The Effects of the Induction of Anesthesia and Tracheal Intubation with Sevoflurane on Blood Pressure, Heart Rate and BIS Value in Adults

Lee, Seung Yun; Lyu, Jang Hee; Kim, Seong Hyop; Kim, Min Jung; Lim, Jung Ae; Kang, Po Soon; Woo, Nam Sik

Abstract

BACKGROUND: Sevoflurane permits the rapid induction and control of anesthetic depth, and its lack of pungency permits anesthesia to be induced by administering it using a face mask. The goal of this study was to evaluate the possibility of induction and tracheal intubation without neuromuscular blocking drugs in adult patients given high inspired concentrations of sevoflurane (8%).
METHODS
Fifty adult patients received 8% sevoflurane with nitrous oxide (2 L/min) and oxygen (2 L/min) by face mask until tracheal intubation. Patients exhaled to residual volume and deeply inspired the gas mixture following introduction. The time of response loss from introduction was noted as the induction time. The change of blood pressure, heart rate and bispectral index (BIS) value during induction and tracheal intubation were also determinated. Jaw relaxation, vocal cords position, and intubating response were used to assess intubation condition.
RESULTS
Mean time for induction of anesthesia was 42.4+/-4.7 seconds and mean time to acceptable intubating conditions was 300.5+/-32.7 seconds. The average BIS values at the time of induction and at the time of intubation were 79.3+/-22.0 and 23.8+/-10.6 respectively. The average time for a BIS value under 40 was 105.5+/-30.8 seconds. Systolic blood pressure, heart rate and BIS values were decrease significantly during the induction of anesthesia (P < 0.05). A significant increase was observed in systolic blood pressure, diastolic blood pressure, heart rate and BIS values were noted after tracheal intubation (P < 0.05). In response to intubation, the incidence of good tracheal intubation was 16%, acceptable 69% and poor 15%.
CONCLUSIONS
The induction of anesthesia in adult patients administered sevoflurane at highconcentration (8%), by face mask, approached the speed of intravenous induction. But the technique did not always make produce satisfactory tracheal intubating conditions without neuromuscular blocking drugs.