Ketamine and midazolam kinetics during continuous hemodiafiltration in patients with multiple organ dysfunction syndrome

Objective: To assess the effect of continuous hemodiafiltration (CHDF) on ketamine and midazolam kinetics in multiple organ dysfunction syndrome (MODS). Design and setting: Consecutive clinical study in a general intensive care unit of a university hospital. Patients: Twelve adult patients with MODS requiring CHDF. Measurements and results: A total of 68 samples were collected during CHDF for ketamine, norketamine, and midazolam assays. The clearance values for ketamine and norketamine were 10.8±6.6 and 10.9±11.5 ml/min and their daily extractions were 21.4±7.1 and 10.2±11.5 mg/day, respectively. Midazolam was not eliminated through the filter during CHDF. There were no changes in Ramsay Sedation Score or Glasgow Coma Scale during CHDF. Conclusions: Small fractions of ketamine and norketamine were eliminated during CHDF in MODS. Midazolam was not eliminated during CHDF. CHDF did not affect the sedation using ketamine and midazolam even in MODS patients.