Peri-Operative Oxygen and the Risk of Surgical Infection

Efficacy of Strategies Intended to Prevent Surgical Site Infection After Lower Limb Revascularization Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The objective of this study is to evaluate the efficacy of strategies intended to prevent surgical site infection (SSI) after lower limb revascularization surgery.

BACKGROUND

SSIs are common, costly complications of lower limb revascularization surgery associated with significant morbidity and mortality.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and Evidence-Based Medicine Reviews (inception to April 28, 2022). Two investigators independently screened abstracts and full-text articles, extracted data, and assessed the risk of bias. We included randomized controlled trials (RCTs) that evaluated strategies intended to prevent SSI after lower limb revascularization surgery for peripheral artery disease. We used random-effects models to pool data and GRADE to assess certainty.

RESULTS

Among 6258 identified citations, we included 26 RCTs (n=4752 patients) that evaluated 12 strategies to prevent SSI. Preincision antibiotics [risk ratio (RR)=0.25; 95% CI, 0.11-0.57; n=4 studies; I2 statistic=7.1%; high certainty] and incisional negative-pressure wound therapy (iNPWT) (RR=0.54; 95% CI, 0.38-0.78; n=5 studies; I2 statistic=7.2%; high certainty) reduced pooled risk of early (≤30 days) SSI. iNPWT also reduced the risk of longer-term (>30 days) SSI (pooled-RR=0.44; 95% CI, 0.26-0.73; n=2 studies; I2 =0%; low certainty). Strategies with uncertain effects on risk of SSI included preincision ultrasound vein mapping (RR=0.58; 95% CI, 0.33-1.01; n=1 study); transverse groin incisions (RR=0.33; 95% CI, 0.097-1.15; n=1 study), antibiotic-bonded prosthetic bypass grafts (RR=0.74; 95% CI, 0.44-1.25; n=1 study; n=257 patients), and postoperative oxygen administration (RR=0.66; 95% CI, 0.42-1.03; n=1 study) (low certainty for all).

CONCLUSIONS

Preincision antibiotics and iNPWT reduce the risk of early SSI after lower limb revascularization surgery. Confirmatory trials are required to determine whether other promising strategies also reduce SSI risk.

Effectiveness of supplemental oxygenation to prevent surgical site infections: A systematic review with meta-analysis

OBJECTIVE

to assess the effectiveness of supplemental oxygenation with high FiO2 when compared to conventional FiO2 in the prevention of surgical site infection.

METHOD

an effectiveness systematic review with meta-analysis conducted in five international databases and portals. The research was guided by the following question: Which is the effectiveness of supplemental oxygenation with high FiO2 (greater than 80%) when compared to conventional FiO2 (from 30% to 35%) in the prevention of surgical site infections in adults?

RESULTS

fifteen randomized clinical trials were included. Although all the subgroups presented a general effect in favor of the intervention, colorectal surgeries had this relationship evidenced with statistical significance (I2=10%;X2=4.42; p=0.352).

CONCLUSION

inspired oxygen fractions greater than 80% during the perioperative period in colorectal surgeries have proved to be effective to prevent surgical site infections, reducing their incidence by up to 27% (p=0.006). It is suggested to conduct new studies in groups of patients subjected to surgeries from other specialties, such as cardiac and vascular. PROSPERO registration No.: 178,453.

Efectividad de la oxigenación suplementaria para prevenir la infección del sitio quirúrgico: revisión sistemática con metaanálisis

Resumen Objetivo: evaluar la efectividad de la oxigenación suplementaria con FiO2 elevada en comparación con la FiO2 convencional para prevenir la infección del sitio quirúrgico. Método: revisión sistemática de eficacia con metaanálisis en cinco bases de datos y portales internacionales. La investigación se guio por la pregunta: ¿Qué tan eficaz es la oxigenación suplementaria con FiO2 alta (más del 80%) en comparación con la FiO2 convencional (del 30 al 35%) para prevenir la infección del sitio quirúrgico en adultos? Resultados: se incluyeron quince ensayos clínicos aleatorizados. Aunque todos los subgrupos mostraron un efecto general a favor de la intervención, en las cirugías colorrectales esa relación tenía significancia estadística (I2=10%; X²=4,42; p=0,352). Conclusión: una fracción inspirada de oxígeno superior al 80% durante el perioperatorio en cirugías colorrectales ha demostrado ser eficaz en la prevención de la infección del sitio quirúrgico, reduciendo su incidencia hasta en un 27% (p=0,006). Se sugiere realizar más estudios en grupos de pacientes sometidos a cirugías en otras especialidades, como cardiaca y vascular. Registro PROSPERO: 178453.

Supplemental Perioperative Oxygen to Reduce Surgical Site Infection After High-Energy Fracture Surgery (OXYGEN Study)

Supplemental perioperative oxygen (SPO) therapy has been proposed as one approach for reducing the risk of surgical site infection (SSI). Current data are mixed regarding efficacy in decreasing SSI rates and hospital inpatient stays in general and few data exist for orthopaedic trauma patients. This study is a phase III, double-blind, prospective randomized clinical trial with a primary goal of assessing the efficacy of 2 different concentrations of perioperative oxygen in the prevention of SSIs in adults with tibial plateau, pilon (tibial plafond), or calcaneus fractures at higher risk of infection and definitively treated with plate and screw fixation. Patients are block randomized (within center) in a 1:1 ratio to either treatment group (FiO2 80%) or control group (FiO2 30%) and stratified by each study injury location. Secondary objectives of the study are to compare species and antibacterial sensitivities of the bacteria in patients who develop SSIs, to validate a previously developed risk prediction model for the development of SSI after fracture surgery, and to measure and compare resource utilization and cost associated with SSI in the 2 study groups. SPO is a low cost and readily available resource that could be easily disseminated to trauma centers across the country and the world if proved to be effective.

Pathogenesis of infection in surgical patients

Purpose of review

Despite the application of prophylactic antimicrobial therapy and advanced technologies, infection remains one of the most common causes of morbidity and mortality in surgical patients. Understanding the pathogenesis of surgical infection would offer new insights into the development of biomarkers to predict and stratify infection in patients, and to explore specific strategies to minimize this serious postoperative complication.

Recent findings

The acute nonspecific inflammatory response triggered by endogenous danger signals evoked by surgical insult is beneficial, while paradoxically associated with reduced resistance to infection. There is growing evidence indicating that primed inflammation by surgical insult exaggerates the dysregulation of the immune-inflammatory response to the invasion of pathogens postoperatively. Innate immune receptors, such as Toll-like receptors (TLRs), contribute to detecting both pathogen-associated molecular patterns and endogenous damage-associated molecular patterns, and to further amplifying inflammatory responses to infection. Current evidence shows the fascinating role of non-TLRs in the process of infection. Non-TLRs, such as membrane-associated triggering receptor expressed on myeloid cells family, cytosolic nucleotide-binding oligomerization domain-like receptors and nuclear receptor nuclear family 4 subgroup A receptors, are also crucial in triggering the immune responses and mounting an effective defense against surgical insults and the second hit of infection.

Summary

Understanding the pivotal role of non-TLRs in sensing exogenous and endogenous molecules, and the influence of primed systemic inflammation and depressed immune status on the defense against pathogen after surgical insult, would be helpful to fully explore the relevant sophisticated phenomena of surgical infection, and to elucidate the occurrence of heterogeneous constellations of clinical signs and symptoms among this special population.

The effects of high perioperative inspiratory oxygen fraction for adult surgical patients

BACKGROUND

Available evidence on the effects of a high fraction of inspired oxygen (FIO2) of 60% to 90% compared with a routine fraction of inspired oxygen of 30% to 40%, during anaesthesia and surgery, on mortality and surgical site infection has been inconclusive. Previous trials and meta-analyses have led to different conclusions on whether a high fraction of supplemental inspired oxygen during anaesthesia may decrease or increase mortality and surgical site infections in surgical patients.

OBJECTIVES

To assess the benefits and harms of an FIO2 equal to or greater than 60% compared with a control FIO2 at or below 40% in the perioperative setting in terms of mortality, surgical site infection, respiratory insufficiency, serious adverse events and length of stay during the index admission for adult surgical patients.We looked at various outcomes, conducted subgroup and sensitivity analyses, examined the role of bias and applied trial sequential analysis (TSA) to examine the level of evidence supporting or refuting a high FIO2 during surgery, anaesthesia and recovery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, BIOSIS, International Web of Science, the Latin American and Caribbean Health Science Information Database (LILACS), advanced Google and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) up to February 2014. We checked the references of included trials and reviews for unidentified relevant trials and reran the searches in March 2015. We will consider two studies of interest when we update the review.

SELECTION CRITERIA

We included randomized clinical trials that compared a high fraction of inspired oxygen with a routine fraction of inspired oxygen during anaesthesia, surgery and recovery in individuals 18 years of age or older.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. We conducted random-effects and fixed-effect meta-analyses, and for dichotomous outcomes, we calculated risk ratios (RRs). We used published data and data obtained by contacting trial authors.To minimize the risk of systematic error, we assessed the risk of bias of the included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied trial sequential analyses. We used Grades of Recommendation, Assessment, Development and Evaluation (GRADE) to assess the quality of the evidence.

MAIN RESULTS

We included 28 randomized clinical trials (9330 participants); in the 21 trials reporting relevant outcomes for this review, 7597 participants were randomly assigned to a high fraction of inspired oxygen versus a routine fraction of inspired oxygen.In trials with an overall low risk of bias, a high fraction of inspired oxygen compared with a routine fraction of inspired oxygen was not associated with all-cause mortality (random-effects model: RR 1.12, 95% confidence interval (CI) 0.93 to 1.36; GRADE: low quality) within the longest follow-up and within 30 days of follow-up (Peto odds ratio (OR) 0.99, 95% CI 0.61 to 1.60; GRADE: low quality). In a trial sequential analysis, the required information size was not reached and the analysis could not refute a 20% increase in mortality. Similarly, when all trials were included, a high fraction of inspired oxygen was not associated with all-cause mortality to the longest follow-up (RR 1.07, 95% CI 0.87 to 1.33) or within 30 days of follow-up (Peto OR 0.83, 95% CI 0.54 to 1.29), both of very low quality according to GRADE. Neither was a high fraction of inspired oxygen associated with the risk of surgical site infection in trials with low risk of bias (RR 0.86, 95% CI 0.63 to 1.17; GRADE: low quality) or in all trials (RR 0.87, 95% CI 0.71 to 1.07; GRADE: low quality). A high fraction of inspired oxygen was not associated with respiratory insufficiency (RR 1.25, 95% CI 0.79 to 1.99), serious adverse events (RR 0.96, 95% CI 0.65 to 1.43) or length of stay (mean difference -0.06 days, 95% CI -0.44 to 0.32 days).In subgroup analyses of nine trials using preoperative antibiotics, a high fraction of inspired oxygen was associated with a decrease in surgical site infections (RR 0.76, 95% CI 0.60 to 0.97; GRADE: very low quality); a similar effect was noted in the five trials adequately blinded for the outcome assessment (RR 0.79, 95% CI 0.66 to 0.96; GRADE: very low quality). We did not observe an effect of a high fraction of inspired oxygen on surgical site infections in any other subgroup analyses.

AUTHORS' CONCLUSIONS

As the risk of adverse events, including mortality, may be increased by a fraction of inspired oxygen of 60% or higher, and as robust evidence is lacking for a beneficial effect of a fraction of inspired oxygen of 60% or higher on surgical site infection, our overall results suggest that evidence is insufficient to support the routine use of a high fraction of inspired oxygen during anaesthesia and surgery. Given the risk of attrition and outcome reporting bias, as well as other weaknesses in the available evidence, further randomized clinical trials with low risk of bias in all bias domains, including a large sample size and long-term follow-up, are warranted.

Effect of postoperative use of nasal oxygen catheter supplementation in wound healing following total knee arthroplasty

OBJECTIVES

Healing is an event that is fundamental to the success of total knee arthroplasty. The aims of the present study were to compare the rates of complications related to wound healing between two groups of volunteers submitted to total knee arthroplasty and to evaluate the effects of postoperative oxygen supplementation by means of a nasal catheter.

METHOD

A total of 109 patients who underwent total knee arthroplasty were randomized into two groups, namely, groups that did and did not receive postoperative oxygen supplementation via a nasal catheter. The surgical wound was monitored every day during the hospital stay and on the 7th, 14th, 21st, 30th and 42nd postoperative days. Characteristics related to healing were observed, including hyperemia, dehiscence, necrosis, phlyctenules and deep and superficial infection.

RESULTS

There were no cases of deep infection. Hyperemia was statistically correlated with the total number of complications in the groups, with oxygen demonstrated to be a protective factor against hyperemia. Approximately 30% of the patients who exhibited hyperemia had other complications, independent of oxygen supplementation.

CONCLUSION

Oxygen supplementation following total knee arthroplasty was shown to be effective in diminishing hyperemia around the operative wound. The development of hyperemia was a precursor to other complications, irrespective of whether oxygen supplementation was used.

Surgeon behavior and knowledge on hand scrub and skin antisepsis in the operating room

BACKGROUND

Surgical site infections adversely affect patients' well-being. In this study, hand-washing details and adherence to surgical site antisepsis applications among surgical staff were observed and recorded. Then, a questionnaire was given to test surgeons' theoretical knowledge on operating room principles.

METHODS

Staffs from 5 surgical units were selected (surgeons and nurses from general surgery, urology, plastic surgery, thoracic surgery, and gynecology and obstetrics) and observed. They were questioned on the choice and properties of antiseptics, proper duration of hand washing and use of brushes, and essentials of patient skin antisepsis.

RESULTS

A total of 107 observations (53 residents, 27 nurses, 6 attending staff, and 21 academic staff) were done. Overall mean (± standard deviation) hand-washing time was 69.1 (49.8) seconds (range: 43.8-98; p: 0.001). Overall, 79 (73.8%) never used a brush, 18 (16.8%) used the brush for the nails only, and 10 (9.4) used the brush for hands and arms as well as the nails. Mean (± standard deviation) time from the application of skin antiseptic to surgical incision time was 6.7 (3.5) minutes (p: 0.088). According to the questionnaire, surgeons believed that proper hand-washing time should be 4.2 ± 2.8 minutes (p = 0.13). Brush usage was questioned and 50 (70.4%) favored brush usage whereas 21 (29.6%) were against it. The question for mechanism of action of povidone iodine is answered as 'bactericidal' by only 69%.

CONCLUSION

The study shows that both adherence to local hand-hygiene protocols and surgical staffs' basic knowledge about surgical antisepsis are low.

Perioperative supplemental oxygen to reduce surgical site infection after open fixation of high-risk fractures: a randomized controlled pilot trial

BACKGROUND

Higher concentrations of fraction of inspired oxygen (FIO2) have been shown to be associated with lower risk for surgical site infection in multiple studies outside the domain of orthopedic surgery. We evaluated the efficacy of high FIO2 administered during the perioperative period to reduce the rate of surgical site infection after open fixation of lower-extremity fractures at high risk of infection.

METHODS

We conducted a randomized controlled, parallel design, double-blind study. Patients sustaining high-energy tibial plateau, tibial pilon, and calcaneus fractures treated in a staged fashion were selected for enrollment because these injuries are associated with high risk of infection. The study population included 222 patients with 235 fractures. Consenting patients were randomized by random number sequence to either the treatment or the control group. Treatment group patients received 80% FIO2 intraoperatively and for 2 hours afterward. Control group patients received 30% FIO2 during the same period. Surgeons, patients, and personnel who performed wound assessments were blinded to group assignment. The primary outcome measure was surgical site infection as defined by the Centers for Disease Control criteria for postoperative wound infection.

RESULTS

The overall rates of postoperative surgical site infection were 12% (14 of 119 fractures) in the treatment group and 16% (19 of 116 fractures) in the control group (p = 0.31). Multivariate analysis, accounting for risk factors for infection, yielded the closest to a statistically significant reduction in the odds of infection with treatment (odds ratio, 0.54; p = 0.17). No treatment-associated events were observed.

CONCLUSION

Use of a high concentration of FIO2 during the perioperative period is safe and shows a trend toward reduction of surgical site infection in patients undergoing open operative fixation of high-energy traumatic lower-extremity fractures. Further study in a larger patient population is indicated.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Effect of intraoperative high inspired oxygen fraction on surgical site infection, postoperative nausea and vomiting, and pulmonary function: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Intraoperative high inspired oxygen fraction (FIO2) is thought to reduce the incidence of surgical site infection (SSI) and postoperative nausea and vomiting, and to promote postoperative atelectasis.

METHODS

The authors searched for randomized trials (till September 2012) comparing intraoperative high with normal FIO2 in adults undergoing surgery with general anesthesia and reporting on SSI, nausea or vomiting, or pulmonary outcomes.

RESULTS

The authors included 22 trials (7,001 patients) published in 26 reports. High FIO2 ranged from 80 to 100% (median, 80%); normal FIO2 ranged from 30 to 40% (median, 30%). In nine trials (5,103 patients, most received prophylactic antibiotics), the incidence of SSI decreased from 14.1% with normal FIO2 to 11.4% with high FIO2; risk ratio, 0.77 (95% CI, 0.59-1.00). After colorectal surgery, the incidence of SSI decreased from 19.3 to 15.2%; risk ratio, 0.78 (95% CI, 0.60-1.02). In 11 trials (2,293 patients), the incidence of nausea decreased from 24.8% with normal FIO2 to 19.5% with high FIO2; risk ratio, 0.79 (95% CI, 0.66-0.93). In patients receiving inhalational anesthetics without prophylactic antiemetics, high FIO2 provided a significant protective effect against both nausea and vomiting. Nine trials (3,698 patients) reported on pulmonary outcomes. The risk of atelectasis was not increased with high FIO2.

CONCLUSIONS

Intraoperative high FIO2 further decreases the risk of SSI in surgical patients receiving prophylactic antibiotics, has a weak beneficial effect on nausea, and does not increase the risk of postoperative atelectasis.

Preoperative risk reduction: strategies to optimize outcomes

The success of hernia repair is measured by absence of recurrence, appearance of the surgical scar, and perioperative morbidity. Perioperative surgical site occurrence (SSO), defined as infection, seroma, wound ischemia, and dehiscence, increases the risk of recurrent hernia by at least 3-fold. The surgeon should optimize all measures that promote healing, reduce infection, and enhance early postoperative recovery. In the population with ventral hernia, the most common complication in the immediate perioperative period is surgical site infection. This article reviews several preoperative measures that have been reported to decrease SSOs and shorten length of hospital stay.

Adherence to surgical care improvement project measures and post-operative surgical site infections

BACKGROUND

Surgical site infection (SSI) is unequivocally morbid and costly. The estimated 300,000 SSIs annually in the United States represent the second most common infection among surgical patients, prolong hospitalization by 7-10 days, and have an estimated annual incremental cost of $1 billion. The mortality rate associated with SSI is 3%, with about three quarters of deaths being attributable directly to the infection. Prevention is possible for the most part, and concerted effort has been made to limit these infections, arguably to little effect.

METHODS

Review of pertinent English-language literature.

RESULTS

Numerous risk factors for SSI and tactics for prevention have been described, but efforts to bundle these tactics into an effective, comprehensive prevention program have been disappointing. Numerous studies now demonstrate that the Surgical Care Improvement Program (SCIP), which focused on process improvement rather than outcomes, has been ineffective despite governmental support, financial penalties for non-compliance, and consequent widespread implementation.

CONCLUSION

Required reporting has increased awareness of the problem of SSI, but just as the complexity of SSI risk, pathogenesis, and preventions reflects the complexity of the disease, many other factors must be taken into account, including the skill and knowledge of the surgical team and promulgation of a culture of quality and safety in surgical patient care.