Employment and disability for work in patients with COPD: a cross-sectional study among Dutch patients.

OBJECTIVES: The aim was to gain insight into work experiences and problems of subjects with chronic obstructive pulmonary disease (COPD) to develop more effective guidelines for preventing work disability and work loss. METHODS: A total of 617 patients aged 45-60, recruited from pulmonary outpatient clinics and general practices, completed a questionnaire on (respiratory) health and work history. RESULTS: Of the patients 43% were female, 52% were employed and more than half were less educated. Comorbidity was present in 52% of the study group. Of those who stopped working (N=260), 36% stopped before the onset of COPD, 39% stopped because of COPD and 25%, although having COPD, had other reasons to stop. Of the patients with a work history 39% had an invalidity benefit: 21% of the working and 60% of the non-working patients. For one-third of these patients COPD was not the reason for having an invalidity benefit. For 56% of those who had a benefit because of COPD, comorbidity contributed to work disability. No difference in current smoking habit was seen between working patients and non-working patients. Yet, non-working patients were more often smokers at the moment they stopped working. Furthermore, former smokers who still worked stopped smoking at a younger age than former smokers who stopped working. Compared with workers and independent of smoking habit, former workers were more exposed to dust/irritants, had their work(place) less frequently modified and had more unfavourable (social) work experiences. CONCLUSION: For employees with COPD, work loss is often multi-factorial. Comorbidity is often present and an important cause for work loss. Therefore occupational health guidance has to take other interfering (health) factors than COPD into consideration as well. In preventing work disability, work(place) adjustment merits more attention.

Prediction of peak oxygen uptake in men using pulmonary and hemodynamic variables during exercise.

PURPOSE: Many attempts have been made to predict peak VO2 from data obtained at rest or submaximal exercise. Predictive submaximal tests using the heart rate (HR) response have limited accuracy. Some tests incorporate submaximal gas exchange data, but a predictive test without gas exchange measurements would be of benefit. Addition of stroke volume and pulmonary function (PF) measurements might increase the predictability of a submaximal exercise test. METHODS: In this study, an incremental exercise test (10 W x min(-1)) was performed in 30 healthy men of various habitual activity levels. Step-wise multiple regression analysis was used to isolate the most important predictor variables of peak VO2 from a set of measurements of PF: lung volumes, diffusion capacity, airway resistance, and maximum inspiratory and expiratory pressures; gas exchange; minute ventilation (V(E)), tidal volume (V(T)), respiratory exchange ratio (RER = carbon dioxide output divided by VO2); and hemodynamics (HR, stroke index (SI) = stroke volume/body surface area, and mean arterial pressure). These measurements were made at rest and during submaximal exercise. RESULTS: Using the set of PF variables (expressed as percentages of predicted), FEV1 explained 30% of the variance of peak VO2. No other PF variables were predictive. After addition of resting hemodynamic data, SI was included in the prediction equation, raising the predictability to 40%. At the 60-W exercise level, 48% of the variance in peak VO2 could be explained by SI and FEV1. At 150 W, the prediction increased to 81%. At this level VCO2/O2 (RER) also entered the prediction equation of peak VO2: 6.44 x FEV1(%) + 13.0 x SI - 1921 x RER + 2380 (SE = 142 mL x min(-1) x m(-2), P < 0.0001). Leaving out the gas exchange variable RER, maximally 64% of the variance in peak VO2 could be explained. CONCLUSION: In conclusion, inclusion of pulmonary function and hemodynamic measurements could improve the prediction accuracy of a submaximal exercise test. The submaximal exercise test should be performed until a level of 150 W is reached. Noninvasive stroke volume measurements by means of EIC have additional value to measurement of HR alone. Finally, measurement of gas exchange significantly improves the predictability of peak VO2.

Assessment of sleep complaints and sleep-disordered breathing in a consecutive series of obese patients.

BACKGROUND/OBJECTIVE: The prevalence of sleep-related complaints (SRC) and the frequency of sleep-disordered breathing (SDB) in obese patients has not been studied extensively. We investigated SRC and SDB in a group of obese persons as part of a preoperative workup for weight reduction (bariatric) surgery. METHODS: All consecutive patients attending a weight-loss clinic for evaluation for bariatric surgery were asked to complete a questionnaire. The questionnaire consisted of a section on SRC and a validated general sleep questionnaire (Sleep Wake Experience List). The patients underwent sleep studies in which an Edentrace recorder registered heart rate, chest wall movements by impedance, airflow and oxygen saturation. RESULTS: Fifty-one patients (14 men, 37 women) were evaluated. Mean body mass index (BMI) was 45 kg/m2 (range 33-61). Eighteen patients (35%) demonstrated SDB, defined as (a) an apnea/hypopnea index 5, and/or (b) more than 2% of registration time with an oxygen saturation below 90%. There was no difference between these 18 patients and patients who did not exhibit SDB in age, sex, BMI or SRC. Seven patients had SDB of a severity warranting closer investigation and perioperative monitoring. CONCLUSION: Both SRC and SDB are common in obese patients. Limited nocturnal respiratory monitoring is indicated as part of the preoperative workup for weight reduction surgery.

The long-term effects of pulmonary rehabilitation in patients with asthma and chronic obstructive pulmonary disease: a research synthesis.

OBJECTIVE: To present a critical review and meta-analysis of studies evaluating the long-term effects of pulmonary rehabilitation in patients with asthma and chronic obstructive pulmonary disease (COPD). DATA SOURCES: A database of articles published over the last 45 years, compiled by using medical subject heading key words pulmonary, obstructive, rehabilitation, and exercise. Articles not written in English, Dutch, or German and abstracts were excluded. STUDY SELECTION: Selected studies (1) evaluated the effects of pulmonary rehabilitation, (2) included patients with asthma or COPD older than 18 years, (3) evaluated outcome measures of exercise capacity or health related quality of life (HRQL), and (4) included a control condition lacking exercise training. DATA EXTRACTION: Independent extraction by two reviewers. DATA SYNTHESIS: For each outcome, summary effects were computed by pooling standardized mean differences as well as raw mean differences. Significant improvements were found for all outcomes (p < .001). Sensitivity analyses for methodological quality of the selected studies did not change summary effect sizes. Effect sizes were significantly heterogeneous for the outcome endurance time (p < .0001). Pooling raw mean differences revealed overall effects in 6-minute walking distance (49+/-26 m) and all 4 dimensions of the chronic respiratory questionnaire (range, 0.5+/-0.3 to 0.8+/-0.3 points), indicating substantial improvements in these outcomes. Significant summary effect sizes were found up to 9 months after finishing rehabilitation for maximal exercise capacity (p < .003) and 6-minute walking distance (p < .005). CONCLUSIONS: Patients with asthma and COPD benefit from pulmonary rehabilitation.

The haemodynamic response to exercise in chronic obstructive pulmonary disease: assessment by impedance cardiography.

This study aimed to determine the differences in haemodynamic responses to a standard incremental exercise test between outpatients with chronic obstructive pulmonary disease (COPD) and age-matched controls and to discover the relationship between severity of airflow obstruction and exercise haemodynamics in COPD. Twenty-two male patients with COPD (forced expiratory volume in one second (FEV1)/vital capacity (VC))<80% predicted) and 20 age-matched male controls performed an incremental exercise test (10 W x min(-1)) with ventilatory function and changes in stroke volume (deltaSV) and cardiac output (deltaCO) measured by means of electrical impedance cardiography (EIC). Submaximal deltaSV and deltaCO were lower in COPD patients. Peak exercise deltaSV were equal in patients and controls (128+/-33 versus 129+/-29%, p=0.98), whereas peak deltaCO was lower in patients (COPD versus controls: 232+/-71 versus 289+/-54%, p<0.005). In COPD patients, FEV1 (% pred) was significantly correlated to deltaSV at all submaximal exercise intensities, to peak exercise deltaSV and to peak exercise deltaCO. FEV1/VC (% pred) was significantly correlated to deltaSV at 30 and 60 W. In conclusion, in chronic obstructive pulmonary disease an aberrant haemodynamic response to exercise was found, especially in patients with severe airflow obstruction. This aberrant response is related to the degree of airflow obstruction and may limit exercise performance in patients with severe chronic obstructive pulmonary disease.

Haemodynamic response to exercise in healthy young and elderly subjects.

Whereas with advancing age, peak heart rate (HR) and cardiac index (CI) are clearly reduced, peak stroke index (SI) may decrease, remain constant or even increase. The aim of this study was to describe the patterns of HR, SI, CI, arteriovenous difference in oxygen concentration (Ca-vO2), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), stroke work index (SWI) and mean systolic ejection rate index (MSERI) in two age groups (A: 20-30 years, n = 20; B: 50-60 years n = 20). After determination of pulmonary function, an incremental bicycle exercise test was performed, with standard, gas-exchange measurements and SI assessment using electrical impedance cardiography. The following age-related changes were found: similar submaximal HR response to exercise in both groups and a higher peak HR in A than in B[185 (SD 9) vs 167 (SD 14) beats.min-1, P < 0.0005]; increase in SI with exercise up to 60-90 W and subsequent stabilization in both groups. As SI decreased towards the end of exercise in B, a higher peak SI was found in A [57.5 (SD 14.0) vs 43.6 (SD 7.7) ml.m-2, P < 0.0005]; similar submaximal CI response-to exercise, higher peak CI in A [10.6 (SD 2.5) vs 7.2 (SD 1.3) 1.min-1.m-2, P < 0.0005]; no differences in Ca-vO2 during exercise; higher MAP at all levels of exercise in B; higher SVRI at all levels of exercise in B; lower SWI in B after recovery; higher MSERI at all levels of exercise in A. The decrease in SI with advancing age would seem to be related to a decrease in myocardial contractility, which can no longer be compensated for by an increase in preload (as during submaximal exercise). Increases in systemic blood pressure may also compromise ventricular function but would seem to be of minor importance.

Nocturnal waking and morning dip of peak expiratory flow in clinically stable asthma patients during treatment. Occurrence and patient characteristics.

The occurrence of nocturnal waking due to asthma and morning dip of the peak expiratory flow (PEF), and the associated patient characteristics were investigated in 103 clinically stable asthmatic patients from a pulmonary outpatient clinic. Analysis of a 1 week diary showed a mean week morning PEF dip (i.e. morning/daytime highest PEF) of 12%. A mean dip of > or = 20% was found in 20% of the patients. Three groups were distinguished: 10% were 'nocturnal-waking patients' (waking up > or = 2 nights a week with a PEF dip of > or = 20%); 19% 'morning-dipping patients' (patients with > or = 3 dips a week of > or = 20% but with waking up on < 2 nights a week) leaving 71% 'remaining patients'. 28% of all patients showed morning PEF dips. In a questionnaire, waking every night was reported by 9%, at least once a week by 42% and once a month by 72%. In 'nocturnal-waking patients' FEV1 and morning and evening PEFs were lower than in 'remaining patients'; complaints during the night and on rising were more severe. The morning PEF dip was the same in 'nocturnal-waking patients' and 'morning-dipping patients'. The occurrence of waking was the same in 'morning-dipping patients' and in the 'remaining patients'. There were no differences in other clinical parameters among the three groups. We conclude that a subset of clinically stable asthma patients presents morning dips and nocturnal waking. They do not differ substantially from the remaining patients in other clinical characteristics.

The effects of a community-based pulmonary rehabilitation programme on exercise tolerance and quality of life: a randomized controlled trial.

The present multicentre study evaluates the differences in efficacy between a 3 month rehabilitation programme including drug treatment, and a 3 month control period of drug treatment only, for asthmatic patients and patients with chronic obstructive pulmonary disease (COPD). The programme was run by physiotherapists in eight local practices, and included exercise training, patient education, breathing retraining, evacuation of mucus, relaxation techniques, and recreational activities. In a randomized controlled trial with a cross-over design, the effects of rehabilitation were evaluated 3 and 6 months after baseline measurements in terms of exercise tolerance and quality of life (QOL). Exercise tolerance was assessed using submaximal cycle ergometer tests and 6 min walking tests. QOL was evaluated by means of the Chronic Respiratory Disease Questionnaire (CRDQ). After 3 months, the patients who started with rehabilitation showed significant improvements in endurance time (421 s) and cardiac frequency (6 beats.min-1) during cycling, walking distance (39 m), and total CRDQ score (17 points) compared to the control group. These improvements were still significant after 6 months. Additional analysis indicated that the asthmatic patients and the patients with COPD responded to rehabilitation in a similar way, with the exception that there was a greater improvement in walking distance for asthmatics. Improvements in exercise tolerance were not significantly correlated with improvements in QOL. Rehabilitation of patients with asthma or chronic obstructive pulmonary disease in local physiotherapy practices improves exercise tolerance and quality of life.

Pulmonary function of patients with spontaneous pneumothorax in relation to the extent of emphysema-like changes.

The aim of the present study was to analyse pulmonary function parameters of patients with spontaneous pneumothorax (SP) in relation to the extent of emphysema-like changes (ELCs). Pulmonary function tests were performed in 85 patients with unilateral SP, 6 weeks after video-assisted thoracoscopy (VAT). In 63 patients, thoracic computer tomography (CT) was obtained. An ELCs score, based on findings of CT and VAT, was used to quantify ELCs, ranging from 0 (expressing no ELCs) to 3 (expressing extensive ELCs). Emphysema-like changes were detected during VAT in 74% of patients, of which 70% were considered larger than 2 cm. An ELCs score > or = 2 was found in 27 patients. Clinical characteristics of the patients grouped according to thoracoscopical findings and ELCs score did not differ, except for age. Patients with large ELCs were significantly older than patients without ELCs or small ELCs (P = 0.0009). In patients with large ELCs and ELCs score > or = 2, increased mean percentages of predicted total lung capacity and decreased diffusing capacity (KCO) were found. None of the patients exhibited all pulmonary function criteria of emphysema, in contrast to 43% of the patients with an ELCs score > or = 2. KCO was the only pulmonary function parameter which was decreased in smokers, especially in patients with large ELCs or ELCs score > or = 2. Static lung compliance (Cstat) was the only pulmonary function parameter which was increased in patients with recurrent SP. The authors concluded that KCO is related to smoking behaviour and ELCs in patients with SP. Cstat is the only parameter which is increased in patients with recurrent SP. The discrepancy between pulmonary function and macroscopical parenchymal changes could be explained by the fact that not all patients with SP are old enough at presentation to show all signs of emphysema with pulmonary function testing. On the other hand, it might be possible that ELCs in SP cause different pulmonary function abnormalities than in centriacinar or panacinar emphysema.

Comparison of the respiratory and hemodynamic responses of healthy subjects to exercise in three different protocols.

Although the importance of exercise testing has been well established, standardization of protocols is lacking. In the current study three protocols were compared with respect to respiratory and hemodynamic variables at submaximal and peak exercise. Fifteen healthy young men underwent three maximal exercise tests using the following protocols: (I) an increase of 30 Watt, every three minutes; (II) an increase of 10 Watt, every minute; (III) a continuous load increase of 10 Watt/min. Respiratory measurements were made of oxygen uptake (VO2), carbon dioxide output (VCO2), minute ventilation (VE) and tidal volume (VT). Hemodynamic measurements were made of ECG, heart rate (HR), blood pressure and stroke volume (SV). The latter variable was measured by means of electrical impedence cardiography (EIC). There were no differences in mean maximum load or peak-VO2 between protocols I, II and III. The course of SV was similar in all protocols, i.e. an increase of about 30% until 100 Watt, with a subsequent stabilization until maximum load. All other hemodynamic measurements were similar in both protocols, too. Significant differences were found in submaximal values of VO2 and VCO2. There were no differences in other gas-exchange variables at any moment during exercise. With respect to the VO2max or the hemodynamic response to exercise, any protocol can be used. For the evaluation of submaximal exercise, the protocol that has been used has to be taken into account. Differences at these levels are not related to differences in hemodynamic responses.

Sleep complaints in postpolio syndrome.

OBJECTIVE: This study evaluated the prevalence of sleep-related and sleep-disordered-breathing (SDB)-related complaints in a group of postpolio patients compared with healthy controls. DESIGN: A questionnaire, consisting of the validated Sleep Wake Experience List (SWEL), and a list of questions pertaining to sleep-disordered breathing (SDB), was mailed to a group of 43 postpolio patients. PARTICIPANTS: The patient group consisted of 43 former polio patients who had been evaluated at a neuromuscular disease clinic in a tertiary referral center for new complaints of progressive muscle weakness. The patients were requested to select two healthy controls from their neighborhood who also filled out a questionnaire. RESULTS: In the group of postpolio patients the frequency of tiredness on waking up and during the day, headache on waking up, daytime sleepiness, and restless legs was significantly higher compared with the control group. Complaints specifically related to SDB, such as apneas and snoring, were not mentioned significantly more often by the postpolio patients. CONCLUSION: Up to half of postpolio patients report complaints of disordered sleep, which is likely to influence daytime functioning. Further studies, including sleep studies into SDB and restless legs, are necessary to elucidate the causes for these complaints.

Treatment of nocturnal asthma by addition of oral slow-release albuterol to standard treatment in stable asthma patients.

Nocturnal and early-morning complaints in asthma patients are sometimes difficult to treat. We investigated the efficacy of an oral osmotically controlled release (OR) formulation of albuterol 8 mg in 35 patients with stable asthma and nocturnal complaints and/or morning dipping of the peak expiratory flow (PEF). The mean age was 45 years (range 22-70), the FEV(1) was 61 +/- 20% of predicted, and inhaled steroids were used by 32 patients. Albuterol OR was added to their usual treatment. The use of theophyllines and oral adrenergics was not allowed. Twice-daily (b.i.d.) dosing was compared to one dose at night and to placebo. The three-period crossover study was double-blind placebo-controlled with treatment periods of 2 weeks. Responses have been analyzed by means of multiple regression analysis at a significance level of 5%. There was no significant difference of the FEV(1) or the weekly means of PEFs between the periods. During the b.i.d. treatment, the daytime and nocturnal symptom scores, used rescue medication, subjective sleep quality, and nocturnal waking tended to be better. Mental fitness was improved, but significantly only in the morning. We concluded that additional treatment with albuterol 8 mg OR once or twice daily did not lead to an overall clinical improvement in this group of patients with nocturnal asthma during standard treatment. In view of the tendency to improvement, it may be worth trying this treatment in individual patients.

Subjective sleep quality and mental fitness in asthmatic patients.

Asthmatic patients from our outpatient pulmonary clinic were asked to fill out a questionnaire about their sleep and daytime fitness. Seventy-eight responded. Sixty-five healthy persons served as a control group. Patients reported decreased sleep quality, decreased daytime mental fitness, and increased daytime somnolence. There was no relation between these features and lung function, bronchial hyperreactivity, or nocturnal asthma. We conclude that these asthmatic patients reported more sleep disturbances and daytime somnolence than healthy control persons.

Adenosine deaminase activity, not diagnostic for tuberculous pleurisy.

We have measured adenosine deaminase (ADA) in pleural effusions of 95 patients, using a method optimalised for rapid determination on a Hitachi 705 analyzer. High ADA activity was found in four of the five patients with tuberculous pleurisy, in four of the seven with empyema and in three of the seven patients with mesothelioma. One patient with very high serum ADA activity due to liver disease also had a high activity in the pleural effusion. Low activity was found in all patients with other neoplastic pleural effusions, parapneumonic pleural effusions, transudates, and in pleural effusions due to some other diseases. We conclude that in a country with a low tuberculosis incidence a high ADA activity in pleural effusion in neither sensitive nor specific enough to rely on the diagnosis of tuberculous pleurisy. Routine determination of ADA is not recommended; in selected cases, however, it may be useful.