Anesthesiology
-
Randomized Controlled Trial Clinical Trial
Interaction of isoflurane and nitrous oxide combinations similar for median electroencephalographic frequency and clinical anesthesia.
The volatile anesthetic sparing effect of nitrous oxide in clinical studies is less than might be expected from the additivity of minimum alveolar concentration values. Other studies identify nonadditive interactions between isoflurane and nitrous oxide. The aim of this study was to quantify the interaction of isoflurane and nitrous oxide at a constant median electroencephalographic frequency. ⋯ The interaction of isoflurane and nitrous oxide in the dose range 0-75 vol% on median electroencephalographic frequency is compatible with additivity. The potency of nitrous oxide as a substitute for isoflurane is less than on a minimum alveolar concentration basis. Maintaining median electroencephalographic frequency more appropriately reflects the clinical usage of isoflurane and nitrous oxide than does maintaining minimum alveolar concentration.
-
Randomized Controlled Trial Clinical Trial
Intravenous lidocaine and bupivacaine dose-dependently attenuate bronchial hyperreactivity in awake volunteers.
In standard textbooks, intravenous lidocaine is recommended for intubation of patients with bronchial hyperreactivity. However, whether and to what extent intravenous local anesthetics attenuate bronchial hyperreactivity in humans is unknown. Accordingly, nine awake volunteers with known bronchial hyperreactivity were subjected to an inhalational challenge with acetylcholine before and during intravenous infusion of lidocaine, bupivacaine, or placebo in a randomized, double-blinded fashion. ⋯ In awake humans, intravenous lidocaine and bupivacaine both dose-dependently attenuated the hyperreactive response to a nonspecific inhalational challenge with acetylcholine.
-
Randomized Controlled Trial Clinical Trial
Preservation of the ration of cerebral blood flow/metabolic rate for oxygen during prolonged anesthesia with isoflurane, sevoflurane, and halothane in humans.
In several animal studies, an increase in cerebral blood flow (CBF) produced by volatile anesthetics has been reported to resolve over time during prolonged anesthesia. It is important to investigate whether this time-dependent change of CBF takes place in humans, especially in clinical situations where surgery is ongoing under anesthesia. In this study, to evaluate the effect of prolonged exposure to volatile anesthetics (isoflurane, sevoflurane, and halothane), the CBF equivalent (CBF divided by cerebral metabolic rate for oxygen (CMRO2) was determined every 20 min during anesthesia lasting more than 4h in patients. ⋯ These results demonstrate that CBF/CMRO2 ratio is markedly increased above normal and maintained during prolonged inhalation of volatile anesthetics in humans. It is impossible to determine whether these data indicate a stable CBF or whether CBF and CMRO2 are changing in parallel during the observation period. The unchanging electroencephalographic pattern suggests that the former possibility is more likely and that the increase of CBF produced by volatile anesthetics is maintained over time without decay, which has been reported in several animal studies. It also is suggested that isoflurane possesses greater capability to maintain global CBF relative to CMRO(2) than does halothane or sevoflurane. time.)
-
Randomized Controlled Trial Clinical Trial
Mivacurium when preceded by pancuronium becomes a long-acting muscle relaxant.
To ensure rapid recovery of neuromuscular block, it might be useful to administer a short-acting relaxant after a long-acting one. Therefore, the interaction between pancuronium and mivacurium was investigated when mivacurium was administered during the recovery from pancuronium block. ⋯ After pancuronium, mivacurium is not a short acting neuromusclar blocking agent.
-
Randomized Controlled Trial Clinical Trial
Role of magnesium sulfate in postoperative analgesia.
N-methyl-D-aspartate antagonists may play a role in the prevention of pain. An assessment was made of the effect of the physiologic N-methyl-D-aspartate antagonist magnesium on analgesic requirements, pain, comfort, and quality of sleep in the postoperative period. ⋯ This is the first clinical study showing that the perioperative application of magnesium sulfate is associated with smaller analgesic requirement, less discomfort, and a better quality of sleep in the postoperative period but not with adverse effects. Magnesium could be of interest as an adjuvant to postoperative analgesia.