Assessment of the impedance cardiogram recorded by an automated external defibrillator during clinical cardiac arrest

NA Cromie, JD Allen, C Navarro, C Turner, JMCC Anderson, AAJ Adgey

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

To assess the impedance cardiogram recorded by an automated external defibrillator during cardiac arrest to facilitate emergency care by lay persons. Lay persons are poor at emergency pulse checks (sensitivity 84%, specificity 36%); guidelines recommend they should not be performed. The impedance cardiogram (dZ/dt) is used to indicate stroke volume. Can an impedance cardiogram algorithm in a defibrillator determine rapidly circulatory arrest and facilitate prompt initiation of external cardiac massage?Clinical study.University hospital.Phase 1 patients attended for myocardial perfusion imaging. Phase 2 patients were recruited during cardiac arrest. This group included nonarrest controls.The impedance cardiogram was recorded through defibrillator/electrocardiographic pads oriented in the standard cardiac arrest position.Phase 1: Stroke volumes from gated myocardial perfusion imaging scans were correlated with parameters from the impedance cardiogram system (dZ/dt(max) and the peak amplitude of the Fast Fourier Transform of dZ/dt between 1.5 Hz and 4.5 Hz). Multivariate analysis was performed to fit stroke volumes from gated myocardial perfusion imaging scans with linear and quadratic terms for dZ/dt(max) and the Fast Fourier Transform to identify significant parameters for incorporation into a cardiac arrest diagnostic algorithm. The square of the peak amplitude of the Fast Fourier Transform of dZ/dt was the best predictor of reduction in stroke volumes from gated myocardial perfusion imaging scans (range = 33-85 mL; p = .016). Having established that the two pad impedance cardiogram system could detect differences in stroke volumes from gated myocardial perfusion imaging scans, we assessed its performance in diagnosing cardiac arrest. Phase 2: The impedance cardiogram was recorded in 132 "cardiac arrest" patients (53 training, 79 validation) and 97 controls (47 training, 50 validation): the diagnostic algorithm indicated cardiac arrest with sensitivities and specificities (+/- exact 95% confidence intervals) of 89.1% (85.4-92.1) and 99.6% (99.4-99.7; training) and 81.1% (77.6-84.3) and 97% (96.7-97.4; validation).The impedance cardiogram algorithm is a significant marker of circulatory collapse. Automated defibrillators with an integrated impedance cardiogram could improve emergency care by lay persons, enabling rapid and appropriate initiation of external cardiac massage.
LanguageEnglish
Pages510-517
JournalCritical Care Medicine, February 01
Volume38
Issue number2
Publication statusPublished - 2010

Fingerprint

Defibrillators
Heart Arrest
Electric Impedance
Myocardial Perfusion Imaging
Stroke Volume
Fourier Analysis
Heart Massage
Emergency Medical Services
Sensitivity and Specificity
Pulse
Shock
Emergencies
Multivariate Analysis
Guidelines
Confidence Intervals

Keywords

  • Adult
  • Aged
  • 80 and over
  • Cardiac Output
  • Cardiography
  • Impedance: standards
  • Defibrillators: standards
  • Electrocardiography
  • Female
  • Heart Arrest: diagnosis
  • Heart Arrest: physiopathology
  • Heart Massage: methods
  • Humans
  • Male
  • Middle Aged
  • Myocardial Perfusion Imaging
  • Sensitivity and Specificity
  • Stroke Volume: physiology

Cite this

@article{9c9df9d803f246728cc11aa6ac987754,
title = "Assessment of the impedance cardiogram recorded by an automated external defibrillator during clinical cardiac arrest",
abstract = "To assess the impedance cardiogram recorded by an automated external defibrillator during cardiac arrest to facilitate emergency care by lay persons. Lay persons are poor at emergency pulse checks (sensitivity 84{\%}, specificity 36{\%}); guidelines recommend they should not be performed. The impedance cardiogram (dZ/dt) is used to indicate stroke volume. Can an impedance cardiogram algorithm in a defibrillator determine rapidly circulatory arrest and facilitate prompt initiation of external cardiac massage?Clinical study.University hospital.Phase 1 patients attended for myocardial perfusion imaging. Phase 2 patients were recruited during cardiac arrest. This group included nonarrest controls.The impedance cardiogram was recorded through defibrillator/electrocardiographic pads oriented in the standard cardiac arrest position.Phase 1: Stroke volumes from gated myocardial perfusion imaging scans were correlated with parameters from the impedance cardiogram system (dZ/dt(max) and the peak amplitude of the Fast Fourier Transform of dZ/dt between 1.5 Hz and 4.5 Hz). Multivariate analysis was performed to fit stroke volumes from gated myocardial perfusion imaging scans with linear and quadratic terms for dZ/dt(max) and the Fast Fourier Transform to identify significant parameters for incorporation into a cardiac arrest diagnostic algorithm. The square of the peak amplitude of the Fast Fourier Transform of dZ/dt was the best predictor of reduction in stroke volumes from gated myocardial perfusion imaging scans (range = 33-85 mL; p = .016). Having established that the two pad impedance cardiogram system could detect differences in stroke volumes from gated myocardial perfusion imaging scans, we assessed its performance in diagnosing cardiac arrest. Phase 2: The impedance cardiogram was recorded in 132 {"}cardiac arrest{"} patients (53 training, 79 validation) and 97 controls (47 training, 50 validation): the diagnostic algorithm indicated cardiac arrest with sensitivities and specificities (+/- exact 95{\%} confidence intervals) of 89.1{\%} (85.4-92.1) and 99.6{\%} (99.4-99.7; training) and 81.1{\%} (77.6-84.3) and 97{\%} (96.7-97.4; validation).The impedance cardiogram algorithm is a significant marker of circulatory collapse. Automated defibrillators with an integrated impedance cardiogram could improve emergency care by lay persons, enabling rapid and appropriate initiation of external cardiac massage.",
keywords = "Adult, Aged, 80 and over, Cardiac Output, Cardiography, Impedance: standards, Defibrillators: standards, Electrocardiography, Female, Heart Arrest: diagnosis, Heart Arrest: physiopathology, Heart Massage: methods, Humans, Male, Middle Aged, Myocardial Perfusion Imaging, Sensitivity and Specificity, Stroke Volume: physiology",
author = "NA Cromie and JD Allen and C Navarro and C Turner and JMCC Anderson and AAJ Adgey",
note = "Comment In: Crit Care Med. 2010 Feb;38(2):712-3[20083940]",
year = "2010",
language = "English",
volume = "38",
pages = "510--517",
journal = "Critical Care Medicine",
issn = "0090-3493",
number = "2",

}

Assessment of the impedance cardiogram recorded by an automated external defibrillator during clinical cardiac arrest. / Cromie, NA; Allen, JD; Navarro, C; Turner, C; Anderson, JMCC; Adgey, AAJ.

In: Critical Care Medicine, February 01, Vol. 38, No. 2, 2010, p. 510-517.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Assessment of the impedance cardiogram recorded by an automated external defibrillator during clinical cardiac arrest

AU - Cromie, NA

AU - Allen, JD

AU - Navarro, C

AU - Turner, C

AU - Anderson, JMCC

AU - Adgey, AAJ

N1 - Comment In: Crit Care Med. 2010 Feb;38(2):712-3[20083940]

PY - 2010

Y1 - 2010

N2 - To assess the impedance cardiogram recorded by an automated external defibrillator during cardiac arrest to facilitate emergency care by lay persons. Lay persons are poor at emergency pulse checks (sensitivity 84%, specificity 36%); guidelines recommend they should not be performed. The impedance cardiogram (dZ/dt) is used to indicate stroke volume. Can an impedance cardiogram algorithm in a defibrillator determine rapidly circulatory arrest and facilitate prompt initiation of external cardiac massage?Clinical study.University hospital.Phase 1 patients attended for myocardial perfusion imaging. Phase 2 patients were recruited during cardiac arrest. This group included nonarrest controls.The impedance cardiogram was recorded through defibrillator/electrocardiographic pads oriented in the standard cardiac arrest position.Phase 1: Stroke volumes from gated myocardial perfusion imaging scans were correlated with parameters from the impedance cardiogram system (dZ/dt(max) and the peak amplitude of the Fast Fourier Transform of dZ/dt between 1.5 Hz and 4.5 Hz). Multivariate analysis was performed to fit stroke volumes from gated myocardial perfusion imaging scans with linear and quadratic terms for dZ/dt(max) and the Fast Fourier Transform to identify significant parameters for incorporation into a cardiac arrest diagnostic algorithm. The square of the peak amplitude of the Fast Fourier Transform of dZ/dt was the best predictor of reduction in stroke volumes from gated myocardial perfusion imaging scans (range = 33-85 mL; p = .016). Having established that the two pad impedance cardiogram system could detect differences in stroke volumes from gated myocardial perfusion imaging scans, we assessed its performance in diagnosing cardiac arrest. Phase 2: The impedance cardiogram was recorded in 132 "cardiac arrest" patients (53 training, 79 validation) and 97 controls (47 training, 50 validation): the diagnostic algorithm indicated cardiac arrest with sensitivities and specificities (+/- exact 95% confidence intervals) of 89.1% (85.4-92.1) and 99.6% (99.4-99.7; training) and 81.1% (77.6-84.3) and 97% (96.7-97.4; validation).The impedance cardiogram algorithm is a significant marker of circulatory collapse. Automated defibrillators with an integrated impedance cardiogram could improve emergency care by lay persons, enabling rapid and appropriate initiation of external cardiac massage.

AB - To assess the impedance cardiogram recorded by an automated external defibrillator during cardiac arrest to facilitate emergency care by lay persons. Lay persons are poor at emergency pulse checks (sensitivity 84%, specificity 36%); guidelines recommend they should not be performed. The impedance cardiogram (dZ/dt) is used to indicate stroke volume. Can an impedance cardiogram algorithm in a defibrillator determine rapidly circulatory arrest and facilitate prompt initiation of external cardiac massage?Clinical study.University hospital.Phase 1 patients attended for myocardial perfusion imaging. Phase 2 patients were recruited during cardiac arrest. This group included nonarrest controls.The impedance cardiogram was recorded through defibrillator/electrocardiographic pads oriented in the standard cardiac arrest position.Phase 1: Stroke volumes from gated myocardial perfusion imaging scans were correlated with parameters from the impedance cardiogram system (dZ/dt(max) and the peak amplitude of the Fast Fourier Transform of dZ/dt between 1.5 Hz and 4.5 Hz). Multivariate analysis was performed to fit stroke volumes from gated myocardial perfusion imaging scans with linear and quadratic terms for dZ/dt(max) and the Fast Fourier Transform to identify significant parameters for incorporation into a cardiac arrest diagnostic algorithm. The square of the peak amplitude of the Fast Fourier Transform of dZ/dt was the best predictor of reduction in stroke volumes from gated myocardial perfusion imaging scans (range = 33-85 mL; p = .016). Having established that the two pad impedance cardiogram system could detect differences in stroke volumes from gated myocardial perfusion imaging scans, we assessed its performance in diagnosing cardiac arrest. Phase 2: The impedance cardiogram was recorded in 132 "cardiac arrest" patients (53 training, 79 validation) and 97 controls (47 training, 50 validation): the diagnostic algorithm indicated cardiac arrest with sensitivities and specificities (+/- exact 95% confidence intervals) of 89.1% (85.4-92.1) and 99.6% (99.4-99.7; training) and 81.1% (77.6-84.3) and 97% (96.7-97.4; validation).The impedance cardiogram algorithm is a significant marker of circulatory collapse. Automated defibrillators with an integrated impedance cardiogram could improve emergency care by lay persons, enabling rapid and appropriate initiation of external cardiac massage.

KW - Adult

KW - Aged

KW - 80 and over

KW - Cardiac Output

KW - Cardiography

KW - Impedance: standards

KW - Defibrillators: standards

KW - Electrocardiography

KW - Female

KW - Heart Arrest: diagnosis

KW - Heart Arrest: physiopathology

KW - Heart Massage: methods

KW - Humans

KW - Male

KW - Middle Aged

KW - Myocardial Perfusion Imaging

KW - Sensitivity and Specificity

KW - Stroke Volume: physiology

M3 - Article

VL - 38

SP - 510

EP - 517

JO - Critical Care Medicine

T2 - Critical Care Medicine

JF - Critical Care Medicine

SN - 0090-3493

IS - 2

ER -