Antibiotic prophylaxis in cardiac operations

Antibiotics for preventing infection at the surgical site: Single dose vs. multiple doses

Background

Surgical site infections are common and expensive infections that can cause fatalities or poor patient outcomes. To prevent these infections, antibiotic prophylaxis is used. However, excessive antibiotic use is related to higher costs and the emergence of antimicrobial resistance.

Objectives

The present meta-analysis aimed to compare the effectiveness of a single dosage versus several doses of antibiotics in preventing the development of surgical site infections.

Methods

PubMed was used to find clinical trials evaluating the effectiveness of a single dosage versus several doses of antibiotics in avoiding the development of surgical site infections. The study included trials that were published between 1984 and 2022. Seventy-four clinical trials were included in the analysis. Odds ratios were used to compare groups with 95% confidence intervals. The data were displayed using OR to generate a forest plot. Review Manager (RevMan version 5.4) was used to do the meta-analysis.

Results

Regarding clean operations, there were 389 surgical site infections out of 5,634 patients in a single dose group (6.90%) and 349 surgical site infections out of 5,621 patients in multiple doses group (6.21%) (OR = 1.11, lower CI = 0.95, upper CI = 1.30). Regarding clean-contaminated operations, there were 137 surgical site infections out of 2,715 patients in a single dose group (5.05%) and 137 surgical site infections out of 2,355 patients in multiple doses group (5.82%) (OR = 0.87, lower CI = 0.68, upper CI = 1.11). Regarding contaminated operations, there were 302 surgical site infections out of 3,262 patients in a single dose group (9.26%) and 276 surgical site infections out of 3,212 patients in multiple doses group (8.59%) (OR = 1.11, lower CI = 0.84, upper CI = 1.47). In general, there were 828 surgical site infections out of 11,611 patients in a single dose group (7.13%) and 762 surgical site infections out of 11,188 patients in multiple doses group (6.81%) (OR = 1.05, lower CI = 0.93, upper CI = 1.20). The difference between groups was not significant.

Conclusion

The present study showed that using a single-dose antimicrobial prophylaxis was equally effective as using multiple doses of antibiotics in decreasing surgical site infections.

The Continuing Plague of Extended-Spectrum β-Lactamase Producing Enterbacterales Infections: An Update

Antimicrobial resistance is a common iatrogenic complication of modern life and medical care. One of the most demonstrative examples is the exponential increase in the incidence of extended-spectrum β-lactamases (ESBLs) production among Enterobacteriaceae, that is, the most common human pathogens outside of the hospital setting. Infections resulting from ESBL-producing bacteria are associated with devastating outcomes, now affecting even previously healthy individuals. This poses an enormous burden and threat to public health. This article aims to narrate the evolving epidemiology of ESBL infections and highlights current challenges in terms of management and prevention of these common infections.

The Continuing Plague of Extended-spectrum β-lactamase-producing Enterobacteriaceae Infections

Antimicrobial resistance is a common iatrogenic complication of modern life and medical care. One of the most demonstrative examples is the exponential increase in the incidence of extended-spectrum β-lactamases (ESBLs) production among Enterobacteriaceae, which is the most common human pathogens outside of the hospital settings. Infections resulting from ESBL-producing bacteria are associated with devastating outcomes, now affecting even previously healthy individuals. This development poses an enormous burden and threat to public health. This paper aims to narrate the evolving epidemiology of ESBL infections, and highlight current challenges in terms of management and prevention of these common infections.

The complex epidemiology of extended-spectrum β-lactamase-producing Enterobacteriaceae

ABSTRACT 

Antimicrobial resistance is a growing worldwide iatrogenic complication of modern medical care. Extended-spectrum β-lactamases have emerged as one of the most successful resistance mechanisms, limiting our therapeutic options to treat various human infections. The dissemination of these enzymes to the community probably signifies an irreversible step. This paper will review the evolution of human infections associated with extended-spectrum β-lactamase-producing organisms in the past 20 years, and will present and discuss the current challenges, controversies, debates and knowledge gaps in this research field.

Antibiotic prophylaxis in cardiac surgery: systematic review and meta-analysis

BACKGROUND

Antibiotic prophylaxis is recommended in cardiac surgery. Current debate concerns the type of antibiotic(s), dosing and the duration of prophylaxis.

METHODS

Systematic review of randomized controlled trials comparing one antibiotic regimen versus another in cardiac surgery. We searched The Cochrane Library, PubMed, LILACS, conference proceedings and bibliographies. Two reviewers independently extracted the data. The primary outcome was deep sternal wound infections (DSWIs). Meta-analysis was performed using the Mantel-Haenszel fixed-effect method. Risk ratios (RRs) with 95% confidence intervals (95% CIs) are reported.

RESULTS

Fifty-nine trials were included. There were no significant differences in DSWI or all other categories of surgical site infections (SSIs) for antibiotic prophylaxis with β-lactams comprising a Gram-negative spectrum of coverage versus prophylaxis targeting Gram-positive bacteria, but the former led to a significantly lower rate of post-operative pneumonia (RR 0.68, 95% CI 0.51-0.90) and all-cause mortality (RR 0.66, 95% CI 0.47-0.92). In trials comparing different antibiotic regimens for different durations, prophylaxis duration of ≤24 h post-operation led to higher rates of DSWI (RR 1.83, 95% CI 1.25-2.66), any sternal SSI, surgical interventions for SSI and endocarditis compared with longer duration prophylaxis. There was no advantage of regimens lasting >48 h post-operation. In the comparison of glycopeptides versus β-lactams, an advantage of glycopeptides was observed when comparators were given for similar duration and for β-lactams when given for a longer duration than the glycopeptides. There was no significant advantage of high antibiotic dosing.

CONCLUSIONS

Evidence supports second- or third-generation cephalosporins for cardiac surgery prophylaxis and points at a possible advantage of prophylaxis prolongation up to 48 h post-operatively.

Does duration of perioperative antibiotic prophylaxis matter in cardiac surgery? A systematic review and meta-analysis

OBJECTIVE

We aimed to compare the efficacy of short-term (<24 hours) versus longer-term antibiotic prophylaxis (≥24 hours) in open heart surgery.

BACKGROUND

The optimal duration of antibiotic prophylaxis for adults undergoing cardiac surgery is unknown and guideline recommendations are inconsistent.

METHODS

We searched MEDLINE, EMBASE, CINAHL, and CENTRAL for parallel-group randomized trials comparing any antibiotic prophylaxis administered for <24 hours to any antibiotic prophylaxis for ≥24 hours in adult patients undergoing open heart surgery. Reference lists of selected articles, clinical practice guidelines, review articles, and congress abstracts were searched. Study selection, data extraction and assessment of risk of bias were performed independently by 2 reviewers.

RESULTS

Of the 1338 citations identified by our search strategy, 12 studies involving 7893 patients were selected. Compared with short-term antibiotic prophylaxis, longer-term antibiotic prophylaxis reduced the risk of sternal surgical site infection (SSI) by 38% (risk ratio 1.38, 95% confidence interval (CI) 1.13-1.69, P = 0.002) and deep sternal SSI by 68% (risk ratio 1.68, 95% CI 1.12-2.53, P = 0.01). There were no statistically significant differences in mortality, infections overall and adverse events. Eleven of the trials were at high risk for bias due to limitations in study design.

CONCLUSIONS

Perioperative antibiotic prophylaxis of ≥24 hours may be more efficacious in preventing sternal SSIs in patients undergoing cardiac surgery compared to shorter regimens. The findings however are limited by the heterogeneity of antibiotic regimens used and the risk of bias in the published studies.

Effect of Aminoglycoside and β‐Lactam Combination Therapy versus β‐Lactam Monotherapy on the Emergence of Antimicrobial Resistance: A Meta‐analysis of Randomized, Controlled Trials

BACKGROUND

The addition of an aminoglycoside to a beta -lactam therapy regimen has been suggested to have a beneficial effect in delaying or preventing the development of antimicrobial resistance. We studied the effect of aminoglycoside/ beta -lactam combination therapy versus beta-lactam monotherapy on the emergence of resistance.

METHODS

We performed a meta-analysis of randomized, controlled trials (RCTs) that compared aminoglycoside/ beta-lactam combination therapy with beta-lactam monotherapy and that reported data regarding the emergence of resistance (primary outcome) and/or development of superinfection, treatment failure, treatment failure attributable to emergence of resistance, treatment failure attributable to superinfection, all-cause mortality during treatment, and mortality due to infection. Data for this meta-analysis were identified from the PubMed database, Current Contents database, Cochrane central register of controlled trials, and references in relevant articles.

RESULTS

A total of 8 RCTs were included in the analysis. Beta -lactam monotherapy was not associated with a greater emergence of resistance than was the aminoglycoside/ beta-lactam combination (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.56-1.47). Actually, beta -lactam monotherapy was associated with fewer superinfections (OR, 0.62; 95% CI, 0.42-0.93) and fewer treatment failures (OR, 0.62; 95% CI, 0.38-1.01). Rates of treatment failure attributable to emergence of resistance (OR, 3.09; 95% CI, 0.75-12.82), treatment failure attributable to superinfection (OR, 0.60; 95% CI, 0.33-1.10), all-cause mortality during treatment (OR, 0.70; 95% CI, 0.40-1.25), and mortality due to infection (OR, 0.74; 95% CI, 0.46-1.21) did not differ significantly between the 2 regimens.

CONCLUSIONS

Compared with beta-lactam monotherapy, the aminoglycoside/ beta-lactam combination was not associated with a beneficial effect on the development of antimicrobial resistance among initially antimicrobial-susceptible isolates.

The measurement of wound infection after breast surgery

Infection in breast wounds often occurs in the form of cellulitis, but the conventional criteria for wound infection are the presence of either pus or a serous discharge containing pathogens. Wound scoring systems may offer a more quantitative and clinically relevant approach when evaluating the morbidity caused by infection in wounds. The aim of this study was to develop a wound scoring system for patients undergoing breast surgery. The components of previously described wound scoring systems were measured in 218 women undergoing nonreconstructive breast surgery. Using conventional criteria, the incidence of wound infection was 5.5% (12/218). However, 22% of the patients exhibited at least one sign of wound infection, and 11% of the patients received antibiotics for cellulitis without any other indication of a wound infection. The validity of the wound scoring system was supported by its strong content validity, the presence of construct validity as evidenced by concordance with the conventional criteria (p < 0.001), and criterion validity in the form of an association between the presence of a seroma and a positive wound score (p < 0.001). It was also noted that 27% of the patients with an appreciable wound score (more than 40 points) had cellulitis but did not satisfy the conventional criteria for a wound infection. In conclusion, it is advisable to use a wound scoring system that includes cellulitis when evaluating patients who have undergone breast surgery.

Local Gentamicin Reduces Sternal Wound Infections After Cardiac Surgery: A Randomized Controlled Trial

BACKGROUND

Sternal wound infections remain a major cause of morbidity after cardiac surgery. Vancomycin is often the only effective antibiotic available for their treatment but its use for routine prophylaxis is inadvisable for ecological reasons. Local application of gentamicin produces high antibiotic concentrations in the wound. We aimed to determine whether this treatment could have an additive effect on the incidence of sternal wound infections when combined with routine prophylaxis.

METHODS

Two thousand cardiac surgery patients were randomized to routine prophylaxis with intravenous isoxazolyl-penicillin alone (control group) or to this prophylaxis combined with application of collagen-gentamicin (260 mg gentamicin) sponges within the sternotomy before wound closure. Endpoint was any sternal wound infection within 2 months postoperatively. Evaluations were double-blind and made on an intention-to-treat basis.

RESULTS

Evaluation was possible in 967 and 983 patients in the control and treatment groups, respectively. The incidence of sternal wound infection was 4.3% in the treatment group and 9.0% in the control group (relative risk 0.47; 95% confidence interval 0.33-0.68; p < 0.001). Early reoperation for bleeding was more common in the treatment group (4.0% vs 2.3%, p = 0.03). No difference in postoperative renal function was noted.

CONCLUSIONS

Local collagen-gentamicin reduced the risk for postoperative sternal wound infections. Further studies are warranted to confirm these results, particularly with regard to deep infections.

Ceftriaxone versus Other Antibiotics for Surgical Prophylaxis

OBJECTIVE

To investigate possible differences in prophylaxis with ceftriaxone compared with other antimicrobial agents for surgical-site infections and remote infections such as respiratory tract infections (RTIs) and urinary tract infections (UTIs).

METHODS

The efficacy of ceftriaxone was compared with that of other antibiotics in the perioperative prophylaxis of local (surgical wound) and remote (RTIs and UTIs) infections in a meta-analysis of randomised controlled trials published between 1984 and 2003. The analysis was based on a 2 x 2 contingency table with classification by treatment and number of infections obtained from individual studies.

RESULTS

Evaluations were performed on 48 studies, for a total of 17 565 patients. Overall, 406 patients (4.8%) in the ceftriaxone group and 525 (6.3%) in the comparator group developed a surgical-site infection (log odds ratio [OR] -0.30 [CI -0.50 to -0.13]; p < 0.0001). RTIs were observed in 292 (6.01%) patients in the ceftriaxone group and in 369 (7.6%) patients in the comparator group, (log OR -0.30 [CI -0.55 to -0.09]; p = 0.0013). UTIs were reported for 2.2% of the ceftriaxone prophylaxis patients compared with 3.74% of the comparator group patients (log OR -0.54 [CI -1.18 to -0.16]; p < 0.0001). Overall, in clean surgery 195 (5.1%) and 234 (6.2%) patients developed a surgical site infection in the ceftriaxone and comparator groups, respectively (log OR -0.22 [CI -0.51 to 0.01]; p = 0.0476). RTIs were prevented for all but 1.57% of patients in the ceftriaxone group and 2.62% of patients in the comparator group (p = 0.01) in clean surgery, and for 9.54% of the ceftriaxone group versus 11.6% of the comparator group (p = 0.01) in clean-contaminated surgery. While results observed in clean surgery did not show statistically significant superiority of ceftriaxone in preventing UTI insurgence (log OR -0.21 [CI 0.0-0.65]; p = 0.7702), this was clearly shown in the clean-contaminated surgery. In fact, 4.47% of patients in the ceftriaxone group versus 7.52% of patients in the comparator group developed a UTI (log OR -0.56 [CI -1.25 to -0.16]; p < 0.0001). Adverse events were observed in a similar proportion in the ceftriaxone prophylaxis and the comparator groups (0.35% and 0.23%, respectively). Duration of prophylaxis did not influence outcome of infection.

CONCLUSIONS

The meta-analysis showed that ceftriaxone is statistically superior to other antibiotics in preventing both local and remote postoperative infections.

Cost comparisons of pharmacological strategies in open-heart surgery

Open-heart surgery (OHS) is performed to bypass occluded arteries, replace malfunctioning cardiac valves or correct congenital abnormalities. The average cost of OHS varies from $US25 057-$US79 795 (1997 values). The objective of this paper was to review economic studies of pharmacological strategies in open-heart surgery. Pharmacological strategies studied include the prevention of postoperative complications such as atrial fibrillation (AF), bleeding and infection. Modifications in anaesthetic technique have been attempted by using agents that promote early extubation. In addition, strategies for postoperative management of sedation, analgesia and AF and use of neuromuscular blockers have also been compared. The majority of studies in this area have been cost analyses with few cost-effectiveness studies performed. Prophylaxis against AF with amiodarone is associated with a reduction in AF and was cost-neutral compared with placebo. Compared with placebo, prevention of bleeding with antifibrinolytics reduces transfusion costs. In direct comparative studies, lysine analogues, due to lower drug acquisition costs, offset transfusion costs to a greater extent than aprotinin. However, safety concerns with the lysine analogues remain. Erythropoietin decreases transfusion requirements and is cost effective compared with no intervention when the cost of postoperative bacterial complications is included. First- and second-generation cephalosporins prevent postoperative infections. Based on drug acquisition cost, the first-generation agents are less expensive although when administration costs are included, both classes have similar costs. Modifications in anaesthetic technique with short-acting anaesthetic agents, results in higher drug costs although nursing and total hospital costs are typically reduced. For neuromuscular blockers, drug acquisition costs are lowest with pancuronium but administration costs and the cost of adverse events have not been included in existing analyses. Midazolam provides an equivalent level of postoperative sedation to propofol but the acquisition cost is lower. The combined use of propofol and midazolam warrants further investigation, as its use is associated with lower sedative agent costs compared with either agent alone. There is limited data on the economics of postoperative analgesia and the management of AF. As the majority of studies to date are partial cost analyses, additional studies that include length of stay and other hospitalisation data are warranted. In future, cost-effectiveness and cost-utility studies, which incorporate quality of life and the cost of adverse effects and other longer term costs, should be undertaken.

Nosocomial cardiac infections

The most important nosocomial cardiac infections include nosocomial infective endocarditis on native and prosthetic valves, and nosocomial infections related to transvenous permanent pacemakers, implantable cardioverter-defibrillators and left ventricular assist devices. Although representing rare complications, they are of great importance because they are associated with high morbidity and mortality. Most of them are encountered in older-age groups, related to nosocomial invasive procedures performed within the preceding four to eight weeks of hospital admission. Nosocomial bacteraemia associated with infected central intravascular devices, genitourinary or gastrointestinal tract surgery and instrumentation, breaks in sterile surgical techniques at the implantation of prosthetic valves and cardiac devices as well as wound and skin infections, represent the most important risk factors. Staphylococcus aureus in native valve endocarditis and S. epidermidis in the presence of foreign bodies are the main implicated pathogens. However, because of the steeply increasing incidence of candidaemia in tertiary hospitals, nosocomial cardiac infections caused by Candida spp. have also been steadily increasing over the last decades. Diagnosis of nosocomial cardiac infections, particularly in the presence of foreign bodies, is often difficult because of the severity of patients' co-morbid illnesses and the co-existence of several risk factors. Diagnosis should be based on positive blood cultures and transoesophageal echocardiographic findings in febrile high-risk patients. Therapy necessitates a combination of antibiotics and surgical removal of foreign bodies. Prophylaxis should mainly target the prevention and/or appropriate treatment of bacteraemias secondary to infected intravascular devices, as well as application of prophylaxis guidelines whenever invasive hospital-based procedures are performed in high-risk individuals.

Antibiotic prophylaxis for patients undergoing breast surgery

Some groups of patients undergoing clean surgery benefit from the provision of antibiotic prophylaxis against wound infection. Breast surgery may belong to this category because several substantial studies have reported that it is accompanied by an unacceptably high rate of wound infection. However, only two clinical trials have addressed this issue and both produced equivocal results. Resolution of this problem is important because, aside from the usual advantages obtained by preventing such complications, wound infection diminishes the proportion of patients with breast cancer who start adjuvant regimens within an optimum time after surgery.

Antimicrobial prophylaxis in adults

Antimicrobial prophylaxis is used by clinicians for the prevention of numerous infections, including sexually transmitted diseases, human immunodeficiency virus infection, tuberculosis, rheumatic fever, recurrent cellulitis, meningococcal disease, recurrent uncomplicated urinary tract infections in women, spontaneous bacterial peritonitis in patients with cirrhosis, influenza, malaria, infective endocarditis, pertussis, plague, anthrax, early-onset group B streptococcal disease in neonates, and animal bite wounds. Certain opportunistic infections such as Pneumocystis carinii pneumonia in immunocompromised patients also can be effectively prevented with primary antimicrobial prophylaxis. Perioperative antimicrobial prophylaxis is recommended for various surgical procedures to prevent surgical site infection. Optimal antimicrobial agents for prophylaxis are bactericidal, nontoxic, inexpensive, and active against the typical pathogens that cause surgical site infection postoperatively. To maximize its effectiveness, intravenous perioperative prophylaxis should be given within 30 to 60 minutes before the time of surgical incision. Antibiotic prophylaxis should be of short duration to decrease toxicity, antimicrobial resistance, and excess cost.

Ceftriaxone versus vancomycin prophylaxis in cardiovascular surgery

The efficacy of antibiotic prophylaxis in cardiac surgery was compared between 97 patients receiving a single 2 g dosage of ceftriaxone and 103 receiving 500 mg of vancomycin i.v. every 6 h for 48 h. The overall infection rate was 13.4% in the ceftriaxone and 10.7% in the vancomycin group. Four (4%) wound infections, including one mediastinitis, occurred in the ceftriaxone group and five (5%) in the vancomycin group, with no statistically significant difference. The findings of this study support the adequacy of a simple single dose of ceftriaxone prophylaxis in cardiac surgery, at least in hospitals with low incidence of vancomycin-resistant staphylococcal infections.

The pharmacokinetics of a single dose of gentamicin (4 mg/kg) as prophylaxis in cardiac surgery requiring cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass has complex effects on drug pharmacokinetics, which is important when considering the use of once-daily aminoglycoside regimens during cardiac surgery.

AIM

To study the effects of cardiopulmonary bypass on the pharmacokinetics of a single dose of gentamicin (4 mg/kg).

PATIENTS AND METHODS

Nine patients undergoing valve replacement surgery were given a single dose of gentamicin (4 mg/kg) at induction of anaesthesia and blood was taken for assay at 0, O.5, 1, 1.5, 2, 2.5, 3, 4, 6, 10, 16, 22 and 24 h following administration. The mean (range) gentamicin Cmax was 18.7 (12.4-26.3) mg/litre. Three patients had concentrations of gentamicin after 24 h of > 1 mg/litre. During cardiopulmonary bypass, the mean (range) gentamicin half-life (t1/2) was 5.1 (2.0-15.1) h and post-bypass the t1/2 was 7.1 (3.0-13.9) h.

CONCLUSION

There is significant correlation between the elimination t1/2 and length of cardiopulmonary bypass (r = 0.89, P < 0.01). These results suggest that gentamicin excretion is delayed following cardiopulmonary bypass so that with dose regimens of > 4 mg/kg there is a risk of toxicity.

Antibiotic prophylaxis in surgery: summary of a Swedish-Norwegian Consensus Conference

This consensus document sets out proposals for antibiotic prophylaxis in abdominal, urological, gynaecological, orthopaedic, vascular and thoracic surgery. As far as possible the recommendations are based on prospective controlled trials. However, for some procedures, e.g. lung surgery and implantation of pacemakers, documentation is lacking but antibiotic prophylaxis is given traditionally. The choice of antibiotics is generally conservative, emphasizing that antibiotics used for therapy should be avoided in prophylactic regimens. Most recommendations are for the use of a first- or second-generation cephalosporin or an isoxazolyl penicillin, when necessary, combined with a nitroimidazole derivative (metronidazole or tinidazole). Suggestions are given for more frequent use of orally administered antibiotics, such as co-trimoxazole, doxycycline, metronidazole or tinidazole. Emphasis is put on short-term prophylaxis. In most cases surgical antibiotic prophylaxis should be given as a single dose and in no case should the prophylaxis time exceed 24 h.

Postcardiac surgery infections

Infections following cardiac surgery, although generally uncommon, are associated with difficult management decisions and significant morbidity and mortality. They often present while the patient is either in a critical care unit, or requires CCU management. This review analyzes infections related to median sternotomy wounds, prosthetic heart valves, transvenous permanent pacemakers, automatic implantable cardioverter-defibrillators, and left ventricular assist devices. The diagnosis, microbiology, treatment and outcome of each is also discussed.

Preoperative antimicrobial prophylaxis with a long-acting cephalosporin for thoracic surgery in 192 non small cell lung cancer patients

The efficacy of preoperative antibiotic prophylaxis in thoracic surgery with a single dose of ceftriaxone was investigated. Here we report the results of a prospective study including 192 patients undergoing thoracic surgery for non small cell lung cancer. Overall, the postoperative infection rate, as measured by wound, respiratory tract, and urinary tract infections, was 8.3% (16/192). Ceftriaxone was well tolerated, and no allergic or other adverse reactions were reported. A single preoperative dose of ceftriaxone was cost-effective and allowed considerable saving of time, material, labor costs and money. This study, even though open and non-comparative, suggests that the routine use of a single preoperative dose of ceftriaxone provides a cost-effective prophylaxis for patients undergoing major thoracic operations.

Duration of antimicrobial prophylaxis in vascular surgery

BACKGROUND

This randomized clinical trial compares the incidence of wound infection after vascular surgery in patients who received prophylaxis using the same antibiotic as either a single-dose or a multiple-dose regimen (until the lines/drain tubes were removed, but not for more than 5 days).

METHODS

Each of the 302 patients who entered the study received ticarcillin 3.0 g/clavulanate 0.1 g (Timentin) intravenously immediately after the induction of anesthesia. Patients randomized to the multiple-dose group received an average of 14.3 doses (range 9 to 20).

RESULTS

The incidence of wound infections was 18% (28 of 153) for patients in the single-dose group and 10% (15 of 149) for patients in the multiple-dose group (P = 0.04; relative risk estimate = 2.00, 95% confidence interval = -1.02 to 3.92).

CONCLUSIONS

A multiple-dose antibiotic regimen, rather than single-dose therapy, provides optimal prophylaxis against wound infection for patients undergoing vascular surgery.

Is single-dose antibiotic prophylaxis sufficient for coronary artery bypass surgery? An analysis of peri- and postoperative serum cefuroxime and vancomycin levels

Preliminary findings have suggested that a single intravenous dose of antibiotic is effective for infection prophylaxis in cardiac surgery. However there are still insufficient data on this proposed regimen. We measured serum cefuroxime and vancomycin levels after three different dosage regimens, in patients undergoing coronary artery bypass grafting (CABG). Sixty patients were randomized into three cefuroxime and three vancomycin groups with 10 patients in each: a group given a one-day course, or an additional dose during cardiopulmonary bypass or a single dose. Serum levels of the antibiotics were measured at various times throughout the operative procedure and until 48 h after the start of prophylaxis. Each of the six dosage regimens maintained serum levels adequate for infection prophylaxis throughout the operative procedure. Serum levels remained above 2 mg/L for more than 8 h postoperatively, even in the single-dose cefuroxime group and above 4 mg/L for more than 24 h with all the vancomycin dosage regimens. Thus a single dose of cefuroxime (3 g or 1.5 g) or vancomycin (1.5 g) seems to achieve and maintain serum levels sufficient for infection prophylaxis several hours after CABG procedures.

Evaluation of a wound scoring method for patients undergoing cardiac surgery

The main endpoint of studies evaluating antimicrobial prophylaxis in surgical patients is wound morbidity. This should consist of more than the solitary declaration of the rate of wound infection. In this study, a modified version of ASEPSIS (a wound scoring system) has been prospectively evaluated in 1000 patients undergoing cardiac surgery. Twenty-one patients (2.1%) had an infected sternal wound. The components of ASEPSIS most significantly associated with a sternal wound infection were: the presence of a purulent exudate, a postoperative stay > 14 days, the identification of pathogenic organisms, and the use of antibiotics (P < 0.0001). Although ASEPSIS is a useful mechanism for conveying information about wounds, it does ignore bleeding into wounds and the extent that troublesome wounds need to be dressed after surgery.

Surgical antibiotic prophylaxis

Improvements in antibiotic prophylaxis, including the timing of initial administration, appropriate choice of antibiotic agents, and the limiting of the duration of administration, have more clearly defined the value of this technique in many clinical surgical settings. Studies of antibiotic prophylaxis designed during the next decade should strongly consider individual patient risk factors when new antibiotic agents are tested or administration techniques are refined. A concentrated effort should be made in areas of clinical surgery in which the value of antibiotic prophylaxis has not been proven. When in doubt, it appears that a one-dose systemic regimen of an appropriately chosen cephalosporin given during the immediate preoperative period is safe and the indicated practice.

Ceftriaxone vs cefuroxime for infection prophylaxis in coronary bypass surgery

The most serious infection after coronary artery bypass grafting (CABG) is mediastinitis following deep sternal wound infection. Antibiotic prophylaxis for at least 48 hours has been recommended. In this trial 551 consecutive patients were randomized to receive ceftriaxone in a single dose or cefuroxime thrice daily until the end of the second postoperative day. The overall infection rate was 7.7% in the ceftriaxone and 8.3% in the cefuroxime group, and the incidence of deep sternal infection was 2.9% in both groups. Significant risk factors for such infection were chronic respiratory disease (p < 0.001) and diabetes (p < 0.01). The antibiotic prophylaxis had no harmful effects on the colonic flora in either group. Acquisition and delivery costs for the prophylactic agents were three times higher in the cefuroxime than in the ceftriaxone group. Both antibiotics are concluded to be equally safe and effective. Single-dose ceftriaxone prophylaxis is as effective as cefuroxime given for 48 hours postoperatively. Single-dose ceftriaxone is also simple to use.