Background and Goal of Study: The potential clinical benefits of the perioperative use of high inspired oxygen fraction (FIO2) for preventing surgical site infections (SSIs) have attracted great interest in recent years. Trials demonstrated that SSIs decreased significantly following colon surgery in patients who received 80% oxygen intraoperatively and for the first hours following surgery. In cardiac surgery, SSIs are serious complications associated with extended hospital stay, increased hospital costs, and higher mortality and morbidity rates.3
In contrast to the findings of Belda et al.2, clinical trials by Pryor et al.4 and, more recently, by Meyhoff et al.5, found no difference in SSI risk when 80% oxygen rather than 30% oxygen was administered during abdominal surgery and for 2 hours postoperatively. Their findings suggested that perioperative hyperoxia was not effective in reducing SSIs. These reports add to the evidence base surrounding the potential role of high FIO2 in SSI prevention.
The rationale for administering high FIO2 to prevent SSIs is to produce a high PaO2 and thereby increase the PsqO2 (tissue oxygen partial pressure), since oxidative killing by neutrophils is the primary defense against surgical pathogens. The risk of infection is thus inversely related to PsqO2.3 Our aim in this study was to analyze the relationship between PaO2 values and SSIs.
Materials and Methods: We designed a prospective study that analyzed the data from 1,024 consecutive patients who underwent cardiac surgery with extracorporeal circulation at our institution from January 30, 2007 to June 30, 2009. The patients were categorized according to the presence or absence of SSIs. The SPSS software package (version 15) was used for statistical analysis. A p < 0.05 was considered significant.
Results and Discussion: SSIs developed after cardiac surgery in 54 (5.3%) patients, 28 (2.8%) superficial or deep incision SSIs and 26 (2.5%) organ/space SSIs. The intraoperative and postoperative PaO2 values were not associated with an increased risk of SSI either by univariate or multivariate analysis. The 30-day mortality rate was similar in both groups: patients without SSIs, n = 72 (7.4%) vs. patients with SSIs, n = 4 (7.4%); (P = .11).
Conclusion(s): Tissue oxygenation improves much less than arterial oxygen in response to supplemental oxygen administration.The PaO2 in adult cardiac surgery patients is not related to SSI rate.