A national survey of out-of-hours working and fatigue in consultants in anaesthesia and paediatric intensive care in the UK and Ireland.

The tragic death of an anaesthetic trainee driving home after a series of night shifts prompted a national survey of fatigue in trainee anaesthetists. This indicated that fatigue was widespread, with significant impact on trainees' health and well-being. Consultants deliver an increasing proportion of patient care resulting in long periods of continuous daytime duty and overnight on-call work, so we wished to investigate their experience of out-of-hours working and the causes and impact of work-related fatigue. We conducted a national survey of consultant anaesthetists and paediatric intensivists in the UK and Ireland between 25 June and 6 August 2018. The response rate was 46% (94% of hospitals were represented): 84% of respondents (95%CI 83.1-84.9%) contribute to a night on-call rota with 32% (30.9-33.1%) working 1:8 or more frequently. Sleep disturbance on-call is common: 47% (45.6-48.4%) typically receive two to three phone calls overnight, and 48% (46.6-49.4%) take 30 min or more to fall back to sleep. Only 15% (14.0-16.0%) reported always achieving 11 h of rest between their on-call and their next clinical duty, as stipulated by the European Working Time Directive. Moreover, 24% (22.8-25.2%) stated that there is no departmental arrangement for covering scheduled clinical duties following a night on-call if they have been in the hospital overnight. Overall, 91% (90.3-91.7%) reported work-related fatigue with over half reporting a moderate or significantly negative impact on health, well-being and home life. We discuss potential explanations for these results and ways to mitigate the effects of fatigue among consultants.

The effect of volatile anaesthetic agents on the filtration performance of paediatric breathing system filters.

The aim of this study was to determine the filtration performance of five commonly used paediatric breathing system filters following exposure to desflurane, isoflurane and sevoflurane. It has been suggested that oil may degrade the performance of filter material. Volatile anaesthetic vapours are organic and hence may affect the filtration performance of breathing system filters during anaesthesia. This has not been tested for various concentrations of volatile agent, type and duration of exposure. The filtration performance of the filters was measured following exposure to desflurane, isoflurane and sevoflurane at 1 and 2 minimum alveolar concentration (MAC) for 1 and 4 h. Penetration of particles through the Clear-Therm Micro, Clear-Therm Mini and Humid-Vent Filter Pedi increased by between 2.4 and 2.8 times after exposure to desflurane at 2 MAC for 4 h compared to that through unexposed filters (p < 0.0001 for all three filters). Further investigation is required to determine whether this reduction in filtration performance by desflurane is clinically significant.

An evaluation of the filtration performance of paediatric breathing system filters at low flows.

The filtration performance of five different types of filter intended for use in paediatric anaesthesia was measured. A total of 120 unused filters (24 samples of each filter type) were evaluated. The pressure drop and filtration performance, using challenges of sodium chloride particles, were measured for each filter at 3 l min(-1) and 15 l min(-1). The pressure drop was less at the lower flow; there was a wide variation in the pressure drop across some filters. The filtration performance of all filter types showed an improvement at 3 l min(-1) compared to 15 l min(-1). Four filter types had filtration efficiencies greater than 95% at 15 l min(-1) and greater than 99% at 3 l min(-1). The remaining filter type had a filtration efficiency less than 90% at 15 l min(-1) and greater than 95% at 3 l min(-1). These levels of performance are comparable to that of breathing system filters intended for use in adult anaesthesia using flows representing mean inspiratory flow.

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.

Sevoflurane (12% and 8%) inhalational induction in children.

BACKGROUND: Sevoflurane induction of anesthesia is frequently used in children. Rapidly performed inhalational induction may reduce excitation during early anesthesia. Increasing the total anesthetic MAC delivered to patients can be achieved by increasing volatile concentration or adding nitrous oxide. The latter reduces inspired oxygen concentration delivered, which may not be desirable. Even 8% sevoflurane induction is associated with excitation. A system capable of delivering 12% sevoflurane using two tandem vaporizers has been developed. METHODS: A randomized double blind study was undertaken to assess whether 12% sevoflurane offered any advantage over 8% in time and quality of induction. Sixty children aged 5-10 years were recruited and received either 12 or 8% sevoflurane. Time to loss of eyelash reflex, central pupils, incidence of adverse events, induction quality, systolic blood pressure and heart rate were recorded. RESULTS: Twelve percent sevoflurane reduced time to loss of eyelash reflex compared with 8% [mean (sd): 35 (12) and 46 (14) P<0.05], but the reduction was only 10% higher than the error in the measurement (assessment every 10 s). Twelve percent sevoflurane offered significantly better quality of induction (P<0.05). There was no difference in cardiovascular stability between groups, although heart rate rose significantly in both groups. Maintaining sevoflurane at 12% for 4 min caused significant amounts of apnea (69% with 12% and 38% with 8%, P<0.05). CONCLUSION: Twelve percent sevoflurane offers a smoother anesthesia induction than 8% in children of this age with no additional consequences for the cardiovascular system.

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.