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Objective: To assess whether severe gastroesophageal reflux (GER) is associated with abnormalities in lung function including measures of lung volume and gas diffusion. Methods: Data from 147 patients with obesity [...]

Clinical spirometry, which should be routine for Australian patients with respiratory symptoms, is discussed, and procedures are described. Indications for use of the tests are described and common pitfalls, equipment standards and quality assurance aspects are covered in this guide for medical practitioners and other involved staff.

BCG vaccination for students and surveillance for tuberculosis (TB) infection during the medical training are implemented variously in Australian medical schools, with BCG vaccination not offered routinely to medical students in Victoria. Since exposure to TB is an occupational hazard for Australian health care workers, a standard approach is recommended for all Australian medical schools that includes offering BCG vaccination to all students even if they test negative to tuberculin skin and TB blood testing.

RationaleHighly prevalent and severe sleep-disordered breathing caused by acute cervical spinal cord injury (quadriplegia) is associated with neurocognitive dysfunction and sleepiness and is likely to impair rehabilitation.ObjectiveTo determine whether 3 months of autotitrating CPAP would improve neurocognitive function, sleepiness, quality of life, anxiety and depression more than usual care in acute quadriplegia.Methods and measurementsMultinational, randomised controlled trial (11 centres) from July 2009 to October 2015. The primary outcome was neurocognitive (attention and information processing as measure with the Paced Auditory Serial Addition Task). Daytime sleepiness (Karolinska Sleepiness Scale) was a prioriidentified as the most important secondary outcome.Main results1810 incident cases were screened. 332 underwent full, portable polysomnography, 273 of whom had an apnoea hypopnoea index greater than 10. 160 tolerated at least 4 hours of CPAP during a 3-day run-in and were randomised. 149 participants (134 men, age 46±34 years, 81±57 days postinjury) completed the trial. CPAP use averaged 2.9±2.3 hours per night with 21% fully ‘adherent’ (at least 4 hours use on 5 days per week). Intention-to-treat analyses revealed no significant differences between groups in the Paced Auditory Serial Addition Task (mean improvement of 2.28, 95% CI −7.09 to 11.6; p=0.63). Controlling for premorbid intelligence, age and obstructive sleep apnoea severity (group effect −1.15, 95% CI −10 to 7.7) did not alter this finding. Sleepiness was significantly improved by CPAP on intention-to-treat analysis (mean difference −1.26, 95% CI −2.2 to –0.32; p=0.01).ConclusionCPAP did not improve Paced Auditory Serial Addition Task scores but significantly reduced sleepiness after acute quadriplegia.Trial registration numberACTRN12605000799651.

Objectives: To explore the effect of using different scoring criteria for hypopneas in the scoring of polysomnographic studies: (1) by estimating the level of agreement between apnea-hypopnea index (AHI) scores [...]

There is urgent need in Australia for a program to assist patients who require long-term ventilator support after discharge from a hospital. The advent of portable ventilators and noninvasive nasal and face masks have broadened the range of clinical conditions that benefit from mechanical ventilation. Patients with restrictive chest-wall disease, neuromuscular diseases, spinal cord injury, and nocturnal breathing problems desire ventilator support in the home. To accomplish this, a program to provide the financial and caregiver support required for success is needed.

To determine whether cerebral metabolite changes may underlie abnormalities of neurocognitive function and respiratory control in OSA.

To examine the impact of using American Academy of Sleep Medicine (AASM) recommended EEG derivations (F4/M1, C4/M1, O2/M1) vs. a single derivation (C4/M1) in polysomnography (PSG) on the measurement of sleep and cortical arousals, including inter- and intra-observer variability.

To compare apnea-hypopnea indices (AHIs) derived using 3 standard hypopnea definitions published by the American Academy of Sleep Medicine (AASM); and to examine the impact of hypopnea definition differences on the measured prevalence of obstructive sleep apnea (OSA).

Previous studies have demonstrated that as little as 18 hours of sleep deprivation can cause deleterious effects on performance. It has also been suggested that sleep deprivation can cause a "tunnel-vision" effect, in which attention is restricted to the center of the visual field. The current study aimed to replicate these behavioral effects and to examine the electrophysiological underpinnings of these changes.

Sleep deprivation and alcohol both impair driving performance. This study assessed the interactive effect of low-dose alcohol and extended wakefulness.

The Maintenance of Wakefulness Test (MWT) examines an individual's ability to stay awake in an environment of decreased sensory stimulation. Only 1 previous study has systematically examined the MWT in normal healthy subjects.

Objective: To assess the use of chloro‐fluorocarbons (CFCs) in metered‐dose aerosols against the background of community concerns regarding the adverse environmental effects of CFCs. Data sources: Data on the constituents of currently available metered‐dose aerosols were supplied by the manufacturers, and details of chemistry and safety were obtained from monographs and papers published in the medical literature. Study selection: Five papers, published in the early 1970s when metered‐dose aerosols first became popular, were reviewed for safety data on CFCs. Several chapters in monographs were searched for data on the nature and function of CFCs in metered‐dose aerosols, and five papers were the source of information on alternatives to CFCs as vehicles for the delivery of inhaled respiratory drugs. Data synthesis: The medical use of CFCs accounts for only 1.5% of this total production in Australia, the majority being used for refrigeration, air‐conditioning and other commercial or industrial purposes. The physicochemical properties of CFCs are such that they function as a suitable storage medium for active drugs within the canister and as an ideal vehicle for drug delivery. Approximately 20 s after inhalation of a clinically recommended dose of a bronchodilator metered‐dose aerosol, CFCs are detectable in the blood, but the concentrations decline rapidly (half‐life<40 s). Although CFCs have been shown to sensitise the myocardium to the arrhythmogenic effects of catecholamines in experimental animals, the requisite concentrations can only be achieved by patients if they inhale from a canister on every breath for approximately 20 successive breaths. Conclusions: CFCs used in metered‐dose aerosols are an effective storage medium and a convenient vehicle for drug delivery. They are non‐toxic ‐ unless amounts far in excess of the clinically recommended doses are used, when arrhythmogenic effects may occur. The medical use of CFCs has minimal environmental impact compared with their industrial and commercial use. Dry powder delivery systems offer an alternative approach, and future research will yield nonozone‐depleting CFCs suitable for replacing those in current metered‐dose aerosols.

This study was designed to evaluate the Breath‐Taker peak flow meter, recently released by the Asthma Foundation of Victoria. The performance characteristics of five Breath‐Taker units were compared with those of five Wright and five mini‐Wright peak flow meters. The between‐unit reproducibility of each type of peak flow meter was measured using an explosive decompression device with a peak flow reproducibility of better than 1%. Each individual meter was used to measure the peak flow delivered by the decompression device three times for each of six flow rates (97‐622 L/min). The coefficient of variation (CV) was lowest for the Wright meters (mean CV, 4.8%) and, similarly to the Breath‐Taker units (mean CV, 8.4%), this decreased with increasing flow. The CV of the mini‐Wright meters, however, increased as flow increased (mean CV, 7.5%). The Breath‐Taker meter had less inter‐unit variability than the mini‐Wright meter at peak flows above 200 L/min. The accuracy of the three meter types was assessed by comparing measurements of peak expiratory flow rate (PEFR) made with each type and also with a computerized pneumotachograph system in 30 subjects with various degrees of irreversible airflow obstruction. Each subject performed at least three reproducible PEFR manoeuvres on the pneumotachograph and on each type of meter, in randomized order. The results showed that in comparison with the pneumotachograph system the Breath‐Taker meter underestimated PEFRs by a mean of 27 L/min and the mini‐Wright meter overestimated PEFRs by a mean of 45 L/min, whereas the Wright meter was not significantly different. Since the differences between the Breath‐Taker meter and the pneumotachograph were independent of flow rate, a scale offset would suffice to “correct” the Breath‐Taker readings.

To compare the clinical effectiveness and patient acceptance of a large spacer device (Nebuhaler™) for delivery of metered dose aerosol (MDI) terbutaline with nebulised wet aerosol terbutaline. Randomised open crossover study over two sequential four week treatment periods, following a two week run‐in. Multi‐centre including five adult thoracic units and three paediatric centres throughout Australia. Thirty‐eight adults and 23 children with clinical asthma and reversible airflow obstruction (increase in forced expiratory volume in one second [FEV1] of ≥15% in response to inhaled bronchodilator) entered the study proper. Six adults and one child withdrew. Terbutaline was administered four times dialy via Nebuhaler/MDI or nebuliser. Clinical assessment with spirometry and peak flow readings was made after run‐in and at the end of each treatment period. Patients recorded on diary cards daily peak expiratory flow rates and symptom scores and comparisons of these results for each treatment period were made. At the completion of the study patients answered a treatment preference questionnaire. No differences were found between the two treatment periods in diary card peak flow recordings and symptom score data, and in clinical assessment of spirometry and peak expiratory flow rates. There were also no differences between spirometry and peak flow values recorded at the clinic at randomisation and at the end of each treatment period, suggesting stable basal airflow obstruction over the period of the study. Thirty‐two per cent of adults and 52% of children preferred the Nebuhaler/MDI combination, mainly because of convenience of use. Treatment preference was not related to any measured index of lung function. MDI terbutaline delivered via Nebuhaler provides clinical benefit similar to that of wet aerosol terbutaline in the long‐term domiciliary management of patients with stable airflow obstruction.

A respirometer was utilized to determine the energy cost of food utilization in the bluegill Lepomis macrochirus. Prior to the study, fish were acclimated to the experimental photoperiod (16 hr light) and temperature (15, 20 and 25 C) for 90 and 14 days, respectively. Each fish was tested in the respirometer for 3-day periods. After an initial acclimation period of 24 hr, metabolic rates were determined at 2-hr intervals for the next 48 hr and were converted to their caloric equivalents. Fish were fed to satiation on mayfly nymphs (Hexagenia limbata) in the morning and evening of day 3. We calculated the energy cost of food utilization by determining the increase in energy of respiration subsequent to feeding. Metabolic rates ranged from 30.7 to 160.9 mg O2/kg-hr. Nocturnal rates were 26% higher for both fed and unfed fish at each experimental temperature. Daily food intake was influenced somewhat by body weight and temperature. Values ranged from 1.16 to 3.43% of the wet weight of the fish. Energy expenditure for food utilization ranged from 4.8 to 24.4% ( =12.7±1.5) of the caloric content of the daily ration. Specific Dynamic Action, that is, the energy freed and lost through protein catabolism, probably comprises a large share of the energy cost of food utilization.

The effects of six weeks of threshold pressure inspiratory muscle training (IMT) on inspiratory muscle performance, breathing pattern and exercise performance were studied in eight patients with severe airflow obstruction. The results indicated that IMT improved inspiratory muscle performance but did not affect exercise performance or breathing pattern during maximal exercise.

Diel feeding periodicity of gizzard shad (Dorosoma cepedianum) in Acton Lake, Ohio, was studied in 1973 and 1974. Grazing on bottom sediments by age-I and age-II gizzard shad usually began in early morning, increased in intensity until 1400–1600 hours, and then declined. After dusk, the fish became inactive, and feeding activity ceased. Exceptions to this pattern were noted in May and June 1974, when food intake decreased markedly during the spawning period. Organic and caloric contents of detrital food material in the gizzards ranged from 3.1 to 61.5% (mean = 18%) of dry weight and 845 to 5,520 cal/g ash-free dry weight (1973, mean = 3,187; 1974, mean = 3,132). The low quality (expressed as calories) of the organic detritus ingested during most of the summer could explain in part why the growth rates of gizzard shad in this system are depressed in relation to those observed in other impoundments at similar latitudes.

Rates of oxygen consumption of 48 gizzard shad, Dorosoma cepedianum, were measured in a flow-through respirometer under naturally occurring variations in photoperiod and water temperature. Body length and time of day had little effect on the observed metabolic rates. The best regression fit of the daily routine metabolic rates (R, mg O2/day) of unfed fish and the independent variables of wet body weight (W, 0.7–256.9 g) and temperature (T, 9.1–24.5 C) was: R = 0.5207W0.4831T1.6117; R2(multiple correlation) = 0.63. High lipid content of older fish, especially in late summer and fall, may account for the low weight exponent in the equation.

Seasonal changes in dry body weight and caloric and lipid contents were studied in ages 0 and I and ages I and II gizzard shad (Dorosoma cepedianum) in 1973 and 1974, respectively. Dry body weight increases were best described by second and third order polynomial equations, with maximum values occurring in late autumn. Data on body caloric and lipid contents indicated a period of rapid storage in late summer and early autumn. Declines in average dry body weight, body calories, and body lipids occurred during the winter months. The intensity of the fattening process was greater in age-I fish than in ages 0 and II fish. The highest values of body lipids (30% of dry weight) and calories (6,909 cal/g ash-free dry weight) were observed in age-I fish on 16 November and 20 November 1973, respectively. Lipid reserves were mobilized during over-wintering and, in age-II fish, during the reproductive cycle. Energy reserves may also be utilized for body maintenance and growth when reductions occur in the availability or quality of the food supply.

Motor vehicle crashes (MVCs) and cardiovascular disease account for the majority of workplace fatalities in the transport industry. This study evaluates the feasibility of a health education and screening program for commercial drivers in the transport industry, assesses its impact on workplace injuries, and determines risk factors for MVCs.