Non-traumatic Out-of-hospital Cardiac Arrest Patients Research Articles

Association between pre-arrest left ventricular ejection fraction and survival in nontraumatic out-of-hospital cardiac arrest.

Out-of-hospital cardiac arrest (OHCA) poses major public health issues. Pre-arrest heart function is a prognostic factor, but the specific contribution of pre-arrest echocardiographic evaluation in predicting OHCA outcome remains limited. The primary objective was to investigate the association between left ventricular ejection fraction (LVEF) measured in echocardiography prior to OHCA and survival to hospital discharge. This multicenter retrospective cohort study analyzed data from the National Taiwan University Hospital and its affiliated hospitals. We included adult nontraumatic OHCA patients who were treated by the emergency medical services (EMS) and underwent echocardiography within 6 months prior to the OHCA event from January 2016 to December 2022. Data included demographics, preexisting diseases, resuscitation events, and echocardiographic reports. The primary outcome was the survival to hospital discharge after post-arrest care. Statistical analysis involved multivariable logistic regression to modify potential confounders, reported as adjusted odds ratio (aOR) and 95% confidence interval (CI), and evaluate the association between echocardiographic findings and survival to hospital discharge. This study analyzed 950 patients, with 33.6% surviving to discharge. A higher pre-arrest LVEF was independently associated with increased survival. Compared to patients with LVEF < 40%, those with LVEF between 40% and 60% had significantly higher odds of survival (aOR = 3.68, 95% CI = 2.14-6.35, P < 0.001), and those with LVEF > 60% had even greater odds of survival (aOR = 5.46, 95% CI = 3.09-9.66, P < 0.001). There was also an association between lower tricuspid regurgitation pressure gradient and survival (aOR = 0.98, 95% CI = 0.97-1.00, P = 0.015). Younger age, male gender, dyslipidemia, stroke, cancer, witnessed arrest, initial shockable rhythm, and shorter low-flow time are other significant predictors of survival. In adult, nontraumatic, EMS-treated OHCA patients, a higher LVEF 6 months prior to OHCA was associated with improved survival at hospital discharge.

Derivation of a clinical decision rule for termination of resuscitation in non-traumatic pediatric out-of-hospital cardiac arrest

AimPrehospital termination of resuscitation (ToR) rules are used to predict medical futility in adult out-of-hospital cardiac arrest (OHCA), however, the available evidence for pediatric patients is limited. The primary aim of this study is to derive a Pediatric Termination of Resuscitation (PToR) prediction rule for use in pediatric non-traumatic OHCA patients. MethodsWe analyzed a retrospective cohort of pediatric OHCA patients within the CARES database over a 10-year period (2013 – 2022). We split the dataset into training and test datasets and fit logistic regressions with Least Absolute Shrinkage and Selection Operator (LASSO) to select predictor variables and estimate predictive test characteristics for the primary outcome of death and a secondary composite outcome of death or survival to hospital discharge with unfavorable neurologic outcome. ResultsWe analyzed a sample of 21,240 children where 2,326 (11.0%) survived to hospital discharge, and 1,894 (8.9%) survived to hospital discharge with favorable neurologic outcome. We derived a PToR rule for death demonstrating a specificity of 99.1% and a positive predictive value (PPV) of 99.8% and a PToR rule for death or survival with poor neurologic outcome with a specificity of 99.7% and PPV of 99.9% within the test dataset. ConclusionWe derived a clinical prediction rule with high specificity and positive predictive value in prehospital settings utilizing Advanced Life Support (ALS) providers which may inform termination of resuscitation considerations in pediatric patients. Further prospective and validation studies will be necessary to define the appropriateness and applicability of these PToR criteria for routine use.

A Simple Scoring System for Identifying Favorable Neurologic Outcomes Among Out-of-Hospital Cardiac Arrest Patients With Asystole

Study objectiveAsystole is the most common initial rhythm in out-of-hospital cardiac arrest (OHCA), but indicates a low likelihood of neurological recovery. This study aimed to develop a novel scoring system to be easily applied at the time of emergency department arrival for identifying favorable neurological outcomes in OHCA survivors with an asystole rhythm. MethodsThis study is a secondary analysis based on a previously collected nationwide database, targeting non-traumatic adult OHCA patients aged ≥ 18 years with an asystole rhythm who achieved Return of Spontaneous Circulation (ROSC) between January 2016 and December 2020. The primary outcome was a favorable neurological outcome defined as Cerebral Performance Categories scores of 1 or 2 at hospital discharge. A prediction model was developed through multivariable logistic regression analysis in a derivation cohort in the form of a scoring system (WBC-ASystole). The performance and calibration of the model were tested using an internal validation cohort. ResultsAmong 19,803 OHCA patients with survival to hospital admission, 6,322 had asystole, and 285 (4.5%) achieved good neurological outcomes. Factors associated with favorable outcomes included age, witness arrest, bystander cardiopulmonary resuscitation, time from call to hospital arrival, and prehospital ROSC achievement. The WBC-ASystole score, totaling 11 points, exhibited a predictive performance with an area under the receiver operating characteristic curve of 0.80 (95% confidence interval [CI]: 0.76–0.83) and 0.79 (95% CI: 0.74–0.83) in the derivation and validation cohorts, respectively. After categorizing patients into three groups based on probability for good neurological outcomes, the sensitivity and specificity were as follows: 0.98 (95% CI: 0.97–0.99) and 0.09 (95% CI: 0.09–0.10) for the very low (WBC-ASystole: ≤2), 0.85 (95% CI: 0.82–0.89) and 0.54 (95% CI: 0.53–0.55) for the low (WBC-ASystole: 3–4), and 0.36 (95% CI: 0.34–0.39) and 0.93 (95% CI: 0.92–0.93) for fair predicted probability group (WBC-ASystole: ≥5). ConclusionsAlthough external validation studies must be performed, among OHCA with asystole, the WBC-ASystole scoring system may identify those patients who are likely to have a favorable neurological outcome.

Machine learning prediction of refractory ventricular fibrillation in out-of-hospital cardiac arrest using features available to EMS

BackgroundShock-refractory ventricular fibrillation (VF) or ventricular tachycardia (VT) is a treatment challenge in out-of-hospital cardiac arrest (OHCA). This study aimed to develop and validate machine learning models that could be implemented by emergency medical services (EMS) to predict refractory VF/VT in OHCA patients. MethodsThis was a retrospective study examining adult non-traumatic OHCA patients brought into the emergency department by Singapore EMS from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Data from April 2010 to March 2020 were extracted for this study. Refractory VF/VT was defined as VF/VT persisting or recurring after at least one shock. Features were selected based on expert clinical opinion and availability to dispatch prior to arrival at scene. Multivariable logistic regression (MVR), LASSO and random forest (RF) models were investigated. Model performance was evaluated using receiver operator characteristic (ROC) area under curve (AUC) analysis and calibration plots. Results20,713 patients were included in this study, of which 860 (4.1%) fulfilled the criteria for refractory VF/VT. All models performed comparably and were moderately well-calibrated. ROC-AUC were 0.732 (95% CI, 0.695 – 0.769) for MVR, 0.738 (95% CI, 0.701 – 0.774) for LASSO, and 0.731 (95% CI, 0.690 – 0.773) for RF. The shared important predictors across all models included male gender and public location. ConclusionThe machine learning models developed have potential clinical utility to improve outcomes in cases of refractory VF/VT OHCA. Prediction of refractory VF/VT prior to arrival at patient’s side may allow for increased options for intervention both by EMS and tertiary care centres.

Association between out-of-hospital cardiac arrest quality indicator and prehospital management and clinical outcomes for major trauma

IntroductionIt is unclear whether emergency medical service (EMS) agencies with good out-of-hospital cardiac arrest (OHCA) quality indicators also perform well in treating other emergency conditions. We aimed to evaluate the association of an EMS agency's non-traumatic OHCA quality indicators with prehospital management processes and clinical outcomes of major trauma. MethodsThis retrospective cross-sectional study analyzed data from registers of nationwide, population-based OHCA (adult EMS-treated non-traumatic OHCA patients from 2017 to 2018) and major trauma (adult, EMS-treated, and injury severity score ≥16 trauma patients in 2018) in South Korea. We developed a prehospital ROSC prediction model to categorize EMS agencies into quartiles (Q1-Q4) based on the observed-to-expected (O/E) ROSC ratio for each EMS agency. We evaluated the national EMS protocol compliance of on-scene management according to O/E ROSC ratio quartile. The association between O/E ROSC ratio quartiles and trauma-related early mortality was determined in a multi-level logistic regression model by adjusted odds ratios (OR) and 95 % confidence intervals (95 % CI). ResultsAmong 30,034 severe trauma patients, 4,836 were analyzed. Patients in Q4 showed the lowest early mortality rate (5.6 %, 5.5 %, 4.8 %, and 3.4 % in Q1, Q2, Q3, and Q4, respectively). In groups Q1 to Q4, increasing compliance with the national EMS on-scene management protocol (trauma center transport, basic airway management for patients with altered mentality, spinal motion restriction for patients with spinal injury, and intravenous access for patients with hypotension) was observed (p for trend <0.05). Multivariable multi-level logistic regression analysis showed significantly lower early mortality in Q4 than in Q1 (adjusted OR [95 % CI] 0.56 [0.35–0.91]). ConclusionMajor trauma patients managed by EMS agencies with high success rates in achieving prehospital ROSC in non-traumatic OHCA were more likely to receive protocol-based care and exhibited lower early mortality.

Utility of end-tidal carbon dioxide to guide resuscitation termination in prolonged out-of-hospital cardiac arrest

Study objectiveTo evaluate if the change in end-tidal carbon dioxide (ETCO2) over time has improved discriminatory value for determining resuscitation futility compared to a single ETCO2 value in prolonged, refractory non-shockable out-of-hospital cardiac arrest (OHCA). MethodsThis is a retrospective analysis of adult refractory non-shockable, non-traumatic OHCA patients in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry) from 2018 to 2021. We defined refractory non-shockable OHCA cases as patients with lack of a shockable rhythm at any time or return of spontaneous circulation at any time prior to 30-min of on-scene resuscitation. We abstracted ETCO2 values first recorded after advanced airway placement and nearest to the 30-min mark of on-scene resuscitation (30 min-ETCO2) from EMS charts. The primary outcome was survival to hospital discharge. We compared 30 min-ETCO2 cutoffs of 10 mmHg and 20 mmHg to the trend (increasing or not) from initial to 30 min-ETCO2 (delta-ETCO2) using sensitivity, specificity, and area under the receiver operating curves (AUROC). ResultsOf 3837 adult OHCA, 2850 were initially non-shockable, and there were 617 (16.1%) cases of refractory non-shockable OHCA at 30-min. We excluded 320 cases without at least two ETCO2 recordings in the EMS chart, leaving 297 cases that met inclusion criteria. Of these, 176 (59.3%) were transported and 2 (0.7%) survived to discharge. Using absolute 30 min-ETCO2 cutoffs, both survivors were in the >10 mmHg group (sensitivity 100.0%, specificity 12.5%), whereas only one survivor was identified in the >20 mmHg group (sensitivity 50.0%, specificity 32.5%). Using delta-ETCO2, both survivors were in the increasing ETCO2 group (sensitivity 100.0%, specificity 60.7%). In comparing the two tests that did not misclassify survivors, the AUROC [95% CI] was higher when using delta-ETCO2 (0.803 [0.775–0.831]) compared to an absolute cutoff of 10 mmHg (0.563 [0.544–0.582]). ConclusionsNearly one-sixth of EMS-treated adult OHCA patients had refractory non-shockable arrests after at least 30 min of ongoing resuscitation. In this group, the ETCO2 trend following advanced airway placement may be more accurate in guiding termination of resuscitation than an absolute ETCO2 cutoff of 10 or 20 mmHg.

Abstract 360: Clinical Characteristics and Outcome in Out-of-Cardiac Arrest Patients With Type A Aortic Dissection Diagnosed by Non-Contrast Computed Tomography

Background: Although type A aortic dissection (AAD) remains a life-threatening disease, the exact epidemiology of out-of-hospital cardiac arrest (OHCA) with AAD is unclear. It has been reported that the non-contrast computed tomography (CT) is useful for diagnosing AAD in patients whose hemodynamic status was unstable. Aim: We evaluated the clinical features and outcome of OHCA patients with AAD diagnosed by non-contrast CT. Methods: Between 2017 and 2022, we retrospectively collected Utstein-style data on non-traumatic adult OHCA patients transferred to our hospital and performed non-contrast full-body CT scan. We divided OHCA patients into 3 groups: patients with AAD diagnosed by CT (Group-AAD), patients with non-cardiac cause without AAD (Group-NC), and patients with cardiac cause (Group-C). The diagnostic criteria of AAD by CT were as follows: visible intimal flap; crescentic high attenuation hematoma; and inward shift of calcified intima. The clinical outcome was defined as return of spontaneous circulation (ROSC). Results: Of the 1018 non-traumatic adult OHCA patients were registered during the study period, 1015 patients underwent non-contrast CT (Group-AAD, n=79; Group-NC, n=159; Group-C, n=779). The patients who achieved return of spontaneous circulation (ROSC) was 271 (26.8%). The proportion of patients who achieved ROSC in Group-AAD was significantly smaller than the other groups (Group-AAD 10.1%, Group-NC 27.7%, Group-C 28.3%, P=0.002). Multivariable logistic regression analysis revealed that patients with AAD diagnosed by CT independently predicted failure to achieve ROSC. The presence of witnessed arrest and initial shockable rhythm were significant indenpent predictors of achieving ROSC ( Table ). Conclusion: OHCA patients with AAD diagnosed with CT were more difficult to obtain ROSC than patients with other cause.

Abstract 220: Association Between Initial Defibrillator Pad Position And Outcomes For Out-of-hospital Cardiac Arrest Patients Presenting With Shockable Rhythms

Background: Ventricular fibrillation (VF) or ventricular tachycardia (VT) are the most treatable causes of out-of-hospital cardiac arrest (OHCA). Yet, it remains unknown if defibrillator pad position, placement in the anterior-posterior (AP) or anterior-lateral (AL) positions, impacts patient outcomes in VF/VT OHCA. Aim: Evaluate the association between initial defibrillator pad placement (AP vs. AL) and OHCA outcomes for patients presenting with VF/VT. Methods: This was a prospective observational study of non-traumatic OHCA patients with initial VF/VT on EMS rhythm analysis treated by a single EMS agency in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry) from July 1st, 2019 through October 15th, 2022. Our primary outcome was return of spontaneous circulation (ROSC) at any time and secondary outcomes were ROSC at emergency department (ED) arrival, survival to admission, survival to discharge, and functional survival (cerebral perfusion category score of ≤2). We performed t-tests, chi-squared tests, and multivariable logistic regressions adjusting for age, sex, witness status, bystander interventions, arrest location, 911 call to EMS arrival time, and year of arrest. Results: A total of 243 OHCA patients met inclusion criteria and 232 (95.5%) had initial pad positioning documented (133 AP and 99 AL). Patients with AP placement had higher rates of ROSC at any time (72.2% vs. 47.5%, p&lt;0.001), survival to admission (56.4% vs. 41.4%, p=0.024), survival to discharge (36.1% vs. 24.2%, p=0.050), and functional survival (36.1% vs. 21.2%, p=0.012) compared to AL, with no difference for ROSC at ED arrival (52.6% vs. 40.4%, p=0.065). AP versus AL placement showed higher adjusted odds (aOR [95% CI]) for ROSC at any time (2.76 [1.55-4.93]) and functional survival (2.06 [1.05-4.05]), but not ROSC at ED arrival (1.50, [0.85-2.64]), survival to admission (1.69 [0.96-2.96]) or survival to discharge (1.68 [0.86-3.27]). Among patients with ROSC at ED arrival, patients with AP placement, had shorter times from 911 call to sustained ROSC (21.0 vs. 28.4 min, p=0.013). Conclusions: Initial AP pad placement, compared to AL, was associated with higher ROSC, a reduction in time to sustained ROSC, and higher functional survival for patients with VF/VT OHCA.

The impacts of anemia burden on clinical outcomes in patients with out-of-hospital cardiac arrest.

Out-of-hospital cardiac arrest (OHCA) has low survival rates, and few patients achieve a desirable neurological outcome. Anemia is common among OHCA patients and has been linked to worse outcomes, but its impact following the return of spontaneous circulation (ROSC) is unclear. This study examines the relationship between anemia burden and clinical outcomes in OHCA patients. Higher anemia burden after ROSC may be related to higher mortality and worse neurologic outcomes. Patients who experienced OHCA and had ROSC were enrolled retrospectively. Anemia burden was defined as the area under curve from the target hemoglobin level over a 72-h period after OHCA. Hemoglobin level was measured at 12-h intervals. The clinical outcomes of the study included mortality and neurological outcomes at Day 30. The study enrolled 258 nontraumatic OHCA patients who achieved ROSC between January 2017 and December 2021. Among the 162 patients who survived more than 72 h, a higher anemia burden, specifically target hemoglobin levels below 7 (hazard ratio [HR]: 1.129, 95% confidence interval [CI]: 1.013-1.259, p = .029), 8 (HR: 1.099, 95% CI: 1.014-1.191, p = .021), and 9 g/dL (HR: 1.066, 95% CI: 1.001-1.134, p = .046) was associated with higher 30-day mortality. Additionally, anemia burden with target hemoglobin levels below 7 (HR: 1.129, 95% CI: 1.016-1.248; p = .024) and 8 g/dL (HR: 1.088; 95% CI: 1.008-1.174, p = .031) was linked to worse neurological outcomes. Anemia burden predicts 30-day mortality and neurological outcomes in OHCA patients who survive more than 72 h. Maintaining higher hemoglobin levels within the first 72 h after ROSC may improve short-term outcomes.

The Association of Prehospital End-Tidal Carbon Dioxide with Survival Following Out-of-Hospital Cardiac Arrest

Objective End tidal carbon dioxide (ETCO2) is often used to assess ventilation and perfusion during cardiac arrest resuscitation. However, few data exist evaluating the relationship between ETCO2 values and mortality in the context of contemporary resuscitation practices. We aimed to explore the association between ETCO2 and mortality following out-of-hospital cardiac arrest (OHCA). Methods We used the 2018–2021 ESO annual datasets to query all non-traumatic OHCA patients with attempted resuscitation. Patients with documented DNR/POLST, EMS-witnessed arrest, ROSC after bystander CPR only, or < 2 documented ETCO2 values were excluded. The lowest and highest ETCO2 values recorded during the total prehospital interval, in addition to the pre- and post-ROSC intervals for resuscitated patients, were calculated. Multivariable logistic regression models adjusted for age, sex, initial rhythm, witnessed status, bystander CPR, etiology, OHCA location, sodium bicarbonate administration, number of milligrams of epinephrine administered, and response interval were used to evaluate the association between measures of ETCO2 and mortality. Results Hospital outcome data were available for 14,122 patients, and 2,209 (15.6%) were classified as surviving to discharge. Compared to patients with maximum prehospital ETCO2 values of 30–40 mmHg, odds of mortality were increased for patients with maximum prehospital ETCO2 values of <20 mmHg (aOR: 3.5 [2.1, 5,9]), 20–29 mmHg (aOR: 1.5 [1.1, 2.1]), and >50 mmHg (aOR: 1.5 [1.2, 1.8]). After 20 minutes of ETCO2 monitoring, <12% of patients had ETCO2 values <10 mmHg. This cutpoint was 96.7% specific and 6.9% sensitive for mortality. Conclusion In this dataset, both high and low ETCO2 values were associated with increased mortality. Contemporary resuscitation practices may make low ETCO2 values uncommon, and field termination decision algorithms should not use ETCO2 values in isolation.

Intra-Aortic Balloon Pump among Shockable Out-of-Hospital Cardiac Arrest Patients: A Propensity-Weighted Analysis in a Multicenter, Nationwide Observational Study in Japan (The JAAM-OHCA Registry).

The effectiveness of IABP for shockable out-of-hospital cardiac arrest (OHCA) has not been extensively investigated. This study aimed to investigate whether the use of an intra-aortic balloon pump (IABP) for non-traumatic shockable OHCA patients was associated with favorable neurological outcomes. From the Japanese Association for Acute Medicine Out-of-Hospital Cardiac Arrest registry, a nationwide multicenter prospective registry, we enrolled adult patients with non-traumatic and shockable OHCA for whom resuscitation was attempted, and who were transported to participating hospitals between 2014 and 2019. The primary outcome was 1-month survival with favorable neurological outcomes after OHCA. After adopting the propensity score (PS) inverse probability of weighting (IPW), we evaluated the association between IABP and favorable neurological outcomes. Of 57,754 patients in the database, we included a total of 2738 adult non-traumatic shockable patients. In the original cohort, the primary outcome was lower in the IABP group (OR with 95% confidence intervals (CIs)), 0.57 (0.48-0.68), whereas, in the IPW cohort, it was not different between patients with and without IABP (OR, 1.18; 95% CI, 0.91-1.53). In adult patients with non-traumatic shockable OHCA, IABP use was not associated with 1-month survival with favorable neurological outcomes.

Spontan Dolaşımın Geri Dönüşünü Tahmin Etmede Delta Karbondioksitin (ΔCO2) Tanısal Değerinin İncelenmesi: Prospektif Tek Merkezli Çalışma

Aim: The carbon dioxide gap or ΔCO2 is the difference between the partial pressure of carbon dioxide&#x0D; (pCO2 ) and end-tidal carbon dioxide (ETCO2 ), which should normally not exceed 3-5mmHg. In critically ill&#x0D; patients ΔCO2 increases as a result of decreased cardiac output and pulmonary blood flow compromise.&#x0D; The primary outcome of this study is to examine the diagnostic accuracy of ΔCO2 in predicting the return&#x0D; of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA) patients.&#x0D; Material and Methods: Non-traumatic OHCA patients over 18 years of age were included in this&#x0D; prospective observational study. ETCO2 values were recorded 1 minute after the intubation and arterial&#x0D; blood gas samples were acquired simutaneously. The difference between the initial ΔCO2 medians of&#x0D; the ROSC+ and ROSC- patient groups were analyzed and the diagnostic test performance in predicting&#x0D; ROSC of ΔCO2 was calculated. A regression model was performed to accurately predict ROSC in&#x0D; OHCA patients.&#x0D; Results: A total of 46 patients were included to the inal analysis. The ΔCO2 median of the ROSC+ group&#x0D; was significantly lower than the ROSC- group (p=0.026, 95%CI:-31 to-3). Area under the curve was&#x0D; calculated as 0.694 (95%CI: 0.532 to 0.855), sensitivity 76.19% (95%CI:52.83 to 91.78%), specificity&#x0D; 76% (95%CI:54.87 to 90.64), and accuracy 76.09% (95%CI:61.23% to87.41%) for the optimal cut-off&#x0D; value (51.4 mmHg). The regression model consists of age, initial ETCO2 , and initial cardiac rhythm&#x0D; showed good discrimination in predicting ROSC (AUC=0.846, 95%CI=0.735 to 0.956, p

Saline versus Plasma Solution-A in Initial Resuscitation of Patients with Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial.

Although saline is commonly used during cardiopulmonary resuscitation (CPR) or post-cardiac arrest care, it has detrimental effects. This trial aimed to evaluate the efficacy of a balanced crystalloid solution (Plasma Solution-A [PS]) in out-of-hospital cardiac arrest (OHCA) patients and compare it with the efficacy of saline. A randomized, unblinded clinical trial was conducted using PS and saline for intravenous fluid administration during CPR and post-cardiac arrest care of non-traumatic OHCA patients admitted to the emergency department of a tertiary university hospital. Patients received saline (saline group) or PS (PS group) within 24 h of hospital arrival. The primary outcomes were changes in arterial pH, bicarbonate, base excess (BE), and chloride levels within 24 h. The secondary outcomes were clinical outcomes including mortality. Of the 364 patients, data from 27 and 26 patients in the saline and PS groups, respectively, were analyzed. Analysis using a linear mixed model revealed a significant difference in BE change over time between the groups (treatment-by-time p = 0.044). Increase in BE and bicarbonate levels from 30 min to 2 h was significantly greater (p = 0.044 and p = 0.024, respectively) and the incidence of hyperchloremia was lower (p < 0.001) in the PS group than in the saline group. However, there was no difference in clinical outcomes. Use of PS for resuscitation resulted in a faster improvement in BE and bicarbonate, especially in the early phase of post-cardiac arrest care, and lower hyperchloremia incidence than the use of saline, without differences in clinical outcomes, in OHCA patients.

The Association of Combined Prehospital Hypotension and Hypoxia with Outcomes following Out-of-Hospital Cardiac Arrest Resuscitation

Background Prehospital post-resuscitation hypotension and hypoxia have been associated with adverse outcomes in the context of out-of-hospital cardiac arrest (OHCA). We aimed to investigate the association between clinical outcomes and post-resuscitation hypoxia alone, hypotension alone, and combined hypoxia and hypotension. Methods We used the 2018–2021 ESO annual datasets to conduct this study. All EMS-treated non-traumatic OHCA patients who had a documented prehospital return of spontaneous circulation (ROSC) and two or more SpO2 readings and systolic blood pressures recorded were evaluated for inclusion. Patients who were less than 18 years of age, pregnant, had a do-not-resuscitate order or similar, achieved ROSC after bystander CPR only, or had an EMS-witnessed cardiac arrest were excluded. Multivariable logistic regression adjusted for standard Utstein factors and highest prehospital Glasgow Coma Scale (GCS) score was used to investigate the association between hypoxia, hypotension, and outcomes. Results We analyzed data for 17,943 patients, of whom 3,979 had hospital disposition data. Hypotension and hypoxia were not documented in 1,343 (33.8%) patients, 1,144 (28.8%) had only hypoxia documented, 507 (12.7%) had only hypotension documented, and 985 (24.8%) had both hypoxia and hypotension documented. In comparison to patients who did not have documented hypotension or hypoxia, patients who had documented hypoxia (aOR: 1.76 [1.38, 2.24]), documented hypotension (aOR: 3.00 [2.15, 4.18]), and documented hypoxia and hypotension combined (aOR: 4.87 [3.63, 6.53]) had significantly increased mortality. The relationship between mortality and vital sign abnormalities (hypoxia and hypotension > hypotension > hypoxia) was observed in every evaluated subgroup. Conclusions In this large dataset, hypotension and hypoxia were independently associated with mortality both alone and in combination. Compared to patients without documented hypotension and hypoxia, patients with documented hypotension and hypoxia had nearly five-fold greater odds of mortality.

Diagnostic yield of computed tomography after non-traumatic out-of-hospital cardiac arrest

AimDetermine the frequency with which computed tomography (CT) after out-of-hospital cardiac arrest (OHCA) identifies clinically important findings. MethodsWe included non-traumatic OHCA patients treated at a single center from February 2019 to February 2021. Clinical practice was to obtain CT head in comatose patients. Additionally, CT of the cervical spine, chest, abdomen, and pelvis were obtained if clinically indicated. We identified CT imaging obtained within 24 hours of emergency department (ED) arrival and summarized radiology findings. We used descriptive statistics to summarize population characteristics and imaging results, report their frequencies and, post hoc, compared time from ED arrival to catheterization between patients who did and did not undergo CT. ResultsWe included 597 subjects, of which 491 (82.2%) had a CT obtained. Time to CT was 4.1 hours [2.8–5.7]. Most (n = 480, 80.4%) underwent CT head, of which 36 (7.5%) had intracranial hemorrhage and 161 (33.5%) had cerebral edema. Fewer subjects (230, 38.5%) underwent a cervical spine CT, and 4 (1.7%) had acute vertebral fractures. Most subjects (410, 68.7%) underwent a chest CT, and abdomen and pelvis CT (363, 60.8%). Chest CT abnormalities included rib or sternal fractures (227, 55.4%), pneumothorax (27, 6.6%), aspiration or pneumonia (309, 75.4%), mediastinal hematoma (18, 4.4%) and pulmonary embolism (6, 3.7%). Significant abdomen and pelvis findings were bowel ischemia (24, 6.6%) and solid organ laceration (7, 1.9%). Most subjects that had CT imaging deferred were awake and had shorter time to catheterization. ConclusionsCT identifies clinically important pathology after OHCA.

Differential diagnosis and cause-specific treatment during out-of-hospital cardiac arrest: a retrospective descriptive study

BackgroundThe cardiopulmonary resuscitation (CPR) guidelines recommend identifying and correcting the underlying reversible causes of out-of-hospital cardiac arrest (OHCA). However, it is uncertain how often these causes can be identified and treated. Our aim was to estimate the frequency of point of care ultrasound examinations, blood sample analyses and cause-specific treatments during OHCA.MethodsWe performed a retrospective study in a physician-staffed helicopter emergency medical service (HEMS) unit. Data on 549 non-traumatic OHCA patients who were undergoing CPR at the arrival of the HEMS unit from 2016 to 2019 were collected from the HEMS database and patient records. We also recorded the frequency of ultrasound examinations, blood sample analyses and specific therapies provided during OHCA, such as procedures or medications other than chest compressions, airway management, ventilation, defibrillation, adrenaline or amiodarone.ResultsOf the 549 patients, ultrasound was used in 331 (60%) and blood sample analyses in 136 (24%) patients during CPR. A total of 85 (15%) patients received cause-specific treatment, the most common ones being transportation to extracorporeal CPR and percutaneous coronary intervention (PCI) (n = 30), thrombolysis (n = 23), sodium bicarbonate (n = 17), calcium gluconate administration (n = 11) and fluid resuscitation (n = 10).ConclusionIn our study, HEMS physicians deployed ultrasound or blood sample analyses in 84% of the encountered OHCA cases. Cause-specific treatment was administered in 15% of the cases. Our study demonstrates the frequent use of differential diagnostic tools and relatively infrequent use of cause-specific treatment during OHCA. Effect on protocol for differential diagnostics should be evaluated for more efficient cause specific treatment during OHCA.

Outcomes associated with intra-arrest hyperoxaemia in out-of-hospital cardiac arrest: A registry-based cohort study

BackgroundAn association between post-arrest hyperoxaemia and worse outcomes has been reported for out-of-hospital cardiac arrest (OHCA) patients, but little is known about the relationship between intra-arrest hyperoxaemia and clinically relevant outcomes. This study aimed to investigate the association between intra-arrest hyperoxaemia and outcomes for OHCA patients. MethodsThis was an observational study using a registry database of OHCA cases that occurred between 2014 and 2017 in Japan. We included adult, non-traumatic OHCA patients who were in cardiac arrest at the time of hospital arrival and for whom partial pressure of arterial oxygen (PaO2) levels was measured during resuscitation. Main exposure was intra-arrest PaO2 level, which was divided into three categories: hypoxaemia, PaO2 < 60 mmHg; normoxaemia, 60–300; or hyperoxaemia, ≥300. Primary outcome was favourable functional survival at one month or at hospital discharge. Multivariable logistic regression was performed to adjust for clinically relevant variables. ResultsAmong 16,013 patients who met the eligibility criteria, the proportion of favourable functional survival increased as the PaO2 categories became higher: 0.5 % (57/11,484) in hypoxaemia, 1.1 % (48/4243) in normoxaemia, and 5.2 % (15/286) in hyperoxaemia (p-value for trend < 0.001). Higher PaO2 categories were associated with favourable functional survival and the adjusted odds ratios increased as the PaO2 categories became higher: 2.09 (95 % CI: 1.39–3.14) in normoxaemia and 5.04 (95 % CI: 2.62–9.70) in hyperoxaemia when compared to hypoxaemia as a reference. ConclusionIn this observational study of adult OHCA patients, intra-arrest normoxaemia and hyperoxaemia were associated with better functional survival, compared to hypoxaemia.

Abstract 214: A Counterfactual Machine Learning Model Study To Estimate The Impact Of Coronary Angiography For Out Of Hospital Cardiac Arrest

Background: The American Heart Association guidelines for resuscitation 2020 recommends emergency coronary angiography (CAG) in cases of out-of-hospital cardiac arrest (OHCA) after return of spontaneous circulation (ROSC) with ST-segment elevation(STE) and, it is unclear how much CAG actually contributes to improved outcomes in various OHCA patient populations. The aim of this study is to estimate the impact of CAG on OHCA using a counterfactual machine learning model. Methods: We analyzed adult non-traumatic OHCA patients (43,977 cases) from June 2014 to December 2019 from the JAAM (Japan Association for Acute Medicine)-OHCA registry, which includes post-hospitalization data from 140 Japanese hospitals. We defined outcomes as favorable neurological outcomes (Cerebral Performance Categories (CPC) 1-2) and survival at 30 and 90 days. We estimated the outcome assuming that all patients had received CAG using a machine learning and counterfactual hypothetical model, and also estimated the outcome assuming that all patients had not received CAG. An average of each individual difference between the two estimations was calculated as average treatment effect (ATE) (%), which represents the effect of CAG on improving outcomes for the population. In addition, subgroup analysis was performed based on ROSC, STE and initial documented rhythm. Results: The ATE(%, 95% confidence interval) of CAG in all OHCA patients for CPC 1-2 at 30 and 90 days was 3.11% (2.92-3.30) and 1.85% (1.74-1.95), and survival at 30 and 90 days was 6.25%(5.93-6.57) and 2.20%(1.88-2.52), respectively. The subgroup analysis of ATE for CPC 1-2 at 90 days was particularly lower in the no STE group, initial pulseless electrical activity (PEA) group and initial asystole group than in the STE group and initial ventricular fibrillation(VF) group (Figure). Conclusions: In the JAAM-OHCA registry, we used a counterfactual machine learning model to estimate the effect of CAG on OHCA.

Abstract 188: Resuscitative Endovascular Occlusion Of The Aorta (REBOA) As A Mechanical Method For Increasing The Coronary Perfusion Pressure In Non-traumatic Out-of-hospital Cardiac Arrest Patients

Goal: Resuscitative endovascular balloon occlusion of the aorta (REBOA), originally designed to block blood flow to the distal part of the aorta by placing a balloon in trauma patients, has recently been shown to increase coronary perfusion in cardiac arrest patients. This study evaluated REBOA in increasing the aortic pressure and coronary perfusion pressure (CPP) in non-traumatic out-of-hospital cardiac arrest (OHCA) patients. Methods: Adult OHCA patients with cerebral performance category 1 or 2 prior to cardiac arrest, and without evidence of aortic disease, were enrolled from Jan. to Dec. 2021. Aortic pressure and right atrial pressure were measured before and after balloon occlusion. CPP was calculated using the measured aortic and right atrial pressures, and the values before and after the balloon occlusion were compared. Results: Fifteen non-traumatic OHCA patients were enrolled in the study. The median call to balloon time was 46.0 (IQR, 38.0-54.5) min. The median CPP before and after balloon occlusion was 13.5 (IQR, 5.8-25.0) and 25.2 (IQR, 12.0-44.6) mmHg, respectively (P=0.001). The median increase in the estimated CPP after balloon occlusion was 86.7%. Conclusion: The results of this study suggest that REBOA may increase the CPP during cardiopulmonary resuscitation (CPR) in patients with non-traumatic OHCA.

Abstract 128: Yield Of Computed Tomography After Non-Traumatic Out-of-Hospital Cardiac Arrest

Background Computed tomography (CT) can identify the etiology of cardiac arrest and injuries related cardiopulmonary resuscitation (CPR). Diagnostic yield of CT has only been characterized in a few small cohort studies with varied imaging practices. Purpose To determine diagnostic yield of CT imaging after out-of-hospital cardiac arrest (OHCA). Methods We included non-traumatic OHCA patients treated at a single center February 2019 to February 2021. Our practice during the study period was to obtain unenhanced head CT in all comatose patients and CT of the cervical spine, chest, abdomen, and pelvis in most cases. We abstracted patient age and sex, CPR duration, and initial neurological examination from our prospective registry. We reviewed clinical records and identified CT imaging obtained within 24 hours of arrival. We reviewed radiology reports, and summarized findings for each body region. Results We included 505 subjects. Mean age was 60 [SD 16] years and 144 (29%) had an initial shockable rhythm. Median CPR duration was 21 [IQR 12-35] minutes and 448 (89%) subjects were comatose on presentation. Almost all subjects had brain imaging (n=481, 95%), of which 33 (7% [95% CI 5-9%]) had intracranial hemorrhage and 157 (33% [95% CI 28-37%]) had cerebral edema. Fewer subjects had a cervical spine CT (n=202, 40%) though 4 (2% [95% CI 0-4%]) had vertebral fractures. Most subjects had a CT of the chest (n=396, 76%), and abdomen and pelvis (n= 347, 69%). Identified chest pathologies included rib or sternal fractures (222, 56% [95% CI 51-61%]), pneumothorax (27, 7% [95% CI 5-10%]), aspiration or pneumonia (300, 76% [95% CI 71-80%]), mediastinal hematoma (18, 5% [95% CI 3-7%]), and pulmonary embolism (13, 3% [95% CI 2-6%]). Significant abdomen and pelvis findings were bowel ischemia (23, 7% [95% CI 4-10%]), and splenic or liver laceration (7, 2% [95% CI 1-4%]). Conclusions Cross sectional imaging identifies clinically important pathology that informs early management.