Effects of BIS monitoring on recovery characteristics, propofol consumption and depth of anaesthesia during TIVA with propofol and fentanyl
European Society of Anaesthesiologists; 8th Annual Meeting with the Austrian International Congress; Vienna, Austria, 1-4 April 2000
Department of Anaesthesiology, Red Cross Hospital, Athens, Greece
Background and goal of study: Bispectral (BIS) index monitoring is proposed as a significant predictor of anaesthetic depth. The effects of BIS monitoring on recovery characteristics, propofol consumption and depth of anaesthesia were studied during TIVA with propofol and fentanyl and were compared to the effects of the same anaesthetic technique conducted without BIS monitoring.
Materials and methods: After institutional approval and written informed consent, forty consective unpremedicated ASA I-II patients undergoing varicose vein surgery were studied. TIVA provided by the same anaesthesiologist to all patients was induced with propropol 2 mg kg−1, fentanyl up to 0.005 mg kg−1, vecuronium 0.1 mg kg−1 and was maintained with propofol infusion 0.1-0.2 mg kg−1 min−1 in 60% N2O in O2. Additional increments of fentanyl and vecuronium were administered as needed. Patients were randomly allocated to different groups with or without BIS monitoring. In group A (n = 20) frontal-temporal BIS monitoring was displayed whereas in group B (n = 20) BIS monitoring was performed but not displayed to the anaesthesia provider. In patients with BIS monitoring propofol infusion was titrated to achieve a BIS index range 45-55. Titration was managed by 10% adjustments in propofol infusion rate according to BIS index. Depth of anaesthesia in patients of group B was controlled by traditional clinical signs. Recovery characteristics (i.e. mean time for tracheal extubation, eye opening, command response), total propofol consumption and depth of anaesthesia estimated by the mean surface of areas out of the predetermined BIS index range were analysed using Student's t-test.
Results and discussion: The recovery characteristics were comparable in two groups. Total propofol consumption was 15% greater in patients under BIS monitoring although no statistical difference was found between groups. Mean surface areas out of the predetermined BIS index range was significantly higher in group A compared to B (P<0.01). This finding suggests that depth of anaesthesia was better controlled with BIS monitoring.
Conclusion: Although titration of propofol infusion according to BIS index results in increased drug consumption, BIS monitoring provides more accurate control of anaesthetic depth.
The abstracts published in this supplement have been typeset from camera-ready copies prepared by the authors. Every effort has been made to reproduce faithfully the abstracts as submitted. However, no responsibility is assumed by the organisers for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of methods, products, instructions or ideas contained in the material herein. Because of the rapid advances in medical sciences, we recommend that independent verification of diagnoses and drug doses should be made.
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