British journal of anaesthesia
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Twenty-four otherwise healthy patients scheduled for elective major abdominal surgery received general anaesthesia plus lumbar extradural analgesia. A loading dose of 0.5% plain bupivacaine was given to produce sensory analgesia (pin prick) from T4 to S5 and followed by a continuous infusion of 0.5% plain bupivacaine 8 ml h-1. Pain, scored on a 5-point scale, and sensory analgesia were assessed hourly for 16 h after skin incision. ⋯ Only three patients maintained their initial levels of sensory analgesia and a pain score of less than 2. In the remaining patients sensory analgesia decreased at least 5 segments or pain score reached 2 between 4 and 16 h after skin incision. We found a weak correlation between increasing age and the duration of sensory analgesia (r = 0.46, P less than 0.05), but no significant correlations between duration of sensory analgesia and sex, weight, height, body surface area, serum albumin concentration, duration or site of operation.
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The effect of the i.v. administration of methylene blue dye on haemoglobin oxygen saturation, measured by a pulse oximeter was investigated. The absorption spectra of various concentrations of haemoglobin, oxyhaemoglobin and methylene blue were compared. The amount of 660-nm light absorbed by methylene blue was sufficient to cause a factitious haemoglobin desaturation as measured by the pulse oximeter.
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Contralateral haemothorax developed as a late complication of subclavian vein cannulation following gradual erosion of the wall of the superior vena cava by the tip of the catheter. The use of a relatively rigid catheter and a left-sided approach may have contributed to this rare, but potentially fatal complication.
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Randomized Controlled Trial Comparative Study Clinical Trial
Controlled comparison of a new sublingual lormetazepam formulation and i.v. diazepam in outpatient minor oral surgery.
In a randomized, double-blind, parallel groups study, 40 patients undergoing surgical removal of impacted 3rd molar teeth received either sublingual lormetazepam 2.5 mg (n = 20) in a new cellulose wafer formulation followed at 35 min by i.v. saline; or sublingual placebo followed at 35 min by i.v. diazepam 10 mg (Diazemuls). Rapid onset of sedation was seen after sublingual lormetazepam, while the course and duration of postoperative sedation, measured using standard psychometric tests, was similar following both treatments. ⋯ Both treatments were tolerated well, with no significant cardiovascular complications. These results indicate that sublingual lormetazepam may have a role in anaesthesia as a premedicant and for conscious sedation.
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Randomized Controlled Trial Clinical Trial
Modification by alfentanil of the haemodynamic response to tracheal intubation in elderly patients. A dose-response study.
Fifty-five elderly patients undergoing elective ophthalmological surgery were randomly allocated to four groups. Following the induction of anaesthesia with thiopentone (given over 2 min) and the administration of atracurium 0.6 mg kg-1, patients received alfentanil 400, 600, 800 or 1000 micrograms. Intubation of the trachea was performed 90 s later. ⋯ In each of the groups there was a significant decrease in systolic arterial pressure and a significant increase in heart rate on induction of anaesthesia. In those patients who received either 400 or 600 micrograms of alfentanil, arterial pressure increased immediately after tracheal intubation, whereas in those receiving alfentanil 800 or 1000 micrograms, arterial pressure decreased immediately after tracheal intubation, and when measured 10 min after intubation. It is suggested that alfentanil 600 micrograms (10 micrograms kg-1) constitutes the optimal dose with which to obtund the haemodynamic response to tracheal intubation in elderly patients, and to minimize cardiovascular depression after tracheal intubation.