Experimental paper| Volume 96, P114-120, November 2015

Download started.


An investigation of thrust, depth and the impedance cardiogram as measures of cardiopulmonary resuscitation efficacy in a porcine model of cardiac arrest



      Optimising the depth and rate of applied chest compressions following out of hospital cardiac arrest is crucial in maintaining end organ perfusion and improving survival. The impedance cardiogram (ICG) measured via defibrillator pads produces a characteristic waveform during chest compressions with the potential to provide feedback on cardiopulmonary resuscitation (CPR) and enhance performance. The objective of this pre-clinical study was to investigate the relationship between mechanical and physiological markers of CPR efficacy in a porcine model and examine the strength of correlation between the ICG amplitude, compression depth and end-tidal CO2 (ETCO2).


      Two experiments were performed using 24 swine (12 per experiment). For experiment 1, ventricular fibrillation (VF) was induced and mechanical CPR commenced at varying thrusts (0–60 kg) for 2 min intervals. Chest compression depth was recorded using a Philips QCPR device with additional recording of invasive physiological parameters: systolic blood pressure, ETCO2, cardiac output and carotid flow. For experiment 2, VF was induced and mechanical CPR commenced at varying depths (0–5 cm) for 2 min intervals. The ICG was recorded via defibrillator pads attached to the animal's sternum and connected to a Heartsine 500P defibrillator. ICG amplitude, chest compression depth, systolic blood pressure and ETCO2 were recorded during each cycle. In both experiments the within-animal correlation between the measured parameters was assessed using a mixed effect model.


      In experiment 1 moderate within-animal correlations were observed between physiological parameters and compression depth (r = 0.69–0.77) and thrust (r = 0.66–0.82). A moderate correlation was observed between compression depth and thrust (r = 0.75). In experiment 2 a strong within-animal correlation and moderate overall correlations were observed between ICG amplitude and compression depth (r = 0.89, r = 0.79) and ETCO2 (r = 0.85, r = 0.64).


      In this porcine model of induced cardiac arrest moderate within animal correlations were observed between mechanical and physiological markers of chest compression efficacy demonstrating the challenge in utilising a single mechanical metric to quantify chest compression efficacy. ICG amplitude demonstrated strong within animal correlations with compression depth and ETCO2 suggesting its potential utility to provide CPR feedback in the out of hospital setting to improve performance.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Resuscitation
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Neumar R.
        • Otto C.
        • Link M.
        • et al.
        Part 8: Adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
        Circulation. 2010; 122: s729-s767
        • Deakin C.
        • Nolan J.
        • Sunde K.
        • Koster R.
        European Resuscitation Council Guidelines for Resuscitation 2010 Section 3. Electrical therapies: automated external defibrillators, defibrillation, cardioversion and pacing.
        Resuscitation. 2010; 81: 1293-1304
        • Kramer-Johansen J.
        • Myklebust H.
        • Wik L.
        • et al.
        Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study.
        Resuscitation. 2006; 71: 283-292
        • Stiell I.
        • Brown S.
        • Nichol G.
        • et al.
        What is the optimal chest compression depth during out-of-hospital cardiac arrest resuscitation of adult patients?.
        Circulation. 2014; 130: 1962-1970
        • Wallace S.
        • Abella B.
        • Becker L.
        Quantifying the effect of cardiopulmonary resuscitation quality on cardiac arrest outcome a systematic review and meta-analysis.
        Circ Cardiovasc Qual Outcomes. 2013; 6: 148-156
        • Kampmeier T.
        • Lukas R.
        • Steffler C.
        • et al.
        Chest compression depth after change in CPR guidelines-improved but not sufficient.
        Resuscitation. 2014; 85: 503-508
        • Wik L.
        • Kramer-Johansen J.
        • Myklebust H.
        • et al.
        Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest.
        JAMA. 2005; 293: 299-304
        • Yeung J.
        • Meeks R.
        • Edelson D.
        • Gao F.
        • Soar J.
        • Perkins G.
        The use of CPR feedback/prompt devices during training and CPR performance: a systematic review.
        Resuscitation. 2009; 80: 743-751
        • Yeung J.
        • Davies R.
        • Gao F.
        • Perkins G.
        A randomised control trial of prompt and feedback devices and their impact on quality of chest compressions—a simulation study.
        Resuscitation. 2014; 85: 553-559
        • Di Maio R.
        • Howe A.
        • McCanny P.
        • et al.
        Is the impedance cardiogram a potential indicator of effective external cardiac massage in a human model? A study to establish if there is a linear correlation between the impedance cardiogram and depth in a cardiac arrest setting.
        Resuscitation. 2012; 83: 62
        • Brody D.
        • Maio D.
        • Crawford P.
        • Navarro C.
        • Anderson J.
        The impedance cardiogram amplitude as an indicator of cardiopulmonary resuscitation efficacy in a porcine model of cardiac arrest.
        J Am Coll Cardiol. 2011; 57: E1134
        • Zhang H.
        • Yang Z.
        • Huang Z.
        • et al.
        Transthoracic impedance for the monitoring of quality of manual chest compression during cardiopulmonary resuscitation.
        Resuscitation. 2012; 83: 1281-1286
        • Ayala U.
        • Eftestol T.
        • Alonso E.
        • et al.
        Automatic detection of chest compressions for the assessment of CPR-quality parameters.
        Resuscitation. 2014; 85: 957-963
        • Aramendi E.
        • Ayala U.
        • Irusta U.
        • Alonso E.
        • Eftestol T.
        • Kramer-Johansen J.
        Suppression of the cardiopulmonary resuscitation artefacts using the instantaneous chest compression rate extracted from the thoracic impedance.
        Resuscitation. 2012; 83: 692-698
        • Stecher F.S.
        • Olsen J.
        • Stickney R.E.
        • Wik L.
        Transthoracic impedance used to evaluate performance of cardiopulmonary resuscitation during out of hospital cardiac arrest.
        Resuscitation. 2008; 79: 432-437
        • Meaney P.
        • Bobrow B.
        • Mancini M.
        • et al.
        Cardiopulmonary resuscitation quality: improving cardiac resuscitation outcomes both inside and outside the hospital: a consensus statement from the American Heart Association.
        Circulation. 2013; 128: 417.17-435.17
        • Vadeboncoeur T.
        • Stolz U.
        • Panchal A.
        • et al.
        Chest compression depth and survival in out-of-hospital cardiac arrest.
        Resuscitation. 2014; 85: 182-188
        • Christenson J.
        • Andrusiek D.
        • Everson-Stewart S.
        • et al.
        Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation.
        Circulation. 2009; 120: 1241-1247
        • Tomlinson A.
        • Nysaether J.
        • Kramer-Johansen J.
        • Steen P.A.
        • Dorph E.
        Compression force—depth relationship during out-of-hospital cardiopulmonary resuscitation.
        Resuscitation. 2007; 72: 364-370
        • Alonso E.
        • González-Otero D.
        • Aramendi E.
        • et al.
        Can thoracic impedance monitor the depth of chest compressions during out-of-hospital cardiopulmonary resuscitation.
        Resuscitation. 2014; 85: 637-643