Anaesthetic team and the role of nurses--European perspective.

The only evidence in favour of the provision of assistance for anaesthesiologists seems to be that single-handed anaesthesiologists generate higher anaesthetic mortality than does a team system. In mainland Europe, the independent scope of the practice of nurse anaesthetists has been constrained while possible new roles for nurses have been suggested in the United Kingdom. In the USA, Anesthesiology Assistants are developing as an alternative to nurse anesthetists. The current fluidity will probably settle in Europe into a cadre of Assistant Anaesthetists, predominantly drawn from graduate nurses but with some graduates in biological or medical sciences, receiving a further 2-year specialist training. To attract people of this calibre, their role will have to offer some degree of clinical autonomy over the management of general anaesthesia. Considerations of safety will constrain this autonomy but the introduction of a monitor of anaesthetic depth and sophisticated communication systems will relieve anxiety about this development.

Quantitative study of Lowe's square-root-of-time method of closed-system anaesthesia.

Intermittent injection of liquid anaesthetic into a closed breathing system is particularly suitable in countries with limited resources. A method of calculating appropriate times and magnitudes of the injected doses was described by Lowe but the method has never been assessed rigorously. Such an assessment was the purpose of this study. The technique was used in a double-blind, randomized comparison of halothane, enflurane and isoflurane in oxygen-air, with 20 ASA I or II patients in each group, undergoing superficial or abdominal surgery. The prescribed times of injection were adhered to, but the doses, after the first two, were adjusted to maintain systolic arterial pressure within 20% of the reference preoperative value. Partial pressures of the anaesthetics were monitored but concealed from the investigator-anaesthetist. The mean doses found necessary for each anaesthetic were within 33% of those calculated to produce 1.3 MAC. However, end-tidal partial pressure (just before each dose) stabilized at a steady level of only 0.97, 0.42 and 0.77 MAC for halothane, enflurane and isoflurane, respectively. Recovery from enflurane was much more rapid than that from the other agents but no patient admitted to any dreams. We conclude that the rate of uptake of anaesthetic declines more slowly than predicted and that the patients receiving enflurane were less deeply anaesthetized because the greater hypotensive effect of enflurane led to the use of smaller doses.

Clonidine inhibits gastric motility in the rat.

We have studied the effect of clonidine on gastric motility, by examining the effect on gastric emptying of indigestible solids. In Wistar rats, either clonidine or saline was injected intraperitoneally, and ten steel balls (1.0 mm in diameter) were inserted into the stomach. Gastric emptying was examined at 3 h. Clonidine delayed gastric emptying of steel balls (ED50 = 0.0071 [95% confidence interval: 0.0033-0.013) mg kg-1). Yohimbine, but not naloxone, significantly antagonized the inhibitory effect of clonidine. We conclude that clonidine inhibits gastric motility through the alpha 2 adrenoceptor.

Comparison of arterialized venous with arterial blood propofol concentrations during sub-anaesthetic infusions in volunteers.

We have compared propofol concentrations in arterial and arterialized venous blood (from the radial artery at the wrist and a vein in the opposite forearm) in five volunteers during a sub-anaesthetic increasing infusion regimen designed to produce pseudo-steady-state arterial concentrations of 0.06, 0.17 and 0.43 micrograms ml-1. As in a previous study, we found no statistically significant difference between sampling sites (P = 0.66). However, changes in the method of arterialization yielded a reduction in the observed variability, with the arterialized venous propofol concentration lying within +/- 23% (95% reference interval) of the corresponding arterial concentration compared with 1 +/- 43%, as reported previously.

Comparison of bupivacaine plus buprenorphine with bupivacaine alone by caudal blockade for post-operative pain relief after hip and knee arthroplasty.

In a double-blind, parallel group trial, 15 patients who were given a caudal injection of 1.8 mg kg-1 of bupivacaine after induction of anaesthesia, were compared with 15 patients in whom 7.2 mg kg-1 of buprenorphine was added to the same dose of bupivacaine, prior to knee or hip replacement surgery. The duration of analgesia was much longer (mean 606 min vs. 126 min P < 0.001) in those receiving added buprenorphine; mean morphine consumption in the first 24 h was halved (14 mg vs. 28 mg) and patient satisfaction greatly increased. There were no significant differences in the incidence of complications although the group which had added buprenorphine had a lower incidence of vomiting.

Comparison of tramadol with morphine for post-operative pain following abdominal surgery.

In a multi-centre, double-blind, randomized study involving 523 patients, the analgesic efficacy of tramadol was compared to that of morphine given in repeated intravenous boluses as required to control post-operative pain following abdominal surgery over 24 h. Intravenous administration of the study analgesic started as soon as the patient reported pain. Patients received an initial dose (either tramadol 100 mg or morphine 5 mg) and, if necessary, repeat doses of tramadol 50 mg or morphine 5 mg could be given on demand over the first 90 min. Further doses up to a total of tramadol 400 mg or morphine 40 mg could then be given after 90 min up to 24 h after the first dose of study medication. The primary efficacy parameter was the responder rate (no or slight pain) within the first 90 min of treatment. Whilst responder rates reached 72.6% with tramadol and 81.2% with morphine, the treatments were statistically equivalent and the observed difference in the responder rates between the groups was within the predefined range of +/- 10%. Mean cumulative doses received by treatment responders amounted to 188.2 mg within the first 1.5 h and 157.1 mg during the subsequent 22.5 h in the tramadol group and 13.9 and 18.4 mg, respectively, in the morphine group. A high incidence of gastrointestinal adverse events were observed with both treatments mostly consisting of mild nausea, dry mouth, vomiting, dyspepsia and hiccups.

Reducing smoking. The effect of suggestion during general anaesthesia on postoperative smoking habits.

In a double-blind randomised trial, 122 female smokers undergoing elective surgery were allocated to receive one of two prerecorded messages while fully anaesthetised. The active message was designed to encourage them to give up smoking whilst the control message was the same voice counting numbers. No patient could recall hearing the tape. Patients were asked about their postoperative smoking behaviour one month later. Significantly more of those who had received the active tape had stopped or reduced their smoking (p < 0.01). This would suggest a level of preconscious processing of information.

Effects of small concentrations of isoflurane on some psychometric measurements.

We have investigated the effects of 9.5% and 14.1% MAC concentrations of isoflurane on some psychometric measurements. Both concentrations depressed peak saccadic velocity (P < 0.01), choice reaction time (P < 0.05) and visual analogue scores for sedation (P < 0.05), but not the critical flicker fusion threshold. The incidence of errors in saccade tasks increased in a dose-related fashion, which made analysis of peak saccadic velocity less accurate at more than 10% MAC. The percentage error itself was an indicator of the depth of sedation. All the objective measures correlated highly with the estimated brain tension of isoflurane (r2 = 0.86-0.96), but not the visual analogue score for sedation (r2 = 0.51). This suggests that a combination of peak saccadic velocity, percentage error and choice reaction time is a potentially useful batch of tests to measure recovery from anaesthesia.

Selecting for specialist training: 2.

Most specialist training posts are filled after short-listing and interview by an ad hoc group representing various interests who never work together as a team. They are rarely required to predict the outcome and receive no feedback on their success. Structuring and planning the interview, training the interviewers, limiting their number and the acquisition of interpersonal skills can improve performance and outcome.

Selecting for specialist training: 1.

Selection for specialist training posts is handled in an amateurish way by the NHS. To a considerable extent, future specialists select themselves, but often without sound reasoning. Few specialties have studied what, if any, characteristics are essential or desirable and so are unable to generate either a proper job specification or person specification. These are essential for success when selecting by interview.

Selecting anaesthetists: the use of psychological tests and structured interviews.

To test the predictive validity of a selection system for Senior House Officers (SHOs) and registrars in anaesthetics, 140 doctors short-listed from 635 applications between 1980 and 1987 were assessed by a semi-structured interview assessed and a personality questionnaire (Cattell 16PFQ-form C). The 62 doctors selected were followed up for between 3 and 8 years. Future performance was predicted from the psychological tests and by the interviewers. Academic, clinical, behavioural, and overall performance were used as criteria of outcome. Correlation coefficients between prediction and outcome measures were statistically highly significant (P < 0.01). Using multiple regression, equations could be derived from five of the Cattell personality factors to predict overall performance. Personality measures discriminated significantly between the best and poorest performers. Interview predictions were also statistically significant (P < 0.01). The method provides a blueprint for the effective selection of junior anaesthetists. Wastage in terms of those leaving the specialty was 16%.