Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1993
Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.
Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. ⋯ Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.
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Anesthesia and analgesia · Nov 1993
Effects of nitric oxide synthase inhibition on regional cerebral blood flow and vascular resistance in conscious and isoflurane-anesthetized rats.
Nitric oxide is an important regulator of the regional cerebral vascular tone. We compared the magnitude of nitric oxide-related changes in the vascular tone by studying the regional cerebral blood flow (rCBF) and vascular resistance in conscious and isoflurane-anesthetized rats by using a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). In the conscious group (n = 12), after cannulation of a femoral artery and two veins under isoflurane anesthesia, rats were allowed to remain awake for 90 min. ⋯ Regional vascular resistance was determined by the ratio of mean arterial blood pressure and rCBF which was measured by [14C]iodoantipyrine. L-NAME significantly increased mean arterial blood pressure in both the conscious (123 to 158 mm Hg) and anesthetized (82 to 144 mm Hg) rats. Regional vascular resistance increased significantly in all 12 brain regions studied with the average value increasing from 1.19 +/- 0.33 mm Hg.mL-1 x min x 100 g to 2.22 +/- 0.48 (P < 0.0001) in the conscious and from 0.78 +/- 0.27 to 1.61 +/- 0.48 (P < 0.0001) in the isoflurane-anesthetized rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Comparative Study Clinical TrialExcitatory effects and electroencephalographic correlation of etomidate, thiopental, methohexital, and propofol.
Excitatory movements have been observed during induction of anesthesia with etomidate, thiopental, methohexital, and propofol. We studied the frequency of these excitatory effects and correlated movements with electroencephalographic (EEG) findings in 67 unpremedicated patients (mean age 66.1 yr, range 45-82 yr). Excitatory effects, including myoclonus, tremor, and dystonic posturing, occurred in 86.6% of patients receiving etomidate; 69.2% of the patient responses were myoclonic. ⋯ In most patients, the excitatory movements were coincident with the early slow phase of the EEG which corresponds to the beginning of deep anesthesia. We conclude that perhaps caution should be exercised when administering etomidate to patients with a history of seizures as the myoclonic activity is associated with seizure activity. The incidence of excitatory movements after administration of propofol is very low.