title: Initial arterial carbon dioxide tension is associated with neurological outcome after resuscitation from cardiac arrest.
abstract: To determine the relationships between partial pressure of arterial carbon dioxide (PaCO2), prescribed minute ventilation (MV), and neurologic outcome in patients resuscitated from cardiac arrest.
  
  
  
  This was a retrospective cohort study utilizing a multicenter database of adult patients with return of spontaneous circulation (ROSC) after cardiac arrest. The primary outcome was neurologic status at hospital discharge, defined by Cerebral Performance Category (CPC) score: CPC 1-2 was favorable, CPC 3-5 was poor. We compared rates of initial normocarbia (PaCO231-49mmHg) and mean sequential PaCO2measurements obtained over the first 24h. We also assessed the influence of MV on the PaCO2at initial, 6, 12, 18, and 24h after cardiac arrest using univariate linear regression.
  
  
  
  One hundred and fourteen patients from 3 institutions met inclusion criteria. Overall, 46/114 (40.4%, 95% CI: 31.4-49.4%) patients survived to hospital discharge, and 33/114 (28.9%, 20.6-37.2%) had CPC 1-2 at the time of discharge. A total of 38.9% (95% CI: 29.9-47.9%) of patients had initial normocarbia; 43.2% (28.6-57.8%) of these patients were discharged with CPC 1-2, compared with 20.3% (10.8-29.8%) of dyscarbic patients. By 6h, neurologic outcomes were not significantly associated with PaCO2. Prescribed MV was not associated with PaCO2at any time point with the exception of a weak correlation at hour 18.
  
  
  
  Initial normocarbia was associated with favorable neurological outcome in patients resuscitated from cardiac arrest. This relationship was not seen at subsequent time points. There was no significant association between prescribed MV and PaCO2or neurologic outcome.
authors.affiliation: Division of Emergency Medicine, Department of Medicine, University of Washington, Seattle WA, United States. Electronic address: mol.tolins@gmail.com.
authors.forename: Molly L
authors.initials: ML
authors.lastname: Tolins
authors.affiliation: Division of Emergency Medicine, Department of Medicine, University of Washington, Seattle WA, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Henning
authors.affiliation: Department of Emergency Medicine, Sidney Kimmel School of Medicine, Thomas Jefferson University, Philadelphia, PA, United States.
authors.forename: David F
authors.initials: DF
authors.lastname: Gaieski
authors.affiliation: Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, MA, United States.
authors.forename: Anne V
authors.initials: AV
authors.lastname: Grossestreuer
authors.affiliation: Department of Emergency Medicine, Boston Medical Center, Boston, MA, United States.
authors.forename: Alison
authors.initials: A
authors.lastname: Jaworski
authors.affiliation: Division of Emergency Medicine, Department of Medicine, University of Washington, Seattle WA, United States; Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Seattle, WA, United States.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood*; D016887:Cardiopulmonary Resuscitation / Q000401:mortality; D002560:Cerebrovascular Circulation; D016009:Chi-Square Distribution; D016208:Databases, Factual; D005260:Female; D006323:Heart Arrest / Q000097:blood* / Q000401:mortality / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010313:Partial Pressure; D012121:Respiration, Artificial / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D002245:Carbon Dioxide
keywords: Carbon dioxide tension; Cardiac arrest; Cerebral Performance category; Neurological outcome; Normocarbia; PaCO(2)