Estimating anesthetic depth by electroencephalography during anesthetic induction and intubation in patients undergoing cardiac surgery.
Intravenous (IV) anesthesia titrated to continuous computer-processed electroencephalograms (EEGs) was studied in 32 consecutive patients undergoing cardiac surgery. Anesthesia was induced with fentanyl 50 micrograms/kg with no EEG monitoring (n = 16) or 25 to 50 micrograms depending on changes in EEG (n = 16). EEG, oxygen saturation by pulse oximeter, intra-arterial blood pressure (BP), central venous pressure (CVP), and pulmonary artery pressure (PAP) (n = 18) were monitored continuously. Cardiac output (CO), CVP, PAP, spectral-edge frequency for each hemisphere, and BP were recorded before induction, immediately before intubation, and 1 and 5 minutes after intubation. With EEG monitoring, intubation was performed when spectral-edge frequency decreased to 10 Hz or less. Recall and pain were investigated 2 to 12 weeks postoperatively. With EEG, the amount of fentanyl used before intubation was significantly lower (39.7 +/- 2 micrograms/kg; p less than 0.005) than without EEG (50 micrograms/kg). The decrease in BP (% change) was less with than without EEG; mean changes in BP between preinduction and preintubation were -7.4% +/- 3.8% and -16.5% +/- 3.1% and between preinduction and 1 minute after intubation 0.3% +/- 3.4% and -12.5% +/- 3.5%, respectively. Percent changes in mean BP between intubation and 1 minute after were 9.6% +/- 4.0% with EEG and 5.2% +/- 3.0% without EEG. No patient in either group had recall. The authors conclude that using EEG monitoring to estimate depth of anesthesia during induction and laryngoscopy may increase safety in high-risk patients undergoing cardiac surgery.
Hadassah University Hospital, Jerusalem.
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Sidi
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Halimi
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Cotev
D000328:Adult; D000771:Anesthesia, Intravenous; D006348:Cardiac Surgical Procedures; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007442:Intubation, Intratracheal / Q000523:psychology; D011939:Mental Recall; D016032:Randomized Controlled Trials as Topic
D005283:Fentanyl