title: Association of Arterial Oxygen Tension During In-Hospital Cardiac Arrest With Return of Spontaneous Circulation and Survival.
abstract: BACKGROUND
  Despite numerous advances in the delivery of resuscitative care, in-hospital cardiac arrest (IHCA) continues to be associated with high morbidity and mortality. We sought to study the impact of arterial oxygen tension (Pao2) on return of spontaneous circulation (ROSC) and survival to discharge in patients with IHCA.
  
  
  METHODS
  The study population included 255 consecutive patients who underwent advanced cardiac life support-guided resuscitation from January 2012 to December 2013 for IHCA at an academic tertiary medical center. Of these patients, 167 underwent arterial blood gas testing at the time of the arrest. Baseline demographic, clinical, laboratory, and clinical outcome data were recorded. The primary outcome of interest was survival to hospital discharge. Secondary outcome of interest was presence of ROSC.
  
  
  RESULTS
  Of the 167 patients studied, Pao2categorization included the following: Pao2< 60 mm Hg (n = 38), Pao2of 60-92 mm Hg (n = 44), Pao2of 93 to 159 mm Hg (n = 43), Pao2of 160 to 299 mm Hg (n = 24), and Pao2≥ 300 mm Hg (n = 18). Patients with higher Pao2levels during the time of cardiac arrest were noted to have higher rates of hypertension and chronic kidney disease. Clinical presentation of IHCA, in particular, the initial rhythm, location of IHCA, and duration of cardiopulmonary resuscitation, was similar in all groups. Patients with higher Pao2levels had higher platelet count, higher arterial pH, and lower arterial carbon dioxide tension (Pco2). With respect to outcomes, patients with higher intra-arrest Pao2levels had progressively higher rates of ROSC (58% vs 71% vs 72% vs 79% vs 100%, P = .021) and survival to discharge (16% vs 23% vs 30% vs 33% vs 56%, P = .031). In multivariate analysis, Pao2≥ 300 mm Hg was independently associated with higher survival to discharge (odds ratio 60.68; 95% confidence interval: 3.04-1210.28; P = .007; referent Pao2< 60 mm Hg).
  
  
  CONCLUSIONS
  Higher intra-arrest Pao2is independently associated with higher rates of survival to discharge in adults with IHCA.
authors.affiliation: 1 Resuscitation Research Group, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Stony Brook University Medical Center, Stony Brook, NY, USA.
authors.forename: Jignesh K
authors.initials: JK
authors.lastname: Patel
authors.affiliation: 2 Department of Preventive Medicine, Stony Brook University Medical Center, Stony Brook, NY, USA.
authors.forename: Elinor
authors.initials: E
authors.lastname: Schoenfeld
authors.affiliation: 3 Division of Cardiovascular Medicine, Department of Medicine, State University of New York at Stony Brook, Stony Brook, NY, USA.
authors.forename: Puja B
authors.initials: PB
authors.lastname: Parikh
authors.affiliation: 1 Resuscitation Research Group, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Stony Brook University Medical Center, Stony Brook, NY, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Parnia
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001784:Blood Gas Analysis; D016887:Cardiopulmonary Resuscitation; D005260:Female; D006323:Heart Arrest / Q000097:blood* / Q000401:mortality / Q000503:physiopathology; D017052:Hospital Mortality; D006801:Humans; D018496:Hyperoxia / Q000097:blood* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010351:Patient Discharge / Q000706:statistics & numerical data*; D020127:Recovery of Function / Q000502:physiology*; D015996:Survival Rate
chemical_list: D015415:Biomarkers; D010100:Oxygen
keywords: Pao2; cardiac arrest; cardiopulmonary resuscitation; oxygen; oxygen delivery; return of spontaneous circulation; survival