Eligible infants are infants of less than 44 weeks postconceptional age and without pulmonary disease or demand for supplemental oxygen or assisted ventilation. Control subjects receive current standard of care (anesthesia induction/pre-oxygenation with 80%, maintenance of anesthesia with 40%, and recovery with 80% inspired oxygen). Intervention subjects are maintained on room air throughout the procedure and supplemental oxygen added only if necessary according to the pre-specified oxygen saturation target. Subjects are monitored according to clinical protocols AND with cerebral oximetry (NIRS), transcutaneous measurement of partial pressure of oxygen (pO2), and blood-gas analyses. Blood and urine samples are collected for later analysis of markers for oxidative stress.