Journal of anesthesia
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Journal of anesthesia · Sep 1996
Clinical evaluation of a new continuous intraarterial blood gas monitoring system in the intensive care setting.
The present study was designed to evaluate a new continuous intraarterial blood gas monitoring system under routine clinical intensive care conditions. Nine mechanically ventilated adult patients were enrolled in this study. A multiparameter intravascular sensor was inserted into the radial or dorsalis pedis artery through a 20-gauge cannula in each patient. ⋯ In clinically important ranges of Po2, less than 200 mmHg in particular, the bias and precision values were -2.25±6.48 mmHg in the range of less than 100mmHg, and 0.98±14.38 mmHg in the range of 100-200 mmHg. Variations of sensor accuracy as a function of elapsed time were within the clinically acceptable range throughout the study period. These findings suggest that this new device is sufficiently useful for routine clinical settings.
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Journal of anesthesia · Sep 1996
Neuromuscular effects of sevoflurane in patients with myasthenia gravis.
The current study evaluated the neuromuscular responses following administration of sevoflurane in 14 patients with myasthenia gravis (MG) (I-IIb in Osserman's classification) scheduled for thymectomy and in 11 control patients (ASA I-II) who underwent elective surgery. The electromyographic (EMG) response of the abductor digiti minimi was measured following train-of-four (TOF) stimulation of the ulnar nerve every 20 s. After induction of anesthesia with a combination of 3-4 mg·kg(-1) thiopental and 1-2 μg·kg(-1) fentanyl with 66% N2O and oxygen, an inspired concentration of 4% sevoflurane was administered via a face mask for 7 min. ⋯ On the other hand, no notable changes were observed in patients with normal neuromuscular functions. The most significant factor that correlated with the depression of the TOFR values induced by 1 MAC sevoflurane was the anti-AchR antibody titers (P=0.029). Our results indicate that MG patients have an increased neuromuscular sensitivity to sevoflurane.
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Journal of anesthesia · Sep 1996
Effect of nicardipine on vascular capacitance: Comparison with sodium nitroprusside during induced hypotension.
The purpose of this study was to examine the effects of nicardipine and sodium nitroprusside (SNP) on vascular capacitance in the rat. In ten rats anesthetized with pentobarbital, mean arterial pressure was lowered to about 70 mmHg and subsequently 50 mmHg by intravenous infusion of nicardipine or SNP. Vascular capacitance was assessed before and during nicardipine- or SNP-induced hypotension by measuring the mean circulatory filling pressure (MCFP). ⋯ MCFP was significantly decreased by SNP from 7.1 ±0.3 mmHg at control to 5.6 ± 0.4 mmHg and 4.4 ± 0.3 mmHg at mean arterial pressures of 70 mmHg and 50 mmHg, respectively. However, MCFP stayed at a similar level to that of the control during nicardipine-induced hypotension. These results suggest that nicardipine has a negligible influence on vascular capacitance during induced hypotension, whereas SNP has a potent vasodilating effect on the venous system as well as the arterial system.
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Journal of anesthesia · Sep 1996
Immunocytochemical study of parvalbumin, calbindin D-28k, and calretinin in the superficial dorsal horn of the rat spinal cord following unilateral hindpaw inflammation.
The effect of noxious stimulation on the immunore-activity of the calcium-binding proteins parvalbumin (PV), calbindin-D-28k (CB) and calretinin (CR) was investigated in the superficial dorsal horn of lumbar levels L5-L3 of the rat spinal cord. Freund's adjuvant was injected unilaterally into the hindpaw to induce inflammation. Immunohistochemical techniques were utilized to investigate changes in the calcium-binding proteins 2h and 1, 2, 4, and 7 days after injection. ⋯ After the peak response, at 24h in most animals, there was a decline in the number of responders at 2 days and no differences were noted at 4 days. However, at 7 days, there was again an increase in the number of animals revealing diminished fluorescence intensity in the ipsilateral substantia gelatinosa. Changes in immunoreactivity of calcium binding proteins in the interneurons of the superficial lumbar dorsal horn may reflect hyperactivity within these neurons following noxious stimulation.
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Journal of anesthesia · Sep 1996
Cervical sympathectomy inhibits axonal transport of gonadotropin-releasing hormone during continuous exposure to light in male rats.
To examine the effects of cervical sympathectomy on the transport of gonadotropin-releasing hormone (GnRH) between the hypothalamic neurons and the median eminence, 16 male rats were assigned into four groups: control (C), light (L), light-sympathectomy (LS), and light-colchicine (LC). The C group was kept under a normal circadian rhythm for 2 weeks, and the L group was kept under continuous exposure to light for the same period. The LS group underwent bilateral cervical sympathectomy before being kept under continuous light conditions for 2 weeks. ⋯ The L group showed a decreased number of GnRH neurons, increased concentrations of GnRH fibers and granules, and an increased LH level; however, in the LS and LC groups, these changes were not seen. The response in the LS group resembled that in the LC group. Considering the action of colchicine, which inhibits axonal transport, it is suggested that cervical sympathectomy also inhibits axonal transports of GnRH between the GnRH neurons and the median eminence during continuous exposure to light.