title: The composition of gas given by mouth-to-mouth ventilation during CPR.
abstract: OBJECTIVE
  To compare the concentration of a rescuer's exhaled O2 and CO2 during mouth-to-mouth ventilation with or without chest compression.
  
  
  METHODS
  Prospective repeated measures study. Simulated one- and two-rescuer cardiopulmonary resuscitation (CPR) was performed as recommended by the American Heart Association.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  Fifty-five healthcare professionals certified in basic and advanced cardiac life support volunteered as rescuers in this study.
  
  
  RESULTS
  Thirty-three volunteers performed one-rescuer CPR, and 22 volunteers performed two-rescuer CPR. Minute ventilation for both groups increased 50% to 130% during CPR (p < 0.05). During the performance of CPR, the concentration of exhaled O2 increased from 16.4 +/- 0.7% to 16.9 +/- 0.5% in the one-rescuer CPR group and from 16.5 +/- 0.9% to 17.8 +/- 0.6% in the two-rescuer CPR group (p < 0.05). The concentration of exhaled CO2 in the one-rescuer CPR group did not change significantly throughout the entire experiment, but decreased in the two-rescuer CPR group from a baseline measurement of 4.0 +/- 0.6% to 3.5 +/- 0.4% (p < 0.05). During CPR, the concentration of exhaled CO2 was 4.0 +/- 0.4% in the one-rescuer CPR group compared with 3.5 +/- 0.4% in the two-rescuer CPR group (p < 0.05).
  
  
  CONCLUSIONS
  The gas given by mouth-to-mouth ventilation is a hypercarbic and hypoxic mixture compared with room air. Mouth-to-mouth ventilation is the only circumstance in which a hypercarbic and hypoxic gas is given as therapy. Further laboratory and clinical studies are necessary to determine the effect of mouth-to-mouth ventilation during CPR.
authors.affiliation: Division of Emergency Medicine, University of Florida College of Medicine, Gainesville.
authors.forename: V
authors.initials: V
authors.lastname: Wenzel
authors.forename: A H
authors.initials: AH
authors.lastname: Idris
authors.forename: M J
authors.initials: MJ
authors.lastname: Banner
authors.forename: R S
authors.initials: RS
authors.lastname: Fuerst
authors.forename: K J
authors.initials: KJ
authors.lastname: Tucker
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D016887:Cardiopulmonary Resuscitation; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000032:analysis*; D011446:Prospective Studies
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen