Hemodynamic Changes after Endotracheal Intubation in Patients with Cerebral Aneurysm

BACKGROUND: Tracheal intubation with a lightwand intubating device (Trachlight) attenuates the hemodynamic stress response to tracheal intubation compared with a direct laryngoscope approach. We compared the effects of the direct laryngoscope (Macintosh blade) and lightwand for intubation in patients with cerebral aneurysm. METHODS: Twenty-four patients undergoing cerebral aneurysm clipping surgery were randomly divided to either the lightwand (Group 1, n = 12) or the laryngoscope (Group 2, n = 12) Group. All patients received fentanyl (2-3microg/kg), midazolam (0.1 mg/kg), and thiopental sodium (2-3microg/kg) followed by vecuronium (0.1- 0.15microg/kg). The lungs were ventilated with 3-4% isoflurane in oxygen, with 1% lidocaine (1-1.5microg/kg) administered before intubation with either the lightwand or the laryngoscope. Systolic, diastolic and mean blood pressures and heart rate were recorded continuously before and for 5 min after intubation. RESULTS: Systolic and mean arterial blood pressure increased significantly (P < 0.05) 1 minute after intubation, but then returned to normal within the next minute. There were no differences in hemodynamic changes between the two groups, and no complications. CONCLUSIONS: Intubation technique did not affect hemodynamic changes in patients with cerebral aneurysm. In patients with aneurysms, appropriate anesthetic levels and pharmacologic manipulation will attenuate the hemodynamic stress response associated with tracheal intubation.

The Effect of Nitrous Oxide on Cerebral Entropy during Isoflurane Inhalational Anesthesia / 대한마취과학회지

BACKGROUND: The bispectral index has limitations in describing the exact depth of anesthesia during nitrous oxide inhalation. This study examined the effect of nitrous oxide on the cerebral entropy measured using an entropy module (M-ENTROPY Module S/5(R), Datex-Ohmeda division, Instrumentarium Corporation, Helsinki, Finland) during the stable anesthetic period with isoflurane inhalation. METHODS: Sixty ASA 1 or 2 adult patients were randomly allocated to three groups. During the stable maintenance period after the skin incision, the baseline entropy values (response entropy, RE; state entropy, SE) were recorded at 2.5 minutes intervals over a 20 minute period on a single frontal channel at 0.9% end-tidal isoflurane. After this, medical air was used continuously (group C) or replaced with nitrous oxide at 40% (group L) or 60% (group H) with continuous hemodynamic and entropy values monitoring. Each of the variables was recorded and analyzed at 2.5 minutes intervals over a 20 minute period. RESULTS: Average values (mean +/-SD) of the RE and SE during experimental period were lower in group H (29.2 +/-12.3 and 28.5 +/-11.7, respectively) than group L (33.9 +/-7.3 and 33.0 +/-7.3, respectively) and the averaged values were lower in group L than in group C (46.6 +/-14.8 and 45.5 +/-14.2, respectively). The percent reduction was larger in group H (42.1 +/-14.2 and 38.7 +/-16.5, respectively) than in group L (25.3 +/-15.1 and 24.4 +/-14.9, respectively) and the percent reduction was larger in group L than in group C (P < 0.01). Conclusions: Added nitrous oxide during the anesthetic maintenance period with isoflurane decreases the level of cerebral entropy.