Effect-site controlled patient maintained propofol sedation: a volunteer safety study.
Effect-site concentration is a mathematical term related to the clinical effect of a drug. We have designed a patient-maintained sedation system for delivering propofol to the predicted effect-site concentration rather than plasma concentration. To assess its efficacy and safety, 20 healthy volunteers deliberately attempted to over-sedate themselves using the system. The new effect-site concentration driven system delivered sedation successfully, and more rapidly than its predecessor. Fifteen volunteers ended the study when the system automatically reduced the effect-site concentration after 6 min of no button presses despite verbal contact and maintenance of arterial oxygen saturation (at effect-site concentration 1.8-3.8 microg x ml(-1)). Four out of 20 volunteers ended with minor arterial desaturation (lowest 88% at effect-site concentration 2.6-3.4 microg x ml(-1)). One volunteer ended after loss of verbal contact at effect-site concentration 3.4 microg x ml(-1). Further modification of the system's design is necessary before it can be recommended for routine practice.
Anderson
K J
KJ
University of Glasgow, Department of Anaesthesia, Glasgow Royal Infirmary, 10 Alexandra Parade, Glasgow, UK. keithanderson@doctors.net.uk
Leitch
J A
JA
Green
J S
JS
Kenny
G N C
GN
D000328:Adult; D001364:Awareness / Q000187:drug effects; D016292:Procedural Sedation / Q000009:adverse effects / Q000379:methods*; D004334:Drug Administration Schedule; D004867:Equipment Design; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage* / Q000097:blood; D008297:Male; D010100:Oxygen / Q000097:blood; D015742:Propofol / Q000008:administration & dosage* / Q000097:blood; D012646:Self Administration / Q000009:adverse effects / Q000379:methods
D006993:Hypnotics and Sedatives; D010100:Oxygen; D015742:Propofol