Introduction: Postoperative pneumonia is a severe complication after cardiac surgery (CS) . Therefore, antibiotic prophylaxis is common in patients with increased pulmonary risk. Levofloxacin, a fluoroquinolone, qualifies for perioperative pulmonary prophylaxis due to its activity against gram-positive and gram-negative bacteria. However, penetration properties of levofloxacin to the lung tissue could be affected by CS: atelectasis, changes in circulation, high volume loads and inflammatory capillary leak influencing drug distribution. Therefore, we measured plasma and lung concentrations of levofloxacin in patients undergoing CS.
Method: Six patients undergoing CS on cardiopulmonary bypass participated in the study. Levofloxacin (500 mg) was administered in addition to the standard antibiotic immediately after the end of surgery. Thereafter, we measured time versus concentration profiles of levofloxacin in interstitial lung tissue and plasma. Microdialysis was used for lung interstitial concentration measurements. Microdialysis is based on sampling of analytes from the interstitial space fluid by means of a semi-permeable membrane.
Results: Patients were 61 ± 8 years of age and had a body mass index of 19.6. Levofloxacin concentrations in lung interstitial tissue were well above the MIC90 (fig). Microdialysis-procedure was well tolerated by all patients.
Conclusion: This study showed the feasibility and the safety of microdialysis in human lung tissue after CS. Data corroborate the use of levofloxacin as a valuable agent in the treatment of bacterial lung infections in high risk patients.
1 Müller M, Haag O, Burgdorff T, et al. Characterization of peripheral-compartment kinetics of antibiotics by in vivo microdialysis in humans. Antimicrob Agents Chemther
; 12: 2703-2709.