We compared blood pressure and heart rate changes in healthy patients during anesthesia with sevoflurane (n = 50) versus isoflurane (n = 25) and the rate of recovery after such anesthesia. After premedication with intravenous administration of midazolam, induction of anesthesia with thiopental, and intubation of the trachea facilitated with succinylcholine or vecuronium, anesthesia was maintained with approximately 1 MAC (sevoflurane, 2.05%; isoflurane, 1.15%) of the volatile anesthetic in oxygen for the duration of the operation. Anesthetic concentration was varied as indicated to maintain arterial blood pressure at +/- 20% of baseline values. Sevoflurane and isoflurane produced similar systolic and diastolic arterial blood pressures, but heart rate after incision was faster in patients given isoflurane. Recovery of response to command was shorter in patients given sevoflurane than that in patients given isoflurane (7.5 +/- 0.5 min versus 18.6 +/- 2.0 min). Consistent with this finding, venous blood drawn after anesthesia showed a more rapid initial decay with sevoflurane. Nausea and vomiting were comparable in both groups. We conclude that sevoflurane anesthesia, as compared with isoflurane, is associated with possible advantageous effects on heart rate and recovery.
Background
The auditory brainstem response (ABR) test is frequently employed to estimate hearing sensitivity and assess the integrity of the ascending auditory system. In persons who cannot participate in conventional tests of hearing, a short-acting general anesthetic is used, recordings are obtained, and the results are compared with normative data. However, several factors (e.g., anesthesia, temperature changes) can contribute to delayed absolute and interpeak latencies, making it difficult to evaluate the integrity of the person’s auditory brainstem function.
Purpose
In this study, we investigated the latencies of ABR responses in children who received general anesthesia.
Research Design
Between subject.
Study Sample
Twelve children between the ages of 29 and 52 mo, most of whom exhibited a developmental delay but normal peripheral auditory function, comprised the anesthesia group. Twelve participants between the ages of 13 and 26 yr with normal hearing thresholds comprised the control group.
Data Collection and Analysis
ABRs from a single ear from children, recorded under general anesthesia, were retrospectively analyzed and compared to those obtained from a control group with no anesthesia. ABRs were generated using 80 dB nHL rarefaction click stimuli. T-tests, corrected for alpha slippage, were employed to examine latency differences between groups.
Results
There were significant delays in latencies for children evaluated under general anesthesia compared to the control group. Delays were observed for wave V and the interpeak intervals I–III, III–V, and I–V.
Conclusions
Our data suggest that caution is needed in interpreting neural function from ABR data recorded while a child is under general anesthesia.
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