PROPOFOL IN PATIENTS NEEDING LONG-TERM SEDATION IN INTENSIVE-CARE - AN ASSESSMENT OF THE DEVELOPMENT OF TOLERANCE - A PILOT-STUDY

Objective: To evaluate the possible development of tolerance in patien ts sedated with propofol in intensive care for more than 5 days. Desig n: An open within patient noncomparative pilot study. Setting: The int ensive care unit of a hospital in the UK. Patients: Twenty-three patie nts who were expected to need sedation with propofol for more than 5 d ays were included; of these, 11 were sedated continuously for between 5 and 10 days. Interventions: Propofol was infused continuously at abo ut 0.5-4 mg/kg per h to provide sedation at level 3 on the Ramsay scal e (drowsy or asleep, responds easily to commands). Alfentanil was infu sed at a rate of about 0.5 mu g/kg per min. Measurements and results: Patients with a statistically significant increase in both infusion ra te and blood concentration were considered to show tolerance, those th at required an increasing infusion rate and constant (or decreasing) b lood concentration were said to show increased clearance, and those th at required constant (or decreasing) infusion rates and blood concentr ations were classed as showing no tolerance. Of the 11 patients who we re sedated for more than 5 days, three showed tolerance and three show ed increased clearance while five showed no tolerance. The desired sed ation level was achieved for the majority of the time for patients sed ated between 5 and 10 days (mean 73-90 %). There was some suggestion o f a relationship between improving health (decreasing APACHE II scores ) and the need for increased infusions of propofol. Conclusions: Altho ugh there were insufficient data to reach firm conclusions, the possib ility of some relationship between the increasing need for propofol an d improving condition in patients needing longer term intensive care c annot be ruled out.