Wound Infections In High-risk Patients Research Articles

A Scoping Review on the Use of Antibiotic-Impregnated Beads and Applications to Vascular Surgery.

Surgical site infection (SSI) presents a ubiquitous concern to surgical specialties, especially in the presence of prosthetic material. Antibiotic-impregnated beads present a novel and evolving means to combat this condition. This review aims to analyze the quality of evidence and methods of antibiotic bead use, particularly for application within vascular surgery. A systematic scoping review was conducted within Embase, MEDLINE, and the Cochrane Registry of Randomized Controlled Trials. Articles were evaluated by 2 independent reviewers. Level of evidence was evaluated using the Oxford Center for Evidence-Based Medicine Criteria and the Cochrane Risk of Bias Tool for Randomized Controlled Trials. The search yielded 6951 papers, with 275 included for final analysis. Publications increased in frequency from 1978 to the present. The most common formulation was polymethyl methacrylate; however publications on biodegradable formulations, including calcium sulfate beads, have been published with increasing frequency. Most publications had positive conclusions (94.2%); however, the data was mainly subjective and may be prone to publication bias. Only 11 randomized controlled trials were identified and all but one was evaluated to be at a high risk of bias. The most common indication was for osteomyelitis (52%), orthopedic prosthetic infections (20%), and trauma (9%). Within vascular surgery, beads have been used primarily for the treatment of graft infection, with freedom from recurrence rates being reported from 41% to 87.5%. Antibiotic-impregnated beads provide a means to deliver high doses of antibiotic directly to a surgical site, without the risks of parenteral therapy. There has yet to be significant high-level quality data published on their use. There is a large body of evidence that suggests antibiotic beads may be used in SSIs in high-risk patients, prosthetic infections, and other complex surgical infections. Important potential areas of application in vascular surgery include graft infection, prevention of wound infection in high-risk patients, and diabetic foot infection.

EComment. Gentamicin-impregnated collagen sponge for high-risk cardiac surgery patients

I read with great interest the paper by Birgand et al. regarding the use of gentamicin-collagen sponges in closure of sternal wounds in high- risk cardiac surgery patients to reduce the incidence of deep sternal wound infections [1]. They conducted a single-centre prospective cohort study enrolling 552 high-risk patients for sternal wound infection. The primary end-point, which is reoperation for deep sternal wound infection, occurred in 40/298 (13.8%) in the group without the antibiotic implants and in 22/175 (12.6%) in the treated group with the gentamicin-collagen sponges. The authors concluded that gentamicin-collagen sponges are not effective in preventing deep sternal wound infections in high-risk patients undergoing cardiac surgery. Gentamicin-collagen sponges were introduced in 1985 for the prevention of surgical site infection and they are mainly used after laparotomy [2]. However, there is no consensus about their use in patients undergoing cardiac surgery [3]. A recently-published review of the literature and a meta-analysis showed conflicting results. A best evidence topic in cardiac surgery concerning the use of gentamicin-collagen sponges to reduce wound infections was recently published in this journal [4]. The authors of this paper concluded that the use of this implant did not reduce the incidence of sternal wound infection in high-risk patients after cardiac surgery. Recently, a meta-analysis of randomized controlled trials was performed by Mavros et al [5]. Four randomized controlled trials were included in this meta-analysis. All 4 trials were considered of high quality (score of 3 or more according to the modified Jadad criteria). By pooling data provided by 4 published trials (4672 patients), gentamicin-collagen sponge use demonstrated a significant reduction in the rate of deep sternal wound infection (RR, 0.62; 95% CI, 0.39-0.97; P =0.04). Regarding the incidence of superficial sternal wound infection, gentamicin-collagen sponges use seemed to add no benefit (RR, 0.65; 95% CI, 0.34- 1.25; P =0.20). Therefore, in view of the clinical implications of their findings from this meta-analysis, the authors suggest that routine prophylactic retrosternal placement of gentamicin-impregnated sponges reduces the incidence of deep sternal wound infection. The implementation of this simple measure could bring particular benefits in high-risk patients. With the purpose of elaborating consensus guidelines for the best management of these high-risk patients, and to draw definitive conclusions, future studies with larger numbers of patients are required. Conflict of interest: none declared

EComment. The devil is in the detail!

I read with great interest the quasi-experimental single-centre prospective cohort study conducted by Birgand et al. [1] evaluating the efficacy of a gentamicin-collagen sponge in decreasing deep sternal-wound infections in high-risk cardiac surgery patients. Interstingly, in their experience gentamicin-collagen sponge was not effective in preventing deep sternal wound infections in high-risk patients. This is contrary to our own experience [2] and the most plausible explanation for the conflicting results lies in the technique of using the gentamicin-collagen sponge. Birgand and associates dipped the sponge in normal saline solution for a few seconds prior to implantation [1]. This manoeuvre of wetting the gentamicin-collagen sponge impacts on the gentamicin content of the implant and affects its potential antibacterial efficacy. Lovering and colleague [3] have recently shown that that even a short period of dipping of gentamicin-collagen sponge, before insertion into the patient, results in a significant loss of gentamicin which may be of clinical significance. They demonstrated that after a very short immersion period there was significant loss of gentamicin from the implants with a mean loss of 6.7% at 2 s, increasing to 40.5% at 1 min and essentially total loss by 6 h of immersion. Loss of gentamicin followed a complex elution profile, with elution half-lives ranging from 50 s on initial immersion to 99 min late in the elution period. It is very clear from the study of Lovering et al. [3] as well as from our own experience [2] that attention to detail will possibly result in different outcomes thereby minimising studies with conflicting results. Conflict of interest: none declared

Does a gentamicin-impregnated collagen sponge reduce sternal wound infections in high-risk cardiac surgery patients?

Sternal wound infections occurring after cardiac surgery have a critical impact on morbidity, mortality and hospital costs. This study evaluated the efficacy of a gentamicin-collagen sponge in decreasing deep sternal-wound infections in high-risk cardiac surgery patients. We conducted a quasi-experimental single-centre prospective cohort study in diabetic and/or overweight patients undergoing coronary-artery bypass surgery with bilateral internal mammary artery grafts. The end-point was the rate of reoperation for deep sternal wound infection. The period from January 2006 to October 2008, before the introduction of the gentamicin sponge, was compared with the period from November 2008 to December 2010. Of 552 patients (median body mass index, 31.5; 37.7% with diabetes requiring insulin), 68 (12.3%) had deep sternal wound infections. Reoperation for deep sternal wound infections occurred in 40/289 (13.8%) preintervention patients and 22/175 (12.6%) patients managed with the sponge. Independent risk factors were female sex and longer time on mechanical ventilation, but not use of the sponge (adjusted odds ratio, 0.95; 95% confidence interval, 0.52-1.73; P = 0.88). The group managed with the sponge had a higher proportion of gentamicin-resistant micro-organisms (21/27, 77.8%) compared with the other patients (23/56, 41.1%; P < 0.01). The median time to reoperation for wound infection was higher with the sponge (21 vs 17 days, P < 0.01). A gentamicin-collagen sponge was not effective in preventing deep sternal wound infections in high-risk patients. Our results suggest that a substantial proportion of wound contaminations occur after bypass surgery with bilateral internal mammary artery grafts.

Evidence-Based Practice Is Wonderful … Sort Of

What should nurses do in caring for intubated patients to prevent ventilatorassociated pneumonia? What is the most effective way to suction patients who are ventilator dependent? Should patients experiencing acute coronary syndrome be given thrombolytics or just be whisked to the catheterization laboratory for a cardiac angiogram, angioplasty, and stent? Should all diabetic patients, regardless of their lipid levels, receive statin therapy? What is the best way to prevent wound infections in high-risk patients? Can pressure ulcers be prevented in comatose patients? The answers to all of these questions are known and well documented in the literature. Every day, clinicians—nurses, physicians, respiratory therapists, and others—confront difficult questions about caring for acutely ill patients. We want to know how to interpret a diagnostic test accurately, how to predict the prognosis of a specific patient, how to identify the comparative effectiveness of 2 therapeutic interventions, and how to compare the costs of our various options. Clinicians, the public, and policy makers all need to know the most effective care—from a clinical and cost perspective—for a patient hospitalized in an acute care setting. Increasingly, the answers to these questions are found in the guidelines that have evolved from systematic research.

Cesarean delivery wound infection in high-risk patients

Objective: To determine whether simple inexpensive measures can reduce the frequency and severity of cesarean delivery wound infections in high-risk patients in a nonteaching hospital.Methods: The charts of 286 patients were reviewed for duration of membrane rupture, duration of labor, number of pelvic examinations, patient’s weight, and coexisting medical conditions. Office visits, at least two for each patient, after hospital discharge also were reviewed for evidence of wound infection. The standard CDC criteria were utilized. The special measures were taken in January 1992. Surgical Techniques: No skin shaving was done. The abdominal wall was scrubbed with soap suds for 3 minutes before drying and “painting.” Copious irrigation with 3–4 liters of lactated Ringer’s was used in the peritoneal cavity, and 1/2 to 1 liter was used in the incision after fascial closure. Nothing was allowed to touch the wound after irrigation. Irrigation solution was poured 12 inches above the patient to dislodge debris. Gloves were changed after extraction of the fetal head from low in the vagina, especially with ruptured membranes. Gloves also were changed before closure of the abdominal wall. Ninety-five percent of the patients were on Medicaid.Results: Of 286 patients, 15% had elective repeat cesarean deliveries, 70% had primary cesarean deliveries, 8% had diabetes and were taking insulin, and 15% percent weighed more than 180 lb. No wound infections were diagnosed in the hospital. One questionable wound exudate was diagnosed after discharge in the office, with negative culture, for an incidence of 0.33%. No patient was readmitted to the hospital after discharge for wound infection.Conclusions: Duration of labor, number of pelvic examinations, stage of labor, and diabetes made no influence on the incidence of wound infection. With simple inexpensive measures, serious wound infection can be completely eliminated and minor infections could be a rare event.

Prospective, randomized study comparing amoxycillin-clavulanic acid and cefamandole for the prevention of wound infection in high-risk patients undergoing elective biliary surgery

The efficacy of amoxycillin-clavulanic acid for prevention of postoperative wound infection was compared with that of cefamandole in 150 patients at risk for infected bile while undergoing elective biliary surgery in a prospective, randomized study. The two groups were comparable for age, sex, risk factors, operative procedures and positive bile cultures. Similar numbers of patients had an uncomplicated postoperative course (amoxycillin-clavulanic acid 70%; cefamandole 73%). Four patients in each group developed wound infection. The incidence of postoperative pneumonia, urinary tract infection and number of days (+/- SD) in hospital (amoxycillin-clavulanic acid 10.1 +/- 4.7; cefamandole 9.7 +/- 5.6) were similar. The efficacy of amoxycillin-clavulanic acid and cefamandole in preventing wound sepsis in high-risk patients undergoing biliary surgery was similar. Economic considerations may favour the use of amoxycillin-clavulanic acid.