Should we treat obesity in COPD? The effects of diet and resistance exercise training.

BACKGROUND AND OBJECTIVE: Obesity is an established risk factor for poor health outcomes, but paradoxically in chronic obstructive pulmonary disease (COPD), it is associated with improved survival and lung function. A major evidence gap exisits to inform treatment recommendations for patients with COPD who are obese. We aimed to determine the effect of weight reduction involving a low-energy diet utilizing a partial meal replacement plan, coupled with resistance exercise training in obese COPD patients. METHODS: In a proof of concept before-after clinical trial, obese (body mass index ≥30 kg/m(2) ) COPD patients received a 12 week weight reduction programme involving meal replacements, dietary counselling by a dietitian and resistance exercise training prescribed and supervised by a physiotherapist. Patients were reviewed face to face by the dietitian and physiotherapist every 2 weeks for counselling. RESULTS: Twenty-eight participants completed the intervention. Mean (standard deviation) body mass index was 36.3 kg/m(2) (4.6) at baseline and reduced by 2.4 kg/m(2) ((1.1) P < 0.0001) after the intervention. Importantly, skeletal muscle mass was maintained. Clinical outcomes improved with weight loss including exercise capacity, health status, dyspnea, strength and functional outcomes. There was also a significant reduction in the body mass index, obstruction, dyspnea and exercise score (BODE). Systemic inflammation measured by C-reactive protein however did not change. CONCLUSION: In obese COPD patients, dietary energy restriction coupled with resistance exercise training results in clinically significant improvements in body mass index, exercise tolerance and health status, whilst preserving skeletal muscle mass. This novel study provides a framework for development of guidelines for the management of obese COPD patients and in guiding future research.

Acute exercise is associated with reduced exhaled nitric oxide in physically inactive adults with asthma.

BACKGROUND: Although exercise has multiple health benefits, relatively little attention has been paid to its potential therapeutic effects in those with asthma. OBJECTIVE: To examine the effects of acute exercise on inflammation in physically inactive and active adults with asthma. METHODS: Fourteen adults with asthma (n = 6 physically inactive, n = 8 physically active) completed (1) 30 minutes of moderate-intensity exercise on a treadmill and (2) 30 minutes of rest in random order, with 4 weeks between sessions. Exhaled nitric oxide (eNO) was measured before and after the intervention (0, 0.5, 1, 2, 4, and 24 hours). Blood inflammatory mediators were measured before and after the intervention (0, 2, and 24 hours). RESULTS: Physically inactive participants had a significant decrease in eNO 4 hours after exercise (-4.8 ppb, -6.4 to -0.5 ppb, P = .028), which was not observed in physically active participants (P = .362). Interluekin-1 receptor antagonist increased in the physically inactive group 2 hours after exercise, with this increase strongly correlated with the decrease in eNO at 4 hours (R = -0.685, P = .007) and 24 hours (R = -0.659, P = .014) after exercise. Interleukin-6 was increased significantly 2 hours after exercise in physically inactive participants. Blood neutrophils and nuclear factor erythroid 2-like 2 gene expression were increased 2 hours after exercise in the overall cohort. CONCLUSION: This study demonstrates that acute moderate-intensity exercise is associated with decreased eNO in physically inactive adults with asthma and suggests that interluekin-1 receptor antagonist could have a role in mediating this effect. The attenuated response in physically active participants might be due to the sustained anti-inflammatory effects of exercise training. Future studies should investigate the impact of exercise intensity and exercise training on airway inflammation in those with asthma. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au), registration number ACTRN12613001014741.

Optimizing respiratory function assessments to elucidate the impact of obesity on respiratory health.

There is an increasing prevalence of obesity worldwide and its impact on respiratory health is of significant concern. Obesity affects the respiratory system by several mechanisms, including by direct mechanical changes due to fat deposition in the chest wall, abdomen and upper airway, as well as via systemic inflammation. The increased mechanical load in obese individuals leads to reduced chest wall and lung compliance and increased work of breathing. While there is generally minimal effect on spirometric values, as body mass index increases, the expiratory reserve volume, and hence functional residual capacity, reduces, often approaching residual volume in more severe obesity. The majority of evidence however suggests that obese individuals free from lung disease have relatively normal gas exchange. The link between asthma and obesity, while initially unclear, is now recognized as being a distinct asthma phenotype. While studies investigating objective markers of asthma have shown that there is no association between obesity and airway hyper-responsiveness, a recent working group identified obesity as a major risk factor for the development of asthma in all demographic groups. Although the temptation may be to attribute obesity as the cause of dyspnoea in symptomatic obese patients, accurate respiratory assessment of these individuals is necessary. Lung function tests can confirm that any altered physiology are the known respiratory consequences of obesity. However, given that obesity causes minimal changes in lung function, significant abnormalities warrant further investigation. An important consideration is the knowledge that many of the respiratory physiology consequences of obesity are reversible by weight loss.

Determinants of weight loss success utilizing a meal replacement plan and/or exercise, in overweight and obese adults with asthma.

BACKGROUND AND OBJECTIVE: While weight loss has been shown to reduce obesity-related comorbidity, many weight loss treatments fail. Factors that enhance weight loss success are unknown, particularly in those with asthma. The aim of the study was to identify patient characteristics that predict weight loss success in adults with asthma. METHODS: Baseline and change in asthma characteristics and eating behaviours were investigated for relationships with weight loss and fat loss using multiple linear regression, in 38 overweight and obese adults with asthma randomized to dietary, exercise or combined interventions targeting weight loss for 10 weeks. RESULTS: Mean ± standard deviation weight loss was 6.6 ± 5.1 kg. Greater %weight loss and %fat loss was achieved in those with poorer asthma-related quality of life at baseline ((rs = 0.398, P = 0.015) and (rs = 0.455, P = 0.005) respectively), with 1.7% greater absolute weight loss at week 10 corresponding to each one unit reduction in the asthma-related quality of life score at baseline. Furthermore, a lower baseline forced expiratory volume in 1 s/forced vital capacity correlated with greater weight loss (rs = 0.398, P = 0.015). Male sex was associated with a 3.6 kg greater weight loss (P = 0.087). Reducing emotional eating during the programme was associated with greater weight loss in women (rs = 0.576, P = 0.010). CONCLUSIONS: This study demonstrates that individuals with more severe asthma at baseline are more successful in achieving weight loss, which could be a consequence of greater motivation and could be used as a motivational tool within the clinical setting. Gender tailoring of weight loss programmes may be useful to enhance weight loss success. Future studies are urgently needed to establish predictors of long-term weight loss maintenance in those with asthma.

Grading the severity of airways obstruction: new wine in new bottles.

The objective of this study was to redesign the current grading of obstructive lung disease so that it is clinically relevant and free of biases related to age, height, sex and ethnic group. Spirometric records from 17 880 subjects (50.4% female) from hospitals in Australia and Poland, and 21 191 records (53.0% female) from two epidemiological studies (age range 18-95 years) were analysed. We adopted the American Thoracic Society(ATS)/European Respiratory Society (ERS) criteria for airways obstruction based on an forced expiratory volume in 1 s (FEV1)/(forced) vital capacity ((F)VC) ratio below the fifth percentile and graded the severity of pulmonary function impairment using z-scores for FEV1, which signify how many standard deviations a result is from the mean predicted value. Using the lower limit of normal for FEV1/(F)VC and z-scores for FEV1 of -2, -2.5, -3 and -4 to delineate severity grades of airflow limitation leads to close agreement with ATS/ERS severity classifications and removes age, sex and height related bias. The new classification system is simple, easily memorised and clinically valid. It retains previously established associations with clinical outcomes and avoids biases due to the use of per cent predicted FEV1. Combined with the Global Lung Function prediction equations it provides a worldwide diagnostic standard, free of bias due to age, height, sex and ethnic group.

Measurement of FEF25-75% and FEF75% does not contribute to clinical decision making.

The aim of this study was to determine the added value of measuring the forced expiratory flow at 25-75% of forced vital capacity (FVC) (FEF25-75%) and flow when 75% of FVC has been exhaled (FEF75%) over and above the measurement of the forced expiratory volume in 1 s (FEV1), FVC and FEV1/FVC ratio. We used spirometric measurements of FEV1, FVC and FEF25-75% from 11 654 white males and 11 113 white females, aged 3-94 years, routinely tested in the pulmonary function laboratories of four tertiary hospitals. FEF75% was available in 8254 males and 7407 females. Predicted values and lower limits of normal, defined as the fifth percentile, were calculated for FEV1, FVC, FEV1/FVC ratio, FEF25-75% and FEF75% using prediction equations from the Global Lung Function Initiative. There was very little discordance in classifying test results. FEF25-75% and FEF75% were below the normal range in only 2.75% and 1.29% of cases, respectively, whereas FEV1, FVC and FEV1/FVC ratio were within normal limits. Airways obstruction went undetected by FEF25-75% in 2.9% of cases and by FEF75% in 12.3% of cases. Maximum mid-expiratory flow and flow towards the end of the forced expiratory manoeuvre do not contribute usefully to clinical decision making over and above information from FEV1, FVC and FEV1/FVC ratio.

Clinical use of pulse oximetry: official guidelines from the Thoracic Society of Australia and New Zealand.

Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and critical-care medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of age-specific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations. Pulse oximetry does not provide information about the adequacy of ventilation or about precise arterial oxygenation, particularly when arterial oxygen levels are very high or very low. Arterial blood gas analysis is the gold standard in these settings. Pulse oximetry may be inaccurate as a marker of oxygenation in the presence of dyshaemoglobinaemias such as carbon monoxide poisoning or methaemoglobinaemia where arterial oxygen saturation values will be overestimated. Technical considerations such as sensor position, signal averaging time and data sampling rates may influence clinical interpretation of pulse oximetry readings.

Implications of adopting the Global Lungs Initiative 2012 all-age reference equations for spirometry.

The aim of this study was to determine the diagnostic and interpretative consequences of adopting the Global Lungs Initiative (GLI) 2012 spirometric prediction equations. We assessed spirometric records from 17 572 subjects (49.5% females), aged 18-85 years, from hospitals in Australia and Poland. We calculated predicted forced expiratory volume in 1 s (FEV1), forced expiratory volume (FVC), FEV1/FVC and lower limits of normal (LLN) using European Community for Steel and Coal (ECSC), National Health and Nutrition Examination Survey (NHANES) III and GLI 2012 equations. Obstruction was defined as FEV1/FVCLLN and FVC20% underdiagnosis of airway obstruction up to the age of 55 years and to 16-23% overdiagnosis in older subjects. GLI 2012 equations increase the prevalence of a "restrictive spirometric pattern" compared to ECSC but decrease it compared to NHANES.

Relationship between airway pathophysiology and airway inflammation in older asthmatics.

BACKGROUND AND OBJECTIVE: Asthma-related morbidity is greater in older compared with younger asthmatics. Airway closure is also greater in older asthmatics, an observation that may be explained by differences in airway inflammation. We hypothesized that in older adult patients with asthma, neutrophil airway inflammation increases airway closure during bronchoconstriction, while eosinophil airway inflammation increases airway hyperresponsiveness (AHR). METHODS: Asthmatic subjects (n = 26), aged ≥55 years (68% female), were studied, and AHR to 4.5% saline challenge was measured by the response-dose ratio (%fall in forced expiratory volume in 1 s (FEV1 )/mg saline). Airway closure was assessed during bronchoconstriction percent change in forced vital capacity (FVC)/percent change in FEV1 (i.e. Closing Index). Airway inflammation was assessed by induced sputum and exhaled nitric oxide (eNO). RESULTS: Mean patient age was 67 years (confidence interval: 63-71) with a mean FEV1 of 78 % predicted (confidence interval: 70-85%). AHR correlated with sputum eosinophils (r = 0.68, P = 0.005) and eNO (r = 0.71, P < 0.001), but not with neutrophils or neutrophil mediators. The Closing Index correlated with total sputum neutrophils (r = 0.66, P = 0.005), neutrophil elastase, matrix metalloproteinase-9 and interleukin-8 (all P < 0.05). Further, FEV1 /FVC and residual volume/total lung capacity at rest correlated with neutrophil elastase (r = -0.46 and 0.66 respectively, P < 0.05) but not with eosinophils or eNO. CONCLUSIONS: In older patients with asthma, airway inflammatory cells are linked to abnormal airway physiology. Eosinophilic airway inflammation is associated with AHR while neutrophilic inflammation may be an important determinant of airflow limitation at rest and airway closure during bronchoconstriction. The clinical implications of these findings remain to be determined.

Effect of singing on respiratory function, voice, and mood after quadriplegia: a randomized controlled trial.

OBJECTIVE: To explore the effects of singing training on respiratory function, voice, mood, and quality of life for people with quadriplegia. DESIGN: Randomized controlled trial. SETTING: Large, university-affiliated public hospital, Victoria, Australia. PARTICIPANTS: Participants (N=24) with chronic quadriplegia (C4-8, American Spinal Injury Association grades A and B). INTERVENTIONS: The 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. MAIN OUTCOME MEASURES: Standard 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. RESULTS: The 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). CONCLUSIONS: Group 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.

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.

Relationship between body composition, inflammation and lung function in overweight and obese asthma.

BACKGROUND: The obese-asthma phenotype is not well defined. The aim of this study was to examine both mechanical and inflammatory influences, by comparing lung function with body composition and airway inflammation in overweight and obese asthma. METHODS: Overweight and obese (BMI 28-40 kg/m(2)) adults with asthma (n = 44) completed lung function assessment and underwent full-body dual energy x-ray absorptiometry. Venous blood samples and induced sputum were analysed for inflammatory markers. RESULTS: In females, android and thoracic fat tissue and total body lean tissue were inversely correlated with expiratory reserve volume (ERV). Conversely in males, fat tissue was not correlated with lung function, however there was a positive association between android and thoracic lean tissue and ERV. Lower body (gynoid and leg) lean tissue was positively associated with sputum %neutrophils in females, while leptin was positively associated with android and thoracic fat tissue in males. CONCLUSIONS: This study suggests that both body composition and inflammation independently affect lung function, with distinct differences between males and females. Lean tissue exacerbates the obese-asthma phenotype in females and the mechanism responsible for this finding warrants further investigation.

Pilot study of remote telemonitoring in COPD.

BACKGROUND: Remote in-home monitoring (RM) of symptoms and physiological variables may allow early detection and treatment of exacerbations of chronic obstructive pulmonary disease (COPD). It is unclear whether RM improves patient outcomes or healthcare resource utilization. This study determined whether RM is feasible in patients with COPD and if RM reduces hospital admissions or length of stay (LOS) or improves health-related quality of life (HRQOL). SUBJECTS AND METHODS: Forty-four patients were randomized to standard best practice care (SBP) (n=22) or SBP+RM (n=22). RM involved daily recording of physiological variables, symptoms, and medication usage. RESULTS: There were no differences (mean±SD, SBP versus SBP+RM) in age (68±8 versus 70±9 years), gender (male:female 10:12 in both groups), or previous computer familiarity (59% versus 50%) between groups. The SBP group had a lower forced expiratory volume in 1 s (0.66±0.24 versus 0.91±0.34 L, p<0.01) and more current smokers (six versus none, p<0.05). There were no differences in number of COPD-related admissions/year (1.5±1.8 versus 1.3±1.7, p=0.76), COPD-related LOS days/year (15.6±19.4 versus 11.4±19.6, p=0.66), total admissions/year (2.2±2.1 versus 2.0±2.3, p=0.86), total LOS days/year (22.1±29.9 versus 21.6±30.4, p=0.88), or HRQOL between the two groups. CONCLUSIONS: The addition of RM to SBP was feasible but did not reduce healthcare utilization or improve quality of life in this group of patients already receiving comprehensive respiratory care.

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 12 week, parallel, double-blinded, randomised, placebo-controlled trial of cylinder air versus cylinder oxygen, provided at 6 l/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±9.8 years, forced expiratory volume in 1 s (FEV(1))1.16±0.51 litres, Pao(2) 9.5±1.1 kPa (71.4±8.5 mm 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 12 weeks 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.

Assessment of breathing patterns and respiratory muscle recruitment during singing and speech in quadriplegia.

OBJECTIVES: To 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. DESIGN: Matched, parallel-group design. SETTING: Large university-affiliated public hospital. PARTICIPANTS: Consenting 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. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Standard 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. RESULTS: The 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). CONCLUSIONS: People 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 changing reference values and definition of the normal range on interpretation of spirometry.

BACKGROUND AND OBJECTIVE: Recent spirometry reference studies are arguably the most valid ever performed and the ATS/ERS now recommend the National Health and Nutrition Assessment Survey (NHANES) equations for North America. It is timely to consider adopting these reference values in Australasia; however, an evaluation of the consequences of such a change is required. METHODS: We analysed data from 1108 patients tested in two pulmonary function laboratories in public hospitals. Lower limits of normal (LLN) were calculated using European Community for Steel and Coal (ECSC) (1993), Knudson (1983), NHANES (1999) and Health Survey of England (HSE) (2004) equations and used to define restriction (FVC < LLN) and obstruction (FEV(1)/FVC < LLN). This interpretative strategy was also compared with the GOLD definition of obstruction (FEV(1)/FVC < 70%). RESULTS: Average age for all patients (50% female) was 60 years (range: 20-91). The mean predicted FVC from NHANES and HSE were similar and consistently higher than those from ECSC and Knudson (average 270 mLs). This translates into a 76% increase in the incidence of 'restrictive' interpretations using NHANES data compared with ECSC and Knudson, and a smaller increase of 40% for HSE. Using FEV(1)/FVC < 70% to diagnose obstruction in those over 65 years would result in false positive rates of approximately 28%. Using the same definition in a younger group (<50 years old) results in a false negative rate of approximately 14%. CONCLUSIONS: Changing to either NHANES or HSE predicted values will significantly increase the rate of 'restrictive' interpretation, and alter the rate of obstructive findings. The NHANES and HSE data confirm that using FEV(1)/FVC < 70% to define obstruction causes misdiagnosis in elderly and younger subjects.

Acute oxygen therapy does not improve cognitive and driving performance in hypoxaemic COPD.

BACKGROUND AND OBJECTIVE: Cognitive and neuropsychological function may be adversely affected by low blood oxygen levels and this has been previously demonstrated in hypoxaemic COPD. The aim of this study was to assess whether supplemental oxygen therapy while driving a motor vehicle is justified in hypoxaemic COPD. We therefore used computer-based driving simulation to investigate whether acute intranasal oxygen therapy improves the cognitive and driving performance of such patients. METHODS: Thirty hypoxaemic COPD subjects with a current driving licence performed a 20-min computer-based driving simulation task and a 10-min psychomotor vigilance task (PVT) at baseline, and while breathing intranasal oxygen or intranasal air in a randomized, double-blind, cross-over protocol. RESULTS: The mean (SD) age of the subjects was 72 years (8) and their mean driving experience was 50 years (10). Mean FEV(1) was 41% (18) of predicted and PaO(2) was 50.5 mm Hg (4.7) on air and 70.7 mm Hg (9.1) on oxygen. There were no statistically significant differences in any measure of driving performance or in reaction time measurements while breathing oxygen compared with air. CONCLUSIONS: Acute oxygen therapy does not improve simulated driving performance or neurocognitive function as assessed by PVT in patients with hypoxaemic COPD. These data do not support the recommendation that oxygen should be used by this patient group while driving.

Predicting the risk of exacerbation in patients with chronic obstructive pulmonary disease using home telehealth measurement data.

BACKGROUND: The use of telehealth technologies to remotely monitor patients suffering chronic diseases may enable preemptive treatment of worsening health conditions before a significant deterioration in the subject's health status occurs, requiring hospital admission. OBJECTIVE: The objective of this study was to develop and validate a classification algorithm for the early identification of patients, with a background of chronic obstructive pulmonary disease (COPD), who appear to be at high risk of an imminent exacerbation event. The algorithm attempts to predict the patient's condition one day in advance, based on a comparison of their current physiological measurements against the distribution of their measurements over the previous month. METHOD: The proposed algorithm, which uses a classification and regression tree (CART), has been validated using telehealth measurement data recorded from patients with moderate/severe COPD living at home. The data were collected from February 2007 to January 2008, using a telehealth home monitoring unit. RESULTS: The CART algorithm can classify home telehealth measurement data into either a 'low risk' or 'high risk' category with 71.8% accuracy, 80.4% specificity and 61.1% sensitivity. The algorithm was able to detect a 'high risk' condition one day prior to patients actually being observed as having a worsening in their COPD condition, as defined by symptom and medication records. CONCLUSION: The CART analyses have shown that features extracted from three types of physiological measurements; forced expiratory volume in 1s (FEV1), arterial oxygen saturation (SPO2) and weight have the most predictive power in stratifying the patients condition. This CART algorithm for early detection could trigger the initiation of timely treatment, thereby potentially reducing exacerbation severity and recovery time and improving the patient's health. This study highlights the potential usefulness of automated analysis of home telehealth data in the early detection of exacerbation events among COPD patients.

A randomized controlled trial of the effectiveness of topical amethocaine in reducing pain during arterial puncture.

OBJECTIVE: To determine if topical 4% amethocaine gel can reduce the pain associated with arterial punctures. DESIGN: Randomized, placebo-controlled, double-blinded trial with parallel groups. SETTING: Teaching hospital. PATIENTS: Adults requiring arterial punctures for blood gas estimation as part of routine care. INTERVENTIONS: Four percent amethocaine gel applied for 30 min prior to the radial arterial puncture, compared with a placebo gel. MAIN OUTCOME MEASURES: Pain scored on a visual analog scale from 0 to 100, and heart rate during the procedure. RESULTS: The mean pain score for the amethocaine group was 16.0 (SD, 23.3) and for the placebo group was 20.7 (SD, 18.5). The mean heart rates during arterial puncture were 84.1 beats/min (SD, 10.7) for the amethocaine group, and 83.8 beats/min (SD, 12.7) for the placebo group. These differences were not statistically significant. CONCLUSION: The topical use of 4% amethocaine gel does not reduce the pain associated with arterial puncture.

Reasons for referral for pulmonary function testing: an audit of 4 adult lung function laboratories.

BACKGROUND: Pulmonary function testing (PFT) is an important tool in the diagnosis and management of most respiratory conditions, and appropriate interpretation of test results is a fundamental component of the final report. As part of developing a structured approach to interpretation of PFT results, we wished to characterize primary reasons for referral for testing in a range of PFT laboratories. METHODS: Four PFT laboratories (3 public, 1 private) using similar PFT databases participated. Reasons for performance of PFTs were extracted from the databases and analyzed. Over 5,000 consecutive tests were evaluated from each lab. RESULTS: Identifiable reason for referral was found in 83% of 24,602 test results and categorized. The major categories were follow-up of known respiratory disease (53% of 20,332 tests), investigation of specific symptoms (18%), possible specific lung disease (13%), possible induced lung disease (5%), investigation of lung function in known other diseases (5%), and other miscellaneous reasons (5%). Testing in known disease and/or assessing for PFT change was the primary reason for testing in 60% of tests performed. These data highlight the predominance of ongoing assessment of pulmonary function and the importance of access to previous test results to provide clinically useful test reports. They also emphasize the need for having valid criteria describing what constitutes a real clinical change in the various PFT parameters. CONCLUSIONS: We have found that the majority of PFTs are performed to follow disease progress or response to treatment. This has implications with inter- pretation of test results and the clinical utility of PFT.