The use of nitrous oxide in paediatric anaesthetic practice in the United Kingdom: a questionnaire survey.

Nitrous oxide pollution is common in paediatric anaesthetic practice. A questionnaire was sent to all UK members of the Association of Paediatric Anaesthetists requesting details of three areas of their paediatric practice relating to nitrous oxide: attitudes to its use; current usage; and availability of alternatives. Replies were received from 296 (68%) consultants. Of these, 169 (57%) stated that their use of nitrous oxide had decreased over the last 5 years. One hundred and fifty-eight (54%) considered theatre pollution a problem in paediatric anaesthesia. One hundred and sixty-nine (57%) reported that in normal circumstances potential deleterious effects on patients influenced their use of nitrous oxide, whilst only 70 (24%) felt potential effects on staff influenced usage. Fifty-five (18%) felt there should be some restriction in the availability of nitrous oxide.

The Cardiff paediatric laryngoscope blade: a comparison with the Miller size 1 and Macintosh size 2 laryngoscope blades.

The Cardiff paediatric laryngoscope blade is a single blade that has been designed for use in children from birth to adolescence. This open, randomised, crossover study compared the Cardiff blade with the straight, size 1, Miller laryngoscope blade in 39 infants under 1 years of age and the curved, size 2, Macintosh blade in 39 children aged 1-16 years. The same laryngoscopic view was obtained with the Cardiff and Miller blades in 26 patients; the view was better with the Cardiff blade in seven patients and better with the Miller blade in six (median (IQR [range]) grade of laryngoscopy 1 (1-2 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.405). The Cardiff blade was faster at gaining a view than the Miller blade (mean (SD) time 8.5 (2.9) s vs. 10.2 (3.5) s, respectively; 95% CI for difference -2.8 to -0.4; p = 0.009). The Cardiff and Macintosh blades produced the same view in 32 patients; the view was better with the Cardiff blade in seven patients (median (IQR [range]) grade of laryngoscopy 1 (1-1 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.008). There was no difference in time to gain these views: mean (SD) 8.7 (3.0) s vs. 9.3 (2.7) s, respectively (95% CI for difference -1.58 to 0.40; p = 0.237). The Cardiff paediatric laryngoscope blade compares favourably with these two established laryngoscope blades in children.

Detection of epidural catheters with ultrasound in children.

BACKGROUND: The aim of this study was to assess whether a noninvasive imaging technique such as ultrasound could visualize an epidural catheter in the epidural space in children. METHODS: Following local ethics committee approval and informed parental consent a pilot study of 12 cases was performed. Children undergoing major surgery requiring epidural analgesia were recruited. All catheters were introduced via the lumbar region. All children were scanned within 24 h of epidural insertion by consultant paediatric radiologists. If the catheter was identified in the epidural space then an attempt was made to visualize the entire length of the catheter. RESULTS: The epidural catheter was detected in nine of 12 patients. All of these were less than 6 months old. The entire length of the catheter was visualized in five of the nine patients. It was possible to estimate the most cephalad level of the catheter in seven of the nine patients. This was in the thoracic region in all cases and an appropriate level for the intended surgical procedure. It was not possible to precisely identify the tip of the catheter as a distinct entity using ultrasound. CONCLUSION: This study shows that it is possible to visualize an epidural catheter in the epidural space in children under 6 months of age using ultrasound.

Interaction of H2-receptor antagonists and benzodiazepine sedation. A double-blind placebo-controlled investigation of the effects of cimetidine and ranitidine on recovery after intravenous midazolam.

H2-receptor antagonists differentially inhibit cytochrome P450 and this may affect the rate at which benzodiazepines are metabolised. However, it is not known whether this delayed clearance results in prolonged psychomotor impairment. In a randomised double-blind trial 28 healthy volunteers received two single doses of midazolam (0.07 mg.kg-1) at an interval of one week during which they took cimetidine 400 mg, ranitidine 150 mg or placebo, each twice daily. Recovery from the benzodiazepine was monitored on each occasion over a 12 h period using a battery of psychometric tests. There was wide individual variation in performance; however, an overall measure of impairment indicated a significant difference at 2.5 h (p < 0.05), the cimetidine group having a high impairment score. This decrement appeared to be in cognitive and psychomotor functions and was not reflected in the subjective assessment.

Effects of posture, phonation and observer on Mallampati classification.

We have studied the effects of phonation and posture on the Mallampati classification of view of the pharyngeal structures. Differences between observers were allowed for by the experimental design and log-linear modelling. Sixty-four patients were assessed on the ward, sitting upright, with and without phonation, by each of two observers. Another 64 patients were assessed without phonation, but both upright and supine, again by both observers. Phonation (the patient saying "Ah") produced a marked, systematic improvement of view; moving to the supine posture produced a small, systematic, non-significant worsening of the view. Differences between observers were non-systematic but substantial. About 25% of patients phonated spontaneously. It is recommended that anaesthetists make their own assessments of Mallampati classification, with the patient in either of the postures but always either with or without phonation, and thereby gradually "calibrate" their assessments against the degree of difficulty encountered in intubation.

The impact of the appearance of the anaesthetist on the patient's perception of the pre-operative visit.

The clinician's appearance is often considered a symbol which identifies and defines specific characteristics of the individual. Opinion of both lay and medical personnel on appropriate clothing inclines towards formal dress. Our aim was to assess the effect of the anaesthetist's appearance during a ward visit on the patient's evaluation of either the visit or the anesthetist himself. In our sample of 66 patients we found no evidence that the style of dress (formal: suit and tie, informal: jeans and open-necked shirt) affected that evaluation. However, when 138 patients were asked to rate the desirability of items of clothing for a male hospital doctor they expressed a preference for traditional clothing; a suit was rated as desirable and jeans as one of the four most undesirable items. We conclude that despite the conservatism of expressed opinions, the clothing worn by the anaesthetist is irrelevant to the patient's satisfaction with the visit.