Arterial blood concentration of sevoflurane during single-breath induction and tracheal intubation in gynecologic patients.
OBJECTIVE
To investigate sevoflurane blood concentrations on loss of consciousness during single-breath induction and ensuing tidal volume ventilation.


METHODS
Prospective study.


METHODS
Operating room, medical center.


METHODS
12 ASA physical status I and II women scheduled for for gynecologic surgery with general anesthesia.


METHODS
All patients were instructed in the vital capacity technique for inhalation induction with primed inspired sevoflurane greater than 7% in 6 L per minute oxygen. Immediately after loss of consciousness, assisted tidal volume ventilation with a fixed 3.5% of sevoflurane was applied for 9 minutes. Tracheal intubation was performed for each patient following succinylcholine 1.5 mg/kg.


METHODS
Inspired and end-expired sevoflurane concentration, blood pressure, and heart rate were recorded. Meanwhile, arterial blood samples were collected via a radial arterial catheter on loss of consciousness as the 0 minute and at the following 1.5th, 3rd, 4.5th, 6th, and 9th minute and determined for sevoflurane concentrations by gas chromatography.


RESULTS
All 12 patients achieved vital capacity induction uneventfully. The mean time of loss of consciousness was 63.0 +/- 16.6 seconds. The arterial blood concentration of sevoflurane was 1.65% +/- 0.53% on loss of consciousness, equaling to that (1.67% +/- 0.26%) at the third-minute ventilation of 3.5% sevoflurane. The blood concentration at the ninth minute was 2.07% +/- 0.26%.


CONCLUSIONS
The depth of sevoflurane after 9 minutes of ventilation of 3.5% sevoflurane is not sufficient to suppress intubation-induced hemodynamic response.
Lin
Tso-Chou
TC
Department of Anesthesiology, Tri-Service General Hospital National Defense Medical Center, Taipei, Taiwan.
Lu
Chih-Cherng
CC
Li
Chi-Yuan
CY
Chang
Cheng-Chang
CC
Ho
Shung-Tai
ST
D000328:Adult; D000769:Anesthesia, Inhalation / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000097:blood*; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D013509:Gynecologic Surgical Procedures; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods; D008738:Methyl Ethers / Q000008:administration & dosage / Q000097:blood*; D011446:Prospective Studies; D000077149:Sevoflurane; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome; D014474:Unconsciousness
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane