British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
An open, randomized comparison of alfentanil, remifentanil and alfentanil followed by remifentanil in anaesthesia for craniotomy.
We studied 52 adults undergoing elective craniotomy, allocated randomly to one of three opioid treatments: alfentanil 50 micrograms kg-1 followed by 0.833 microgram kg-1 min-1 until dural closure (group Alf.); alfentanil 50 micrograms kg-1 followed by 0.833 microgram kg-1 min-1 for 2 h, then remifentanil 0.25 microgram kg-1 min-1 (group Alf.-Remi.); or remifentanil 1 microgram kg-1 followed by 0.5 microgram kg-1 min-1 reducing to 0.25 microgram kg-1 min-1 after craniotomy (group Remi.). Anaesthesia was maintained with infusion of propofol and 66% nitrous oxide in oxygen. Infusions of propofol and remifentanil were stopped at head bandaging. ⋯ Times to tracheal extubation and obey commands were similar in all groups. In all patients in group Alf.-Remi. and group Remi., the trachea was extubated 27 min from the end of anaesthesia; three patients in group Alf. were slower to recover. Use of analgesia in the recovery room and time to transfer to the neurosurgical unit were similar in the three groups.
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Randomized Controlled Trial Clinical Trial
Effect of preoperative extradural bupivacaine and morphine on stump sensation in lower limb amputees.
We have examined the effect of preoperative extradural bupivacaine and morphine on postoperative stump sensation in 31 patients undergoing amputation of the lower limb in a prospective, randomized, double-blind study. Patients were allocated randomly to one of two groups: group 1 received extradural 0.25% bupivacaine 4-7 ml h-1 and morphine 0.16-0.28 ml h-1 before and during operation; group 2 received extradural saline before and during amputation and conventional analgesics for pain treatment. All patients received general anaesthesia for the amputation and extradural bupivacaine and morphine after operation. ⋯ The following were measured: pressure pain thresholds (pressure algometry), touch and pain detection thresholds (von Frey hairs), thermal sensibility (thermal rolls), and allodynia and wind-up-like pain. There were no differences between the two groups at any of the postoperative assessments for mechanical and thermal sensibility or rate of allodynia and wind-up-like pain. Our study suggests that preoperative and intraoperative extradural block had no long-term prophylactic effect on hyperalgesia, allodynia or wind-up-like pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Saline as an alternative to air for filling the laryngeal mask airway cuff.
We have assessed a new method to evacuate saline completely from the laryngeal mask airway (LMA) cuff and tested the hypothesis that intracuff pressures, fibreoptic position and oropharyngeal leak pressures are similar for saline compared with air during nitrous oxide-oxygen anaesthesia. Eight size 4 LMA were inflated with saline 30 ml. After syringe evacuation, median residual weight was 0.56 (range 0.24-0.98) g; after additional manual cuff squeezing it was 0.26 (0.21-0.35) g; and after drying for 12 h at 60 degrees C with the valve open it was -0.02 (-0.05-0.04) g. ⋯ Oropharyngeal leak pressures were similar between groups. We conclude that the saline-inflated LMA cuff was reliably emptied and more stable in terms of intracuff pressures and possibly fibreoptic position. Filling the LMA cuff with saline is a viable option during laser surgery to the airway.
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Randomized Controlled Trial Clinical Trial
Factors affecting assessment of cerebral autoregulation using the transient hyperaemic response test.
The transient hyperaemic response in the middle cerebral artery blood flow velocity on the release of brief compression of the ipsilateral common carotid artery has been validated as an indicator of cerebral autoregulation. We evaluated, in three stages, the effect of experimental factors such as duration of compression of the common carotid artery and magnitude of the decrease in blood flow velocity during common carotid artery compression on the transient hyperaemic response. In stage 1, 13 healthy volunteers underwent six transient hyperaemic response tests each; two tests each for either 3, 6 or 10 s duration of compression of the common carotid artery. ⋯ We conclude that experimental factors such as duration of common carotid artery compression and magnitude of the decrease in blood flow velocity during common carotid artery compression can significantly influence the transient hyperaemic response. These factors should be controlled if the transient hyperaemic response test is used for a comparison between repeated measurements. A compression time of 10 s and a compression ratio of 40% or more, allow maximum expression of the hyperaemic response in healthy volunteers.
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Percutaneous tracheostomy is being used increasingly in the intensive care unit and endoscopic control of this procedure affords an improved level of safety. Training in such new minimal access techniques can be a significant risk factor in patient outcome. ⋯ We present a method of training in percutaneous endoscopic tracheostomy using a simulation model based on animal tissue. Our experience with this model is reported.