British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Removal of the laryngeal mask airway in children: anaesthetized compared with awake.
We studied 60 children, aged 12 months to 8 yr, undergoing plastic surgery under general anaesthesia supplemented by regional anaesthesia. Patients were allocated randomly to have the laryngeal mask airway removed either on awakening or while anaesthetized. ⋯ There were no differences in the incidences of laryngospasm, desaturation (< 95%) and excess salivation between the groups. Removed of the laryngeal mask airway during deep anaesthesia reduced coughing in the immediate postoperative period.
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Comparative Study
Differential effects of desflurane and halothane on peripheral airway smooth muscle.
Volatile anaesthetics have been shown to have direct relaxant effects on airway smooth muscle. We have examined the effects of 0.9, 1.9, and 2.8 dog MAC of desflurane and halothane on isolated proximal and distal canine airways precontracted with acetylcholine. The proximal and distal airway smooth muscle relaxed with increasing concentration of each anaesthetic in a dose-related manner. ⋯ The distal airway smooth muscle was more sensitive to volatile anaesthetics than the proximal airway smooth muscle with either halothane or desflurane at all concentrations tested. This effect may be a result of differences in cartilage content, myosin content, epithelium-dependent effects, receptor density, myofilament sensitivity to Ca2+, sarcoplasmic reticulum Ca2+ control, or ionic fluxes in the proximal airway compared with the distal airway. The increased sensitivity of airway smooth muscle to desflurane compared with halothane is not known but may be related to possible differences in the effects of Ca2+ homeostasis.
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Randomized Controlled Trial Clinical Trial
Surgical pain is followed not only by spinal sensitization but also by supraspinal antinociception.
Nociception can produce segmental spinal sensitization or descending supraspinal antinociception. We assessed both types of sensory change after surgery during isoflurane-nitrous oxide anaesthesia with or without fentanyl before nociception. Patients undergoing back surgery received fentanyl 3 micrograms kg-1 (n = 15) or placebo (n = 15) before anaesthesia in a prospective, randomized, blinded study. ⋯ Pain scores and morphine consumption were similar. The study demonstrated both supraspinal analgesia and spinal sensitization after surgery. Fentanyl administration before operation augmented the former while decreasing the latter, and hence sensitization, especially if neuropathic, may particularly benefit from pre-emptive analgesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Cricoid pressure applied after placement of the laryngeal mask prevents gastric insufflation but inhibits ventilation.
We studied 50 patients, in a blind, crossover study, to assess if cricoid pressure applied after placement of the laryngeal mask prevented gastric insufflation without affecting ventilation. After induction of anaesthesia and neuromuscular block, a laryngeal mask was inserted and confirmed to be placed correctly. The lungs were ventilated with a maximum inflation pressure of 15 cm H2O. ⋯ In no patient was the mask dislodged after these procedures. Thus, although cricoid pressure applied after insertion of the laryngeal mask prevented gastric insufflation, it also decreased ventilation. The inhibitory effect of cricoid pressure on ventilation without support of the neck was greater than cricoid pressure with support of the neck.
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Randomized Controlled Trial Comparative Study Clinical Trial
Sevoflurane-nitrous oxide or halothane-nitrous oxide for paediatric bronchoscopy and gastroscopy.
We have studied 120 infants and children, in three age groups (3-11 months, 1-5 yr and 6-15 yr), to compare anaesthesia with sevoflurane or halothane for bronchoscopy or gastroscopy, or both. Premedication or i.v. anaesthetic agents were not used. Patients were allocated randomly to receive either 7% sevoflurane or 3% halothane in 66% nitrous oxide in oxygen for induction of anaesthesia. ⋯ Physiological and psychomotor recovery were more rapid after sevoflurane than after halothane. At 24-h follow-up, children who received sevoflurane had significantly less nausea and vomiting. We conclude that sevoflurane was superior to halothane for paediatric bronchoscopy and gastroscopy.