title: Electrical and mechanical recovery of cardiac function following out-of-hospital cardiac arrest.
abstract: BACKGROUND
  Compression pauses may be particularly harmful following the electrical recovery but prior to the mechanical recovery from cardiopulmonary arrest.
  
  
  RESULTS
  A convenience sample of patients with out-of-hospital cardiac arrest (OOHCA) were identified. Data were exported from defibrillators to define compression pauses, electrocardiogram rhythm, PetCO2, and the presence of palpable pulses. Pulse-check episodes were randomly assigned to a derivation set (one-third) and a validation set (two-thirds). Both an unweighted and a weighted receiver-operator curve (ROC) analysis were performed on the derivation set to identify optimal thresholds to predict ROSC using heart rate and PetCO2. A sequential decision guideline was generated to predict the presence of ROSC during compressions and confirm perfusion once compressions were stopped. The ability of this decision guideline to correctly identify pauses in which pulses were and were not palpated was then evaluated. A total of 145 patients with 349 compression pauses were included. The ROC analyses on the derivation set identified an optimal pre-pause heart rate threshold of >40 beats min(-1) and an optimal PetCO2 threshold of >20 mmHg to predict ROSC. A sequential decision guideline was developed using pre-pause heart rate and PetCO2 as well as the PetCO2 pattern during compression pauses to predict and rapidly confirm ROSC. This decision guideline demonstrated excellent predictive ability to identifying compression pauses with and without palpable pulses (positive predictive value 95%, negative predictive value 99%). The mean latency period between recovery of electrical and mechanical cardiac function was 78 s (95% CI 36-120 s).
  
  
  CONCLUSIONS
  Heart rate and PetCO2 can predict ROSC without stopping compressions, and the PetCO2 pattern during compression pauses can rapidly confirm ROSC. Use of a sequential decision guideline using heart rate and PetCO2 may reduce unnecessary compression pauses during critical moments during recovery from cardiopulmonary arrest.
authors.affiliation: Division of Emergency Medicine, Department of Medicine, UC San Diego, San Diego, CA, United States. davismd@cox.net
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Davis
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Sell
authors.forename: Nathan
authors.initials: N
authors.lastname: Wilkes
authors.forename: Renee
authors.initials: R
authors.lastname: Sarno
authors.forename: Ruchika D
authors.initials: RD
authors.lastname: Husa
authors.forename: Edward M
authors.initials: EM
authors.lastname: Castillo
authors.forename: Brenna
authors.initials: B
authors.lastname: Lawrence
authors.forename: Roger
authors.initials: R
authors.lastname: Fisher
authors.forename: Criss
authors.initials: C
authors.lastname: Brainard
authors.forename: James V
authors.initials: JV
authors.lastname: Dunford
mesh_terms: D000368:Aged; D019540:Area Under Curve; D002140:California; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000503:physiopathology* / Q000628:therapy*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D020127:Recovery of Function; D012680:Sensitivity and Specificity; D016896:Treatment Outcome