Automated responsiveness test and bispectral index monitoring during propofol and propofol/N2O sedation
The Outcomes Research Institute and Department of Anesthesiology and Pharmacology, University of Louisville, Louisville, KY 40202, USA. Acta Anaesthesiologica Scandinavica
(Impact Factor: 2.32).
09/2003; 47(8):951-7. DOI: 10.1034/j.1399-6576.2003.00184.x
Sedation practice, especially when non-anaesthesia personnel are involved, requires efficient anaesthetic depth monitoring. Therefore, we used prediction probability (PK) to evaluate the performance of the bispectral index (BIS) of the EEG and automated responsiveness test (ART) to predict sedation depth and loss of subject's responsiveness during propofol sedation, with and without N2O.
Twenty volunteers were studied during propofol administration with (N2O) and without (Air) N2O. The protocol consisted of sequential 15-min cycles. After a control period, propofol was infused to a target effect-site concentration of 0.25 microg/ml (N2O) or 1.5 microg/ml (Air), which was subsequently increased by 0.25 or 0.5 microg/ml, respectively, until loss of responsiveness was detected by loss of response to command [observer's assessment of alertness/sedation (OAA/S) score <or= 2].
Deeply sedated patients did not respond to ART indicating that the sensitivity was 1.0 with or without N2O. The specificity of ART was 0.24 with Air and 0.98 with N2O. The BIS was better than ART in predicting OAA/S score (PK = 0.84 vs. 0.77) and loss of responsiveness (PK = 0.87 vs. 0.69) during the Air trial. Nitrous oxide decreased the performance of BIS in predicting OAA/S score (PK = 0.76), but increased the performance of ART to predict loss of responsiveness (PK = 0.85).
BIS and ART comparably predict sedation and loss of responsiveness. However, ART, because of its resistance to false-normal responses, might prove to be more useful on an individual patient basis - especially in the presence of agents that impair BIS sensitivity.
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ABSTRACT: The purpose of this study was to provide data of propofol-based total intravenous anesthesia (TIVA) for ambulatory surgery in developing a fast-track technique. One hundred and forty-two patients scheduled for elective surgery were studied: mean (SD) age 42.21 (16.23) years, male to female 72:70, mean (SD) body weight 60.75 (11.67) kg and American Society of Anesthesiologists (ASA) physical status I/II/III 66/38/38. Mean (SD) thiopental induction 225 (55.69) mg was maintained with mean (SD) propofol 199.64 (86.26) mg for mean (SD) anesthetic time 29.02 (11.21) minutes. Various narcotics were used: fentanyl 73.48 +/- 24.38 microg for 123 cases, morphine 3.27 +/- 1.10 mg for 10 cases, remifentanil 492 +/- 105.26 microg for 7 cases and pethidine 23.33 +/- 2.88 mg for 2 cases. Midazolam was given 2.70 +/- 1.05 mg. Patients were positioned in supine, lithotomy or lateral decubitus. One-fourth were PS III with a diagnosis of chronic renal failure and renal transplants coming for incision and drainage of perianal abscess. The mean (SD) wake-up time was 36.02 (17.69) seconds. Only one case (chronic renal failure) had severe hypotension after induction. Anesthetic agents and ideas of fast-track anesthesia were discussed.
Journal of the Medical Association of Thailand = Chotmaihet thangphaet 07/2004; 87(6):656-9.
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ABSTRACT: 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.
Women scheduled for insertion of tension-free vaginal tape under local anaesthetic infiltration.
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)).
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.
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.
Annales Françaises d Anesthésie et de Réanimation 08/2004; 23(7):675-80. DOI:10.1016/j.annfar.2004.04.017 · 0.84 Impact Factor
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