Effects of propofol containing EDTA on mineral metabolism in medical ICU patients with pulmonary dysfunction

Objective: To determine whether the addition of disodium edetate (EDTA) to propofol significantly alters mineral metabolism, adverse events, and outco me in critically ill medical patients with acute pulmonary dysfunction. Design: Multicentre, double-randomised, double-blind, comparative trial. Setting: Medical intensive care units of 5 health centres. Patients: A total of 85 haemodynamically stable men and women aged 18-81 ye ars who had pulmonary dysfunction or adult respiratory distress syndrome as a primary diagnosis or complication and who were expected to require at le ast 48 hours of sedation and mechanical ventilation. Interventions: Patients were randomised to receive propofol with or without EDTA and then to 1 of 2 sedation levels: light (Modified Ramsay Sedation S cale [MRSS] score of 2 to 3) or deep (MRSS score of 4 to 5). Propofol was a dministered by continuous infusion at an initial rate of 5 mug/kg per min a nd titrated as needed. Measurements and Results: Approximately 63 % of patients had a high severit y of illness as indicated by an Acute Physiology and Chronic Health Evaluat ion II score greater than or equal to 19. As expected, these patients had a higher mortality rate but did not require a higher dose of propofol or pro pofol with EDTA. Extensive evaluation of cation homeostasis showed that ion ised calcium and magnesium concentrations remained remarkably stable during treatment. Total calcium concentration was low as a result of hypoalbumine mia. Parathyroid hormone (PTH) concentration was elevated in both study gro ups at baseline, on day 4, and at the end of sedation. There were no signif icant differences in electrolyte levels and no progression to renal dysfunc tion. There were also no significant differences in haemodynamic or adverse -event profiles. Treatment-related adverse events occurred in 5 patients in each group; 4 of these (in 3 patients receiving propofol and 1 patient rec eiving propofol with EDTA) were considered serious. Because a large percent age of patients experienced a change in sedation level, no analyses were pe rformed using sedation level. Conclusions: The addition of EDTA to propofol does not alter calcium and ma gnesium homeostasis in critically ill patients with acute pulmonary dysfunc tion. The reason for the elevation in PTH concentrations in such patients i s not known.