A Reliable Method for Rhythm Analysis during Cardiopulmonary Resuscitation

Abstract

Interruptions in cardiopulmonary resuscitation (CPR) compromise defibrillation success. However, CPR must be interrupted to analyze the rhythm because although current methods for rhythm analysis during CPR have high sensitivity for shockable rhythms, the specificity for nonshockable rhythms is still too low. This paper introduces a new approach to rhythm analysis during CPR that combines two strategies: a state-of-the-art CPR artifact suppression filter and a shock advice algorithm (SAA) designed to optimally classify the filtered signal. Emphasis is on designing an algorithm with high specificity. The SAA includes a detector for low electrical activity rhythms to increase the specificity, and a shock/no-shock decision algorithm based on a support vector machine classifier using slope and frequency features. For this study, 1185 shockable and 6482 nonshockable 9-s segments corrupted by CPR artifacts were obtained from 247 patients suffering out-of-hospital cardiac arrest. The segments were split into a training and a test set. For the test set, the sensitivity and specificity for rhythm analysis during CPR were 91.0% and 96.6%, respectively. This new approach shows an important increase in specificity without compromising the sensitivity when compared to previous studies.

Fully automatic rhythm analysis during chest compression pauses

“…[21][22][23] Generally, the specificity of these methods is below the 95% value recommended by the AHA. 13 Furthermore, when used to continuously monitor the rhythm during CPR their performance degrades substantially.…”

“…13 Several approaches have been studied such as adaptive artefact filters [18][19][20] or new SAAs designed to analyse either the artefacted 21,22 or the filtered ECG. 23 When tested on short strips (< 20 s) of OHCA data from defibrillators, only a recently published SAA 23 produced sensitivity and specificity results above 90% and 95%, the performance goals recommended by the American Heart Association (AHA). 24 Nevertheless, the reported sensitivities and specificities were well below those obtained for SAAs on artefactfree ECG.…”

An automatic system for the comprehensive retrospective analysis of cardiac rhythms in resuscitation episodes

“…Future developments should explore the design of CARFs for resuscitation rhythm annotation and the design of RCEs specifically for rhythm classification during CC-intervals, in line with some recent developments for shock advice algorithms. 25…”

Hands-on defibrillation and electrocardiogram artefact filtering technology increases chest compression fraction and decreases peri-shock pause duration in a simulation model of cardiac arrest

“…13 A study by Ruiz et al found that AFT reduces pauses in chest compressions during shockable arrest 14 and that the use of this particular AFT filter has reportedly high sensitivity (91.0%) and specificity (96.6%) for rhythm analysis during CPR in both shockable and non-shockable rhythms. 15 Despite the encouraging numbers, most manufacturers recommend a confirmatory pause prior to shock delivery. For this reason, we incorporated this pause into our study, but, as confidence in the technology increases, further gains may be made in improving CCF.…”