[Target-controlled infusion of propofol for intraoperative sedation: determination of effect-site concentration and assessment of bispectral index].
OBJECTIVE
To determine the effect-site concentration (Ce) of propofol, required to achieving adequate sedation. To assess the efficacy and safety of a target-controlled infusion system during monitored anaesthesia care and to evaluate the ability of bispectral index (BIS) to predict sedation level. Study design. - Prospective clinical study.


METHODS
Women scheduled for insertion of tension-free vaginal tape under local anaesthetic infiltration.


METHODS
After premedication with hydroxyzine, 1% propofol was infused using the Diprifusor system at an initial target plasma concentration (Cc) of 1 microg/ml and then adjusted by steps of 0.2 microg/ml at 5 min intervals. The level of sedation was assessed using the observer's assessment of alertness/sedation (OAA/S) scale; the objective was to obtain an OAA/S level at 4 or 3 (response to verbal stimulation). Ce of propofol and BIS were noted every 5 min. Relation between Ce or BIS and OAA/S scale was analysed by linear regression and probability of prediction (P(K)).


RESULTS
Fifty patients aged 62 +/- 12 years were studied. Sedation at level 4 or 3 was observed in all patients. Ce of propofol and BIS to maintain this OAA/S score were, respectively, 1.0 +/- 0.2 microg/ml and 87 +/- 7. There was a linear relation between OAA/S scale and BIS or Ce; however, individual values demonstrate wide variability. The average of P(K) values computed for each patient for the BIS and Ce was 0.84 and 0.83, respectively.


CONCLUSIONS
Target-controlled infusion of propofol provides easy and safe management of intraoperative sedation, allowing a fast and precise adjustment of the propofol concentration to the clinical response of the patient.
Département d'anesthésie-réanimation-I, CHU Pellegrin, 33076 Bordeaux cedex, France.
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A
Quinart
K
K
Nouette-Gaulain
R
R
Pfeiff
P
P
Revel
F
F
Sztark
D000368:Aged; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D006993:Hypnotics and Sedatives; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D012044:Regression Analysis; D014549:Urinary Incontinence / Q000601:surgery
D018686:Anesthetics, Intravenous; D006993:Hypnotics and Sedatives; D015742:Propofol