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Summary Sixty ASA 1 and 2 children aged between 2 and 16 years who required tracheal intubation as part of anaesthesia for elective surgery were studied. We evaluated intubating conditions, haemodynamic responses and duration of apnoea following propofol 4 mg.kg−1 combined with either remifentanil 1.25 μg.kg−1 (group R), or suxamethonium 1 mg.kg−1 (group S). Tracheal intubation was graded as excellent, good or poor according to ease of laryngoscopy, vocal cord position, coughing, and jaw relaxation and limb movement. Thirty of group S and 28 of group R children were successfully intubated on the first attempt. Overall, intubation conditions were excellent or good in 26/30 (87%) patients in group S and 20/30 (67%) in group R (p

Propulsive movements of the caudal oscillating flukes produce large forces chat could induce equally large recoil forces at the cranial end of the animal, and, thus, affect stability. To examine these vertical oscillations, video analysis was used to measure the motions of the rostrum, pectoral flipper, caudal peduncle, and fluke tip for seven odonrocere cetaceans: Delphinapterus leucas, Globicepbala melaena, Lagenvrhyncbus obliquidens, O~cinus orra, Pseudorca crassidens, Stenella plagiodon, and TarJiops truncatus. Animals swam over a range of speeds of 1.4-7.3 mlsec. For each species, oscillatory frequency of the fluke tip increased linearly with swimming speed. Peak-to-peak amplitude at each body position remained constanc with respect ro swimming speed for all species. Mean peak-to-peak amplitude ranged from 0.02 to 0.06 body length at the rostrum and from 0.17 to 0.25 body length at the fluke tip. The phase relationships between the various body components remain constant with respect to swimming speed. Oscillations of the rostrum were nearly in phase with the fluke tip with phase differences out of -9.4"-33.0" of a cycle period of 360". Pectoral flipper oscillations trailed fluke oscillations by 60.9°-123.40. The lower range in amplitude at the rostrum compared co rhe fluke rip reflects increased resistance to vertical oscillation at the cranial end, which enhances the animal's stability. This resistance is likely due to both active and passive increased body stiffness, resistance on the flippers, phased movements of body components, and use of a lift-based propulsion. Collectively, these mechanisms srabilize the body of cetaceans during active swimming, which can reduce locomotor energy expenditure and reduce excessive motions of the head affecting sensory capabilities.

Postoperative analgesia in patients who receive regular oral opioids pre-operatively is frequently suboptimal. To improve management we introduced a regimen using subcutaneous diamorphine infusions with incremental doses. Infusion doses were calculated as half the daily pre-operative dose of oral morphine with the increments as one-sixth of the infusion dose. Results were recorded on the first two postoperative days before (n = 13) and after (n = 23) commencing the new regimen. The percentage of patients reporting severe pain at rest and on movement were significantly reduced by the new regimen (54% and 69% vs. 13% and 40%, respectively) since the opioid dose as a percentage of the pre-operative dose was significantly higher (160% vs. 352%). There were no instances of excessive sedation or slow respiratory rate in any patient. The use of the regimen has resulted in greater doses of opioids being administered with fewer patients in severe pain without significant complications.

The predictive performance of a 'Diprifusor' target controlled infusion system for propofol was examined in 46 patients undergoing major surgery, divided into three age groups (18-40, 41-55 and 56-80 years). Measured arterial propofol concentrations were compared with values calculated (predicted) by the target controlled infusion system. Performance indices (median performance error and median absolute performance error) were similar in the three age groups, with study medians of 16.2% and 24.1%, respectively. Mean values for 'divergence' and 'wobble' were -7.6%.h-1 and 21.9%, respectively. Measured concentrations tended to be higher than calculated concentrations, particularly following induction or an increase in target concentration. The mean (SD) propofol target concentration of 3.5 (0.7) micrograms.ml-1 during maintenance was lower in older patients, compared with higher target concentrations of 4.2 (0.6) and 4.3 (0.7) micrograms.ml-1 in the two younger age groups, respectively. The control of depth of anaesthesia was good in all patients and the predictive performance of the 'Diprifusor' target controlled infusion system was considered acceptable for clinical purposes.

Changes in-intra-ocular pressure during spontaneous ventilation with a laryngeal mask were compared with controlled ventilation using a tracheal tube in 40 patients undergoing intra-ocular surgery under general anaesthesia. Intra-ocular pressure was measured before induction, after establishing the airway, at the end of the operation and after removal of the airway device. Anaesthesia was induced with propofol and maintained with enflurane and nitrous oxide in oxygen. Mean end-tidal carbon dioxide tension was significantly higher during spontaneous ventilation than during controlled ventilation 5 min after establishing the airway (5.7 versus 4.5) and at the end of surgery (6.1 versus 4.2) (p < 0.001). Despite this, intra-ocular pressures were lower than baseline and similar in the two groups throughout anaesthesia. At the end of surgery, intra-ocular pressure (mmHg) was 11.2 and 8.6 during spontaneous or controlled ventilation respectively. One min after removal of the device, mean intra-ocular pressure (mmHg) in the tracheal tube group (16.0) was slightly higher than baseline (15.3) and was significantly higher than the laryngeal mask group (10.9) (p < 0.01). Spontaneous ventilation with a laryngeal mask is an acceptable alternative to controlled ventilation with tracheal intubation in elective intra-ocular surgery.

Summary A new system for sampling from arterial cannulae has been designed which avoids the need to aspirate flushing solution before taking a sample and limits blood loss. The new system was compared with a standard sampling system and direct arterial sampling using in vitro models. A series of haemoglobin concentrations wen- prepared and sampled using the three sampling methods. There were no clinically significant differences in the values obtained with the different sampling techniques.