Ease and comfort of pre-oxygenation with high-flow nasal oxygen cannulae vs. facemask: a randomised controlled trial.

The Difficult Airway Society recommends that all patients should be pre-oxygenated before the induction of general anaesthesia, but this may not always be easy or comfortable and anaesthesia may often be induced without full pre-oxygenation. We tested the hypothesis that high-flow nasal oxygen cannulae would be easier and more comfortable than facemasks for pre-oxygenation. We randomly allocated 199 patients undergoing elective surgery aged ≥ 10 years to pre-oxygenation using either high-flow nasal oxygen or facemask. Ease and comfort were assessed by anaesthetists and patients on 10-cm visual analogue scale and six-point smiley face scale, respectively. Secondary endpoints included end-tidal oxygen fraction after securing a definitive airway and time to secure an airway. A mean difference (95%CI) between groups in ratings of -0.76 (-1.25 to -0.27) cm for ease of use (p = 0.003) and -0.45 (-0.75 to -0.13) points for comfort (p = 0.006), both favoured high-flow nasal oxygen. A mean difference (95%CI) between groups in end-tidal oxygen fraction of 3.89% (2.41-5.37%) after securing a definitive airway also favoured high-flow nasal oxygen (p < 0.001). There was no significant difference between groups in the number of patients with hypoxaemia (Sp O2 < 90%) or severe hypoxaemia (Sp O2 < 85%) lasting ≥ 1 min or ≥ 2 min; in the proportion of patients with an end-tidal oxygen fraction < 87% in the first 5 min after tracheal intubation (52.2% vs. 58.9% in facemask and high-flow nasal oxygen groups, respectively; p = 0.31); or in time taken to secure an airway (11.6 vs. 12.2 min in facemask and high-flow nasal oxygen groups, respectively; p = 0.65). In conclusion, we found pre-oxygenation with high-flow nasal oxygen to be easier for anaesthetists and more comfortable for patients than pre-oxygenation with a facemask, with no clinically relevant differences in end-tidal oxygen fraction after securing a definitive airway or time to secure an airway. The differences in ease and comfort were modest.

A retrospective audit of postoperative days alive and out of hospital, including before and after implementation of the WHO surgical safety checklist.

We implemented the World Health Organization surgical safety checklist at Auckland City Hospital from November 2007. We hypothesised that the checklist would reduce postoperative mortality and increase days alive and out of hospital, both measured to 90 postoperative days. We compared outcomes for cohorts who had surgery during 18-month periods before vs. after checklist implementation. We also analysed outcomes during 9 years that included these periods (July 2004-December 2013). We analysed 9475 patients in the 18-month period before the checklist and 10,589 afterwards. We analysed 57,577 patients who had surgery from 2004 to 2013. Mean number of days alive and out of hospital (95%CI) in the cohort after checklist implementation was 1.0 (0.4-1.6) days longer than in the cohort preceding implementation, p < 0.001. Ninety-day mortality was 395/9475 (4%) and 362/10,589 (3%) in the cohorts before and after checklist implementation, multivariable odds ratio (95%CI) 0.93 (0.80-1.09), p = 0.4. The cohort changes in these outcomes were indistinguishable from longer-term trends in mortality and days alive and out of hospital observed during 9 years, as determined by Bayesian changepoint analysis. Postoperative mortality to 90 days was 228/5686 (4.0%) for Maori and 2047/51,921 (3.9%) for non-Maori, multivariable odds ratio (95%CI) 0.85 (0.73-0.99), p = 0.04. Maori spent on average (95%CI) 1.1 (0.5-1.7) fewer days alive and out of hospital than non-Maori, p < 0.001. In conclusion, our patients experienced improving postoperative outcomes from 2004 to 2013, including the periods before and after implementation of the surgical checklist. Maori patients had worse outcomes than non-Maori.

Haemodynamic profiles of etomidate vs propofol for induction of anaesthesia: a randomised controlled trial in patients undergoing cardiac surgery.

BACKGROUND: Etomidate is frequently selected over propofol for induction of anaesthesia because of a putatively favourable haemodynamic profile, but data confirming this perception are limited. METHODS: Patients undergoing cardiac surgery were randomised to induction of anaesthesia with propofol or etomidate. Phase I (n=75) was conducted as open-label, whereas Phase II (n=75) was double blind. Mean arterial blood pressure (MAP) and boluses of vasopressor administered after induction were recorded. The primary endpoint was the area under the curve below baseline MAP (MAP-time integral) during the 10 min after induction. Secondary endpoints were the use of vasopressors over the same period, and the effect of blinding on the aforementioned endpoints. Groups were compared using regression models with phase and anaesthetist as factors. RESULTS: The mean difference between etomidate and propofol in the MAP-time integral below baseline was 2244 mm Hg s (95% confidence interval, 581-3906; P=0.009), representing a 34% greater reduction with propofol. Overall, vasopressors were used in 10/75 patients in the etomidate group vs 21/75 in the propofol group (P=0.38), and in 20/74 patients during the blinded phase vs 11/76 during the open-label phase (P=0.31). The interaction between randomisation and phase (open-labelled or blinded) was not significant for either primary (P=0.73) or secondary endpoints (P=0.90). CONCLUSIONS: Propofol caused a 34% greater reduction in MAP-time integral from baseline after induction of anaesthesia than etomidate, despite more frequent use of vasopressors with propofol, confirming the superior haemodynamic profile of etomidate in this context. The proportion of patients receiving vasopressors increased slightly, albeit not significantly, in both groups in the blinded phase. CLINICAL TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12614000717651.

The incidence of hyperthermia during craniotomy.

There is evidence that even mild hyperthermia may exacerbate brain injury. There seem reasonable grounds for considering patients undergoing craniotomy as at risk for brain injury. A retrospective observational study was undertaken to measure the incidence of mild hyperthermia in craniotomy cases in which the patient was initially normothermic. Auckland City Hospital's database of electronic anaesthetic records was searched for adult patients who were normothermic (≤37°C) prior to undergoing craniotomy procedures. For each case, demographic data, intraoperative naso- or oropharyngeal temperature measurements, and paracetamol use were extracted. We identified the proportion of patients whose temperature rose to exceed normal (>37°C) and subdivided that group into the proportion in whom the temperature rose to ≥38°C. Two thousand, nine hundred and thirty-five craniotomy cases began their operations while normothermic and had adequate temperature data collected. There were 984 (33.5%) cases that had at least one temperature reading >37°C, for a mean (standard deviation [SD]) time of 66.0 (64.6) minutes, and 49 (1.7%) cases that had at least one reading ≥38°C for a mean (SD) time of 40.4 (38.1) minutes. The majority (77.8%) who became mildly hyperthermic remained so at the end of the procedure. New mild hyperthermia occurs commonly during craniotomy. In view of the compelling evidence of potential harm arising from mild hyperthermia in brain injury, these findings suggest an opportunity for practice improvement in the anaesthetic management of craniotomy patients. Reasonable steps should be taken by anaesthetists to avoid intraoperative hyperthermia of any degree.

Standards for simulation in anaesthesia: creating confidence in the tools.

Simulation is an accepted part of training, assessment, and research in aviation, nuclear power, and the military. Confidence in results in these industries is underpinned by relatively comprehensive and widely accepted standards. In contrast, although there have been major advances in the technology and tools used for simulation in the healthcare industry over the last few decades, little work has been done in setting standards for simulation in healthcare. Standards are essential for achieving the full potential of simulation-based education, assessment, and research at all levels and specialities in healthcare. The absence of standards undermines confidence in the results of any simulation-based endeavour and increases the risk of negative learning. We propose a practical framework for setting standards for simulators for anaesthesia.

Clinical assessment of a new anaesthetic drug administration system: a prospective, controlled, longitudinal incident monitoring study.

A safety-orientated system of delivering parenteral anaesthetic drugs was assessed in a prospective incident monitoring study at two hospitals. Anaesthetists completed an incident form for every anaesthetic, indicating if an incident occurred. Case mix data were collected and the number of drug administrations made during procedures estimated. From February 1998 at Hospital A and from June 1999 at Hospital B, until November 2003, 74,478 anaesthetics were included, for which 59,273 incident forms were returned (a 79.6% response rate). Fewer parenteral drug errors occurred with the new system than with conventional methods (58 errors in an estimated 183,852 drug administrations (0.032%, 95% CI 0.024-0.041%) vs 268 in 550,105 (0.049%, 95% CI 0.043-0.055%) respectively, p = 0.002), a relative reduction of 35% (difference 0.017%, 95% CI 0.006-0.028%). No major adverse outcomes from these errors were reported with the new system while 11 (0.002%) were reported with conventional methods (p = 0.055). We conclude that targeted system re-design can reduce medical error.

Simulators for use in anaesthesia.

There are many simulators available for use in anaesthetic-related education and research. Those who wish to purchase a simulator or to establish a simulation facility face a daunting task in understanding the differences between simulators. Recent reviews have focused on narrower areas of simulation, such as airway management or basic life support, or on the application of simulators. It would be difficult to deal in detail with every simulator ever made for anaesthesia, but in the present review we cover the spectrum of currently available anaesthetic simulators, provide an overview of different types of simulator, and discuss a selection of simulators of particular interest, including some of historical significance and some examples of 'home made' simulators. We have found no common terminology amongst authors for describing or classifying simulators, and propose a framework for describing (or classifying) them that is simple, clear and applicable to any simulator.