British journal of anaesthesia
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Randomized Controlled Trial Multicenter Study Clinical Trial
Remifentanil in combination with propofol for spontaneous ventilation anaesthesia.
We have investigated the effect of four doses of remifentanil on the incidence of respiratory depression and somatic response at incision. Remifentanil was administered as a loading dose of 0.125, 0.25, 0.375 or 0.5 microgram kg-1 and at a maintenance infusion rate of 0.025, 0.05, 0.075 or 0.1 microgram kg-1 min-1, respectively, with an infusion of propofol 6 mg kg-1 h-1. Responses occurred in 88% of patients with remifentanil 0.025 microgram kg-1 min-1 compared with 30-40% in the other groups. ⋯ Reductions in remifentanil doses to 0.025-0.05 microgram kg-1 min-1 resulted in adequate respiration at the end of surgery in 88% of patients. Maintenance infusions of the two drugs for spontaneous ventilation are likely to be in these ranges. However, the ideal loading doses and infusion rates for induction remain to be established.
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Randomized Controlled Trial Comparative Study Clinical Trial
Sevoflurane compared with halothane for tracheal intubation in children.
We have studied 40 healthy children, aged 3-10 yr, undergoing adenotonsillectomy, in a double-blind, randomized study. Intubating conditions were assessed when the pupils had become small and central after inhalation induction with either 5% halothane and 60% nitrous oxide in oxygen or 8% sevoflurane and 60% nitrous oxide in oxygen. ⋯ Time to reach the clinical end-point for intubation was reached sooner with halothane (P = 0.015). In all children the trachea was intubated successfully at the first attempt and all remained haemodynamically stable throughout induction.
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Randomized Controlled Trial Clinical Trial
Caudal anaesthesia with 0.375% ropivacaine or 0.375% bupivacaine in paediatric patients.
We have determined the effectiveness and degree of motor block produced by the new local anaesthetic, ropivacaine, when used for caudal anaesthesia in children. We studied 60 children, aged 3-6 yr, ASA I, allocated randomly in a double-blind manner, to receive one of two local anaesthetics: 0.375% ropivacaine 1.0 ml kg-1 or 0.375% bupivacaine 1.0 ml kg-1. Patients were anaesthetized with continuous infusion of propofol 200 micrograms kg-1 min-1. ⋯ The ropivacaine group showed a shorter duration of motor block than the bupivacaine group (P < 0.05). Postoperative analgesia was required at a mean time of 5 (SD 3.2) h in the ropivacaine group compared with 5 (2.8) h in the bupivacaine group. These findings suggest that caudal anaesthesia with ropivacaine in paediatric patients is effective and produces less motor block in the postoperative period.
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Randomized Controlled Trial Clinical Trial
Appropriate size and inflation of the laryngeal mask airway.
We have compared size 3 and size 4 laryngeal masks in 30 females and size 4 and size 5 in 30 males for success rate of insertion, incidence of airleak and pressure exerted on the pharynx. First, the ex vivo volume-pressure relationship of the mask was obtained. Second, after insertion of a mask, the cuff was inflated with the recommended maximum volume of air and intracuff pressure measured. ⋯ In females, airleak occurred in 15 patients with the size 3 and in five patients with the size 4 (difference: P = 0.005) and in males, 21 patients with the size 4 and in four patients with the size 5 (P < 0.001). Removal of air to the minimum effective volume significantly decreased intracuff pressure and pressure on the pharynx; on removal of the mask, pressures were similar to, or lower than, initial pressures. Therefore, a larger mask (size 4 in females and size 5 in males) provided a better seal than a smaller size without producing higher pressures on the pharynx.