title: Moderate hyperoxic versus near-physiological oxygen targets during and after coronary artery bypass surgery: a randomised controlled trial.
abstract: BACKGROUND
  The safety of perioperative hyperoxia is currently unclear. Previous studies in patients undergoing coronary artery bypass surgery suggest reduced myocardial damage when avoiding extreme perioperative hyperoxia (>400 mmHg). In this study we investigated whether an oxygenation strategy from moderate hyperoxia to a near-physiological oxygen tension reduces myocardial damage and improves haemodynamics, organ dysfunction and oxidative stress.
  
  
  METHODS
  This was a single-blind, single-centre, open-label, randomised controlled trial in patients undergoing elective coronary artery bypass surgery. Fifty patients were randomised to a partial pressure of oxygen in arterial blood (PaO2) target of 200-220 mmHg during cardiopulmonary bypass and 130-150 mmHg during intensive care unit (ICU) admission (control group) versus lower targets of 130-150 mmHg during cardiopulmonary bypass and 80-100 mmHg at the ICU (conservative group). Primary outcome was myocardial injury (CK-MB and Troponin-T) at ICU admission and 2, 6 and 12 hours thereafter.
  
  
  RESULTS
  Weighted PaO2 during cardiopulmonary bypass was 220 mmHg (interquartile range (IQR) 211-233) vs. 157 (151-162) in the control and conservative group, respectively (P < 0.0001). During ICU admission, weighted PaO2 was 107 mmHg (86-141) vs. 90 (84-98) (P = 0.03), respectively. Area under the curve of CK-MB was median 23.5 μg/L/h (IQR 18.4-28.1) vs. 21.5 (15.8-26.6) (P = 0.35) and 0.30 μg/L/h (0.25-0.44) vs. 0.39 (0.24-0.43) (P = 0.81) for Troponin-T. Cardiac index, systemic vascular resistance index, creatinine, lactate and F2-isoprostane levels were not different between groups.
  
  
  CONCLUSIONS
  Compared to moderate hyperoxia, a near-physiological oxygen strategy does not reduce myocardial damage in patients undergoing coronary artery bypass surgery. Conservative oxygen administration was not associated with increased lactate levels or hypoxic events.
  
  
  BACKGROUND
  Netherlands Trial Registry NTR4375, registered on 30 January 2014.
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands. b.smit@vumc.nl.
authors.forename: Bob
authors.identifier: http://orcid.org/0000-0003-0862-8014
authors.initials: B
authors.lastname: Smit
authors.affiliation: Department of Internal Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Yvo M
authors.initials: YM
authors.lastname: Smulders
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Monique C
authors.initials: MC
authors.lastname: de Waard
authors.affiliation: Department of Anaesthesiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Christa
authors.initials: C
authors.lastname: Boer
authors.affiliation: Department of Cardiothoracic Surgery, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Alexander B A
authors.initials: AB
authors.lastname: Vonk
authors.affiliation: Department of Cardiothoracic Surgery, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Dennis
authors.initials: D
authors.lastname: Veerhoek
authors.affiliation: Department of Anaesthesiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Kamminga
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Harm-Jan S
authors.initials: HJ
authors.lastname: de Grooth
authors.affiliation: Department of Molecular Cell Biology & Immunology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: García-Vallejo
authors.affiliation: Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Rene J P
authors.initials: RJ
authors.lastname: Musters
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Armand R J
authors.initials: AR
authors.lastname: Girbes
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Heleen M
authors.initials: HM
authors.lastname: Oudemans-van Straaten
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Angelique M E
authors.initials: AM
authors.lastname: Spoelstra-de Man
mesh_terms: D000368:Aged; D000758:Anesthesia; D001784:Blood Gas Analysis; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality*; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D009426:Netherlands; D011183:Postoperative Complications / Q000517:prevention & control; D016037:Single-Blind Method
keywords: CABG; Cardiac surgery; Hyperoxia; Intensive care unit; Oxygen