Abstract 87: Duration of Longest Chest Compression Interruption Predicts Poor Cardiac Arrest Survival Independent of Chest Compression Fraction
Long pauses in chest compressions (cc) are thought to be harmful. However, prior clinical analyses have only evaluated peri-shock pauses (PSP) of the first 1 - 3 shocks, or cc fraction over the first few minutes of the resuscitation. We analyzed full recordings from a large cohort of resuscitations to explore relationships between long PSPs, long pauses for other reasons (non-PSP), and survival.
In an observational study of prospectively collected data, we enrolled all patients with cardiac cause out-of-hospital cardiac arrest presenting with VT/VF during calendar year 2009 in five EMS systems. Continuous ECG and impedance recordings from all defibrillators (AED and manual) used during resuscitation were analyzed to measure longest PSP (longest interval without cc containing a shock), and longest non-PSP (longest interval without cc prior to the last shock, and not containing a shock). Because pause durations are inversely related to cc fraction, we also measured cc fraction over the entire resuscitation.
In 319 enrolled patients, survival rate was 38% and CC fraction was median (IQR) 79% (71%, 84%). Longest PSP was 26 (16, 42) sec and longest non-PSP was 24 ( 11, 38) sec. Both the longest PSP [Odds Ratio (OR) = 0.91 per 5 sec increment (0.86, 0.97)] and the longest non-PSP [OR = 0.84 (0.76, 0.92)] were significantly associated with survival to discharge in a multivariate regression model adjusting for recognized Utstein predictors. These significant associations did not change when additionally adjusted for cc fraction. In 36% of patients, the longest non-PSP was ≥ the longest PSP. Survival was significantly lower in this group than in the 64% of patients where the longest PSP was longer than any non-PSP (27% vs 44%, p=0.004), despite a higher median CC fraction (80% vs 77%, p=0.04).
Prolonged cc pauses have a significant negative association with survival that is not explained by chest compression fraction. The longest non-PSP had a lower odds ratio for survival than the longest PSP, and it was the longest pause prior to the last shock in more than a third of the cases. Avoiding long pauses for interventions other than defibrillation may be even more important than minimizing PSPs or further increasing chest compression fraction.
- © 2012 by American Heart Association, Inc.