title: The effect of differing support surfaces on the efficacy of chest compressions using a resuscitation manikin model.
abstract: OBJECTIVE
  External chest compression (ECC) efficacy is influenced by factors including the surface supporting the patient. Air-filled support surfaces are deflated for cardiopulmonary resuscitation, with little evidence to substantiate this. We investigated the effect that differing support surfaces had on ECC efficacy using a CPR manikin model.
  
  
  METHODS
  Four participants carried out four cycles of ECC with an assistant ventilating. The subjects were blinded to the seven support surfaces and the order was randomised. For each participant/surface combination, ECC variables and the participants' perceptions were measured.
  
  
  RESULTS
  Participants produced effective ECC with the manikin on the floor (mean proportion correct, 94.5%; mean depth, 42.5 mm). Compared with the floor: the proportion of correct ECC was less for the overlay inflated (P<0.05); the depth of ECC was less effective (30-37 mm) for the overlay inflated/deflated and low-air-loss inflated and foam mattresses (P<0.05). The foam mattress, overlay inflated/deflated, and low-air-loss inflated were perceived as being less stable and as having reduced ECC efficacy compared with the floor. There was no difference or agreement, regarding subjects' perceptions or ECC variables, between the support surfaces or between inflated/deflated air-filled support surfaces.
  
  
  CONCLUSIONS
  The efficacy of ECC is affected by the support surfaces. There seems little evidence to substantiate deflating all air-filled support surfaces for CPR.
authors.affiliation: Respiratory Medicine, Leicester Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK. m.j.tweed@warwick.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Tweed
authors.forename: C
authors.initials: C
authors.lastname: Tweed
authors.forename: G D
authors.initials: GD
authors.lastname: Perkins
mesh_terms: D001513:Beds; D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008348:Manikins; D016037:Single-Blind Method; D013499:Surface Properties; D011795:Surveys and Questionnaires; D016896:Treatment Outcome