Michael J. Belman

Benefits and Problems of a Physical Training Program for Asthmatic Patients

The clinical and physiological effects of a medically supervised, indoor physical training programme were investigated in 36 asthmatic subjects aged 16-40 years. After clinical evaluation, lung function assessment, and progressive incremental exercise testing subjects were randomly allocated to control and training groups. The measurements were repeated after a six week run in period and after a further three months in which those in the training group underwent an indoor training programme. The measurements made at three months were compared with those at the end of the run in period. There was no significant change in anthropometric characteristics, blood lipid profiles, or the provocative concentration of histamine causing a 20% fall in FEV1 (histamine PC20) in the group who underwent training. After training there were significant increases in mean maximal oxygen uptake (ml kg-1 min-1) from 23 (5) to 28 (6), oxygen pulse (ml/beat) from 8.8 (2.3) to 10.8 (2.4), and anaerobic threshold (1/min) from 1.11 (0.27) to 1.38 (0.33). These changes were significantly greater in the group undergoing training than in the control group. There was also a significant fall in breathlessness scores (Borg ratings), blood lactate, carbon dioxide output, and minute ventilation during submaximal exercise in the training group, with no change in the control group. The subjects motivation, the initial level of fitness, and the symptom score at the time of training were the most important factors influencing improvements in cardiorespiratory fitness. Thus submaximal physical exercise of controlled intensity, sustained for three months, produced significant improvements in fitness and cardiorespiratory performance that should be advantageous to the exercising asthmatic patient. The availability of medical supervision throughout the exercise programme appears to have contributed to the successful outcome.

Quality of Life in Patients With Chronic Obstructive Pulmonary Disease Improves After Rehabilitation at Home

We have developed a rehabilitation programme at home and have investigated its effects on quality of life (QOL), lung function, and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). We studied 43 patients with severe airflow obstruction: forced expiratory volume in one second (FEV1) 1.3 +/- 0.4 l (mean +/- SD), FEV1/inspiratory vital capacity (IVC) 37 +/- 7.9%. After stratification, 28 patients were randomly allocated in a home rehabilitation programme for 12 weeks. Fifteen patients in a control group received no rehabilitation. The rehabilitation group received physiotherapy by the local physiotherapist, and supervision by a nurse and a general practitioner. Quality of life was assessed by the four dimensions of the Chronic Respiratory Questionnaire (CRQ). We found a highly significant improvement in the rehabilitation group compared to the control group for the dimensions dyspnoea, emotion, and mastery. Lung function showed no changes in the rehabilitation group. The exercise tolerance improved significantly in the rehabilitation group compared to the control group. The improvement in quality of life was not correlated with the improvement in exercise tolerance. Rehabilitation of COPD patients at home may improve quality of life; this improvement is not correlated with an improvement in lung function and exercise tolerance.

Use of a Combined Oxygen and Carbon Dioxide Transcutaneous Electrode in the Estimation of Gas Exchange During Exercise

BACKGROUNDnAccurate and reliable measurement of gas exchange during exercise has traditionally involved arterial cannulation. Non-invasive devices to estimate arterial oxygen (O2) and carbon dioxide (CO2) tensions are now available. A method has been devised and evaluated for measuring gas exchange during exercise with a combined transcutaneous O2 and CO2 electrode.nnnMETHODSnSymptom limited exercise tests were carried out in 24 patients reporting effort intolerance and breathlessness. Exercise testing was performed by bicycle ergometry with a specifically designed protocol involving gradual two minute workload increments. Arterial O2 and CO2 tensions were measured at rest and during exercise by direct blood sampling from an indwelling arterial cannula and a combined transcutaneous electrode heated to 45 degrees C. The transcutaneous system was calibrated against values obtained by direct arterial sampling before each test.nnnRESULTSnIn all tests the trend of gas exchange measured by the transcutaneous system was true to the trend measured from direct arterial sampling. In the 140 measurements the mean difference between the O2 tensions estimated by direct sampling and the transcutaneous method was 0.08 kPa (0.62 mm Hg, limits of agreement 4.42 and -3.38 mm Hg). The mean difference between the methods for CO2 was 0.02 kPa (0.22 mm Hg, limits of agreement 2.20 and -1.70 mm Hg). There was no morbidity associated with the use of the transcutaneous electrode heated to 45 degrees C.nnnCONCLUSIONSnA combined transcutaneous O2 and CO2 electrode heated to 45 degrees C can be used to provide a reliable estimate of gas exchange during gradual incremental exercise in adults.

Metered-Dose Inhaler Adherence in a Clinical Trial

We studied patterns of inhaler usage in a sample of participants from two centers in the Lung Health Study clinical trial. The inhaler, containing either ipratropium bromide or a placebo, was prescribed to be taken as two inhalations three times daily. For 4 months we recorded adherence by both self-report (n = 95) and canister weight change (n = 70). We compared these results with data obtained from a microprocessor monitoring device, the Nebulizer Chronolog (NC), which records the date and time of each inhaler actuation. Seventy-three percent of the participants reported using the inhaler an average of three times daily; however, NC data showed that only 15% of the participants actually used the inhaler an average of 2.5 or more times per day. Canister weight overestimated adherence because only 62% of the NC sets contained the prescribed two actuations. Fourteen percent showed a pattern of actuation of their inhalers more than 100 times in a 3-h interval. We interpret this usage pattern to reflect deliberate emptying of inhalers to appear to be in good compliance with the prescribed program. We conclude that self-report and weighing of inhaler canisters overestimate adherence to the prescribed regimens. Furthermore, a substantial number of monitored inhaler users appear to deliberately dump their medication prior to follow-up visits.

Pulmonary Rehabilitation that Includes Arm Exercise Reduces Metabolic and Ventilatory Requirements for Simple Arm Elevation

Simple arm elevation results in increased metabolic and ventilatory requirements in patients with chronic airflow obstruction (CAO). These demands contribute to the dyspnea that is frequently reported when these patients perform activities of daily living involving the arms. We hypothesized that a comprehensive pulmonary rehabilitation (PR) program that includes upper extremity training would lower the ventilatory requirement for arm elevation. Metabolic and ventilatory responses to 2 min of simple arm elevation were studied in 14 patients with CAO before and after PR. Respiratory muscle strength was determined in 11 patients by measurement of maximal transdiaphragmatic pressure (Pdimax). Oxygen uptake (VO2), carbon dioxide production (VCO2), heart rate (HR), minute ventilation (VE), tidal volume (VT), and respiratory rate were measured at rest with the arms down and during 2 min of arm elevation. Before PR, arm elevation led to significant increases in VO2, VCO2, HR, and VE. After PR, pulmonary function, Pdimax, and resting metabolic and ventilatory parameters with the arms down were unchanged; however, during arm elevation, VO2, VCO2, and VE were significantly less than they were before PR. We conclude that a comprehensive PR program that includes upper extremity exercises leads to a reduction in the ventilatory requirement for simple arm elevation. This type of program may allow patients with CAO to perform sustained upper extremity activities with less dyspnea.

Controlled Trial of Respiratory Muscle Training in Chronic Airflow Limitation

BACKGROUNDnWhether respiratory muscle training is of benefit to patients with chronic airflow limitation is controversial. The objective of the study was to determine the effect of resistance breathing training on physiological and functional measures in patients with chronic airflow obstruction.nnnMETHODSnThe design was a randomised, double blind, controlled trial with a six month follow up. Eighty two patients with a forced expiratory volume in one second (FEV1) of less than 70% predicted, and an FEV1/vital capacity ratio of less than 0.7, were randomised to receive training for 10 minutes five times daily with progressively larger resistances through a resistive breathing device (PFLEX) as tolerated or to a sham device which gave minimal resistance. The main outcome measures, respiratory muscle strength and endurance, a progressive exercise test, a six minute walk test and physical and emotional function (chronic respiratory questionnaire) were assessed at monthly intervals. Patients in both groups were also randomised to wear or not wear nose clips during their training.nnnRESULTSnNo significant differences were observed between treatment and control groups, with or without nose clips, for any of the outcomes. Confidence intervals on the difference between treatments were narrow, excluding clinically important difference in any major outcome.nnnCONCLUSIONnThis training regimen fails to strengthen respiratory muscles or improve exercise or functional capacity in patients with chronic airflow limitation.

Reversing Disability of Irreversible Lung Disease

Pulmonary rehabilitation is a comprehensive multifaceted team approach for integrating medical management, coping skills, self-management techniques, and exercise reconditioning. It provides patients with chronic lung disease the ability to adapt and live full and nearly normal lives. These changes are possible because the overall disability includes significant reversible components: Patients have bronchospasm, infection, and cor pulmonale; they respond to progressively impaired lungs by progressive inactivity, leading to physical deconditioning. Both factors contribute to dyspnea. Because patients naturally fear dyspnea, they panic easily. During panic, their work of breathing may increase and respiratory failure may result. Pulmonary rehabilitation provides good medical management; provides exercises to increase strength, endurance, and tolerance to dyspnea; and trains patients in panic control. These programs have not been shown to lengthen life span or improve static lung function. They increase exercise performance and render patients functional, independent, and subject to fewer hospital admissions. Pulmonary rehabilitation is the only approach to chronic lung disease short of lung transplantation that improves the long-term outlook for these patients.

Exercise Training in Patients With Chronic Obstructive Pulmonary Disease

Most patients with chronic obstructive pulmonary disease (COPD) demonstrate positive responses to exercise conditioning. Dyspnea is reduced and work tolerance is extended with little or no change in pulmonary function noted. Possible explanations for the increased ability to better tolerate exercise and activities of daily living (ADL) after training include: 1) psychological encouragement, 2) improvements in mechanical efficiency, 3) improved cardiovascular conditioning, 4) improved muscle function, 5) biochemical adaptations responsible for reducing glucose utilization, 6) desensitization to dyspnea, and 7) contributions from better self-care. However, not all patients respond positively to exercise conditioning. This may represent differences in patient selection, training approaches, and/or comorbidity issues commonly seen in patients with COPD. Alternatively, the answer may reside in devising an optimal training intensity, duration, and frequency combination for patients with COPD. This is not an easy matter because of the diversity of patients categorized as COPD. We have reviewed these issues from the available data and presented areas where additional research is warranted. What is needed at present is a series of well-controlled studies that focus on identifying and improving training responses in patients with COPD. Secondary to this issue is the long term epidemiologic surveillance of trained patients to document sustained effects.