title: Quality of cardiopulmonary resuscitation in out-of-hospital cardiac arrest before and after introduction of a mechanical chest compression device, LUCAS-2; a prospective, observational study.
abstract: BACKGROUND
  Mechanical chest compressions have been proposed to provide high-quality cardiopulmonary resuscitation (CPR), but despite the growing use of mechanical chest compression devices, only few studies have addressed their impact on CPR quality. This study aims to evaluate mechanical chest compressions provided by LUCAS-2 (Lund University Cardiac Assist System) compared with manual chest compression in a cohort of out-of-hospital cardiac arrest (OHCA) cases.
  
  
  METHODS
  In this prospective study conducted in the Central Denmark Region, Denmark, the emergency medical service attempted resuscitation and reported data on 696 non-traumatic OHCA patients between April 2011 and February 2013. Of these, 155 were treated with LUCAS CPR after an episode with manual CPR. The CPR quality was evaluated using transthoracic impedance measurements collected from the LIFEPAK 12 defibrillator, and the effect was assessed in terms of chest compression rate, no-flow time and no-flow fraction; the fraction of time during resuscitation in which the patient is without spontaneous circulation receiving no chest compression.
  
  
  RESULTS
  The median total episode duration was 21 minutes, and the episode with LUCAS CPR was significantly longer than the manual CPR episode, 13 minutes vs. 5 minutes, p < 0.001. The no-flow fraction was significantly lower during LUCAS CPR (16%) than during manual CPR (35%); difference 19% (95% CI: 16% to 21%; p < 0.001). No differences were found in pre- and post-shock no-flow time throughout manual CPR and LUCAS CPR. Contrary to the manual CPR, the average compression rate during LUCAS CPR was in conformity with the current Guidelines for Resuscitation, 102/minute vs. 124/minute, p < 0.001.
  
  
  CONCLUSIONS
  Mechanical chest compressions provided by the LUCAS device improve CPR quality by significantly reducing the NFF and by improving the quality of chest compression compared with manual CPR during OHCA resuscitation. However, data on end-tidal Co2 and chest compression depth surrogate parameters of CPR quality could not be reported.
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark. tinne.tranberg@clin.au.dk.
authors.forename: Tinne
authors.initials: T
authors.lastname: Tranberg
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark. jens.lassen@clin.au.dk.
authors.forename: Jens F
authors.initials: JF
authors.lastname: Lassen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark. anne.kaltoft@clin.au.dk.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Kaltoft
authors.affiliation: Department of Prehospital Medical Care Service, Central Denmark Region, Aarhus, Denmark. troehans@rm.dk.|Prehospital Critical Care Team, Aarhus University Hospital, Aarhus, Denmark. troehans@rm.dk.|Helicopter Emergency Medical Service, Central Denmark Region, Aarhus, Denmark. troehans@rm.dk.
authors.forename: Troels M
authors.initials: TM
authors.lastname: Hansen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark. carsten.stengaard@clin.au.dk.
authors.forename: Carsten
authors.initials: C
authors.lastname: Stengaard
authors.affiliation: Helicopter Emergency Medical Service, Central Denmark Region, Aarhus, Denmark. lars.knudsen@dadlnet.dk.
authors.forename: Lars
authors.initials: L
authors.lastname: Knudsen
authors.affiliation: Falck A/S, Copenhagen, Denmark. st@falck.dk.
authors.forename: Sven
authors.initials: S
authors.lastname: Trautner
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark. christian.juhl.terkelsen@clin.au.dk.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Terkelsen
mesh_terms: D000368:Aged; D003718:Denmark; D005260:Female; D006336:Heart Massage / Q000295:instrumentation*; D006801:Humans; D008297:Male; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D012984:Software; D013997:Time Factors; D016896:Treatment Outcome