RESUMEN
BACKGROUND: Non-shockable in-hospital cardiac arrest (IHCA) is a condition with diverse aetiology, predictive factors, and outcome. This study aimed to compare IHCA with initial asystole or pulseless electrical activity (PEA), focusing specifically on their aetiologies and the significance of predictive factors. METHODS: Using the Swedish Registry of Cardiopulmonary Resuscitation, adult non-shockable IHCA cases from 2018 to 2022 (n = 5788) were analysed. Exposure was initial rhythm, while survival to hospital discharge was the primary outcome. A random forest model with 28 variables was used to generate permutation-based variable importance for outcome prediction. RESULTS: Overall, 60% of patients (n = 3486) were male and the median age was 75 years (IQR 67-81). The most frequent arrest location (46%) was on general wards. Comorbidities were present in 79% of cases and the most prevalent comorbidity was heart failure (33%). Initial rhythm was PEA in 47% (n = 2702) of patients, and asystole in 53% (n = 3086). The most frequent aetiologies in both PEA and asystole were cardiac ischemia (24% vs. 19%, absolute difference [AD]: 5.4%; 95% confidence interval [CI] 3.0% to 7.7%), and respiratory failure (14% vs. 13%, no significant difference). Survival was higher in asystole (24%) than in PEA (17%) (AD: 7.3%; 95% CI 5.2% to 9.4%). Cardiopulmonary resuscitation (CPR) durations were longer in PEA, 18 vs 15 min (AD 4.9 min, 95% CI 4.0-5.9 min). The duration of CPR was the single most important predictor of survival across all subgroup and sensitivity analyses. Aetiology ranked as the second most important predictor in most analyses, except in the asystole subgroup where responsiveness at cardiac arrest team arrival took precedence. CONCLUSIONS: In this nationwide registry study of non-shockable IHCA comparing asystole to PEA, cardiac ischemia and respiratory failure were the predominant aetiologies. Duration of CPR was the most important predictor of survival, followed by aetiology. Asystole was associated with higher survival compared to PEA, possibly due to shorter CPR durations and a larger proportion of reversible aetiologies.
RESUMEN
OBJECTIVES: Resuscitation on in-hospital cardiac arrest (IHCA) is estimated to occur in 200,000 hospitalised patients annually in the US. The duration of the resuscitation attempt, measured as minutes of cardiopulmonary resuscitation (CPR), and its impact on survival remains unknown. AIM: Investigate if there is a difference in 30-day survival among IHCA who experience return of spontaneous circulation (ROSC) depending on the duration of CPR. MATERIAL AND METHODS: All patients ≥18 years who experienced ROSC after an IHCA at Karolinska University Hospital between 2007 and 2017 were included. Data regarding the IHCA, patient characteristics, and death dates were obtained from medical records linked to Swedish national registries. Patients who experienced ROSC were stratified into quartiles depending on the length of CPR (in minutes). The difference in 30-day survival between the quartiles (Q) was assessed with adjusted logistic regression models and presented as odds ratios with 95% confidence intervals (OR 95% CI). Adjustments included sex, age, Charlson Comorbidity Index, first rhythm, ECG-surveillance, witnessed or not, time between CA and call, year of IHCA and location of the IHCA. RESULTS: In all, 1639 patients suffered an IHCA, of whom 840 (51%) experienced ROSC and 471 (29% of the total, 56% of those with ROSC) survived for at least 30 days. Among the 840 patients with ROSC, 768 (91%) had a documented duration of their CPR in their medical file with a median of 5 min (interquartile range 2-12 min). Among those with ROSC, the adjusted OR for 30-day survival was OR 0.69 (0.37-1.29) for Q2 (3-5 min), 0.35 (0.19-0.65) for Q3 (6-12 min) and 0.10 (0.05-0.20) Q4. A cut-off time of 15 min, 20 min and 60 min, respectively, captures 90%, 95% and 99% of the 30-day survivors. CONCLUSION: Resuscitation attempts on IHCA are often short and duration of CPR is associated with 30-day survival among those with ROSC. Still, the 30-day survival is high enough to question the use of CPR duration as a prognostic marker in post-resuscitation care, and ideal duration of resuscitation should remain a bedside decision taking into consideration the whole clinical picture.