Systemic inflammatory response syndrome criteria and vancomycin dose requirement in patients with sepsis

Vancomycin has been used in patients with sepsis infected by MRSA and shows large interindividual variability in its dosing. In this observational study the potential influence of sepsis status on the vancomycin dose requirement in relation to systemic inflammatory response syndrome (SIRS) criteria was assessed. From about 250 patients receiving serum vancomycin monitoring from May 2006 to April 2011 at the Osaka National Hospital, 105 adult patients who had been assessed using the SIRS criteria were identified. Patients on chemotherapy or intermittent positive pressure ventilation in whom the SIRS criteria could not accurately evaluate inflammatory status were excluded. Using two vancomycin serum concentrations at peak and trough, individual pharmacokinetic parameters were calculated by the Bayesian estimation method using a two-compartment model. Creatinine clearance rate was estimated by the Cockcroft-Gault formula (eCcr). Patients with SIRS had a significantly higher vancomycin clearance than those without SIRS, indicating that SIRS patients had a higher elimination capacity. The vancomycin clearance was positively correlated with the SIRS score defined as the number of positive items in the criteria, and negatively with age, except in patients with renal dysfunction. A linear relationship between the vancomycin clearance and eCcr remained even in the supernormal eCcr phase (more than approximately 120 mL/min). This study provides a new insight into the need for quick prediction of dose requirement. That is, an increased vancomycin dosage would be needed in patients with a higher SIRS score to maintain the therapeutic target concentration, in particular in those with a high eCcr value.