Validation of a Dosing Strategy for Cefazolin for Surgery Requiring Cardiopulmonary Bypass.
BACKGROUND
A prospective, single center, open-label study was conducted to determine if the standard practice for surgical prophylaxis, which includes standardized dosing of cefazolin, at the University of Maryland Medical Center (UMMC) is adequate for patients placed on bypass during cardiac surgery.


METHODS
All patients were given the same standard dosing regimen regardless of weight: two grams of cefazolin administered within 1 h of incision, an additional one gram injected into the bypass circuit at the onset of bypass, and two grams every 3 h after the initial dose. Cefazolin serum concentrations were collected immediately after incision, after the start of bypass, each hour of bypass, at the end of bypass and at sternal closure.


RESULTS
Ten patients were consented and completed the study with an average age of 62 y, average weight of 84.7 kg and average cardiopulmonary bypass time of 116 min. The free serum concentrations of cefazolin stayed above the pre-defined inhibitory threshold of 16 mcg/mL throughout the procedure for 100% of participants. The mean total serum concentration in the blood throughout surgery was 160 mcg/mL. No patients were found to have surgical site infections using standard criteria and no adverse events were observed.


CONCLUSIONS
For patients undergoing cardiac surgery with cardiopulmonary bypass, the UMMC dosing regimen surpassed targeted cefazolin concentrations during the entire surgical procedure for all patients regardless of weight or time on bypass.
1 University of Maryland Medical Center , Department of Pharmacy, Baltimore, Maryland.
Allison L
AL
Hollis
1 University of Maryland Medical Center , Department of Pharmacy, Baltimore, Maryland.
Emily L
EL
Heil
2 Center for Anti-Infective Research, Hartford Hospital , Hartford, Connecticut.
David P
DP
Nicolau
3 University of Maryland School of Medicine , Baltimore, Maryland.
Patrick
P
Odonkor
4 University of Maryland School of Pharmacy , Baltimore, Maryland.
Thomas C
TC
Dowling
3 University of Maryland School of Medicine , Baltimore, Maryland.
Kerri A
KA
Thom
D000046:Academic Medical Centers; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D002315:Cardiopulmonary Bypass; D002437:Cefazolin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D006801:Humans; D008396:Maryland; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies
D000900:Anti-Bacterial Agents; D002437:Cefazolin