title: The impact of severe acidemia on neurologic outcome of cardiac arrest survivors undergoing therapeutic hypothermia.
abstract: BACKGROUND
  Therapeutic Hypothermia (TH) has become a standard of care in improving neurological outcomes in cardiac arrest (CA) survivors. Previous studies have defined severe acidemia as plasma pH<7.20. We investigated the influence of severe acidemia at the time of initiation of TH on neurological outcome in CA survivors.
  
  
  METHODS
  A retrospective analysis was performed on 196 consecutive CA survivors (out-of-hospital CA and in-hospital CA) who underwent TH with endovascular cooling between January 2007 and October 2012. Arterial blood gas drawn prior to initiation of TH was utilized to measure pH in all patients. Shockable and non-shockable CA patients were divided into two sub-groups based on pH (pH<7.2 and pH≥7.2). The primary end-point was measured using the Pittsburgh Cerebral Performance Category (CPC) scale prior to discharge from the hospital: good (CPC 1 and 2) and poor (CPC 3 to 5) neurologic outcome.
  
  
  RESULTS
  Sixty-two percent of shockable CA patients with pH≥7.20 had good neurological outcome as compared to 34% patients with pH<7.20. Shockable CA patients with pH≥7.20 were 3.3 times more likely to have better neurological outcome when compared to those with pH <7.20 [p=0.013, OR 3.3, 95% CI (1.28-8.45)]. In comparison, non-shockable CA patients with p≥7.20 did not have a significantly different neurological outcome as compared to those with pH<7.20 [p=0.97, OR 1.02, 95% CI (0.31-3.3)].
  
  
  CONCLUSIONS
  Presence of severe acidemia at initiation of TH in shockable CA survivors is significantly associated with poor neurological outcomes. This effect was not observed in the non-shockable CA survivors.
authors.affiliation: Division of Cardiology, The Henry Low Heart Center, Hartford Hospital, Hartford, CT, USA.
authors.forename: Harsha V
authors.initials: HV
authors.lastname: Ganga
authors.forename: Kamala R
authors.initials: KR
authors.lastname: Kallur
authors.forename: Nishant B
authors.initials: NB
authors.lastname: Patel
authors.forename: Kelly N
authors.initials: KN
authors.lastname: Sawyer
authors.forename: Pampana B
authors.initials: PB
authors.lastname: Gowd
authors.forename: Sanjeev U
authors.initials: SU
authors.lastname: Nair
authors.forename: Venkata K
authors.initials: VK
authors.lastname: Puppala
authors.forename: Aswathnarayan R
authors.initials: AR
authors.lastname: Manandhi
authors.forename: Ankur V
authors.initials: AV
authors.lastname: Gupta
authors.forename: Justin B
authors.initials: JB
authors.lastname: Lundbye
mesh_terms: D000138:Acidosis / Q000150:complications*; D000368:Aged; D005260:Female; D006323:Heart Arrest / Q000097:blood* / Q000150:complications; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007036:Hypothermia, Induced / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: Acidemia; Cardiac arrest; Hypothermia; Neurological outcome