The Society of Thoracic Surgeons Practice Guideline Series: Antibiotic Prophylaxis in Cardiac Surgery, Part I: Duration

Sternal Wound Complications: Results of Routine Use of Negative Pressure Wound Therapy

INTRODUCTION

Negative pressure wound therapy (NPWT) has significantly improved outcomes in individuals with superficial and deep sternal wound dehiscence (SWD). We report our experience with NPWT to evaluate factors influencing effectiveness, duration of treatment and postoperative hospital stay.

METHODS

We reviewed 92 patients with postoperative SWD following a median sternotomy. Patients were divided into 2 groups: those with a superficial SWD (Group 1; 72, 78%) and those with a deep SWD (Group 2; 20, 28%). Group 1 was further divided into 3 subgroups based on NPWT duration.

RESULTS

In both groups, none of the preoperative characteristics examined showed a significant association with longer NPWT duration. In Group 2, there was a trend for postoperative bleeding and neurological complications to be associated with longer treatment duration. In the entire series, staph infection resulted a weak predictor of NPWT duration. In each Group 1 subgroup and in Group 2, treatment days were compared with duration of hospitalization until discharge. Mean post-NPWT hospital stay was 6 days in subgroup 1, 12 days in subgroup 2 and 20 days in subgroup 3 (P<0.0001). At a median 3-year follow-up, there were 4 late deaths, none related to wound complications. No cases of SWD recurrence were observed.

CONCLUSION

Our results confirm the effectiveness of NPWT in SWD management, while excessive treatment duration might have a negative impact on the length of hospital stay. Further studies are needed to define an optimal use of NPWT protocol.

Immediate postoperative complications following coronary artery bypass grafting in patients with type 2 diabetes: A prospective cohort study

AIMS

Several studies in patients with type 2 diabetes mellitus (T2DM) from the United States and European countries have demonstrated a higher risk of morbidity and mortality than those without T2DM following coronary artery bypass grafting (CABG). The data from Indian patients are scarce. Therefore, this study was carried out to focus on immediate postoperative complications following CABG in Indian patients.

METHODS

Eighteen hundred consecutive patients who underwent elective CABG were included. Following exclusion criteria, a total of 1017 subjects were included for final analysis. 692 (68%) patients had T2DM and 325 (32%) patients had no T2DM. Data were obtained by collecting clinical data, routine biochemistry and chest imaging. Patients were followed up to 7 days postoperatively.

RESULTS

At baseline, hypertension, triple vessel coronary artery disease, chronic kidney disease and peripheral vascular disease were more common in patients with T2DM. Intraoperatively, use of blood products and intra-aortic balloon pump were more common in T2DM patients. Postoperatively, 13.2% patients with T2DM developed acute kidney injury versus 5.3% in non-T2DM group. Requirement of dialysis was not different between groups (P = 0.394). Pneumonia occurred in 2 patients in both groups (P = 0.370). Catheter-associated urinary tract infections were similar in two groups (P = 0.507). Mortality occurred only in one T2DM patient and none in non-T2DM group (P = 0.618).

CONCLUSIONS

A significant number of patients with T2DM developed acute kidney injury following CABG. There was no difference in infective complications such as pneumonia and catheter-associated urinary tract infection, between the two groups.

Procalcitonin to stop antibiotics after cardiovascular surgery in a pediatric intensive care unit-The PROSACAB study

INTRODUCTION AND OBJECTIVE

Children admitted to the pediatric intensive care unit after cardiovascular surgery usually require treatment with antibiotics due to suspicion of infection. The aim of this study was to assess the effectiveness of procalcitonin in decreasing the duration of antibiotic treatment in children after cardiovascular surgery.

METHODS

Prospective, interventional study carried out in a pediatric intensive care unit. Included patients under 18 years old admitted after cardiopulmonary bypass. Two groups were compared, depending on the implementation of the PCT-guided protocol to stop or de-escalate the antibiotic treatment (Group 1, 2011-2013 and group 2, 2014-2018). This new protocol was based on the decrease of the PCT value by 20% or 50% with respect to the maximum value of PCT. Primary endpoints were mortality, stewardship indication, duration of antibiotic treatment, and antibiotic-free days.

RESULTS

886 patients were recruited. There were 226 suspicions of infection (25.5%), and they were confirmed in 38 cases (16.8%). The global rate of infections was 4.3%. 102 patients received broad-spectrum antibiotic (4.7±1.7 days in group 1, 3.9±1 days in group 2 with p = 0.160). The rate of de-escalation was higher in group 2 (30/62, 48.4%) than in group 1 (24/92, 26.1%) with p = 0.004. A reduction of 1.1 days of antibiotic treatment (group 1, 7.7±2.2 and group 2, 6.7±2.2, with p = 0.005) and 2 more antibiotic free-days free in PICU in group 2 were observed (p = 0.001), without adverse outcomes.

CONCLUSIONS

Procalcitonin-guided protocol for stewardship after cardiac surgery seems to be safe and useful to decrease the antibiotic exposure. This protocol could help to reduce the duration of broad-spectrum antibiotics and the duration of antibiotics in total, without developing complications or adverse effects.

Prevention of Arrhythmia Device Infection Trial: The PADIT Trial

BACKGROUND

Infection of implanted medical devices has catastrophic consequences. For cardiac rhythm devices, pre-procedural cefazolin is standard prophylaxis but does not protect against methicillin-resistant gram-positive organisms, which are common pathogens in device infections.

OBJECTIVE

This study tested the clinical effectiveness of incremental perioperative antibiotics to reduce device infection.

METHODS

The authors performed a cluster randomized crossover trial with 4 randomly assigned 6-month periods, during which centers used either conventional or incremental periprocedural antibiotics for all cardiac implantable electronic device procedures as standard procedure. Conventional treatment was pre-procedural cefazolin infusion. Incremental treatment was pre-procedural cefazolin plus vancomycin, intraprocedural bacitracin pocket wash, and 2-day post-procedural oral cephalexin. The primary outcome was 1-year hospitalization for device infection in the high-risk group, analyzed by hierarchical logistic regression modeling, adjusting for random cluster and cluster-period effects.

RESULTS

Device procedures were performed in 28 centers in 19,603 patients, of whom 12,842 were high risk. Infection occurred in 99 patients (1.03%) receiving conventional treatment, and in 78 (0.78%) receiving incremental treatment (odds ratio: 0.77; 95% confidence interval: 0.56 to 1.05; p = 0.10). In high-risk patients, hospitalization for infection occurred in 77 patients (1.23%) receiving conventional antibiotics and in 66 (1.01%) receiving incremental antibiotics (odds ratio: 0.82; 95% confidence interval: 0.59 to 1.15; p = 0.26). Subgroup analysis did not identify relevant patient or site characteristics with significant benefit from incremental therapy.

CONCLUSIONS

The cluster crossover design efficiently tested clinical effectiveness of incremental antibiotics to reduce device infection. Device infection rates were low. The observed difference in infection rates was not statistically significant. (Prevention of Arrhythmia Device Infection Trial [PADIT Pilot] [PADIT]; NCT01002911).

Minimization of Surgical Site Infections in Patients With Delayed Sternal Closure After Pediatric Cardiac Surgery

BACKGROUND

Delayed sternal closure (DSC) following pediatric cardiac surgery is commonly implemented at many centers. Infectious complications occur in 18.7% of these patients based on recent multicenter data. We aimed to describe our experience with DSC, hypothesizing that our practices surrounding the implementation and maintenance of the open sternum during DSC minimize the risk of infectious complications.

METHODS

We reviewed patients less than 365 days who underwent DSC between 2012 and 2016 at our institution. Infectious complications as defined by the Society of Thoracic Surgeons Congenital Heart Surgery Database were recorded. Patients with and without infectious complications were compared using Wilcoxon rank sum tests or Fisher exact tests as appropriate.

RESULTS

We identified 165 patients less than 365 days old who underwent DSC, 135 (82%) of whom had their skin closed over their open sternum. Median duration of open sternum was 3 days (range: 1-32 days). Infectious complications occurred in 15 (9.1%) patients-13 developed clinical sepsis with positive blood cultures, one patient developed ventilator-associated pneumonia, and one patient developed wound infection (0.6%). No cases of mediastinitis occurred. No statistical differences in characteristics between patients with and without infectious complications could be identified.

CONCLUSION

Infectious complications after DSC at our institution were notably less than reported in recent literature, primarily due to minimization of surgical site infections. Practices described in the article, including closing skin over the open sternum whenever possible, could potentially aid other institutions aiming to reduce infectious complications associated with DSC.

Surgical site infections: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of post-operative surgical site infections (SSIs) in solid organ transplantation. SSIs are a significant cause of morbidity and mortality in SOT recipients. Depending on the organ transplanted, SSIs occur in 3%-53% of patients, with the highest rates observed in small bowel/multivisceral, liver, and pancreas transplant recipients. These infections are classified by increasing invasiveness as superficial incisional, deep incisional, or organ/space SSIs. The spectrum of organisms implicated in SSIs in SOT recipients is more diverse than the general population due to other important factors such as the underlying end-stage organ failure, immunosuppression, prolonged hospitalizations, organ transportation/preservation, and previous exposures to antibiotics in donors and recipients that could predispose to infections with multidrug-resistant organisms. In this guideline, we describe the epidemiology, clinical presentation, differential diagnosis, potential pathogens, and management. We also provide recommendations for the selection, dosing, and duration of peri-operative antibiotic prophylaxis to minimize post-operative SSIs.

Ventricular assist device-related infections and solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

The Infectious Diseases Community of Practice of the American Society of Transplantation has published evidenced-based guidelines on the prevention and management of infectious complications in SOT recipients since 2004. This updated guideline reviews the epidemiology of ventricular assist device (VAD) infections and provides recommendations for the management and prevention of these infections. Almost one half of those awaiting heart transplantation are supported with VADs. Despite advances in device technologies, VAD infections commonly complicate mechanical circulatory support and remain typified by common components and anatomic locations. These infections have important implications for transplant candidates, most notably increased wait-list mortality. Strategic management of these infections is crucial for successful transplantation. Coincidentally, explantation of all VAD components at the time of transplantation is often the definitive cure for the device-associated infection. Highlighted in this updated guideline is the reported success of transplantation in patients with a variety of pre-existing VAD infections and guidance on post-transplant management strategies.

Prevention of Infections in Cardiac Surgery study (PICS): study protocol for a pragmatic cluster-randomized factorial crossover pilot trial

Background

A wide range of prophylactic antibiotic regimens are used for patients undergoing open-heart cardiac surgery. This reflects clinical equipoise in choice and duration of antibiotic agents. Although individual-level randomized control trials (RCT) are considered the gold standard when evaluating the efficacy of an intervention, this approach is highly resource intensive and a cluster RCT can be more appropriate for testing clinical effectiveness in a real-world setting.

Methods/design

We are conducting a factorial cluster-randomized crossover pilot trial in cardiac surgery patients to evaluate the feasibility of this design for a definite trial to evaluate the optimal duration and choice of perioperative antibiotic prophylaxis. Specifically, we will evaluate: (a) the non-inferiority of a single preoperative dose compared to prolonged prophylaxis and (b) the potential superiority of adding vancomycin to routine cefazolin in terms of preventing deep and organ/space sternal surgical site infections (s-SSIs). There are four strategies: (i) short-term cefazolin, (ii) long-term cefazolin, (iii) short-term cefazolin + vancomycin, and (iv) long-term cefazolin + vancomycin. These strategies are delivered in a different order in each health-care center participating in the trial. The centers are randomized to an order, and the current strategy becomes the standard operating procedure in that center during the study.

The three feasibility outcomes include: (1) the proportion of patients receiving preoperative, intra-operative, and postoperative antibiotics according to the study protocol, (2) the proportion of completed follow-up assessments, and (3) a full and final assessment of the incidence of s-SSIs by the outcome adjudication committee.

Discussion

We believe that a cluster-randomized factorial crossover trial is an effective and feasible design for these research questions, allowing an evaluation of the clinical effectiveness in a real-world setting. A waiver of individual informed consent was considered appropriate by the research ethics boards in each participating site in Canada as long as an information letter with an opt-out option was provided. However, a waiver of consent was not approved at two sites in Germany and Switzerland, respectively.

Trial registration

Clinicaltrials.gov, NCT02285140. Registered on 15 October 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3080-y) contains supplementary material, which is available to authorized users.

Cardiopulmonary Bypass Time Predicts Early Postoperative Enterobacteriaceae Bloodstream Infection

BACKGROUND

A bloodstream infection in patients undergoing cardiovascular operations is crucial because it can result in significantly worse outcomes. However, microbiological patterns have rarely been investigated in these patients.

METHODS

We retrospectively reviewed the data of 1,041 adult patients who underwent cardiovascular operations using cardiopulmonary bypass from January 2013 to December 2017 at the National Cheng Kung University Hospital, Tainan, Taiwan. The microbiological pattern and associated variables were analyzed in patients with early postoperative primary bloodstream infection.

RESULTS

Primary bloodstream infection developed in 28 patients (2.7%) within 7 days after cardiovascular operations using cardiopulmonary bypass. In patients with early primary bloodstream infection, 36 microorganisms were isolated, and a gram-negative bacillus was identified to be the predominant pathogen (28 of 36 [77.8%]). The most common microorganisms comprised the Enterobacter (n = 8) and Acinetobacter (n = 7) species, and 16 of the 28 gram-negative bacilli belonged to the Enterobacteriaceae family. Compared with those without postoperative bloodstream infection, patients with Enterobacteriaceae family-related early postoperative bloodstream infections had a significantly longer cardiopulmonary bypass time and also worse early and late survival rates.

CONCLUSIONS

Most patients with early primary bloodstream infection after cardiovascular operations using cardiopulmonary bypass were infected with gram-negative bacilli, and the Enterobacteriaceae family was the most common microorganism observed. Endogenous bacterial translocation after prolonged cardiopulmonary bypass is a possible mechanism of Enterobacteriaceae family-related early primary bloodstream infection in these patients. Prophylactic use of an antibiotic regimen with broader gram-negative bacteria coverage in cardiovascular surgical patients with prolonged cardiopulmonary bypass should be considered.

Effects of cardiopulmonary bypass on the disposition of cefazolin in patients undergoing cardiothoracic surgery

The aim of the study was to evaluate the disposition of plasma unbound cefazolin in patients undergoing cardiothoracic surgery with cardiopulmonary bypass (CPB). Adult patients undergoing cardiothoracic surgery with CPB were enrolled in the study. Cefazolin sodium was given intravenously before skin incision (1 g) and at the beginning of CPB (2 g). Thereafter, an additional dose (1 g) was given every 4 hours. Seven to ten blood samples were collected before and during surgery. Plasma total and unbound (ultrafiltrated) cefazolin concentrations were analyzed using an HPLC-UV method. Plasma protein binding was analyzed with the Langmuir model. Twenty-seven patients (aged 70 ± 12 years, body weight 62 ± 12 kg, mean ± SD) with GFR >30 mL min-1 completed the study. There was a significant (P < 0.001) increase in median plasma unbound fraction of cefazolin from 21% before skin incision to 45% during CPB (P < 0.001), which was accompanied by a significant (P < 0.001) reduction in median plasma albumin concentration from 36 to 27 g L-1. Plasma concentrations of unbound cefazolin exceeded the assumed target thresholds of 2 μg mL-1 in all samples and of 8 μg mL-1 in all but one of 199 samples. The increased plasma unbound fraction of cefazolin would be attributable to dilutional reduction of serum albumin at the beginning of CPB and to saturable plasma protein binding of cefazolin. These data reveal CPB may alter the plasma protein binding and possibly distribution of cefazolin. Further studies are warranted to reappraise the protocol of antimicrobial prophylaxis with cefazolin in patients undergoing surgery with CPB.

A review of the AATS guidelines for the prevention and management of sternal wound infections

Purpose

To summarize the AATS guidelines for the prevention and treatment of sternal wound infections.

Methods

The current AATS guidelines for the prevention of sternal wound infections during the preoperative, intraoperative, and postoperative periods, and the most effective methods and techniques to treat sternal wound infections were reviewed.

Results

The guidelines identified multiple interventions that can be instituted during the preoperative, intraoperative, and postoperative periods to reduce sternal wound infections during cardiac surgery. These include the use of perioperative antibiotics, glycemic control to maintain serum glucose < 180 mg/dl, avoidance of bone wax and the use of vancomycin paste to the sternal edges, and figure of eight suture techniques to re-approximate the sternum. Wound Vac therapy should be instituted whenever possible to treat and enhance recovery from mediastinitis.

Conclusions

The prevention of sternal wound infections and mediastinitis can be achieved by adherence to the AATS guidelines. The institution of these interventions requires a multi-disciplinary team effort among surgeons, anesthesiologists, referring physicians, nurses, and OR and ICU personnel.

Incidence and risk factors for potentially suboptimal serum concentrations of vancomycin during cardiac surgery

AIM

To investigate the incidence and risk factors for vancomycin concentrations less than 10 mg/L during cardiac surgery.

METHODS

In this prospective study, patients undergoing cardiac surgery received a single dose of 1000 mg of vancomycin. Multiple arterial samples were drawn during surgery. Exclusion criteria were hepatic dysfunction; renal dysfunction; ongoing infectious diseases; solid or hematologic tumors; severe insulin-dependent diabetes; body mass index of < 17 or > 40 kg/m²; pregnancy or lactation; antibiotic, corticosteroid, or other immunosuppressive therapy; vancomycin or nonsteroidal anti-inflammatory drug therapy in the previous 2 wk; chemotherapy or radiation therapy in the previous 6 mo; allergy to vancomycin or cefazolin; drug abuse; cardiac surgery in the previous 6 mo; previous or scheduled organ transplantation; preoperative stay in the intensive care unit for more than 24 h; emergency procedure or lack of adequate preparation for surgery; and participation in another trial.

RESULTS

Over a 1-year period, 236 patients were enrolled, and a total of 1682 serum vancomycin concentrations (median 7/patient) were measured. No vancomycin levels under 10 mg/L were recorded in 122 out of 236 patients (52%), and 114 out of 236 patients (48%) were found to have at least 1 serum sample with a vancomycin level < 10 mg/L; 54 out of 236 patients (22.9%) had at least 5 serum samples with a vancomycin level lower than 10 mg/L. Vancomycin infusion was administered for 60 min in 97 out of 236 patients (41%). In 47 patients (20%), the duration of infusion was longer than 60 min, and in 92 patients (39%) the duration of infusion was shorter than 60 min. The maximum concentration and area under the concentration-time curve were significantly higher in patients with no vancomycin levels less than 10 mg/L (P < 0.001). The multivariate analysis identified female gender, body mass index (BMI) > 25 kg/m², and creatinine clearance above 70 mL/min as risk factors for vancomycin levels less than 10 mg/L.

CONCLUSION

Results of this study identified female gender, BMI > 25 kg/m², and creatinine clearance above 70 mL/min as risk factors for suboptimal vancomycin serum concentration during cardiac surgery; no relationship was found between infusion duration and vancomycin levels less than 10 mg/L. These findings call attention to the risk of facilitating the emergence of vancomycin-resistant methicillin-resistant Staphylococcus aureus strains.

The risk of mediastinitis and deep sternal wound infections with single and bilateral, pedicled and skeletonized internal thoracic arteries

Bilateral internal thoracic artery (BITA) grafting may prolong survival in coronary artery bypass graft (CABG) patients, but its use has been curtailed due to concerns of deep sternal wound infections (DSWI) resulting in mediastinitis. This article examines the association of single internal thoracic artery (SITA) and BITA grafting and the role of harvesting techniques with the development of DSWI in CABG patients. The development of DSWI following BITA grafting is multifactorial and is independent of the harvesting technique.

Safety of a 2-Day Antibiotic Regimen After Delayed Chest Closure Post Pediatric Cardiac Surgery

BACKGROUND

There is no consensus for the length of prophylactic antibiotics after delayed chest closure (DCC) postcardiac surgery in pediatrics. In September 2014, our institution's pediatric cardiac intensive care unit changed the policy on length of prophylactic antibiotics after DCC from 5 days (control) to 2 days (study group). The objective of the study was to determine whether a 2-day course of antibiotics is as effective as a 5-day course in preventing blood stream and sternal wound infections in pediatric DCC.

METHODS

Retrospective and prospective study. Primary end points included incidence of sternal wound infections and positive sternal imaging for infection. Surrogate markers of infection were collected at 4 time points.

RESULTS

During the study period, 139 patients had DCC postcardiac surgery of which 110 patients were included for analysis, 54 patients in the control and 56 in the study group. There was no difference in total number of positive wound cultures/chest computed tomography (CT) findings (4/54 [7.5%] control vs 5/56 [8.9%] study group, P = .3), positive blood cultures (P = .586), median postsurgical length of stay (P = .4), or readmissions within 30 days postsurgery (P = .6). All secondary end points were similar in both groups except peak heart rate between weeks 2 and 4 (P = .041).

CONCLUSION

Two days of prophylactic antibiotics is not inferior to 5 days of prophylactic antibiotics after DCC following pediatric cardiac surgery.

Current perspectives on diagnosis and management of sternal wound infections

Deep sternal wound infection (DSWI), also known as mediastinitis, is a serious and potentially fatal condition. The diagnosis and treatment of DSWI are challenging. In this current narrative review, the epidemiology, risk factors, diagnosis, and surgical and antimicrobial management of DSWI are discussed. Ideally, the management of DSWI requires early and sufficient surgical debridement and appropriate antibiotic therapy. When foreign material is present, biofilm-active antibiotic therapy is also needed. Because DSWI is often complex, the management requires the involvement of a multidisciplinary team consisting of cardiothoracic surgeons, plastic surgeons, intensivists, infectious disease specialists, and clinical microbiologists.

Prevention of deep sternal wound infection in cardiac surgery: a literature review

BACKGROUND

Deep sternal wound infection (DSWI) is a dreaded complication of cardiac surgery with considerable consequences in terms of mortality, morbidity and treatment costs. In addition to standard surgical site infection prevention guidelines, multiple specific measures in the prevention of DSWI have been developed and evaluated in the past decades. This review focuses on these specific measures to prevent DSWI.

METHODS

An extensive literature search was performed to assess interventions in the prevention of DSWI. Articles describing results of a randomized controlled trial were categorized by type of intervention. Results were yielded and, if possible, pooled.

RESULTS

From a total of 743 articles found, 48 randomized controlled trials were selected. Studies were divided into 12 categories, containing pre-, peri- and postoperative preventive measures. Specific measures shown to be effective were: antibiotic prophylaxis with a first-generation cephalosporin for at least 24 h, application of local gentamicin before chest closure, sternal closure with figure-of-eight steel wires, and postoperative chest support using a corset or vest.

CONCLUSION

This study identified several measures that prevent DSWI after cardiac surgery that are not frequently applied in current practice. It is recommended that the guidelines on prevention of surgical site infection in cardiac surgery should be updated.

Infections after lung transplantation

The good clinical result of lung transplantation is constantly undermined by the high incidence of infection, which negatively impacts on function and survival. Moreover, infections may also have immunological interactions that play a role in the acute rejection and in the development of chronic lung allograft dysfunction. There is a temporal sequence in the types of infection that affects lung allograft: in the first postoperative month bacteria are the most frequent cause of infection; following this phase, cytomegalovirus and Pneumocystis carinii are common. Fungal infections are particularly feared due to their association with bronchial complication and high mortality. Scrupulous postoperative surveillance is mandatory for the successful management of lung transplantation patients with respect to early detection and treatment of infections. This paper is aimed to address clinicians in the management of the major infectious complications that affect the lung transplant population.

Population Pharmacokinetic Model for Vancomycin Used in Open Heart Surgery: Model-Based Evaluation of Standard Dosing Regimens

The purpose of this study was to investigate the population pharmacokinetics of vancomycin in patients undergoing open heart surgery. In this observational pharmacokinetic study, multiple blood samples were drawn over a 48-h period of intravenous vancomycin in patients who were undergoing open heart surgery. Blood samples were analyzed using an Architect i4000SR immunoassay analyzer. Population pharmacokinetic models were developed using Monolix 4.4 software. Pharmacokinetic-pharmacodynamic (PK-PD) simulations were performed to explore the ability of different dosage regimens to achieve the pharmacodynamic targets. A total of 168 blood samples were analyzed from 28 patients. The pharmacokinetics of vancomycin are best described by a two-compartment model with between-subject variability in clearance (CL), the volume of distribution of the central compartment (V₁), and volume of distribution of the peripheral compartment (V₂). The CL and the V₁ of vancomycin were related to creatinine CL (CL_CR), body weight, and albumin concentration. Dosing simulations showed that standard dosing regimens of 1 and 1.5 g failed to achieve the PK-PD target of AUC_0-24/MIC > 400 for an MIC of 1 mg/liter, while high weight-based dosing regimens were able to achieve the PK-PD target. In summary, the administration of standard doses of 1 and 1.5 g of vancomycin two times daily provided inadequate antibiotic prophylaxis in patients undergoing open heart surgery. The same findings were obtained when 15- and 20-mg/kg doses of vancomycin were administered. Achieving the PK-PD target required higher doses (25 and 30 mg/kg) of vancomycin.

Population Pharmacokinetic Model-Based Evaluation of Standard Dosing Regimens for Cefuroxime Used in Coronary Artery Bypass Graft Surgery with Cardiopulmonary Bypass

The purpose of this study was to investigate the population pharmacokinetics (PK) of cefuroxime in patients undergoing coronary artery bypass graft (CABG) surgery. In this observational pharmacokinetic study, multiple blood samples were collected over a 48-h interval of intravenous cefuroxime administration. The samples were analyzed by using a validated high-performance liquid chromatography (HPLC) method. Population pharmacokinetic models were developed using Monolix (version 4.4) software. Pharmacokinetic-pharmacodynamic (PD) simulations were performed to explore the ability of different dosage regimens to achieve the pharmacodynamic targets. A total of 468 blood samples from 78 patients were analyzed. The PK for cefuroxime were best described by a two-compartment model with between-subject variability on clearance, the volume of distribution of the central compartment, and the volume of distribution of the peripheral compartment. The clearance of cefuroxime was related to creatinine clearance (CL_CR). Dosing simulations showed that standard dosing regimens of 1.5 g could achieve the PK-PD target of the percentage of the time that the free concentration is maintained above the MIC during a dosing interval (fT_MIC) of 65% for an MIC of 8 mg/liter in patients with a CL_CR of 30, 60, or 90 ml/min, whereas this dosing regimen failed to achieve the PK-PD target in patients with a CL_CR of ≥125 ml/min. In conclusion, administration of standard doses of 1.5 g three times daily provided adequate antibiotic prophylaxis in patients undergoing CABG surgery. Lower doses failed to achieve the PK-PD target. Patients with high CL_CR values required either higher doses or shorter intervals of cefuroxime dosing. On the other hand, lower doses (1 g three times daily) produced adequate target attainment for patients with low CL_CR values (≤30 ml/min).

Surgical Site Infection After Pediatric Cardiothoracic Surgery

BACKGROUND

Surgical site infection (SSI) occurs in 0.25% to 6% of children after cardiothoracic surgery (CTS). There are no published data regarding the financial impact of SSI after pediatric CTS. We sought to determine the attributable hospital cost and length of stay associated with SSI in children after CTS.

METHODS

We performed a retrospective, matched cohort study in a 26-bed cardiac intensive care unit (CICU) from January 2010 through December 2013. Cases with SSI were identified retrospectively and individually matched to controls 2:1 by age, gender, Risk Adjustment for Congenital Heart Surgery score, Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category, and primary cardiac diagnosis and procedure.

RESULTS

Of the 981 cases performed during the study period, 12 with SSI were identified. There were no differences in demographics, clinical characteristics, or intraoperative data. Median total hospital costs were higher in participants with SSI as compared to controls (US$219,573 vs US$82,623, P < .01). Children with SSI had longer median CICU length of stay (9 vs 3 days, P < .01), hospital length of stay (18 vs 8.5 days, P < .01), and duration of mechanical ventilation (2 vs 1 day, P < .01) and vasoactive administration (4.5 vs 1 day, P < .01).

CONCLUSIONS

Children with SSI after CTS have an associated increase in hospital costs of US$136,950/case and hospital length of stay of 9.5 days/case. The economic burden posed by SSI stress the importance of infection control surveillance, exhaustive preventative measures, and identification of modifiable risk factors.

Fluid Overload and Cumulative Thoracostomy Output Are Associated With Surgical Site Infection After Pediatric Cardiothoracic Surgery

OBJECTIVES

To determine the impact of cumulative, postoperative thoracostomy output, amount of bolus IV fluids and peak fluid overload on the incidence and odds of developing a deep surgical site infection following pediatric cardiothoracic surgery.

DESIGN

A single-center, nested, retrospective, matched case-control study.

SETTING

A 26-bed cardiac ICU in a 303-bed tertiary care pediatric hospital.

PATIENTS

Cases with deep surgical site infection following cardiothoracic surgery were identified retrospectively from January 2010 through December 2013 and individually matched to controls at a ratio of 1:2 by age, gender, Risk Adjustment for Congenital Heart Surgery score, Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category, primary cardiac diagnosis, and procedure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twelve cases with deep surgical site infection were identified and matched to 24 controls without detectable differences in perioperative clinical characteristics. Deep surgical site infection cases had larger thoracostomy output and bolus IV fluid volumes at 6, 24, and 48 hours postoperatively compared with controls. For every 1 mL/kg of thoracostomy output, the odds of developing a deep surgical site infection increase by 13%. By receiver operative characteristic curve analysis, a cutoff of 49 mL/kg of thoracostomy output at 48 hours best discriminates the development of deep surgical site infection (sensitivity 83%, specificity 83%). Peak fluid overload was greater in cases than matched controls (12.5% vs 6%; p < 0.01). On receiver operative characteristic curve analysis, a threshold value of 10% peak fluid overload was observed to identify deep surgical site infection (sensitivity 67%, specificity 79%). Conditional logistic regression of peak fluid overload greater than 10% on the development of deep surgical site infection yielded an odds ratio of 9.4 (95% CI, 2-46.2).

CONCLUSIONS

Increased postoperative peak fluid overload and cumulative thoracostomy output were associated with deep surgical site infection after pediatric cardiothoracic surgery. We suspect the observed increased thoracostomy output, fluid overload, and IV fluid boluses may have altered antimicrobial prophylaxis. Although analysis of additional pharmacokinetic data is warranted, providers may consider modification of antimicrobial prophylaxis dosing or alterations in fluid management and diuresis in response to assessment of peak fluid overload and fluid volume shifts in the immediate postoperative period.

[Analysis of Postoperative Complications and Risk Factors of Patients with Lung Cancer through Clavien-Dindo Classification]

背景与目的

术后并发症是肺切除术后患者死亡的重要原因。在本研究中，我们应用Clavien-Dindo并发症分级系统对肺癌术后并发症按照严重程度进行分级，并分析术后并发症的发生率，探讨不同分级术后并发症的危险因素。

方法

回顾性分析2013年6月-2014年12月四川大学华西医院胸外科966例行肺叶切除术的肺癌患者，依据术后30 d内是否发生并发症将此966例患者分为并发症组与无并发症组；同时根据Clavien-Dindo分级系统将并发症分为4级，并针对不同分级的并发症进行危险因素分析。

结果

966例患者中，并发症组占15.0%（145/966），发生总数380次；依据Clavien-Dindo分级系统将此380次并发症进行分级，其中Ⅰ级、Ⅱ级、Ⅲ级、Ⅳ级及以上分别占6.8%、75.3%、15.0%和2.9%。Logistic回归分析结果显示术前第1秒用力呼气容积（forded expiratory volume in one second, FEV₁）、肺一氧化碳弥散量（diffusion capacity for carbon monoxide of the lung single breath, DLco SB）及术前合并慢性阻塞性肺疾病（chronic obstructive pulmonary disease, COPD）是术后并发症的独立危险因素；其中术前FEV₁是Ⅰ级、Ⅱ级、Ⅲ级及以上并发症的独立危险因素。

结论

在Clavien-Dindo分级系统下，Ⅱ级并发症在术后30天内最常见；FEV₁与术后并发症的发生密切相关，可作为评估术后并发症发生风险的可靠指标之一。

[Classification and Risk-factor Analysis of Postoperative Cardio-pulmonary Complications after Lobectomy in Patients with Stage I Non-small Cell Lung Cancer]

背景与目的

随着医学技术的进步，医学检测手段的更新，体检筛查的普及以及社会健康意识的提高，越来越多的早期肺癌能够得到及时的发现并接受手术治疗，而关于患者术后并发症发生种类和高危因素的研究很少；针对Ⅰ期非小细胞肺癌（non-small cell lung cancer, NSCLC）术后并发症及其高危因素的研究，可为此类患者术后心肺相关并发症的预防、干预提供依据，并加速患者康复。

方法

回顾性分析2012年1月-2013年12月四川大学华西医院胸外科行肺叶切除的Ⅰ期NSCLC患者421例，以术后30天是否发生心肺相关并发症分为：并发症组和无并发症组。

结果

最终421例患者被纳入研究，其中64例为并发症组（15.2%, 64/421），357例为非并发症组（84.8%, 357/421）。421例患者中，发生肺部感染的比例最高（8.8%, 37/421），其他主要的并发症包括肺不张（5.9%, 25/421）、中量以上胸腔积液（5.0%, 21/421），持续性肺漏气（3.6%, 15/421）等；术前合并慢性阻塞性肺部疾病（chronic obstructive pulmonary disease, COPD）（P=0.027），术前白细胞计数（P < 0.001），中性淋巴比（neutrophil-lymphocyte ratio, NLR）（P < 0.001），术中出血量（P=0.034）以及手术时间（P=0.007）在两组间差异有统计学意义；采用二分类Logistics回归分析后发现，术前白细胞计数（OR=1.451, 95%CI: 1.212-1.736, P < 0.001）、术前合并COPD（OR=0.031, 95%CI: 0.012-0.078, P < 0.001）是术后发生心肺相关并发症的独立危险因素。

结论

术前白细胞计数以及术前合并COPD是Ⅰ期肺癌患者术后心肺相关并发症发生的独立危险因素，可能可以作为预测术后心肺相关并发症的可靠指标。

Violation of prophylactic vancomycin administration timing is a potential risk factor for rate of surgical site infections in cardiac surgery patients: a prospective cohort study

Background

Intensivists and cardiothoracic surgeons are commonly worried about surgical site infections (SSIs) due to increasing length of stay (LOS), costs and mortality. The antimicrobial prophylaxis is one of the most important tools in the prevention of SSIs. The objective of this study was to investigate the relationship between the timing of antimicrobial prophylaxis administration and the rate of SSIs.

Methods

A prospective cohort study was carried out over 1-year period in all consecutive adult patients undergoing elective cardiac surgery. The population was stratified in patients whose antimicrobial prophylaxis administration violated or not the vancomycin timing protocol (i.e., when the first skin incision was performed before the end of vancomycin infusion). To compare SSI rates, the cohort was further stratified in patients at low and high risk of developing SSIs.

Results

Over the study period, 1020 consecutive adult patients underwent cardiac surgery and according to study inclusion criteria, 741 patients were prospectively enrolled. A total of 60 SSIs were identified for an overall infection rate of 8.1%. Vancomycin prophylaxis timing protocol was violated in 305 (41%) out of 741 enrolled patients. SSIs were observed in 3% of patients without violation of the antimicrobial prophylaxis protocol (13/436) compared with 15.4% of patients with a violation of the timing protocol (47/305) (P < 0.0001). Patients at low risk with protocol violation had a higher occurrence of SSIs (P = 0.004) and mortality (P = 0.03) versus patients at low risk without protocol violation. Similarly, patients at high risk with protocol violation had a higher occurrence of SSIs (P < 0.001) and mortality (P < 0.001) versus patients at high risk without protocol violation. The logistic regression analysis showed that internal mammary artery use (P = 0.025), surgical time (P < 0.001), intensive care unit (ICU) LOS (P = 0.002), high risk of developing SSIs (P < 0.001) and protocol violation (P < 0.001) were risk factors for SSI occurrence as well as age (P = 0.003), logistic EuroSCORE (P < 0.001), ICU LOS (P < 0.001), mechanical ventilation time (P < 0.001) and protocol violation (P < 0.001) were risk factors for mortality.

Conclusions

This study showed that violation of the timing of prophylactic vancomycin administration significantly increased the probability of SSIs and mortality from infectious cause in cardiac surgery patients.

Dosing antibiotic prophylaxis during cardiopulmonary bypass-a higher level of complexity? A structured review

In highly invasive procedures such as open heart surgery, the risk of post-operative infection is particularly high due to exposure of the surgical field to multiple foreign devices. Adequate antibiotic prophylaxis is an essential intervention to minimise post-operative morbidity and mortality. However, there is a lack of clear understanding on the adequacy of traditional prophylactic dosing regimens, which are rarely supported by data. The aim of this structured review is to describe the relevant pharmacokinetic/pharmacodynamic (PK/PD) considerations for optimal antibiotic prophylaxis for major cardiac surgery including cardiopulmonary bypass (CPB). A structured review of the relevant published literature was performed and 45 relevant studies describing antibiotic pharmacokinetics in patients receiving extracorporeal CPB as part of major cardiac surgery were identified. Some of the studies suggested marked PK alterations in the peri-operative period with increases in volume of distribution (V_d) by up to 58% and altered drug clearances of up to 20%. Mechanisms proposed as causing the PK changes included haemodilution, hypothermia, retention of the antibiotic within the extracorporeal circuit, altered physiology related to a systemic inflammatory response, and maldistribution of blood flow. Of note, some studies reported no or minimal impact of the CPB procedure on antibiotic pharmacokinetics. Given the inconsistent data, ongoing research should focus on clarifying the influence of CPB procedure and related clinical covariates on the pharmacokinetics of different antibiotics during cardiac surgery. Traditional prophylactic dosing regimens may need to be re-assessed to ensure sufficient drug exposures that will minimise the risk of surgical site infections.

Prevention and Infection Management in Mechanical Circulatory Support Device Recipients

There are currently no guidelines for the management of infection and its prevention in mechanical circulatory support (MCS) device recipients. The International Society of Heart and Lung Transplantation (ISHLT) has initiated a multidisciplinary collaboration for the creation of a consensus document to guide clinicians in infection prevention and management in MCS patients. Most medical centers use local protocols that are based on expert opinion. MCS recipients are debilitated and have some immunological dysfunction. Over the years there have been technical advancements with smaller devices and drivelines with improved durability. The pulsatile devices have been replaced with newer-generation continuous-flow devices. Patient are living longer with MCSs for bridge to transplant (BTT) and destination therapy (DT). MCS centers have improved patient management by introducing standardized driveline protocols, leading to reduced infection rates among MCS recipients.

Avoidance of Hospital-Acquired Infections in Pediatric Cardiac Surgical Patients

OBJECTIVES

The objectives of this review are to discuss the prevalence and risk factors associated with the development of hospital-acquired infections in pediatric patients undergoing cardiac surgery and the published antimicrobial prophylaxis regimens and rational approaches to the diagnosis, prevention, and treatment of nosocomial infections in these patients.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

Hospital-acquired infections remain a significant source of potentially preventable morbidity and mortality in pediatric cardiac surgical patients. Through improved understanding of these conditions and implementation of avoidance strategies, centers caring for these patients may improve outcomes in this vulnerable population.

Circulating 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Concentrations and Postoperative Infections in Cardiac Surgical Patients: The CALCITOP-Study

BACKGROUND

Vitamin D has immunomodulatory properties and seems to reduce the risk of infections. Whether low vitamin D concentrations are independent risk factors for nosocomial postoperative infections in surgical patients remains to be studied in detail.

METHODS

In 3,340 consecutive cardiac surgical patients, we investigated the association of circulating 25-hydroxyvitamin D (25OHD; indicator of nutritional vitamin D status) and 1,25-dihydroxyvitamin D (1,25[OH]2D; active vitamin D hormone) with nosocomicial infections. The primary endpoint was a composite of thoracic wound infection, sepsis, and broncho-pulmonary infection. Vitamin D status was measured on the last preoperative day. Infections were assessed until discharge. Logistic regression analysis was used to examine the association between vitamin D metabolite concentrations and the composite endpoint.

RESULTS

The primary endpoint was reached by 5.6% (n = 186). In patients who reached and did not reach the endpoint, in-hospital mortality was 13.4% and 1.5%, respectively (P<0.001). Median (IQR) 25OHD and 1,25(OH)2D concentrations were 43. 2 (29.7-61.9) nmol/l and 58.0 (38.5-77.5) pmol/l, respectively. Compared with the highest 1,25(OH)2D quintile (>81.0 pmol/l), the multivariable-adjusted odds ratio of infection was 2.57 (95%CI:1.47-4.49) for the lowest 1,25(OH)2D quintile (<31.5 pmol/l) and 1.85 (95%CI:1.05-3.25) for the second lowest quintile (31.5-49.0 pmol/l). There was no significant association between 25OHD concentrations and the primary endpoint.

CONCLUSIONS

Our data indicate an independent association of low 1,25(OH)2D levels with the risk of postoperative infections in cardiac surgical patients. Future studies should pay more attention on the clinical relevance of circulating 1,25(OH)2D and its regulation.

Preoperative Antibiotic Prophylaxis Does Not Reduce the Risk of Postoperative Infectious Complications in Patients Undergoing Elective Hepatectomy

BACKGROUND AND AIM

Postoperative infection is not uncommon after hepatectomy. This study assessed the effectiveness of preoperative antibiotic prophylaxis in elective hepatectomy in a randomized clinical trial setting.

METHODS

A total of 120 patients who were scheduled to undergo elective hepatectomy were equally randomized to receive either intravenous cefuroxime 1.5 g (group A) or placebo (group B) within 30 min prior to skin incision.

RESULTS

Overall, postoperative infection occurred in 26 (21.6 %) of the 120 patients. There was no statistically significant difference between groups A and B in the incidence of overall infection (23.3 vs. 20.0 %, P = 0.658), surgical site infection (13.3 vs. 15 %, P = 0.793), and remote site infection (13.3 vs. 11.7 %, P = 0.783).

CONCLUSION

The use of preoperative antibiotic prophylaxis as a routine practice in patients undergoing elective hepatectomy is unnecessary because it does not reduce the risk of postoperative infectious complications.

Impact of standardization of antimicrobial prophylaxis duration in pediatric cardiac surgery

OBJECTIVES

The optimal duration of antimicrobial prophylaxis following pediatric cardiac surgery is still debated. Adult studies suggest that shorter durations are adequate, but there is a paucity of data on pediatric patients.

METHODS

This quasi-experimental study reviewed the charts of patients 18 years and younger who underwent cardiac surgery from April 2011 to November 2014 at a single institution. Starting in April 2013, a protocol was implemented to limit antimicrobial prophylaxis to 48 hours following sternal closure. Two analyses were performed: (1) identification of risk factors for surgical site infections from the entire cohort, and (2) comparison of surgical site infection incidence in the pre- and postprotocol groups.

RESULTS

In the entire cohort, delayed sternal closure (adjusted odds ratio [OR], 5.7; 95% confidence interval [CI], 1.8-17.9) and younger age (adjusted OR, 2.1; 95% CI, 1.1-3.8) were associated with incidence of surgical site infection. Following the protocol change, duration of antimicrobial prophylaxis decreased from 4.2 ± 2.7 to 1.9 ± 1.3 days (P < .0001). After adjusting for age and delayed sternal closure, the postprotocol group had an adjusted OR of 0.98 (95% CI, 0.32-3.00) for occurrence of surgical site infection. Other outcomes were not altered following the protocol change.

CONCLUSIONS

Restricting antimicrobial prophylaxis to 48 hours following pediatric cardiac surgery did not increase the incidence of surgical site infection at our institution. Further study is needed to validate this finding and to identify practices that reduce surgical site infections in those with delayed sternal closure.

Optimizing Prophylactic Antibiotic Practice for Cardiothoracic Surgery by Pharmacists' Effects

Pharmacists' role may be ideal for improving rationality of drug prescribing practice. We aimed to study the impact of multifaceted pharmacist interventions on antibiotic prophylaxis in patients undergoing clean or clean-contaminated operations in cardiothoracic department. A pre-test-post-test quasiexperimental study was conducted in a cardiothoracic ward at a tertiary teaching hospital in Suzhou, China. Patients admitted to the ward were collected as baseline group (2011.7-2012.12) and intervention group (2013.7-2014.12), respectively. The criteria of prophylaxis antibiotic utilization were established on the basis of the published guidelines and official documents. During the intervention phase, a dedicated pharmacist was assigned and multifaceted interventions were implemented in the ward. Then we compared the differences in antibiotic utilization, bacterial resistance, clinical and economic outcomes between the 2 groups. Furthermore, patients were collected after the intervention (2015.1-2015.6) to evaluate the sustained effects of pharmacist interventions. 412 and 551 patients were included in the baseline and intervention groups, while 156 patients in postintervention group, respectively. Compared with baseline group, a significant increase was found in the proportion of antibiotic prophylaxis, the proportion of rational antibiotic selection, the proportion of suitable prophylactic antibiotic duration, and the proportion of suitable timing of administration of the first preoperative dose (P < 0.001). Meanwhile, a significant reduction was seen in the rate of unnecessary replacement of antibiotics and the rate of unnecessary combinations (P < 0.001). Besides, pharmacist intervention resulted in favorable outcomes with significantly decreased rates of surgical site infections, prophylactic antibiotic cost, and significantly shortened length of stay (P < 0.05). Furthermore, there were also significant decreases of the rates of antibiotic resistant enterobacter cloacae, klebsiella pneumonia, and staphylococcus aureus (P < 0.05). Moreover, the effects were sustained after discontinuation of the active interventions, as shown in prophylactic antibiotic utilization data. Pharmacist interventions in cardiothoracic surgery result in a high adherence to evidence-based treatment guidelines and a profound culture change in drug prescribing with favorable outcomes. The effects of pharmacist intervention are sustained and the role of pharmacists is emphasized for rational medication and optimal outcomes in clinical treatment.

Routine postoperative care of patients undergoing coronary artery bypass grafting on cardiopulmonary bypass

The postoperative course of a patient undergoing cardiac surgery (CS) is dictated by a largely predictable set of interactions between disease-specific and therapeutic factors. ICU personnel need to quickly develop a detailed understanding of the patient's current status and how critical care resources can be used to promote further recovery and eventual independence from external support. The goal of this article is to describe a typical operative and postoperative course, with emphasis on the latter, and the diagnostic and therapeutic options necessary for the proper care of these patients. This paper will focus on coronary artery bypass grafting as a model for understanding the course of CS patients; however, many of the principles discussed are applicable to most cardiac surgery patients.

Deep sternal wound infection after cardiac surgery: Evidences and controversies

Despite many advances in prevention and perioperative care, deep sternal wound infection (DSWI) remains a pressing concern in cardiac surgery, with a still relevant incidence and with a considerable impact on in-hospital mortality and also on mid- and long-term survival. The permanent high impact of this complication is partially related to the increasing proportion of patients at high-risk for infection, as well as to the many patient and surgical risk factors involved in the pathogenesis of DSWI. The prophylactic antibiotic therapy is one of the most important tools in the prevention of DSWI. However, the choice of antibiotic, the dose, the duration, the adequate levels in serum and tissue, and the timing of antimicrobial prophylaxis are still controversial. The treatment of DSWI ranges from surgical revision with primary closure to surgical revision with open dressings or closed irrigation, from reconstruction with soft tissue flaps to negative pressure wound therapy (NPWT). However, to date, there have been no accepted recommendations regarding the best management of DSWI. Emerging evidence in the literature has validated the efficacy and safety of NPWT either as a single-line therapy, or as a “bridge” prior to final surgical closure. In conclusion, the careful control of patient and surgical risk factors - when possible, the proper antimicrobial prophylaxis, and the choice of validated techniques of treatment could contribute to keep DSWIs at a minimal rate.

Antibiotic prophylaxis and risk of Clostridium difficile infection after coronary artery bypass graft surgery

OBJECTIVE

Antibiotic use, particularly type and duration, is a crucial modifiable risk factor for Clostridium difficile. Cardiac surgery is of particular interest because prophylactic antibiotics are recommended for 48 hours or less (vs ≤24 hours for noncardiac surgery), with increasing vancomycin use. We aimed to study associations between antibiotic prophylaxis (duration/vancomycin use) and C difficile among patients undergoing coronary artery bypass grafting.

METHODS

We extracted data on coronary artery bypass grafting procedures from the national Premier Perspective claims database (2006-2013, n = 154,200, 233 hospitals). Multilevel multivariable logistic regressions measured associations between (1) duration (<2 days, "standard" vs ≥2 days, "extended") and (2) type of antibiotic used ("cephalosporin," "cephalosporin + vancomycin," "vancomycin") and C difficile as outcome.

RESULTS

Overall C difficile prevalence was 0.21% (n = 329). Most patients (59.7%) received a cephalosporin only; in 33.1% vancomycin was added, whereas 7.2% received vancomycin only. Extended prophylaxis was used in 20.9%. In adjusted analyses, extended prophylaxis (vs standard) was associated with significantly increased C difficile risk (odds ratio, 1.43; confidence interval, 1.07-1.92), whereas no significant associations existed for vancomycin use as adjuvant or primary prophylactic compared with the use of cephalosporins (odds ratio, 1.21; confidence interval, 0.92-1.60, and odds ratio, 1.39; confidence interval, 0.94-2.05, respectively). Substantial inter-hospital variation exists in the percentage of extended antibiotic prophylaxis (interquartile range, 2.5-35.7), use of adjuvant vancomycin (interquartile range, 4.2-61.1), and vancomycin alone (interquartile range, 2.3-10.4).

CONCLUSIONS

Although extended use of antibiotic prophylaxis was associated with increased C difficile risk after coronary artery bypass grafting, vancomycin use was not. The observed hospital variation in antibiotic prophylaxis practices suggests great potential for efforts aimed at standardizing practices that subsequently could reduce C difficile risk.