Preliminary observations in systemic oxygen consumption during targeted temperature management after cardiac arrest

Resuscitation. 2018 Jun;127:89-94. doi: 10.1016/j.resuscitation.2018.04.001. Epub 2018 Apr 4.

Abstract

Aim: Limited data suggests low oxygen consumption (VO2), driven by mitochondrial injury, is associated with mortality after cardiac arrest. Due to the challenges of measurement in the critically ill, post-arrest metabolism remains poorly characterized. We monitored VO2, carbon dioxide production (VCO2) and the respiratory quotient (RQ) in post-arrest patients and explored associations with outcome.

Methods: Using a gas exchange monitor, we measured continuous VO2 and VCO2 in post- arrest patients treated with targeted temperature management. We used area under the curve and medians over time to evaluate the association between VO2, VCO2, RQ and the VO2:lactate ratio with survival.

Results: In 17 patients, VO2 in the first 12 h after return of spontaneous circulation (ROSC) was associated with survival (median in survivors 3.35 mL/kg/min [2.98,3.88] vs. non-survivors 2.61 mL/kg/min [2.21,2.94], p = .039). This did not persist over 24 h. The VO2:lactate ratio was associated with survival (median in survivors 1.4 [IQR: 1.1,1.7] vs. non-survivors 0.8 [IQR: 0.6,1.2] p < 0.001). Median RQ was 0.66 (IQR 0.63,0.70) and 71% of RQ measurements were <0.7. Patients with initial RQ < 0.7 had 17% survival versus 64% with initial RQ > 0.7 (p = .131). VCO2 was not associated with survival.

Conclusions: There was a significant association between VO2 and mortality in the first 12 h after ROSC, but not over 24 h. Lower VO2: lactate ratio was associated with mortality. A large percentage of patients had RQs below physiologic norms. Further research is needed to explore whether these parameters could have true prognostic value or be a potential treatment target.

Keywords: Cardiopulmonary resuscitation; Cell respiration; Energy metabolism; Heart arrest; Oxygen consumption.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Area Under Curve
  • Female
  • Heart Arrest / therapy*
  • Humans
  • Hypothermia, Induced / mortality*
  • Male
  • Middle Aged
  • Monitoring, Physiologic
  • Oxygen Consumption*
  • Prospective Studies
  • Pulmonary Gas Exchange*
  • Respiration, Artificial