Sandra Ware

Differences between asthma exacerbations and poor asthma control

BACKGROUND Increased variation in peak expiratory flow (PEF) is characteristic of poorly controlled asthma, and measurement of diurnal variability of PEF has been recommended for assessment of asthma severity, including during exacerbations. We aimed to test whether asthma exacerbations had the same PEF characteristics as poor asthma control. METHODS Electronic PEF records from 43 patients with initially poorly controlled asthma were examined for all exacerbations that occurred after PEF reached a plateau with inhaled corticosteroid treatment. Diurnal variability of PEF was compared during exacerbations, run-in (poor asthma control), and the period of stable asthma before each exacerbation. FINDINGS Diurnal variability was 21.3% during poor asthma control and improved to 5.3% (stable asthma) with inhaled corticosteroid treatment. 40 exacerbations occurred in 26 patients over 2-16 months; 38 (95%) of exacerbations were associated with symptoms of clinical respiratory infection. During exacerbations, consecutive PEF values fell linearly over several days then improved linearly. However, diurnal variability during exacerbations (7.7%) was not significantly higher than during stable asthma (5.4%, p=0.1). PEF data were consistent with impaired response to inhaled beta2-agonist during exacerbations but not during poorly controlled asthma. INTERPRETATION Asthmatics remain vulnerable to exacerbations during clinical respiratory infections, even after asthma is brought under control. Calculation of diurnal variability may fail to detect important changes in lung function. PEF variation is strikingly different during exacerbations compared with poor asthma control, suggesting differences in beta2-adrenoceptor function between these conditions.

Analysis of adherence to peak flow monitoring when recording of data is electronic

Peak flow monitoring is widely recommended in international asthma guidelines. However, suspicions about the accuracy of conventional pen and paper records were confirmed when studies with electronic spirometers showed poor adherence and falsification of data.1 There seems to be a prevailing nihilistic attitude to peak flow monitoring, largely based on the perception that satisfactory adherence cannot be achieved. We aimed to measure long term adherence to electronic peak flow monitoring when participants were aware that data were being stored and used to guide treatment. We obtained data from a 72 week randomised study comparing two starting doses of budesonide in patients aged 18-75 with poorly controlled asthma. The design and outcomes of the study are reported elsewhere.2 The study incorporated two novel features: twice daily monitoring with electronic diary spirometers (MicroMedical DiaryCard; MicroMedical, Rochester, UK) and titration of dose of budesonide (weeks 17-72) by using a clinical algorithm based on peak flow and diary data. …

Apneic Oxygenation Was Associated With Decreased Desaturation Rates During Rapid Sequence Intubation by an Australian Helicopter Emergency Medicine Service

STUDY OBJECTIVE The Greater Sydney Area Helicopter Emergency Medical Service undertakes in excess of 2,500 physician/paramedic out-of-hospital and interhospital retrievals each year, of which 8% require intubation. Emergency anesthesia of critically ill patients is associated with complications, including hypoxia. In July 2011, the service introduced apneic oxygenation with nasal cannulae to its emergency anesthesia standard operating procedure to reduce rates of desaturation during rapid sequence intubation. We evaluate the association between the introduction of apneic oxygenation and incidence of desaturation during rapid sequence intubation in both out-of-hospital and interhospital retrievals. METHODS This was a retrospective study of prospectively collected airway registry data. Consecutive patients who underwent rapid sequence intubation by Greater Sydney Area Helicopter Emergency Medical Service personnel between September 2009 and July 2013, spanning the introduction of apneic oxygenation, were included for analysis (n=728). We compared patients who underwent rapid sequence intubation before the service introduced apneic oxygenation (n=310) with those who underwent it after its introduction (n=418). We evaluated the association between the introduction of apneic oxygenation and the incidence of desaturation. RESULTS During the study period, 9,901 missions were conducted with 728 rapid sequence intubations (310 pre- and 418 postapneic oxygenation). The introduction of apneic oxygenation was followed by a decrease in desaturation rates from 22.6% to 16.5% (difference=6.1%; 95% confidence interval 0.2% to 11.2%). CONCLUSION Introduction of apneic oxygenation was associated with decreased incidence of desaturation in patients undergoing rapid sequence intubation.

Projected mesothelioma incidence in men in New South Wales

Objectives: Based on observed numbers of incident mesotheliomas since 1972, to predict future numbers in men in New South Wales. Methods: The incidence of mesothelioma was modelled in two ways. First by using an age/birth cohort model, and second by using a model based on potential exposure to asbestos in terms of age and calendar year. The latter model included a term for clearance of asbestos fibres from the lungs, and a term for diagnostic fraction. The age and calendar year model was based on the model introduced by Hodgson and colleagues but replaced piecewise effects by smooth functions represented by cubic splines. Results: The number of mesotheliomas between 2004 and 2060 was predicted as 6690 with the age-cohort model and as 6779 by the age and calendar year model, with peak annual numbers of 187 in the year 2021 and 196 in the year 2014 with the two models respectively. Conclusions: The pattern of parameter estimates in the two models was in accord with the known use of amphibole asbestos in Australia. The predicted peak year of 201421 is 3035 years after the phasing out of amphibole use, and this period is in accord with predictions for the UK and the US; in the latter country the peak was 1015 years earlier corresponding to a marked decline of amphibole use in and following the 1960s.

Pitfalls in processing home electronic spirometric data in asthma

Electronic spirometers offer the prospect of paperless home monitoring, but data quality is not automatically better than from conventional monitoring. The aim of this study was to determine the extent to which the quality and processing of self-recorded spirometric data from patients with asthma complied with international guidelines for spirometry. Data were from 33 subjects with poorly controlled asthma who had completed the first 9 weeks of a clinical budesonide trial. MicroMedical DiaryCard electronic spirometers were used to record three spirometric manoeuvres in twice-daily sessions. Confounding events were recorded in a paper diary. Within-session reproducibility was calculated for forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) during the first week of run-in and week 9 of budesonide treatment. Geometric means of within-session reproducibility (mean difference between highest and second-highest value from each session over a one-week period) for FEV1, FVC and PEF were 76 mL, 116 mL and 18 L x min(-1), respectively, during run-in. Times of spirometric sessions varied widely, with some overlap between morning and evening session times. Manoeuvre-induced falls in PEF and FEV1 occurred only as often as expected by chance. Nonasthma events including equipment faults and painful conditions caused changes in spirometric results. Home spirometric monitoring can be carried out with excellent reproducibility in patients with asthma. However, quality-control issues are complex and an accompanying paper diary remains essential.

Improving documentation in prehospital rapid sequence intubation: investigating the use of a dedicated airway registry form

Objective The quality of medical documentation is integral to audit, clinical governance, education, medico-legal aspects and continuity of patient care. This study aims to investigate the introduction of a dedicated ‘Airway Registry Form’ (ARF) on the quality of documentation in prehospital rapid sequence intubation. Methods A retrospective review and comparison of 96 cases predating the introduction of the ARF and 90 cases immediately following its introduction were performed. Results The introduction of the ARF yielded significant improvement in the recording of selected data points: difficult airway indicators (p<0.0001), Cormack–Lehane grade of laryngoscopy at first attempt (p<0.0001), documentation of confirmation of tracheal intubation with end-tidal carbon dioxide monitoring (p=0.015) and recording of intubators details (p<0.0001). Conclusions This study validates the use of a dedicated ARF for the improvement of documentation and data collection related to prehospital rapid sequence intubation when compared with post-event extraction of data from a generic case-record.

Analysis of Out-of-Hospital Pediatric Intubation by an Australian Helicopter Emergency Medical Service

Study objective We examine first‐look success in emergency pediatric intubation by a physician‐staffed helicopter emergency medical service (EMS). Methods A database analysis of all pediatric (<16 years) intubations during a 64‐month period was undertaken, using data from a prospectively enrolled electronic airway registry form. Recorded findings included patient demographics, operator background, airway intervention including intubation attempts, complications, and critical timings. Results Eighty‐two subjects were identified during the 64‐month study. All patients were successfully intubated. The overall first‐look success rate was 75 of 82 (91%), registrars achieving a first‐look success rate of 26 of 26 (100%), consultants 16 of 17 (94%), and paramedics 33 of 39 (85%). Overall complication rate was 14%; 84% of cases were rapid sequence induction, whereas 16% were “cold intubations.” Difficult airway indicators were present in 77% of patients. Conclusion A high first‐look success rate for pediatric intubation was achieved by adult helicopter EMS physicians and intensive care paramedics. To our knowledge, this compares favorably with the rate in published literature in pediatric emergency departments and critical care units.

Cutaneous vascular response to calcitonin gene-related peptide in psoriasis and normal subjects

To determine whether cutaneous blood vessels in subjects with psoriasis possess a generalized inherently abnormal response to neuropeptides, the effect of three doses of intradermally injected calcitonin gene‐related peptide (CGRP) on skin blood flow in normal subjects (n= 10), and on clinically normal skin (greater than 5 cm from psoriatic lesions) in subjects with psoriasis (n= 9) was measured using a laser Doppler technique. Calcitonin gene‐related peptide caused a dose‐dependent increase in local blood flow in both psoriatic and normal subjects, which was not statistically different between the two groups. This study has shown that the cutaneous vasculature at sites distant from lesions of psoriasis (> 5 cm) is not inherently different from normal skin in its response to CGRP.

Helicopter emergency medical service registrars do not comprehensively document primary surveys.

Objectives In-hospital primary surveys undertaken on traumatically injured patients can be inaccurate and incomplete. This study examined the documentation of prehospital primary surveys conducted by Greater Sydney Area Helicopter Emergency Medical Service registrars on trauma patients. Methods A retrospective case sheet review of prehospital trauma primary surveys documented by Greater Sydney Area Helicopter Emergency Medical Service registrars was carried out using previously published methodologies. A 13-item prehospital primary survey score was created and analysed by registrar specialty. A linear mixed model was used to determine whether differences in prehospital primary survey score existed between specialties. A one-point difference in the mean scores was considered clinically significant. Results A total of 75 charts were reviewed. An unadjusted mean of 9.5±1.6 (SD) items, out of a possible 13, was documented. Documentation was found to be less complete for anaesthetic trainees (adjusted mean score=9.10) than for emergency medicine trainees (adjusted mean score=10.34). The difference in the mean scores was 1.24 (95% confidence interval, 0.25–2.23, t53d.f.=2.52, P=0.01). A significant clustering effect was identified for individual registrars (&khgr;21d.f.=6.03, P=0.01). A very good level of agreement was obtained between the PPSS raters (&kgr;=0.93, 95% confidence interval, 0.87–0.99). Conclusion Helicopter emergency medical service registrars do not comprehensively document prehospital primary surveys on traumatically injured patients. However, emergency medicine trainees document more completely than anaesthetic trainees. Individual registrar variation contributes significantly towards the completeness of prehospital primary survey documentation.

The reliability of thromboelastography in a simulated rotary wing environment

Background With the increasing role of point-of-care coagulation testing in trauma, we sought to test the reliability of the thromboelastography (TEG)6s machine in a simulated rotary wing environment. Method A two-arm study was conducted, running TEG6s quality control cartridges in a helicopter flight simulator with realistic vibration and in stable ground conditions. The flight conditions during testing included take-offs, landings and inflight emergencies such as engine failures. TEG values for R time, K time, α-angle and maximum amplitude (MA) were collected and compared with manufacturers’ normal ranges. Results 148 TEG samples were included for analysis (72 simulator arm, 76 ground arm). In the simulator arm, four of our K time values fell below the normal range and four MA values were above the normal range. All other values in both simulator and ground arms were in the normal range. Conclusion The TEG6s is a viable technology in the simulated rotary wing environment, and it is feasible to conduct further studies using human blood in live rotary wing conditions. Extreme flight conditions should be avoided during further testing.