title: Time to first compression using Medical Priority Dispatch System compression-first dispatcher-assisted cardiopulmonary resuscitation protocols.
abstract: BACKGROUND
  Without bystander cardiopulmonary resuscitation (CPR), cardiac arrest survival decreases 7%-10% for every minute of delay until defibrillation. Dispatcher-assisted CPR (D-CPR) has been shown to increase the rates of bystander CPR and cardiac arrest survival. Other reports suggest that the most critical component of bystander CPR is chest compressions with minimal interruption. Beginning with version 11.2 of the Medical Priority Dispatch System (MPDS) protocols, instructions for mouth-to-mouth ventilation (MTMV) and pulse check were removed and a compression-first pathway was introduced to facilitate rapid delivery of compressions. Additionally, unconscious choking and third-trimester pregnancy decision-making criteria were added in versions 11.3 and 12.0, respectively. However, the effects of these changes on time to first compression (TTFC) have not been evaluated.
  
  
  OBJECTIVE
  We sought to quantify the TTFC of MPDS versions 11.2, 11.3, and 12.0 for all calls identified as cardiac arrest on call intake that did not require MTMV instruction.
  
  
  METHODS
  Audio recordings of all D-CPR events for October 2005 through May 2010 were analyzed for TTFC. Differences in TTFC across versions were compared using the Kruskal-Wallis test.
  
  
  RESULTS
  A total of 778 cases received D-CPR. Of these, 259 were excluded because they met criteria for MTMV (pediatric patients, allergic reaction, etc.), were missing data, or were not initially identified as cardiac arrest. Of the remaining 519 calls, the mean TTFC was 240 seconds, with no significant variation across the MPDS versions (p = 0.08).
  
  
  CONCLUSIONS
  Following the removal of instructions for pulse check and MTMV, as well as other minor changes in the MPDS protocols, we found the overall TTFC to be 240 seconds with little variation across the three versions evaluated. This represents an improvement in TTFC compared with reports of an earlier version of MPDS that included pulse checks and MTMV instructions (315 seconds). However, the MPDS TTFC does not compare favorably with reports of older, non-MPDS protocols that included pulse checks and MTMV. Efforts should continue to focus on improving this key, and modifiable, determinant of cardiac arrest survival.
authors.affiliation: Wake County EMS, Raleigh, North Carolina 27601, USA. lee.vanvleet@co.wake.nc.us
authors.forename: Lee M
authors.initials: LM
authors.lastname: Van Vleet
authors.forename: Michael W
authors.initials: MW
authors.lastname: Hubble
mesh_terms: D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000401:mortality; D016208:Databases, Factual; D004631:Emergency Medical Service Communication Systems / Q000706:statistics & numerical data*; D004632:Emergency Medical Services / Q000379:methods; D004638:Emergency Treatment / Q000379:methods; D005260:Female; D006336:Heart Massage / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality* / Q000628:therapy*; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome