Prophylactic use of vancomycin in adult cardiology and cardiac surgery

The Effect of Modified Ultrafiltration on Serum Vancomycin Levels During Cardiopulmonary Bypass in Cardiac Surgery

OBJECTIVE

The aim of this study was to investigate whether the use of modified ultrafiltration at the end of cardiopulmonary bypass for cardiac surgical procedures significantly changes vancomycin serum concentrations.

DESIGN

Prospective study.

SETTING

Single tertiary cardiac center.

PARTICIPANTS

Twenty-six elective adult patients undergoing cardiac surgery with cardiopulmonary bypass from April 2014 to April 2015.

INTERVENTIONS

Serum vancomycin concentrations were measured just before cardiopulmonary bypass; during cardiopulmonary bypass at 5, 30, 60 minutes and then every 60 minutes; after completion of cardiopulmonary bypass before initiation of modified ultrafiltration; and at the end of modified ultrafiltration.

MEASUREMENTS AND MAIN RESULTS

Seventeen patients received modified ultrafiltration at the end of cardiopulmonary bypass. Serum vancomycin concentrations prior to cardiopulmonary bypass (45.9 ± 17.3 μg/mL) were significantly higher (P < 0.0001) than each time point following cardiopulmonary bypass (5 min 20.4 ± 6.4 μg/mL, 30 min 18.8 ± 5.4 μg/mL, 60 min 16.6 ± 4.9 μg/mL, and 120 min 14.3 ± 4.7 μg/mL). In the modified ultrafiltration group, serum vancomycin concentrations were 14.7 ± 4.6 μg/mL prior to modified ultrafiltration and 13.9 ± 4.3 μg/mL after ultrafiltration; this difference was statistically significant (P  =  0.0288). The mean modified ultrafiltration volume was 465 ± 158 mL.

CONCLUSIONS

Using modified ultrafiltration at the end of cardiopulmonary bypass significantly decreases serum vancomycin levels, but not by a clinically relevant amount. The decrease is to a concentration that is still significantly higher than the minimum inhibitory concentration for Staphylococcus epidermidis and Staphylococcus aureus; thus additional vancomycin administration is not recommended.

The Efficacy of Post-Cardiopulmonary Bypass Dosing of Vancomycin in Cardiac Surgery

Objective. Vancomycin is administered widely to patients undergoing cardiac surgery as prophylaxis against resistant Gram-positive sternal wound and venous donor site infections. The purpose of this study was to determine the efficacy of a standardized prebypass and postbypass dosing regimen of vancomycin by assessing plasma concentrations in the immediate postoperative period and postoperative surgical site infections (SSIs). Design. Retrospective cohort study. Setting . Cardiothoracic surgical intensive care unit in a tertiary care academic medical center. Methods. A total of 34 consecutive adult patients who had undergone cardiac surgery with cardiopulmonary bypass (CPB) were analyzed retrospectively. Each patient received 1000 mg of vancomycin administered over 1 hour around the time of induction of anesthesia and 500 mg after discontinuation of CPB. Trough vancomycin levels were sampled in the intensive care unit 12 hours after the last dose given in the operating room. Along with patient characteristics, postoperative readmission rates and SSIs were recorded for 1 year after surgery. Results. The nadir serum vancomycin level before the next dose was 9.3 ± 4.5 µg/mL (mean ± standard deviation). One superficial SSI was noted. Readmission rate for SSIs was 2.94%. Conclusion . Vancomycin concentrations in the serum were greater than the minimum inhibitory concentration for most staphylococci ranging from 4 to 19.3 µg/mL producing acceptable therapeutic serum concentrations and low rate of infectious complications. Thus postbypass dosing is acceptable in vancomycin cardiac surgical prophylaxis.

An economic model for the prevention of MRSA infections after surgery: non-glycopeptide or glycopeptide antibiotic prophylaxis?

AIM

Surgical site infection is commonly caused by Staphylococcus aureus. The multiresistant strains (MRSA) are resistant to most antibiotic prophylaxis regimens. Our aim was to explore whether there is a threshold of MRSA prevalence at which switching to routine glycopeptide-based antibiotic prophylaxis becomes cost-effective.

METHODS

An indicative model was designed to explore the cost-effectiveness of vancomycin, cephalosporin or a combination, in patients undergoing primary hip arthroplasty.

RESULTS

If the MRSA infection rate is equal to or above 0.25% and the rate of other infections with cephalosporin prophylaxis is equal to or above 0.2%, use of the combination antibiotic prophylaxis is optimal.

DISCUSSION

Modelling the cost-effectiveness of interventions for MRSA prevention is complex due to uncertainty around resistance and effectiveness of glycopeptides.

CONCLUSIONS

The indicative model provides a framework for evaluation. More work is needed to understand the impact of antibiotic resistance over time in these currently effective antibiotics.

Treatment and prevention of Staphylococcus epidermidis experimental biomaterial-associated infection by bactericidal peptide 2

Biomaterial-associated infections (BAI) are the major cause of failure of indwelling medical devices and are predominantly caused by staphylococci, especially Staphylococcus epidermidis. We investigated the in vitro microbicidal activity of the synthetic antimicrobial peptide bactericidal peptide 2 (BP2) and its efficacy in a murine model of S. epidermidis BAI. BP2 showed potent microbicidal activity at micromolar concentrations against a broad spectrum of microorganisms, including antibiotic-resistant bacteria. The staphylocidal activity of BP2 was not affected by physiological salt concentrations and was only slightly affected by the presence of human plasma. In the BAI model, injection of BP2 (5 mg/kg of body weight) 1 h after challenge with S. epidermidis resulted in an 80% reduction in the number of culture-positive implants and a 100-fold reduction in survival of S. epidermidis in peri-implant tissue at 24 h postchallenge. When BP2 was injected along implants 3 h prior to bacterial challenge, the median numbers of CFU cultured from biomaterial implants and peri-implant tissue were reduced by 85% and 90%, respectively. In conclusion, BP2 has potent, broad-spectrum in vitro microbicidal activity and showed potent in vivo activity in a murine model of S. epidermidis biomaterial-associated infection.

Wise use of perioperative antibiotics

NOSOCOMIAL SURGICAL SITE INFECTIONS (SSIs), especially those caused by antibiotic-resistant organisms, are a major concern for perioperative nurses. Administering the correct antibiotic at its effective dose within the optimal time frame can help prevent SSIs. THE SIGNIFICANT RELATIONSHIP between microbial resistance and overuse of antibiotics justifies an examination of practices and a move away from widespread antibiotic administration. NEW ANTIBIOTIC GUIDELINES and research support recommendations for antibiotic administration for specific cardiac, colorectal, gynecologic, ophthalmologic, orthopedic, and urinary surgical procedures. Perioperative nurses can help protect their patients from nosocomial SSIs by using this clinical evidence.