Optimal loop duration during the provision of in-hospital advanced life support (ALS) to patients with an initial non-shockable rhythm

Resuscitation. 2014 Jan;85(1):75-81. doi: 10.1016/j.resuscitation.2013.08.261. Epub 2013 Sep 12.

Abstract

Background: In advanced life support (ALS), time-cycled "loops" of chest compressions form the basis of action. However, the provider must compromise between interrupting compressions and detecting a change in cardiac rhythm. An "optimal" loop duration would best balance these choices. The current international CPR guidelines recommend 2-min loop durations. The aim of this study was to investigate the "optimal" loop duration in patients with initial asystole or pulseless electrical activity (PEA).

Materials and methods: Detailed defibrillator recordings from 249 in-hospital cardiac arrests at the University of Chicago Medicine (Chicago, IL) and St. Olav University Hospital (Trondheim, Norway) were analysed. The clinical states of asystole, PEA, ventricular fibrillation/-tachycardia (VF/VT) and return of spontaneous circulation (ROSC) were annotated along the time axis. PEA and asystole were combined as a single state for the analysis of state development. The probability of staying in PEA/asystole over time was estimated non-parametrically. In addition, to distinguish between initial and secondary PEA/asystole, the latter was defined by the transition from VF/VT or ROSC.

Results: Among patients with initial PEA (n=179), 25% and 50% of patients had left PEA/asystole after 4 and 9 min of ALS efforts, respectively. The corresponding time points for patients with initial asystole (n=70) were 7.3 and 13.3 min, respectively. The probability of transition from secondary PEA/asystole to ROSC or VF/VT varied between 10% and 20% in each 2-4 min interval.

Conclusion: The "optimal" first loop duration may be 4 min in initial PEA and 6-8 min in initial asystole. If secondary PEA/asystole is encountered, 2-min loop duration seems appropriate.

Keywords: Cardiac arrest; Cardiopulmonary resuscitation; Dynamics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Advanced Cardiac Life Support / methods*
  • Aged
  • Female
  • Heart Arrest / physiopathology*
  • Heart Arrest / therapy
  • Hospitalization
  • Humans
  • Male
  • Middle Aged
  • Time Factors