCO2 - etCO2). For baseline analyses, ΔCO2 was dichotomized into a low and high group with separation at the median. Good neurological outcome on day 30, expressed as Cerebral Performance Category 1-2, defined our primary endpoint. Survival to 30 days was used as secondary endpoint.Results: Out of 302 screened patients, 128 remained eligible for analyses. ΔCO2 was lower in 30-day survivors with good neurological outcome (12.2 mmHg vs. 18.8 mmHg, p = 0.009) and in 30-day survivors (12.5 mmHg vs. 20.0 mmHg, p = 0.001). In patients with high ΔCO2, a cardiac etiology of arrest was found less often. They had a higher body mass index, longer duration of resuscitation, higher amounts of epinephrine, lower pO2 levels but both higher pCO2 and blood lactate levels, resulting in lower blood pH and HCO3- levels at admission. In a crude binary logistic regression analysis, ΔCO2 was associated with 30-day neurological outcome (OR = 1.041 per mmHg of ΔCO2, 95% CI 1.008-1.074, p = 0.014). This association persisted after the adjustment for age, sex, witnessed arrest and shockable first rhythm. However, after addition of the duration of resuscitation or the cumulative epinephrine dosage to the model, ΔCO2 lost its association.Conclusion: ΔCO2 at admission after a successfully resuscitated cardiac arrest is associated with 30 days survival with good neurological outcome. However, a higher ΔCO2 may rather be a surrogate for unfavorable resuscitation circumstances than an independent outcome predictor. [ABSTRACT FROM AUTHOR]

Aims: The end-tidal carbon dioxide (ETCO2) is frequently measured in cardiac arrest (CA) patients, for management and for predicting survival. Our goal was to study the PaCO2 and ETCO2 in hypothermic cardiac arrest patients.Methods: We included patients with refractory CA assessed for extracorporeal cardiopulmonary resuscitation. Hypothermic patients were identified from previously prospectively collected data from Poland, France and Switzerland. The non-hypothermic CA patients were identified from two French cohort studies. The primary parameters of interest were ETCO2 and PaCO2 at hospital admission. We analysed the data according to both alpha-stat and pH-stat strategies.Results: We included 131 CA patients (39 hypothermic and 92 non-hypothermic). Both ETCO2 (p < 0.001) and pH-stat PaCO2 (p < 0.001) were significantly lower in hypothermic compared to non-hypothermic patients, which was not the case for alpha-stat PaCO2 (p = 0.15). The median PaCO2-ETCO2 gradient was greater for hypothermic compared to non-hypothermic patients when using the alpha-stat method (46 mmHg vs 30 mmHg, p = 0.007), but not when using the pH-stat method (p = 0.10). Temperature was positively correlated with ETCO2 (p < 0.01) and pH-stat PaCO2 (p < 0.01) but not with alpha-stat PaCO2 (p = 0.5). The ETCO2 decreased by 0.5 mmHg and the pH-stat PaCO2 by 1.1 mmHg for every decrease of 1° C of the temperature. The proportion of survivors with an ETCO2 ≤ 10 mmHg at hospital admission was 45% (9/25) for hypothermic and 12% (2/17) for non-hypothermic CA patients.Conclusions: Hypothermic CA is associated with a decrease of the ETCO2 and pH-stat PaCO2 compared with non-hypothermic CA. ETCO2 should not be used in hypothermic CA for predicting outcome. [ABSTRACT FROM AUTHOR]

Interpretation of end-tidal CO 2 (ETCO 2) during manual cardiopulmonary resuscitation (CPR) is affected by variations in ventilation and chest compressions. This study investigates the impact of standardising ETCO 2 to constant ventilation rate (VR) and compression depth (CD) on absolute values and trends. Retrospective study of out-of-hospital cardiac arrest cases with manual CPR, including defibrillator and clinical data. ETCO 2 , VR and CD values were averaged by minute. ETCO 2 was standardised to 10 vpm and 50 mm. We compared standardised (ET s) and measured (ET m) values and trends during resuscitation. Of 1,036 cases, 287 met the inclusion criteria. VR was mostly lower than recommended, 8.8 vpm, and highly variable within and among patients. CD was mostly within guidelines, 49.8 mm, and less varied. ET s was lower than ET m by 7.3 mmHg. ET s emphasized differences by sex (22.4 females vs. 25.6 mmHg males), initial rhythm (29.1 shockable vs. 22.7 mmHg not), intubation type (25.6 supraglottic vs. 22.4 mmHg endotracheal) and return of spontaneous circulation (ROSC) achieved (34.5 mmHg) vs. not (20.1 mmHg). Trends were different between non-ROSC and ROSC patients before ROSC (–0.3 vs. + 0.2 mmHg/min), and between sustained and rearrest after ROSC (–0.7 vs. –2.1 mmHg/min). Peak ET s was higher for sustained than for rearrest (53.0 vs. 42.5 mmHg). Standardising ETCO 2 eliminates effects of VR and CD variations during manual CPR and facilitates comparison of values and trends among and within patients. Its clinical application for guidance of resuscitation warrants further investigation. [ABSTRACT FROM AUTHOR]

The control of PaCO 2 in ventilated patients is known to be of particular importance in the management and prognosis of trauma patients. Although EtCO 2 is often used as a continuous, non-invasive, surrogate marker for PaCO 2 in ventilated trauma patients in the emergency department (ED), previous studies suggest a poor correlation in this cohort. However, previous data has predominantly been collected retrospectively, raising the possibility that the elapsed time between PaCO 2 sampling and EtCO 2 recording may contribute to the poor correlation. As such this study aimed to analyse the correlation of PaCO 2 to EtCO 2 in the ventilated blunt trauma patient presenting to the ED through contemporaneous sampling. This study was conducted as a prospective observational study analysing the near simultaneous recording of EtCO 2 and Arterial Blood Gas sampling of ventilated adult trauma patients in the ED of a Level 1 trauma centre over a 12-month period. Data was analysed using linear regression and subgroup analysis by Injury Severity Score (ISS) and Abbreviated Injury Score (AIS) of the Chest. Linear regression of EtCO 2 vs PaCO 2 demonstrated a moderate correlation with r = 0.54 (p < 0.01, n = 51, 95 % CI 0.31–0.71). Subgroup analysis by ISS, revealed a stronger correlation in those with minor ISS (0–11) (r = 0.76, p < 0.01, n = 13, 95 % CI 0.36–0.92) compared to those more severely injured patients (ISS > 15) (r = 0.44, P < 0.01, n = 38, 95 % CI 0.14–0.67). Analysis by AIS Chest demonstrated similar correlation between patients without chest injuries (AIS 0) (r = 0.55, n = 29, p < 0.01, 95 % CI 0.23–0.76) and those with an AIS >1 (r = 0.51, n = 22, p = 0.02, 95 % CI 0.11–0.77). In patients with traumatic head injuries who had an EtCO 2 between 30 and 39 mmHg, only 57 % had a measured PaCO 2 within 5 mmHg. As patients transition from minor to seriously injured, a decreasing strength of PaCO 2 to EtCO 2 correlation is observed, decreasing the reliability of EtCO 2 as a surrogate marker of PaCO 2 in this patient group. This inconsistency cannot be accounted for by the presence of chest injuries and worryingly is frequently seen in those with traumatic brain injuries. [ABSTRACT FROM AUTHOR]

Background: Chest compression (CC) depth, CC rate and ventilatory rate (VR) are known to have an impact on end-tidal carbon dioxide (ETCO2) values. Chest compression release velocity (CCRV) is increasingly acknowledged as a novel metric in cardiopulmonary resuscitation (CPR). The objective of this study was to analyze whether CCRV would have any effect on ETCO2 values.Methods: In out-of-hospital cardiac arrests (OHCA), effects of CC depth, CC rate, CCRV and VR on ETCO2 were analyzed through linear mixed effect models. A stratification was made on a CCRV of 300, 400 and 500 mm/s. In these categories, mean ETCO2 values were corrected for CC depth and compared through a one-way ANOVA.Results: A 10 mm increase in CC depth was associated with a 1.5 mmHg increase in ETCO2 (p < 0.001), a 100 mm/s increase in CCRV with a 0.8 mmHg increase (p = 0.010) and a 5 breaths per minute increase in VR with a 2.0 mmHg decrease (p < 0.001). CC depth was strongly correlated with CCRV (Pearson's r = 0.709, p < 0.001). After adjusting for CC depth, ETCO2 was on average 6.5 mmHg higher at a CCRV of 500 than at 400 mm/s (p = 0.005) and 5.3 mmHg higher than at 300 mm/s (p = 0.033).Conclusions: In OHCA patients, higher CCRV values resulted in higher ETCO2 values. This effect is independent of CC depth, despite the strong correlation between CCRV and CC depth. [ABSTRACT FROM AUTHOR]

Background: Active compression-decompression cardiopulmonary resuscitation (ACD-CPR) utilises a suction cup to lift the chest-wall actively during the decompression phase (AD). We hypothesised that mechanical ACD-CPR (Intervention), with AD up to 30 mm above the sternal resting position, would generate better haemodynamic results than standard mechanical CPR (Control).Methods: This out-of-hospital adult non-traumatic cardiac arrest trial was prospective, block-randomised and non-blinded. We included intubated patients with capnography recorded during mechanical CPR. Exclusion criteria were pregnancy, prisoners, and prior chest surgery. The primary endpoint was maximum tidal carbon dioxide partial pressure (pMTCO2) and secondary endpoints were oxygen saturation of cerebral tissue (SctO2), invasive arterial blood pressures and CPR-related injuries. Intervention device lifting force performance was categorised as Complete AD (≥30 Newtons) or Incomplete AD (≤10 Newtons). Haemodynamic data, analysed as one measurement for each parameter per ventilation (Observation Unit, OU) with non-linear regression statistics are reported as mean (standard deviation). A two-sided p-value < 0.05 was considered as statistically significant.Results: Of 221 enrolled patients, 210 were deemed eligible (Control 109, Intervention 101). The Control vs. Intervention results showed no significant differences for pMTCO2: 29(17) vs 29(18) mmHg (p = 0.86), blood pressures during compressions: 111(45) vs. 101(68) mmHg (p = 0.93) and decompressions: 21(20) vs. 18(18) mmHg (p = 0.93) or for SctO2%: 55(36) vs. 57(9) (p = 0.42). The 48 patients who received Complete AD in > 50% of their OUs had higher SctO2 than Control patients: 58(11) vs. 55(36)% (p < 0.001).Conclusions: Mechanical ACD-CPR provided similar haemodynamic results to standard mechanical CPR. The Intervention device did not consistently provide Complete AD.Clinical Trial Registration: ClinicalTrials.gov identifier (NCT number): NCT02479152. The Haemodynamic Effects of Mechanical Standard and Active Chest Compression-decompression During Out-of-hospital CPR. [ABSTRACT FROM AUTHOR]

Introduction: End-tidal carbon dioxide (ETCO2) has been suggested to have prognostic implications during out-of-hospital cardiac arrest (OHCA). Our objective was to determine if the change in ETCO2 (delta ETCO2) during resuscitation was predictive of future return of spontaneous circulation (ROSC) in patients with pulseless electrical activity (PEA) arrests.Methods: We performed a retrospective, observational study of adult (≥18 years of age) non-traumatic PEA OHCAs in two Canadian EMS systems over a two-year time frame beginning on January 1, 2018. Cases were excluded if there was a Do Not Resuscitate order (DNR), had no advanced airway, or had less than two ETCO2 recordings. We performed multivariable logistic regression to examine the association between ETCO2 measures and ROSC. Second, we examined the prognostic performance (sensitivity, specificity, NPV, PPV) for ETCO2 at specific thresholds for predicting ROSC.Results: A total of 208 OHCA met inclusion criteria of which 67 (32%) obtained ROSC. After adjusting for pre-determined confounders, there was an association between delta ETCO2 and ROSC (odds ratio [OR] per 10 mmHg increase in ETCO2 of 1.74 (95% confidence interval [CI] 1.35 to 2.24); P value < 0.001). We also found significant associations between both initial ETCO2 and final ETCO2 with ROSC.Conclusion: Our analysis indicates that there is a positive linear relationship between delta ETCO2 and ROSC with values of delta ETCO2 > 20 mmHg being highly specific for ROSC in PEA patients. As such, patients with up-trending ETCO2 values should have resuscitation continued unless there is overwhelming clinical evidence to the contrary. [ABSTRACT FROM AUTHOR]

Aim: Ventricular fibrillation amplitude spectral area (AMSA) and end-tidal carbon dioxide (ETCO2) are predictors of shock success, understood as restoration of an organized rhythm, and return of spontaneous circulation (ROSC). However, little is known about their combined use. We aimed to assess the prediction accuracy when combined, and to clarify if they are correlated in out of hospital cardiac arrest' victims.Materials and Methods: Records acquired by external defibrillators in out-of-hospital cardiac arrest patients of the Lombardia Cardiac Arrest registry were processed. The 1-min pre-shock ETCO2 median value (METCO2) was computed from the capnogram and AMSA (2-48 mV.Hz range) computed applying the Fast Fourier Transform to a 2-second pre-shock filtered ECG interval (0.5-30 Hz). Support Vector Machine (SVM) predictive models based on METCO2, AMSA and their combination were fit; results were given as the area under the curve (AUC) of the receiver operating characteristic (ROC) curves.Results: We considered 112 patients with 391 shocks delivered. METCO2 and AMSA were predictors of shock success [AUC (IQR) of the ROC curve: 0.59 (0.56-0.62); 0.68 (0.65-0.72), respectively] and of ROSC [0.56 (0.53-0.59); 0.74 (0.71-0.78),]. Their combination in a SVM model increased the accuracy for predicting shock success [AUC (IQR) of the ROC curve: 0.71 (0.68-0.75)] and ROSC [0.77 (0.73-0.8)]. AMSA and METCO2 were significantly correlated only in patients who achieved ROSC (rho = 0.33 p = 0.03).Conclusions: AMSA and ETCO2 predict shock success and ROSC after every shock, and their predictive power increases if combined. Notably, they were correlated only in patients who achieved ROSC. [ABSTRACT FROM AUTHOR]

Objective: This study first aims to assess the utility of ETCO2 levels in evaluating the severity of dehydration in adult patients that present to the ED with acute gastroenteritis. AGE. Second, it intends to evaluate the correlation between ETCO2 and several metabolic parameters: creatinine, pH, bicarbonate (HCO3), and bases excessive (BE).Method: This prospective study was conducted with AGE patients in the ED of a training and research hospital between June 2018 and April 2019 after approval of the local ethical-committee. The two groups were defined according to the severity of AGE: mild and non-mild groups. For both groups, ETCO2 levels were measured and recorded on admission of the patients.Results: 87 patients were included in the analyses. The median of ETCO2 values was found as lower in non-mild group than mild group; 30 (25-35) & 39 (33-34), respectively (p < 0.001). In ROC analysis for distinguishing between the both groups, the AUC value was found to be 0.988 and the best cut-off level was found as 33.5 with 95% sensitivity and 93% specificity. In addition, strong negative correlation between ETCO2 and creatinine (p < 0.001, r: -0.771) were found.Conclusion: ETCO2 levels decreased in the non-mild group of AGE patients; it could be useful to distinguish the mild group from the non-mild group. ETCO2 could be a reliable marker in predicting AKI in the management of AGE patients. [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]

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]

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]

Abstract: Measurements of pH, SpO2 and ETCO2 are fundamental to safe clinical practice in anaesthesia, and are part of the monitoring standards defined by the Association of Anaesthetists in Great Britain and Ireland. Invasive measurement of blood pH enables the acid–base state of the patient to be determined, and is frequently used in the hospital environment. Pulse oximetry and capnography allow non-invasive monitoring of patients during anaesthesia, and it is essential to understand the fundamental principles on which they are based. [Copyright &y& Elsevier]