Hyperoxia During Cardiopulmonary Bypass Is Associated With Mortality in Infants Undergoing Cardiac Surgery*

Abstract

Patients undergoing cardiac surgery using cardiopulmonary bypass have variable degrees of blood oxygen tension during surgery. Hyperoxia has been associated with adverse outcomes in critical illness. Data are not available regarding the association of hyperoxia and outcomes in infants undergoing cardiopulmonary bypass. We hypothesize that among infants undergoing cardiac surgery, hyperoxia during cardiopulmonary bypass is associated with greater odds of morbidity and mortality.DESIGN: Retrospective study. SETTING: Single center at an academic tertiary children's hospital.

Editor’s Choice Articles for May

“…Beshish AG, Jahadi O, Mello A, et al: Hyperoxia During Cardiopulmonary Bypass is Associated With Mortality in Infants Undergoing Cardiac Surgery (1).…”

Linking Hyperoxia and Harm: Consequence or Merely Subsequence?*

“…Psychologist Baron-Cohen (18) argues that the "systematizer" (pattern recognition) trait is key in human creativity, inventiveness, and progress. Beshish et al (3) have recognized a clear pattern in their data, which could lead to important progress. Now, we need to try to reproduce the association in other populations and to hunt for unmeasured confounders.…”

“…Or maybe hyperoxia reflects a more generally inappropriate aggressive approach that is harmful via other mechanisms. Although appealingly simple, this "hyperoxia as a marker of general overtreatment" argument does not easily explain the association of death with hyperoxia on cardiopulmonary bypass as described by Beshish et al (3). Operative bypass is a decrete and shortlived exposure outside of the ICU.…”

Statistical Note: Confounding and Causality in Observational Studies

“…In the accompanying editorial, Dr. Peters highlights the natural temptation that we all have to infer causal relationships from patterns proximate to one another in time and space (3). Indeed, several studies have examined the relationship between hyperoxemia and outcome among critically ill children and identified associations between supra-physiologic oxygen levels and mortality (2,(4)(5)(6)(7)(8)(9)(10)(11)(12). It is a research question with a biologically plausible basis in that reactive oxygen species are recognized to wreak molecular havoc in cells and tissue.…”

“…As already mentioned, illness severity is an important confounder in many studies examining the relationship between hyperoxemia and outcome. A common technique to control for illness severity is multivariable modeling, often incorporating some version of a validated measure of disease severity, such as the Pediatric Risk of Mortality (PRISM) score, Pediatric Index of Mortality (PIM), or Pediatric Logistic Organ Dysfunction (PELOD) score (2,4,6,(8)(9)(10)(11). Each of these scoring systems has a track record that includes external validation and robust predictive performance.…”