NEW YORK (Reuters Health) – Women given supplemental oxygen during and after cesarean delivery do not have decreased rates of wound infection or endometritis, according to a new study published online June 20 in the American Journal of Obstetrics and Gynecology.
Oxidative killing of bacteria by neutrophils depends on the production of superoxide radicals, which in turn is dependent on the partial pressure of oxygen in tissue, explain the researchers. Since wounds are hypoxic because of impaired vascular supply, it is biologically plausible that raising wound oxygen tension by increasing inspired oxygen could reduce the risk of postoperative wound infections.
This strategy has been tested in general and gynecological surgery patients with mixed results. Notwithstanding the fact that one trial involving women undergoing c-section was stopped for futility, Dr. Christina M. Scifres and colleagues at the Washington University School of Medicine in St. Louis, Missouri conducted a randomized trial of supplemental oxygen in 584 women undergoing cesarean delivery.
Women assigned to the standard-care group were given 2 liters of oxygen via nasal cannula during delivery only, while those in the intervention group were given 10 liters of oxygen via non-rebreather mask during cesarean delivery and were encouraged to continue with the mask for 2 hours postop.
The participants were followed for 1 month. Infectious morbidity, including wound infection and endometritis, developed in 25 of 297 women (8.8%) receiving standard care compared with 35 of 288 women (12.2%) in the supplemental oxygen group, the team found. The between-group difference (relative risk 1.4) was not statistically significant.
“Since we did not observe a benefit of supplemental oxygen in reducing post-cesarean infectious morbidity in the overall study, or in any particular subgroup, we do not recommend the use of supplemental oxygen for the prevention of post-cesarean infectious morbidity,” Dr. Scifres and colleagues conclude. “The decision to administer oxygen therapy in women undergoing cesarean delivery should be based on maternal and fetal physiologic needs.”
Supplemental Oxygen for the Prevention of Post-Cesarean Infectious Morbidity: A Randomized Controlled Trial
Am J Obstet Gynecol 2011.