Tissue and wound healing effects of short duration postoperative oxygen therapy

High inspired oxygen versus low inspired oxygen for reducing surgical site infection: a meta-analysis

To perform a meta-analysis of published literature to assess the role of high-concentration inspired oxygen in reducing the incidence of surgical site infections (SSIs) following all types of surgery, a comprehensive search for published randomized controlled trials (RCTs) comparing high- with low-concentration inspired oxygen for SSIs was performed. The related data were extracted by two independent authors. The fixed and random effects methods were used to combine data. Twelve RCTs involving 6750 patients were included. Our pooled result found that no significant difference in the incidence of SSIs was observed between the two groups, but there was high statistic heterogeneity across the studies [risk ratio (RR): 0·91; 95% confidence interval (CI): 0·72-1·14; P = 0·40; I² = 54%]. The sensitivity analysis revealed the superiority of high-concentration oxygen in decreasing the SSI rate (RR: 0·86; 95% CI: 0·75-0·98; P = 0·02). Moreover, a subgroup analysis of studies with intestinal tract surgery showed that patients experienced less SSI when high-concentration inspired oxygen was administrated (RR: 0·53; 95% CI: 0·37-0·74; P = 0·0003). Our study provided no direct support for high-concentration inspired oxygen in reducing the incidence of SSIs in patients undergoing all types of surgery.

Oxygen and wound care: a review of current therapeutic modalities and future direction

While the importance of oxygen to the wound healing process is well accepted, research and technological advances continue in this field and efforts are ongoing to further utilize oxygen as a therapeutic modality. In this paper, the authors briefly review the role of oxygen in wound healing and discuss the distinct mechanism of action as well as the advantages and disadvantages of the three major oxygen-based therapies currently in clinical use (Hyperbaric Oxygen and Topical Oxygen and Continuous Diffusion of Oxygen), as well as review the existing literature regarding these distinct therapeutic modalities.

Low flow oxygenation of full-excisional skin wounds on diabetic mice improves wound healing by accelerating wound closure and reepithelialization

Oxygen-based therapies have proven effective in treating chronic and difficult-to-heal skin wounds, but the current therapeutic approaches suffer from major limitations and they do not allow for continuous wound treatment. Here we examined whether the continuous treatment of wounds with pure oxygen at low flow rates accelerates wound closure and improves wound healing in a murine model of diabetic skin wounds. Two full-excisional dorsal skin wounds were generated on 15-week-old diabetic db/db mice and treated for 10 weeks continuously with pure oxygen (>99·9%) at low flow rates (3 ml/h). After 6 days, oxygen treatment resulted in a mean reduction of the original wound size by 60·2% as compared with only 45·2% in wounds on control mice that did not receive pure oxygen.(P = 0·022). After 10 days, oxygen-treated wounds were 83·1% closed compared with 71·2% in wounds on control mice. While reepithelialisation was complete after 10 days in over 57% of wounds receiving low flow oxygen treatment, significant epithelial gaps remained in 75% wounds from mice that did not receive oxygen. Continuous low flow oxygenation significantly improves healing of diabetic skin wounds in mice and may therefore be an effective treatment for chronic cutaneous and possibly other slow-healing wounds in diabetic patients.

Supplemental perioperative oxygen for reducing surgical site infection: a meta-analysis

OBJECTIVE

To assess the efficacy of supplemental perioperative oxygenation for prevention of surgical site infection (SSI). Data sources Computerized PUBMED and MEDLINE search supplemented by manual searches for relevant articles. Study selection Randomized, controlled trials evaluating efficacy of supplemental perioperative oxygenation versus standard care for prevention of SSI in patients' undergoing colorectal surgery. Data synthesis Data on incidence of SSI were abstracted as dichotomous variables. Pooled estimates of the relative risk (RR) and 95% confidence interval (CI) were obtained using the DerSimonian and Laird random effects model and the Mantel-Haenzel fixed effects model. Heterogeneity was assessed using the Cochran Q statistic and I(2).

RESULTS

Four randomized controlled trials met the inclusion criteria. Supplemental perioperative oxygenation resulted in a reduced incidence of SSI [RR 0.70 (95% CI 0.52-0.94), P = 0.01], using a fixed effects model. Using the more conservative random effects model, the point estimate was similar [RR 0.74 (95% CI 0.39-1.43), P = 0.37], but the results failed to achieve statistical significance. The I(2) test showed moderate heterogeneity.

CONCLUSIONS

Our analysis showed that supplemental perioperative oxygenation is beneficial in preventing SSI in patients undergoing colorectal surgery. Because of heterogeneity in study design and patient population, additional randomized trials are needed to determine whether this confers benefit in all patient populations undergoing other types of surgery. Supplemental perioperative oxygenation is a low-cost intervention that we recommend be implemented in patients undergoing colorectal surgery pending the results of further studies. Further research is needed to determine whether or not supplemental hyperoxia may cause unanticipated adverse effects.

Surgical Site Infections and Supplemental Perioperative Oxygen in Colorectal Surgery Patients: A Systematic Review

BACKGROUND

Four randomized trials have evaluated the impact of supplemental perioperative oxygen on the incidence of surgical site infections (SSIs), with mixed results. The objectives of this meta-analysis were: (1) To evaluate further the effect of supplemental perioperative oxygen on SSIs after colorectal surgery; and (2) to generate a strategy for future studies to determine definitively the value of this intervention.

METHODS

We conducted a MEDLINE search to identify randomized trials of supplemental perioperative oxygen with a primary endpoint of SSI. Fixed-effects and random-effects models were employed, and the null association was tested for each. Tests also were performed for heterogeneity and publication bias.

RESULTS

Four studies were identified that satisfied the search criteria. The total number of patients was 943, of whom 477 received supplemental oxygen and 466 served as controls. The pooled risk ratio (RR) for SSI favored the patients who received supplemental oxygen (RR = 0.68; 95% confidence interval [CI] 0.49, 0.94), but this difference was not maintained with a random-effects model (RR = 0.73; 95% CI 0.42, 1.28; p = 0.27). Heterogeneity was present among the studies. There was no evidence of publication bias.

CONCLUSIONS

Supplemental perioperative oxygen is associated with a lower risk of SSI in patients undergoing colorectal surgery. The heterogeneity among the individual reports may be secondary to differences in study protocols.

Supplemental perioperative oxygen and fluids to improve surgical wound outcomes: Translating evidence into practice

Numerous reports support the concept that tissues require an adequate oxygen supply to heal well and to prevent complications of infection. Adequate oxygen supply to tissue depends on perfusion as well as arterial oxygen tension, and tissue oxygen tension, particularly in peripheral tissues, is dependent on adequate vascular volume. Therefore, potential benefits to wound healing and reduction in infection in postsurgical patients might be attained by judicious manipulation of supplemental oxygen and/or fluids in the perioperative period. This article reviews evidence that suggests such manipulations are beneficial and proposes that integrated care pathways be developed that include these interventions.