Cation metabolism during propofol sedation with and without EDTA in patients with impaired renal function

Objective: To compare the effects of propofol with and without disodium ede tate (EDTA) on cation metabolism in intensive care unit (ICU) patients with renal insufficiency who received propofol or propofol plus EDTA (propofol EDTA) for sedation and mechanical ventilation. Design: Double-blind, randomised, multicentre study. Setting: Medical and surgical ICUs from 5 hospitals. Patients: Thirty-nine ICU patients with acute and chronic renal impairment expected to require at least 24 hours of continuous sedation and respirator y failure necessitating mechanical ventilation. Interventions: Propofol or propofol EDTA administered for sedation by conti nuous intravenous infusion. Measurements and Results: The depth of sedation, as measured by the Modifie d Ramsay Sedation Scale, was similar in the 2 groups, when adjusted for dos ing differences. The amount of propofol required to maintain adequate sedat ion was decreased in both groups compared to propofol requirements in ICU p atients with normal renal function. EDTA levels were elevated at baseline i n both groups. In the propofol EDTA group, the EDTA levels increased furthe r by 20 % but decreased to below baseline EDTA levels at 48 hours after sed ation. In the propofol group, EDTA levels decreased during sedation and rem ained below baseline levels at 48 hours after sedation. Patients in both gr oups were hypocalcaemic and hyperphosphataemic at baseline with low levels of 1,25-dihydroxyvitamin D and elevated parathyroid hormone (PTH) levels. O ther than a slight difference in ionised serum calcium levels at 4 h after the start of sedation, there were no significant differences observed in se rum calcium levels between the two groups. There were no significant differ ences in 1,25-dihydroxyvitamin D or PTH levels over time between the two gr oups. There was no significant effect on renal function in either group. Conclusions: The results of this study suggest that adding EDTA to propofol does not adversely affect cation homeostasis or renal function when used f or sedation of ICU patients with renal insufficiency. Although EDTA levels increased over time from baseline levels in patients with renal insufficien cy who receive propofol EDTA, this increase does not appear to be clinicall y significant, and EDTA levels return to below baseline levels within 48 ho urs of discontinuing the propofol EDTA infusion. The efficacy of propofol w ith and without EDTA also appears comparable in these patients.