Danny J. Brazzale

A randomised trial of domiciliary, ambulatory oxygen in patients with COPD and dyspnoea but without resting hypoxaemia

Background Patients with chronic obstructive pulmonary disease (COPD) who are not severely hypoxaemic at rest may experience significant breathlessness on exertion, and ambulatory oxygen is often prescribed in this circumstance despite a lack of conclusive evidence for benefit. This study aimed to determine whether such patients benefit from domiciliary ambulatory oxygen and, if so, which factors may be associated with benefit. Methods This was a 12u2005week, parallel, double-blinded, randomised, placebo-controlled trial of cylinder air versus cylinder oxygen, provided at 6u2005l/min intranasally, for use during any activity provoking breathlessness. Patients underwent baseline measurements of arterial blood gases and lung function. Outcome measures assessed dyspnoea, health-related quality of life, mood disturbance, functional status and cylinder utilisation. Data were analysed on an intention-to-treat basis, p≤0.05. Results 143 subjects (44 female), mean±SD age 71.8±9.8u2005years, forced expiratory volume in 1u2005s (FEV1)1.16±0.51 lites, Pao2 9.5±1.1u2005kPa (71.4±8.5u2005mm Hg) were randomised, including 50 patients with exertional desaturation to ≤88%. No significant differences in any outcome were found between groups receiving air or oxygen. Statistically significant but clinically small improvements in dyspnoea and depression were observed in the whole study group over the 12u2005weeks of the study. Conclusion In breathless patients with COPD who do not have severe resting hypoxaemia, domiciliary ambulatory oxygen confers no benefits in terms of dyspnoea, quality of life or function. Exertional desaturation is not predictive of outcome. Intranasal gas (either air or oxygen) may provide a placebo benefit. Clinical trial number ACTRN12605000457640.

Effect of Singing on Respiratory Function, Voice, and Mood After Quadriplegia: A Randomized Controlled Trial

OBJECTIVEnTo explore the effects of singing training on respiratory function, voice, mood, and quality of life for people with quadriplegia.nnnDESIGNnRandomized controlled trial.nnnSETTINGnLarge, university-affiliated public hospital, Victoria, Australia.nnnPARTICIPANTSnParticipants (N=24) with chronic quadriplegia (C4-8, American Spinal Injury Association grades A and B).nnnINTERVENTIONSnThe experimental group (n=13) received group singing training 3 times weekly for 12 weeks. The control group (n=11) received group music appreciation and relaxation for 12 weeks. Assessments were conducted pre, mid-, immediately post-, and 6-months postintervention.nnnMAIN OUTCOME MEASURESnStandard respiratory function testing, surface electromyographic activity from accessory respiratory muscles, sound pressure levels during vocal tasks, assessments of voice quality (Perceptual Voice Profile, Multidimensional Voice Profile), and Voice Handicap Index, Profile of Mood States, and Assessment of Quality of Life instruments.nnnRESULTSnThe singing group increased projected speech intensity (P=.028) and maximum phonation length (P=.007) significantly more than the control group. Trends for improvements in respiratory function, muscle strength, and recruitment were also evident for the singing group. These effects were limited by small sample sizes with large intersubject variability. Both groups demonstrated an improvement in mood (P=.002), which was maintained in the music appreciation and relaxation group after 6 months (P=.017).nnnCONCLUSIONSnGroup music therapy can have a positive effect on not only physical outcomes, but also can improve mood, energy, social participation, and quality of life for an at-risk population, such as those with quadriplegia. Specific singing therapy can augment these general improvements by improving vocal intensity.

Assessment of Breathing Patterns and Respiratory Muscle Recruitment During Singing and Speech in Quadriplegia

OBJECTIVESnTo explore how respiratory impairment after cervical spinal cord injury affects vocal function, and to explore muscle recruitment strategies used during vocal tasks after quadriplegia. It was hypothesized that to achieve the increased respiratory support required for singing and loud speech, people with quadriplegia use different patterns of muscle recruitment and control strategies compared with control subjects without spinal cord injury.nnnDESIGNnMatched, parallel-group design.nnnSETTINGnLarge university-affiliated public hospital.nnnPARTICIPANTSnConsenting participants with motor-complete C5-7 quadriplegia (n=6) and able-bodied age-matched controls (n=6) were assessed on physiologic and voice measures during vocal tasks.nnnINTERVENTIONSnNot applicable.nnnMAIN OUTCOME MEASURESnStandard respiratory function testing, surface electromyographic activity from accessory respiratory muscles, sound pressure levels during vocal tasks, the Voice Handicap Index, and the Perceptual Voice Profile.nnnRESULTSnThe group with quadriplegia had a reduced lung capacity (vital capacity, 71% vs 102% of predicted; P=.028), more perceived voice problems (Voice Handicap Index score, 22.5 vs 6.5; P=.046), and greater recruitment of accessory respiratory muscles during both loud and soft volumes (P=.028) than the able-bodied controls. The group with quadriplegia also demonstrated higher accessory muscle activation in changing from soft to loud speech (P=.028).nnnCONCLUSIONSnPeople with quadriplegia have impaired vocal ability and use different muscle recruitment strategies during speech than the able-bodied. These findings will enable us to target specific measurements of respiratory physiology for assessing functional improvements in response to formal therapeutic singing training.

Effects of Adopting the New Global Lung Function Initiative 2012 Reference Equations on the Interpretation of Spirometry

Background: The recently generated spirometry reference equations from the Global Lung Function Initiative (GLI2012) provide a long-awaited opportunity for the adoption of a globally applicable set of normal reference values. Objective: The aim of this study was to document the likely interpretative effects of changing from commonly used current spirometry reference equations to the GLI2012 equations on interpretation of test results in a clinical spirometry dataset. Methods: Spirometry results from 2,400 patients equally distributed over the age range of 5-85 years were obtained from clinical pulmonary function laboratories at three public hospitals. The frequency of obstruction [FEV1/FVC below the lower limits of normal (LLN)] and spirometric restriction (FVC below the LLN) was assessed using the GLI2012, the National Health and Nutrition Assessment Survey (NHANES III), the European Community of Steel and Coal (ECSC) and the Stanojevic all-ages reference equations. Results: The rates of obstruction (range 20.0-28.5%) and spirometric restriction (range 14.2-25.8%) were similar across the four sets of reference equations. The highest level of agreement with the new GLI2012 equations was seen with the NHANES III equations (97.6% for obstruction and 93.6% for spirometric restriction) and the lowest with those from the ECSC (96.0 for obstruction and 92.0% for restriction). These data can be used to estimate likely diagnostic spirometry interpretation effects in the clinical setting when switching to GLI2012 spirometry reference data. Conclusions: We have found the effects on interpretation of changing to GLI2012 reference data to be minimal when changing from NHANES III and most significant when changing from ECSC reference data.

Cardiorespiratory responses to 6-minute walk test in interstitial lung disease: not always a submaximal test

BackgroundThe 6-minute walk test (6MWT) is used to measure exercise capacity and assess prognosis in interstitial lung disease (ILD). Although the 6MWT is usually considered to be a test of submaximal exercise capacity in ILD, the physiological load imposed by this test is not well described and 6MWT outcomes are poorly understood. This study aimed to compare cardiorespiratory responses to 6MWT and cardiopulmonary exercise test (CPET) in people with ILD.Methods47 participants with ILD (27 idiopathic pulmonary fibrosis (IPF), mean age 71 (SD 12) years, diffusing capacity for carbon monoxide (TLCO) 49(15) %predicted) undertook CPET and 6MWT on the same day in random order. Oxygen uptake (VO2), ventilation (VE) and carbon dioxide production (VCO2) were assessed during each test using a portable metabolic cart.ResultsThe VO2peak during the 6MWT was lower than during CPET (1.17(0.27) vs 1.30(0.37) L.min−1, pu2009=u20090.001), representing an average of 94% (range 62-135%) of CPET VO2peak. Achieving a higher percentage of CPET VO2peak on 6MWT was associated with lower TLCO %predicted (ru2009=u2009−0.43, pu2009=u20090.003) and more desaturation during walking (ru2009=u2009−0.46, pu2009=u20090.01). The VEpeak and VCO2peak were significantly lower during 6MWT than CPET (pu2009<u20090.05). However, participants desaturated more during the 6MWT (86(6)% vs 89(4)%, pu2009<u20090.001). The degree of desaturation was not affected by the percent of peak VO2 achieved during the 6MWT. Responses were similar in the subgroup with IPF.ConclusionsOn average, the 6MWT elicits a high but submaximal oxygen uptake in people with ILD. However the physiological load varies between individuals, with higher peak VO2 in those with more severe disease that may match or exceed that achieved on CPET. The 6MWT is not always a test of submaximal exercise capacity in people with ILD.

Acute effects of hyperoxia on resting pattern of ventilation and dyspnoea in COPD

Background and objective:u2003 Hyperoxia has been shown to reduce resting ventilation, hyperinflation and dyspnoea in patients with severely hypoxaemic COPD. This study assessed the effects of hyperoxia on these resting measures in patients with COPD of varying disease severity and characterized those patients who responded.

The effect of body mass and sex on the accuracy of respiratory magnetometers for measurement of end-expiratory lung volumes

Respiratory magnetometers are increasingly being used in sleep studies to measure changes in end-expiratory lung volume (EELV), including in obese obstructive sleep apnea patients. Despite this, the accuracy of magnetometers has not been confirmed in obese patients nor compared between sexes. Thus we compared spirometer-measured and magnetometer-estimated lung volume and tidal volume changes during voluntary end-expiratory lung volume changes of 1.5, 1, and 0.5 l above and 0.5 l below functional respiratory capacity in supine normal-weight [body mass index (BMI) < 25 kg/m] and healthy obese (BMI > 30 kg/m) men and women. Two different magnetometer calibration techniques proposed by Banzett et al. [Banzett RB, Mahan ST, Garner DM, Brughera A, Loring SH. J Appl Physiol (1985) 79: 2169-2176, 1995] and Sackner et al. [Sackner MA, Watson H, Belsito AS, Feinerman D, Suarez M, Gonzalez G, Bizousky F, Krieger B. J Appl Physiol (1985) 66: 410-420, 1989] were assessed. Across all groups and target volumes, magnetometers overestimated spirometer-measured EELV by ~65 ml (<0.001) with no difference between techniques (0.07). The Banzett method overestimated the spirometer EELV change in normal-weight women for all target volumes except +0.5 l, whereas no differences between mass or sex groups were observed for the Sackner technique. The variability of breath-to-breath measures of EELV was significantly higher for obese compared with nonobese subjects and was higher for the Sackner than Banzett technique. On the other hand, for tidal volume, both calibration techniques underestimated spirometer measurements (<0.001), with the underestimation being more marked for the Banzett than Sackner technique (0.03), in obese than normal weight (<0.001) and in men than in women (0.003). These results indicate that both body mass and sex affect the accuracy of respiratory magnetometers in measuring EELV and tidal volume.