Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2000
Comparative StudyThe epileptogenic properties of the volatile anesthetics sevoflurane and isoflurane in patients with epilepsy.
No study comparing epileptogenicity of sevoflurane to other volatile anesthetics has been performed. We compared the epileptogenic properties of sevoflurane to isoflurane in patients with epilepsy. In 24 mentally and/or physically disabled patients, 12 with epilepsy and 12 without epilepsy, electroencephalograms were recorded under anesthesia with 1.0 minimum alveolar anesthetic concentration (MAC), 1.5 MAC, and then 2.0 MAC sevoflurane or isoflurane under three ventilatory conditions: (A) 100% oxygen, and end-tidal CO(2) partial pressure (ETCO(2)) = 40 mm Hg, (B) 50% oxygen, 50% nitrous oxide, ETCO(2) = 40 mm Hg, and (C) 100% oxygen, ETCO(2) = 20 mm Hg. Spike activity was evaluated as a spike-and-wave index (% durations of spike and wave). The spike-and-wave index increased (P<0.05) from 1.99%+/-0.96% during 1.0 MAC sevoflurane to 6.14% +/- 4.45% during 2.0 MAC sevoflurane in (A) in the epilepsy group, while no spike activity was observed in the nonepilepsy group. Only a few spikes were observed under isoflurane anesthesia, 0.04% +/- 0.04% in (A), with no spikes in (B) and (C). Supplementation with 50% nitrous oxide or hyperventilation (P<0.05) suppressed the occurrence of spikes. Sevoflurane has a stronger epileptogenic property than isoflurane, but nitrous oxide or hyperventilation counteracts this specific epileptogenic property. ⋯ The stronger epileptogenicity of sevoflurane than isoflurane was confirmed in a controlled study in patients with epilepsy. Hyperventilation and supplementation of nitrous oxide under sevoflurane anesthesia suppressed epileptogenicity. A combination of sevoflurane and nitrous oxide may be a safer method for seizure-prone patients than the use of sevoflurane alone.
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Anesthesia and analgesia · Oct 2000
Case ReportsAn unusual case of malignant hyperthermia during desflurane anesthesia in an African-American patient.
Malignant hyperthermia is an uncommon, heritable condition triggered by anesthesia and is followed by an increase in temperature that may be fatal without prompt treatment. It is rare with desflurane and in black individuals of African descent. We present a case of malignant hyperthermia in an African-American patient during desflurane anesthesia.
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Anesthesia and analgesia · Oct 2000
Smaller-than-expected sevoflurane concentrations using the Sevotec 5 vaporizer at low fill states and high fresh gas flows.
Smaller-than-expected concentrations of sevoflurane were delivered by Sevotec 5 vaporizers (Datex-Ohmeda, Madison, WI) at low-fill states, 8% dialed concentrations, and high fresh gas flows. Clinically, this would lead to prolonged induction times. The risk of complications from prolonged inhaled induction could be increased when using a vaporizer with these characteristics.
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Anesthesia and analgesia · Oct 2000
Case ReportsA modified intubating laryngeal mask for endotracheal tube exchange.
It is often necessary to change a patient's breathing tube (endotracheal tube). This can be a risky procedure. This report describes a technique for changing an endotracheal tube by using a modified "intubating laryngeal mask" (a commonly used airway and breathing device) and a fiberoptic bronchoscope.
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On two occasions, sevoflurane distributed for clinical practice has been found to be contaminated with compounds thought to include hydrogen fluoride (HF) and silicon tetrafluoride (SiF(4)). Both compounds can produce pulmonary injury. However, injury would require fractional distillation of the compounds during the course of sevoflurane vaporization. ⋯ Nuclear magnetic resonance studies indicated that HF interaction with glass changed all HF to three other compounds, one being SiF(4) and the others being unknown. HF and SiF4 distill from sevoflurane more rapidly than sevoflurane is vaporized. Measurement of acidity after sevoflurane administration may not reveal a previous presence of such contaminants.