title: Quality of chest compressions during 10min of single-rescuer basic life support with different compression: ventilation ratios in a manikin model.
abstract: BACKGROUND
  Good quality basic life support (BLS) improves outcome during cardiac arrest. As fatigue may reduce BLS performance over time we wanted to examine the quality of chest compressions in a single-rescuer scenario during prolonged BLS with different compression:ventilation ratios (C:V ratios).
  
  
  METHODS
  Professional paramedics were asked to perform single-rescuer BLS with C:V ratios of 15:2, 30:2 and 50:2 for 10 min each in random order. A Laerdal Medical Resusci Anne Simulator with PC Skillreporting System was used for BLS quality analysis. Total number of chest compressions, compression depth and compression rate were measured and the differences between the C:V ratios were analysed with repeated measures ANOVA. For analysis of fatigue, chest compression variables for each 2-min period were analysed and compared with the first 2-min period using repeated measures ANOVA.
  
  
  RESULTS
  Altogether 50 paramedics completed the study. The mean number of chest compressions increased significantly from 604 to 770 and 862 with C:V ratios of 15:2, 30:2 and 50:2, respectively. Chest compression rate was significantly higher with C:V ratio of 15:2 compared to 30:2 and 50:2 but was above 100 per minute for all three ratios. However, the mean chest compression depth did not change significantly between the different C:V ratios. The number of chest compressions did not change significantly with time for any of the three C:V ratios. Compression depth did decline after the first 2-min period for 30:2 and 50:2 as did compression rate for all three ratios. However all were above the guideline limits for the entire test period.
  
  
  CONCLUSIONS
  Increasing the C:V ratio increases the number of chest compressions during 10 min of BLS. Compression depth and compression rate were within guideline recommendations for all three ratios. We found no decline in chest compression quality below guideline recommendations during 10 min of BLS with any of the three different C:V ratios.
authors.affiliation: Department of Anaesthesia and Intensive Care, Division of Acute Care Medicine, Stavanger University Hospital, Stavanger, Norway. bjco@sus.no
authors.forename: Conrad Arnfinn
authors.initials: CA
authors.lastname: Bjørshol
authors.forename: Eldar
authors.initials: E
authors.lastname: Søreide
authors.forename: Tor Harald
authors.initials: TH
authors.lastname: Torsteinbø
authors.forename: Kristian
authors.initials: K
authors.lastname: Lexow
authors.forename: Odd Bjarte
authors.initials: OB
authors.lastname: Nilsen
authors.forename: Kjetil
authors.initials: K
authors.lastname: Sunde
mesh_terms: D000488:Allied Health Personnel / Q000193:education*; D000704:Analysis of Variance; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000592:standards; D006323:Heart Arrest / Q000628:therapy*; D006336:Heart Massage / Q000379:methods* / Q000592:standards; D006801:Humans; D008348:Manikins; D012123:Pulmonary Ventilation; D011787:Quality of Health Care