Analysis and characterisation of biosignals for the optimisation of cardiopulmonary resuscitation

  • Olibhear McAlister

Student thesis: Doctoral Thesis


Cardiac arrest (CA) is a leading cause of death globally. During an out-of-hospital CA event, the person who identifies a CA assumes the role of rescuer and is encouraged to perform cardiopulmonary resuscitation (CPR) and use an automated external defibrillator (AED) without hesitation. Resuscitation guidelines specify that a chest compression (CC) depth of 50 to 60 mm is indicative of effective CPR; however, devices additional to AED are required to measure depth. This research project characterised the role of depth in resuscitation and explored alternative measures for providing feedback.

This research in the present thesis was explored in three investigations. An initial three-phase investigation was conducted to evaluate the physiological response to CC quality and if suitable alternatives to CC depth may be used to guide resuscitation, including thoracic impedance, end-tidal carbon dioxide and arterial blood pressure. A second investigation assessed the effect of CC quality on quantitative waveform measurements (QWM) extracted from ventricular fibrillation (VF). The effect of CC quality on defibrillation success and return of spontaneous circulation were evaluated. The final investigation explored the use of an acoustic sensor to detect presence of a pulsatile rhythm during resuscitation was explored.

Physiological response to CPR was effectively characterised, where deeper CC depths were associated with greater response in all physiological measures (r: 0.78-0.95). The response to a specific CC depth however varied between subjects. The initial investigation discovered that thoracic impedance (TI) was closely related to CC depth (r = 0.95); therefore, a novel TI-thresholding CPR feedback system was developed to control CC quality. An association was found between CC quality and QWM extracted from VF (Amplitude spectrum area; p
Date of AwardMay 2022
Original languageEnglish
SponsorsHeartSine Technologies Ltd
SupervisorRaymond Bond (Supervisor), Dewar Finlay (Supervisor) & Daniel Guldenring (Supervisor)


  • Thoracic impedance
  • Chest compressions
  • Cardiac arrest
  • Defibrillation
  • Ventricular fibrillation
  • Thoracic audio

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