title: Manual versus Mechanical Chest Compressions on Surfaces of Varying Softness with or without Backboards: A Randomized, Crossover Manikin Study.
abstract: BACKGROUND
  Chest compression quality is decisive for overall outcome after cardiac arrest. Chest compression depth may decrease when cardiopulmonary resuscitation (CPR) is performed on a mattress, and the use of a backboard does not necessarily improve compression depth. Mechanical chest compression devices may overcome this problem.
  
  
  OBJECTIVE
  We sought to investigate the effectiveness of manual chest compressions both with and without a backboard compared to mechanical CPR performed on surfaces of different softness.
  
  
  METHODS
  Twenty-four advanced life support (ALS)-certified rescuers were enrolled. LUCAS2 (Physio-Control, Redmond, WA) delivers 52 ± 2 mm deep chest compressions and active decompressions back to the neutral position (frequency 102 min(-1); duty cycle, 50%). This simulated CPR scenario was performed on a Resusci-Anne manikin (Laerdal, Stavanger, Norway) that was lying on 3 different surfaces: 1) a concrete floor, 2) a firm standard mattress, and 3) a pressure-relieving mattress. Data were recorded by the Laerdal Skill Reporting System.
  
  
  RESULTS
  Manual chest compression with or without a backboard were performed correctly less often than mechanical chest compressions (floor: 33% [interquartile range {IQR}, 27-48%] vs. 90% [IQR, 86-94%], p < 0.001; standard mattress: 32% [IQR, 20-45%] vs. 27% [IQR, 14-46%] vs. 91% [IQR, 51-94%], p < 0.001; and pressure-relieving mattress 29% [IQR, 17-49%] vs. 30% [IQR, 17-52%] vs. 91% [IQR, 87-95%], p < 0.001). The mean compression depth on both mattresses was deeper with mechanical chest compressions (floor: 53 mm [range, 47-57 mm] vs. 56 mm [range, 54-57 mm], p = 0.003; standard mattress: 50 mm [range, 44-55 mm] vs. 51 mm [range, 47-55 mm] vs. 55 mm [range, 54-58 mm], p < 0.001; and pressure-relieving mattress: 49 mm [range, 44-55 mm] vs. 50 mm [range, 44-53 mm] vs. 55 mm [range, 55-56 mm], p < 0.001). In this ∼6-min scenario, the mean hands-off time was ∼15 to 20 s shorter in the manual CPR scenarios.
  
  
  CONCLUSIONS
  In this experimental study, only ∼30% of manual chest compressions were performed correctly compared to ∼90% of mechanical chest compressions, regardless of the underlying surface. Backboard use did not influence the mean compression depth during manual CPR. Chest compressions were deeper with mechanical CPR. The mean hands-off time was shorter with manual CPR.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Putzer
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Fiala
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Patrick
authors.initials: P
authors.lastname: Braun
authors.affiliation: Department of Medical Statistics, Informatics and Health Economics, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Neururer
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Karin
authors.initials: K
authors.lastname: Biechl
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Keilig
authors.affiliation: Institute of Mountain Emergency Medicine at the European Academy, Bozen, Italy.
authors.forename: Werner
authors.initials: W
authors.lastname: Ploner
authors.affiliation: Institute of Mountain Emergency Medicine at the European Academy, Bozen, Italy.
authors.forename: Ernst
authors.initials: E
authors.lastname: Fop
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Paal
mesh_terms: D001513:Beds; D018592:Cross-Over Studies; D004867:Equipment Design; D006336:Heart Massage / Q000295:instrumentation / Q000379:methods*; D008348:Manikins; D011312:Pressure
keywords: CPR; LUCAS; backboard; chest compressions; manikin; mattress