Oxygen in Critically Ill Patients: Too Much of a Good Thing Might Do Harm

Increasingly, excess oxygen administration is recognized as a risk factor for adverse outcomes when used perioperatively (NEJM JW Infect Dis Nov 2009 and JAMA 2009; 302:1543) or after myocardial infarction (NEJM JW Hosp Med Aug 2015 and Circulation 2015; 131:2143). But is excessive oxygen harmful in the intensive care unit (ICU) setting?

In this open-label, single-center Italian trial, 480 adults who were admitted to the ICU with >3 days expected length of stay were randomized to receive either a conservative oxygen strategy (lowest possible fraction of inspired oxygen [FiO₂] to keep arterial oxyhemoglobin saturation [SpO₂] at 94%–98% or partial pressure of O₂ [PaO₂] at 70 mm Hg–100 mm Hg) or a conventional ICU oxygen protocol (FiO₂ ≥0.4 to …