Non-pharmacologic prevention of surgical wound infection

Abstract

Surgical site infections are among the most common serious perioperative complications. Infections are established during a decisive period that lasts a few hours after contamination. Adequacy of host immune defenses is the primary factor that determines whether inevitably wound contamination progresses into a clinical infection. As it turns out, many determinants of infection risk are under the direct control of anesthesiologists; factors that are at least as important as prophylactic antibiotics. Major outcome studies demonstrate that the risk of surgical wound infection is reduced threefold simply by keeping patients normothermic. Infection risk is reduced by an additional factor of two by if supplemental oxygen is provided (80% versus 30%) during surgery and for the initial hours after surgery. The contribution, if any, of other factors including, tight glucose control, fluid management, and mild hypercapnia have yet to be suitably tested.

Figures

Fig. 1

Subcutaneous oxygen tension, the primary determinant of wound infection risk, during surgery and in the postoperative care unit (*P 2 = 80% vs. 30%); the effect was less during the postoperative period. Results are expressed as means ± SDs.

Fig. 2

From Akça et al. [114] Relatively small amounts of pulmonary atelectasis were observed on the CT scans, and the percentages did not differ significantly in the patients given 30% oxygen (2.5 ± 3.2%) or 80% oxygen (3.0 ± 1.8%). Results are shown for individual patients, along with the group means and SDs. These data provided a 99% chance of detecting a 2% difference in atelectasis volume at an alpha level of 0.05. Poorly-aerated regions were also comparable between the groups (9.5 ± 4.4% in the patients given 30% oxygen vs. 10.3 ± 4.2% in the patients given 80% oxygen).

Fig. 3

From Kotani et al. [86] the fraction of alveolar macrophages ingesting opsonized and non-opsonized particles during anesthesia with 100% (n = 30, circles) and 30% (n = 30, squares) inspired oxygen. Asterisks (*) indicate statistically significant differences (P < 0.05) from elapsed time zero in each group; pounds signs (#) identify significant differences (P < 0.01) between the two groups. Data are expressed as means ± SDs.

Fig. 4

A of pain scores and tissue oxygenation in patients given intra-articular lidocaine (squares) or saline (circles). Pain scores, on a 100-mm visual-analog scale, were much larger in patients given saline, and their tissue oxygen partial pressures averaged 25 mmHg less. All values differed significantly between the two groups; data are presented as means ± SDs. Reprinted from The Lancet, 354, Akça O, Melischek M, Scheck T, et al. Postoperative pain and subcutaneous oxygen tension. Page 41, Copyright (1999), with permission from Elsevier [63].

Fig. 5

From Akça et al. [112] a study subcutaneous tissue oxygen as a function of end-tidal PCO2 in patients undergoing major surgery. Measurements were made on the lateral aspect of the upper arm with a polargraphic electrode system. The mean oxygen tension in the group given 45 mmHg C02 was significantly greater (P = 0.014) than the group given 30 mmHg. Results are presented as means ± SDs.