Out-of-hospital cardiac arrest: manual or mechanical CPR?
Authors: Marcus Eng Hock Ong, Venkataraman Anantharaman
Journal: The Lancet (2014)

The appropriate role for mechanical chest compression devices in pre-hospital care has been debated in recent years.1Ong ME Mackey KE Zhang ZC et al.Mechanical CPR devices compared to manual CPR during out-of-hospital cardiac arrest and ambulance transport: a systematic review.Scand J Trauma Resusc Emerg Med. 2012; 20: 39Crossref PubMed Scopus (54) Google Scholar The quality of manual cardiopulmonary resuscitation (CPR) during out-of-hospital cardiac arrest is often less than optimum, and affects survival.2Wik L Kramer-Johansen J Myklebust H et al.Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest.JAMA. 2005; 293: 299-304Crossref PubMed Scopus (1057) Google Scholar Mechanical compression devices are an attractive alternative: they never get tired, give consistent chest compressions, and allow CPR to continue during transfer of the patient. Results from two studies3Casner M Andersen D Isaacs SM The impact of a new CPR assist device on rate of return of spontaneous circulation in out-of-hospital cardiac arrest.Prehosp Emerg Care. 2005; 9: 61-67Crossref PubMed Scopus (99) Google Scholar, 4Ong MEH Ornato JP Edwards DP et al.Use of an automated, load-distributing band chest compression device for out-of-hospital cardiac arrest resuscitation.JAMA. 2006; 295: 2629-2637Crossref PubMed Scopus (185) Google Scholar of implementation of mechanical CPR devices in the so-called real world showed higher rates of return of spontaneous circulation and survival to discharge with mechanical CPR than with manual CPR. However, results from three randomised trials5Hallstrom A Rea TD Sayre MR et al.Manual chest compression vs use of an automated chest compression device during resuscitation following out-of-hospital cardiac arrest.JAMA. 2006; 295: 2620-2628Crossref PubMed Scopus (292) Google Scholar, 6Rubertsson S Lindgren E Smekal D et al.Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest: the LINC randomized trial.JAMA. 2014; 311: 53-61Crossref PubMed Scopus (290) Google Scholar, 7Wik L Olsen JA Persse D et al.Manual vs integrated automatic load-distributing band CPR with equal survival after out of hospital cardiac arrest. The randomized CIRC trial.Resuscitation. 2014; 85: 741-748Summary Full Text Full Text PDF PubMed Scopus (211) Google Scholar did not show significant survival benefit for mechanical CPR compared with manual CPR. In The Lancet, Gavin Perkins and colleagues8Perkins GD Lall R Quinn T et al.Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial.Lancet. 2014; (published online Nov 16.)http://dx.doi.org/10.1016/S0140-6736(14)61886-9Google Scholar describe a pragmatic, cluster-randomised trial including adults with non-traumatic out-of-hospital cardiac arrest from four UK ambulance services. Ambulances were randomly assigned to either mechanical CPR (with the LUCAS-2 device, figure) or manual CPR. The investigators enrolled 4471 patients (1652 patients in the LUCAS-2 group, and 2819 patients in the control group). However, only 985 (60%) patients in the mechanical CPR group actually received the LUCAS-2 intervention, as did 11 (<1%) in the control group. 30 day survival (analysed by intention to treat) was similar for mechanical CPR (104 [6%] of 1652 patients) and manual CPR (193 [7%] of 2819 patients; adjusted OR 0·86, 95% CI 0·64–1·15). Neurological survival with favourable neurological outcome at 3 months was lower in the mechanical CPR group than in the manual CPR group (adjusted OR 0·72, 95% CI 0·52–0·99). The authors should be commended for attempting a real-world clinical trial on an important issue for Emergency Medical Services (EMS) systems worldwide. This study portrays the complexities and difficulties surrounding large-scale resuscitation trials, and the importance of attention to implementation and training in the assessment of any new technology. The somewhat low device usage rate (60%) reported in this study was due to difficulties in device use (15%), unknown reasons (6%), and non-compliance (16%). Even with apparent compliance, whether operational issues resulted in implementation delays with the mechanical device is unknown. The absence of difference (or even inferiority) in outcomes in the trial group might not be due to the treatment or device itself, but to attention to training, compliance to protocols, and implementation. When implementing a programme with a mechanical device that has weight and bulk, we cannot presume that ambulance crews would always carry the device with them when attending to a call. It would be relevant to know whether the LUCAS device was immediately started at the site or later, including in the ambulance. If later, substantial time delays in initiating mechanical CPR might have negated potential for benefit in device use. The time from emergency call to arrival of the vehicle or ambulance crew at the patient's side, as an indicator of duration of collapse before intervention by ambulance crew, might underestimate collapse intervals. This study8Perkins GD Lall R Quinn T et al.Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial.Lancet. 2014; (published online Nov 16.)http://dx.doi.org/10.1016/S0140-6736(14)61886-9Google Scholar did not calculate collapse time or collapse duration before application of interventions. Conventional therapies for cardiac arrest seem to have minimum effect after long collapse intervals. Long intervals in the intervention group might conceal the effect of these interventions. Assessment of the effect of this collapse interval on outcomes after mechanical CPR might throw light on the relative usefulness of this mode of resuscitation. About 60% of cardiac arrests attended were deemed not eligible and had no resuscitation attempted (6482 of 11 171). This proportion is rather high compared with that in many EMS systems internationally. This finding raises questions of selective resuscitation by ambulance crews, although the study team did monitor for enrolment bias and noted no difference between study groups. Quality of implementation is an especially important issue with regard to the benefit or harm of mechanical CPR. Interruptions to CPR and delays in application of mechanical CPR devices are major factors that affect outcomes.9Ong ME Annathurai A Shahidah A et al.Cardiopulmonary resuscitation interruptions with use of a load-distributing band device during emergency department cardiac arrest.Ann Emerg Med. 2010; 56: 233-241Summary Full Text Full Text PDF PubMed Scopus (42) Google Scholar Wang and colleagues showed that human error and lack of training with mechanical CPR led to prolonged intervals without chest compression.10Wang HC Chiang WC Chen SY et al.Video-recording and time-motion analyses of manual versus mechanical cardiopulmonary resuscitation during ambulance transport.Resuscitation. 2007; 74: 453-460Summary Full Text Full Text PDF PubMed Scopus (68) Google Scholar Attention to team training and focusing on quality of deployment of mechanical CPR devices alone can greatly improve outcomes.11Ong ME Quah JL Annathurai A et al.Improving the quality of cardiopulmonary resuscitation by training dedicated cardiac arrest teams incorporating a mechanical load-distributing device at the emergency department.Resuscitation. 2013; 84: 508-514Summary Full Text Full Text PDF PubMed Scopus (51) Google Scholar The absence of quality implementation measures in this study,8Perkins GD Lall R Quinn T et al.Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial.Lancet. 2014; (published online Nov 16.)http://dx.doi.org/10.1016/S0140-6736(14)61886-9Google Scholar such as data on delays in application of the device or CPR interruptions, makes it difficult to refute the hypothesis that the outcomes noted are possibly more an effect of the quality of implementation rather than the therapy in question. Although this study does not give us a definitive answer to the debate between manual and mechanical CPR, it does throw a spotlight on implementation and quality. EMS services should aim to provide the best quality of CPR possible. High-quality manual CPR requires EMS commitment to training and quality review. Mechanical CPR requires the same commitment to training and attention to deployment practices. Mechanical CPR is also more costly than manual CPR. EMS systems worldwide routinely transport patients with cardiac arrest to hospital with ongoing manual CPR of doubtful quality.12Russi CS Kolb LJ Myers LA Hess EP White RD A comparison of chest compression quality delivered during on-scene and transport cardiopulmonary resuscitation.Prehosp Emerg Care. 2011; 15: 106Crossref Scopus (2) Google Scholar Safety concerns for unrestrained crew using manual CPR in a moving ambulance are real. Mechanical CPR allows crews to be safely belted up and is a logical choice from the safety perspective.13Ong MEH Shin SD Soon SS et al.Recommendations on ambulance cardiopulmonary resuscitation in basic life support systems.Prehosp Emerg Care. 2013; 17: 491-500Crossref PubMed Scopus (11) Google Scholar MEHO is principal investigator of an industry-funded study involving a mechanical CPR device; has received grants from Laerdal Medical, grants and personal fees from Zoll Medical Corporation, and non-financial support from Bard Medical and Zoll Medical Corporation; and has a patent method of predicting patient survival licensed to Zoll Medical Corporation, and a patent system and method of determining a risk score for triage pending. VA is principal investigator in an industry-funded study on use of a mechanical CPR device in the out-of-hospital situation; has received non-financial support from Physio-Control Inc; and is a member of the Medical Advisory Board of Falck Foundation. Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trialWe noted no evidence of improvement in 30 day survival with LUCAS-2 compared with manual compressions. On the basis of ours and other recent randomised trials, widespread adoption of mechanical CPR devices for routine use does not improve survival. Full-Text PDF Open Access