[Pressor responses to inhalation of isoflurane during induction of anesthesia and subsequent tracheal intubation].
BACKGROUND
Marked hypertension may occur during induction of isoflurane anesthesia. The hemodynamic responses to mask ventilation using isoflurane and subsequent tracheal intubation were evaluated.


METHODS
In 26 ASA physical status I patients, anesthesia was induced with thiamylal followed by mask ventilation with 0.5% isoflurane in oxygen. Isoflurane concentration was increased to 4% in 2 min, and the trachea was intubated after 3 min of ventilation with 4% isoflurane. Blood pressure (BP) and heart rate (HR) were recorded every minute from induction of anesthesia.


RESULTS
In 9 patients, systolic BP before intubation increased significantly to more than 10 mmHg (26 +/- 16%) compared before induction, but decreased (-7 +/- 7%) in the others after a transient slight increase. Tracheal intubation induced a marked increase in BP in all patients, but there was a negative correlation between the isoflurane-induced increase in BP and that induced by intubation. Tachycardia was seen in all patients regardless of the values of BP.


CONCLUSIONS
Inhalation of 4% isoflurane during induction of anesthesia induces lasting hypertension in some patients and this pressor response has no relation with the tachycardia. Tracheal intubation induced a larger increase in blood pressure in the isoflurane-induced hypertensive patients, but the increase is within the limits of that seen in patients without pressor response to isoflurane.
Kobayashi
Yasuo
Y
Department of Anesthesia, Hakodate Municipal Hospital, Hakodate 041-8680.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000769:Anesthesia, Inhalation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D007431:Intraoperative Complications / Q000209:etiology*; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D007530:Isoflurane / Q000009:adverse effects*; D017214:Laryngeal Masks / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D012737:Sex Factors
D007530:Isoflurane