Journal of anesthesia
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Journal of anesthesia · Jun 1994
Differential effects of vecuronium on the thumb and the big toe muscles evaluated by acceleration measurement.
To clarify the differential effects of vecuronium on the thumb and on the big toe, train-of-four (TOF) stimuli were applied to the ulnar nerve at the wrist and the tibial nerve at the ankle in anesthetized patients using two acceleration transducers. Ten adult patients, aged 21-55 years, were studied. Anesthesia was induced by an intravenous injection of thiopental, and vecuronium 0.1 mg·kg-1 was used for paralysis. ⋯ The duration of time to the maximal twitch depression on the thumb and the big toe was 136.5±32.5 s and 183.0±40.1 s (P<0.05), respectively. The time to 25% recovery of the twitch height on the thumb and the big toe was 48.1±17.3 min and 39.1±11.6 min, respectively; the time to 50% recovery of twitch height on the thumb and the big toe was 54.1±16.1 min and 40.0±9.2 min (P<0.05), respectively. When paralysis was reversed at 25% of TOF ratio on the thumb, the value of the TOF ratio on the big toe was 58.5±18.2% (P<0.01).
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Journal of anesthesia · Jun 1994
Epidural anesthesia affects pulse oximeter readings and response time.
We investigated the effects of epidural anesthesia on pulse oximeter readings (Spo2) and response time because this type of anesthesia causes significant changes in microcirculation at measurement sites. Twenty patients were divided into lumbar epidural (L-EPI;n=10) and the cervical epidural (C-EPI;n=10) groups. Spo2 and skin blood flow (SBF) were measured at the finger and toe simultaneously by pulse oximeter and laser Doppler flowmeter, respectively. ⋯ The difference in the response time became larger in the C-EPI group and smaller or opposite in the L-EPI group after anesthesia. The difference in response time and SBF were significantly correlated (r=0.71;P<0.05). These results indicated that epidural anesthesia lowerd Spo2 and shortened the response time through vasodilation in the blocked area and caused the opposite reactions in the nonblocked area through compensatory vasoconstriction.
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We observed the changes in partial pressure of arterial oxygen (PaO 2) and carbon dioxide (PaCO 2) before and during assumption of the lateral position prior to lumbar puncture in 81 patients to investigate whether lung volume decreased and ventilation was suppressed. PaO 2 significantly decreased while the patients were in the lateral position, while PaCO 2 remained unchanged. ⋯ The fact that closing volume increases with age implies that the decrease in functional residual capacity in the lateral position could have caused the decrease in PaO 2. It is therefore advisable to continuously monitor arterial oxygenation using a noninvasive monitor, such as a pulse oximeter, while performing spinal or epidural block, especially in elderly patients.