Relationship between clinical endpoints for induction of anesthesia and bispectral index and effect-site concentration values

Kim, Dae Woo; Kil, Ho Yeong; White, Paul F

Next »Journal of Clinical Anesthesia
Volume 14, Issue 4 , Pages 241-245, June 2002

Relationship between clinical endpoints for induction of anesthesia and bispectral index and effect-site concentration values☆

Dae Woo Kim, MD, PhD
- Associate Professor, Department of Anesthesiology, St. Vincent Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Department of Anesthesiology, The Catholic University of Korea, Seoul, South Korea
Ho Yeong Kil, MD, PhD
- Professor, Department of Anesthesiology, School of Medicine, Hallym University, Seoul, Korea
- Hallym University, Seoul, South Korea
Paul F White, PhD, MD
- University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9068, USA
- Professor and Holder of the Margaret Milam McDermott Distinguished Chair in Anesthesiology, Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas
- Address correspondence to Dr. P.F. White, Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9068 USA

Received 28 August 2001; received in revised form 4 February 2002; accepted 4 February 2002.

Abstract

Study Objective: To assess the relationship between clinical endpoints for induction of anesthesia and the electroencephalographic (EEG) bispectral index (BIS) and effect-site concentration (C_E) values when using a target-controlled infusion (TCI) of either thiopental sodium or propofol, by hypothesizing that yawning may be a useful alternative to other commonly used clinical signs for determining loss of consciousness.

Design: Randomized observational clinical study.

Setting: Operating room of a university-based hospital.

Patients: 60 healthy adult patients (aged 20–50 yrs) scheduled for elective surgery with general anesthesia.

Interventions: During a TCI of propofol (n = 30) or thiopental (n = 30), clinical endpoints for loss of verbal responsiveness (LOV), loss-of-eyelash reflex (LOE), occurrence of yawning, and apnea were assessed at 15-second intervals. In addition, BIS and C_E values were recorded at each of the endpoints.

Measurements and Main Results: In both anesthetic groups, the sequence of occurrence of the clinical endpoints was similar, namely LOV, LOE, yawning, and, lastly, apnea. Compared with LOV and LOE, yawning was associated with lower BIS and higher C_E values with both anesthetics. The frequency of yawning was higher with thiopental than propofol (83% vs. 63%, respectively). However, the frequency of apnea was higher with propofol than thiopental (77% vs. 53%, respectively).

Conclusion: The correlation of the clinical endpoints with BIS and C_E values was highest for LOV. Yawning was as unreliable as LOE for determining the onset of unconsciousness during induction of anesthesia. This clinical sign failed to be observed in 17% and 37% of patients induced with thiopental and propofol, respectively.

Keywords: Anesthetic, IV, propofol, thiopental, induction of anesthesia, clinical endpoints, monitoring, electroencephalographic bispectral index, target-controlled infusion, effect-site concentrations

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☆ Financial support for this report was provided by The Catholic University of Korea, St. Vincent Hospital, Seoul, Korea and The White Mountain Institute of Los Altos, Los Altos, California (Dr. P.F. White, President).

PII: S0952-8180(02)00348-3

Next »Journal of Clinical Anesthesia
Volume 14, Issue 4 , Pages 241-245, June 2002

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