Conflict of Interest Declaration
The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: (none, although Olasveengen has received research funding from Zoll Foundation and Laerdal Foundation)
The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: (none applicable)
CoSTR Citation
Ristagno G, Olasveengen TM, Mancini MB, Avis S, Brooks S, Castren M, Chung S, Considine J, Kudenchuk P, Perkins G, Semeraro F, Smyth M , -on behalf of the International Liaison Committee on Resuscitation BLS Life Support Task Force. Rhythm check timing Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, Dec 28th 2019. Available from: http://ilcor.org
Methodological Preamble
The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of basic life support conducted by Giuseppe Ristagno (BLS Task Force member), with involvement of clinical content experts (Giuseppe Ristagno and Theresa Olasveengen). Evidence for adult and pediatric literature was sought and considered by the Basic Life Support Adult Task Force and the Pediatric Task Force groups respectively.
«Cardiac rhythm check» was defined as assessment of ECG rhythm. This definition was considered different from «Pulse check», considered as assessment of return of spontaneous circulation. Available studies compare different CPR protocol characterized not only by different rhythm check timings but also different compression/ventilation ratios, compression intervals between shocks, and ventilation strategies. This represents a serious bias for indirectness considered in the evaluation of the certainty level of evidence.
Additional scientific literature estimating optimal chest compression point using various imaging techniques was identified and described in the justifications and evidence to decision highlights section of this CoSTR. These data were taken into account when formulating the Treatment Recommendations.
PICOST
The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)
Population: Adults with presumed cardiac arrest in in-hospital or out-of-hospital settings receiving a defibrillation attempt during CPR
Intervention: Checking the cardiac rhythm immediately after defibrillation
Comparators: Immediate resumption of chest compressions with delayed check of the cardiac rhythm.
Outcomes: Critical: Survival with good neurological function (i.e. at hospital discharge, 1 month, 6 months, 1 year), survival (i.e. hospital discharge, 1 month, 6 months, 1 year survival). Important: short term survival (return of spontaneous circulation – ROSC, hospital admission), rates of recurrence of fibrillation/re-fibrillation), CPR quality parameters (i.e. compression fraction).
Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion. Animal/lab studies, mathematical models, simulation and manikin studies, algorithm studies for rhythm analysis recognition with no outcome data, unpublished studies (e.g., conference abstracts, trial protocols) and reviews were excluded
Timeframe: All years and all languages were included provided there was an English abstract. Literature search updated to the 2nd November 2019.
Consensus on Science
For the critical outcome of «survival with favorable neurologic outcome at discharge», we identified low-certainty evidence (downgraded for serious risk of bias and indirectness) from 1 RCT enrolling 415 OHCAs showing no benefit for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 0.90; 95% CI, 0.70–1.15, 40 fewer patients/1000 survived with the intervention [95% CI, 119 fewer patients/1000 to 60 more patients/1000 survived with the intervention]) (Beesems 2016, 1) and a very-low-certainty evidence (downgraded for serious risk of bias, indirectness, and imprecision) from 3 observational studies enrolling 763 OHCAs showing a harmful effect for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 0.62; 95% CI, 0.51–0.75, 174 fewer patients/1000 survived with the intervention [95% CI, 224 fewer patients/1000 to 13 fewer patients/1000 survived with the intervention]) (Kellum 2006, 335; Rea 2006, 2760; Bobrow 2008, 1158).
For the critical outcome of «survival to hospital discharge», we identified low-certainty evidence (downgraded for serious risk of bias and indirectness) from 2 RCTs enrolling 1260 OHCAs showing no benefit for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 0.89; 95% CI, 0.72–1.10, 24 fewer patients/1000 survived with the intervention [95% CI, 63 fewer patients/1000 to 23 more patients/1000 survived with the intervention]) (Jost 2010, 1614; Beesems 2016, 1) and very-low-certainty evidence (downgraded for serious risk of bias and indirectness) from 3 observational studies enrolling 3094 OHCAs showing a harm effect for checking rhythm immediately after defibrillation (RR, 0.55; 95% CI, 0.45–0.67, 76 fewer patients/1000 survived with the intervention [95% CI, 93 fewer patients/1000 to 56 fewer patients/1000 survived with the intervention]) (Kellum 2006, 335; Rea 2006, 2760; Bobrow 2008, 1158).
For the important outcome of «survival to hospital admission», we identified low-certainty evidence (downgraded for serious risk of bias and indirectness) from 2 RCTs enrolling 1260 victims of OHCA showing no benefit for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 1.02; 95% CI, 0.91–1.14, 9 more patients/1000 survived with the intervention [95% CI, 43 fewer patients/1000 to 69 more patients/1000 survived with the intervention]) (Jost 2010, 1614; Beesems 2016, 1).
For the important outcome of «ROSC», we identified very-low-certainty evidence (downgraded for serious risk of bias and indirectness) from 2 observational studies enrolling 2969 victims of OHCA showing a harm effect for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 0.69; 95% CI, 0.61–0.78, 111 fewer patients/1000 survived with the intervention [95% CI, 139 fewer patients/1000 to 80 fewer patients/1000 survived with the intervention]) (Rea 2006, 2760; Bobrow 2008, 1158).
For the important outcome of «recurrence of VF», we identified a very-low-certainty (downgraded for serious risk of bias, indirectness, and imprecision) evidence from 2 RCTs, enrolling 551 OHCAs showing no benefit for interrupting chest compressions to check rhythm immediately after shock delivery (RR, 1.08; 95% CI, 0.95–1.22, 47 more patients/1000 survived with the intervention [95% CI, 13 fewer patients/1000 to 5 more patients/1000 survived with the intervention]) (Berdowski 2010, 72; Beesems 2016, 1).
In addition, for the important outcome «chest compression fraction», data from 3 RCTs enrolling 1412 OHCAs showed a harm effect for interrupting chest compressions to check rhythm immediately after shock delivery (Jost 2010, 1614; Berdowski 2010, 72; Beesems 2016, 1).
Treatment Recommendations
We suggest immediate resumption of chest compressions after shock delivery for adults in cardiac arrest in any setting (weak recommendation, very-low-certainty evidence). If there is alternative physiologic evidence of ROSC (eg, arterial waveform or rapid rise in ETCO2), chest compressions can be paused briefly for rhythm analysis.
Justification and Evidence to Decision Framework Highlights
Although there is only very low-certainty evidence addressing this question, there seems to be a signal for harm associated with immediate check for cardiac rhythm after defibrillation for both short-term and long term outcomes. The effect of immediate check on VF recurrence is unclear; an observational study exploring this specific issue did not find VF recurrence within 30 seconds of a defibrillatory shock to be dependent on timing of chest compressions resumption, (Conover 2014 633) and this may not be a major factor affecting outcomes. Protocols including immediate cardiac rhythm check after defibrillation are reported to have reduced chest compression fractions; these increased pauses could be a potential pathway for worse outcomes.
Knowledge Gaps
There were no studies identified that evaluated this question in the paediatric/in-hospital setting. No RCTs compared the specific intervention with standard care in any patient population, although one RCT assessed a CPR protocol characterized not only by different rhythm check timings but also different compression/ventilation ratios, compression intervals between shocks, and ventilation strategies.
Current knowledge gaps include but are not limited to:
- Currently available studies compare different CPR protocols characterized not only by different rhythm check timings but also by different compression/ventilation ratios, compression intervals between shocks, and ventilation strategies.
- Studies specifically addressing the cardiac rhythm check timing are lacking.
- Specific research is required.
Attachments
Evidence-to-Decision Table: Rhythm check timing
References
Beesems SG, Berdowski J, Hulleman M, Blom MT, Tijssen JG, Koster RW. Minimizing pre- and post-shock pauses during the use of an automatic external defibrillator by two different voice prompt protocols. A randomized controlled trial of a bundle of measures. Resuscitation 2016;106:1-6.
Berdowski J, Tijssen JG, Koster RW. Chest compressions cause recurrence of ventricular fibrillation after the first succesful conversion by defibrillation in out-of-hospital cardiac arrest. Circ Arrhythm Electrophysiol 2010;3(1):72-8.
Bobrow BJ, Clark LL, Ewy GA, Chikani V, Sanders AB, Berg RA, Richman PB, Kern KB. Minimally interrupted cardiac resuscitation by emergency medical services for out-of-hospital cardiac arrest. JAMA 2008;299(10):1158-65.
Conover Z, Kern KB, Silver AE, Bobrow BJ, Spaite DW, Indik JH. Resumption of chest compressions after successful defibrillation and risk for recurrence of ventricular fibrillation in out-of-hospital cardiac arrest. Circ Arrhythm Electrophysiol. 2014;7:633-9.
Jost D, Degrange H, Verret C, Hersan O, Banville IL, Chapman FW, Lank P, Petit JL, Fuilla C, Migliani R, Carpentier JP; DEFI 2005 Work Group. DEFI 2005: a randomized controlled trial of the effect of automated external defibrillator cardiopulmonary resuscitation protocol on outcome from out-of-hospital cardiac arrest. Circulation 2010;121(14):1614-22.
Kellum MJ, Kennedy KW, Ewy GA. Cardiocerebral resuscitation improves survival of patients with out-of-hospital cardiac arrest. Am J Med. 2006;119:335-40.
Rea TD, Helbock M, Perry S, Garcia M, Cloyd D, Becker L, Eisenberg M. Increasing use of cardiopulmonary resuscitation during out-of-hospital ventricular fibrillation arrest: survival implications of guideline changes. Circulation 2006;114(25):2760-5.