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