Biomedical subjects
G J Wesseling
Publications and source records attributed to G J Wesseling.
Use of out of hours services: a comparison between two organisations.
OBJECTIVES: To investigate differences in numbers and characteristics of patients using primary or emergency care because of differences in organisation of out of hours care. BACKGROUND: Increasing numbers of self referrals at the accident and emergency (A&E) department cause overcrowding, while a substantial number of these patients exhibit minor injuries that can be treated by a general practitioner (GP). METHODS: Two different organisations of out of hours care in two Dutch cities (Heerlen and Maastricht) were investigated. Important differences between the two organisations are the accessibility and the location of primary care facility (GP cooperative). The Heerlen GP cooperative is situated in the centre of the city and is respectively 5 km and 9 km away from the two A&E departments situated in the area of Heerlen. This GP cooperative can only be visited by appointment. The Maastricht GP cooperative has free access and is located within the local A&E department. During a three week period all registration forms of patient contacts with out of hours care (GP cooperative and A&E department) were collected and with respect to the primary care patients a random sample of one third was analysed. RESULTS: For the Heerlen and Maastricht GP cooperative the annual contact rate, as extrapolated from our data, per 1000 inhabitants per year is 238 and 279 respectively (chi(2)((1df))=4.385, p=0.036). The contact rate at the A&E departments of Heerlen (n=66) and Maastricht (n=52) is not different (chi(2)((1df))=1.765, p=0.184). Some 51.7% of the patients attending the A&E department in Heerlen during out of hours were self referred, compared with 15.9% in Maastricht (chi(2)((1df))=203.13, p<0.001). CONCLUSIONS: The organisation of out of hours care in Maastricht has optimised the GP's gatekeeper function and thereby led to fewer self referrals at the A&E department, compared with Heerlen.
[The last breath. The decision of whether or not to ventilate patients with severe chronic obstructive pulmonary disease].
Explore the source record for details and available documents.
Detecting patients at a high risk of developing chronic obstructive pulmonary disease in general practice: cross sectional case finding study.
OBJECTIVES: To investigate the effectiveness of case finding of patients at risk of developing chronic obstructive pulmonary disease, whether the method is suitable for use in general practice, how patients should be selected, and the time required. DESIGN: Cross sectional study. SETTING: Two semirural general practices in the Netherlands. PARTICIPANTS: 651 smokers aged 35 to 70 years. MAIN OUTCOME MEASURES: Short standardised questionnaire on bronchial symptoms for current smokers, lung function with a spirometer, and the quality of the spirometric curve. RESULTS: Of the 201 smokers not taking drugs for a pulmonary condition, 169 produced an acceptable curve (fulfilling American Thoracic Society criteria). Of these, 30 (18%, 95% confidence interval 12% to 24%) had a forced expiratory volume in one second (FEV(1)) <80% of predicted. When smokers were preselected on the basis of chronic cough, the proportion with an FEV(1) <80% of predicted increased to 27% (17 of 64; 12% to 38%). Chronic cough was a better predictor of airflow obstruction than other symptoms, such as wheeze and dyspnoea. The presence of two symptoms was a slightly better predictor than cough only (odds ratio 3.02 (1.37 to 6.64) v 2.50 (1.14 to 5.52)). Age was also a good predictor of obstruction; smokers over 60 with cough had a 48% chance of having an obstruction. The mean time needed for spirometry was four minutes. Detecting one smoker with an FEV(1) <80% of predicted cost 5 pound sterling to 10 pound sterling. CONCLUSIONS: Trained practice assistants could check all patients who smoke for chronic obstructive pulmonary disease at little cost to the practice. Cough and age are the most important predictors of the disease. By testing one smoker a day, an average practice could identify one patient at risk a week.
A molecular dosimetry approach to assess human exposure to environmental tobacco smoke in pubs.
Although the involvement of environmental tobacco smoke (ETS) in human lung cancer is no longer a matter of dispute, the magnitude of its impact still is. This is mainly due to the inefficiency of methodology to assess exposure to ETS especially in public places. Setting a real life exposure condition (3 h stay in local pubs) and using a matched-control study design, we quantified smoke-related DNA adducts in induced sputum and peripheral blood lymphocytes (PBL) of healthy non-smokers (n = 15) before and after a single pub visit by means of the (32)P-post-labeling assay. For verification, we also measured a spectrum of polycyclic aromatic hydrocarbons (PAH) in the ambient air of the pubs by personal air monitors, and determined the plasma concentrations of nicotine and cotinine by gas chromatography/mass spectrometry. The ambient air concentrations of all PAH were several orders of magnitude higher than those already reported for other indoor environments. The plasma concentrations of both nicotine and cotinine increased significantly after the pub visit (P = 0.001 and P = 0.0007, respectively). Accordingly, the overall DNA adduct profile in induced sputum, but not in PBL, changed quantitatively and qualitatively after the pub visit. Of most significance was the formation of a distinct DNA adduct in induced sputum of three individuals consequent to ETS exposure. This adduct co-migrated with the standard (+/-)-anti-benzo[a]pyrene diol epoxide-DNA adduct, which is known to form at lung cancer mutational hotspots. We conclude that real life exposure to ETS can give rise to pro-mutagenic lesions in the lower airway, and this can be best investigated in a relevant surrogate matrix such as induced sputum.
Glucocorticoid receptor mRNA levels in bronchial epithelial cells of patients with COPD: influence of glucocorticoids.
Glucocorticoids (gcs) are known to be effective in the treatment of asthma. In chronic obstructive pulmonary disease (COPD), however, no beneficial effects are demonstrated in most patients. Hypothetically, this may be explained by an overexpressed beta-glucocorticoid receptor (GR) compared to the alpha-GR. The aim of this study was to investigate alpha- and beta-GR mRNA levels and ratios in patients with COPD with or without glucocorticoid treatment. GR and, as a control, metallothionein (MT) 2 mRNA levels were compared between patients with COPD receiving glucocorticoids (COPD + gcs), glucocorticoid naive COPD-patients (COPD - gcs) and non-COPD control patients not using gcs. Bronchoscopy was performed and bronchial epithelial cells were sampled with brushing. Smoking did not influence alpha- and beta-GR levels and ratios, nor the MT2 mRNA expression level. The alpha-GR mRNA expression was lower in the COPD - gcs group than in controls. Both GR forms were higher in the COPD + gcs patients than in the COPD - gcs patients, but not different from the levels measured in the controls. alpha 1/beta-GR mRNA ratios did not differ between the groups and averaged 1.7, suggesting no inhibitory effect of the beta-GR on the alpha 1 form. MT2 levels were upregulated in the COPD + gcs patients as compared to the COPD - gcs group, indicating a pharmacological glucocorticoid effect. In the present study it is demonstrated that basal GR mRNA levels are lower in patients with COPD. Although this needs to be investigated further, this might explain, in part, the non-responsiveness of patients with COPD to gcs.
Low diagnostic value of respiratory impedance measurements in children.
The aim of this study was to determine whether impedance values in children with various chronic respiratory complaints differed from those observed in symptom-free children. Respiratory impedance was measured using the forced oscillation technique in 1,776 Dutch children aged 6-12 yrs. In addition to the commonly used parameters of resistance and reactance, further impedance parameters were obtained by using linear and quadratic regression to describe individual resistance and reactance curves as a function of frequency. Furthermore, the diagnostic value of the individual impedance parameters was evaluated by means of receiver operator characteristic (ROC) curves. Statistically significant differences in impedance values were found in girls with symptoms suggesting asthma compared to symptom-free girls, but not in boys. In children with chronic cough, impedance was not significantly different from the values of symptom-free children. The results obtained by the additional impedance parameters were comparable to those of the commonly used measures. We conclude that the diagnostic values of the impedance parameters appeared to be low, as no cut-off points were found to discriminate clearly between symptomatic and symptom-free children. These findings may reflect absence of functional abnormalities in symptomatic children at this age.
The rate of respiratory symptoms among primary school children in two Dutch regions.
UNLABELLED: A cross-sectional study was conducted to evaluate possible interregional differences in respiratory health in primary school children living in two different towns of the Netherlands, Melick/Herkenbosch Asenray (MHA) (n = 511) and Leek (LK) (n = 612). The prevalence of respiratory symptoms was determined by means of a questionnaire and respiratory impedance was measures using the forced oscillation technique (FOT). Respiratory symptoms were reported consistently more often in MHA than in LK; chronic cough (17% MHA vs 5% LK), shortness of breath (15% vs 8%), wheeze (16% vs 13%) and attacks of shortness of breath with wheeze (10% vs 7%). However, doctor-diagnosed asthma was reported as 7% in MHA and 6% in LK. The prevalence rates expressed as odds ratios of MHA versus LK were all > 1 even when adjusted for known indoor environmental factors. Living in MHA appeared to be a statistically significant determinant of the reported symptom prevalence. Furthermore, the child's age, maternal smoking (> 10 cigarettes/day), and having had domestic animals were positively associated with one or more respiratory symptoms. Calculating adjusted differences in respiratory impedance between the regions resulted in a small but statistically significant difference in resonant frequency, LK being slightly at a disadvantage. Measured outdoor air pollution levels of SO2, NO2, O3 and PM10 were in general higher in MHA. In both regions however, the average levels remained below the present WHO guidelines, except for NO2 in MHA where the guideline was slightly exceeded. CONCLUSION: In this study prevalence rates of key symptoms of asthma were found to be significantly higher in children living in one region of the Netherlands (MHA) compared to another (LK). Known (indoor) risk factors for respiratory disease could not explain the observed differences in symptom prevalence between the regions. However, statistically but not clinically significant interregional differences in respiratory impedance values were found between children living in MHA and children living in LK. Further research will have to incorporate techniques to evaluate the potential influence of information bias.
A five year follow-up of lung function among chemical workers using flow-volume and impedance measurements.
Impedance of the respiratory system, measured using the forced oscillation technique (FOT), has repeatedly been proposed as a tool for occupational health screening. The aim of this study was to compare the outcome of impedance measurements and flow-volume curves, and to study relationships between lung function decline and specific exposures and smoking. Both measurements were applied in 136 chemical workers from seven main production/personnel groups during a 5 year follow-up (1990-1995). The prevalence of airway obstruction (forced expiratory volume in one second (FEV1) < 80% of predicted) at both time-points was about 5% but did not necessarily include the same subjects. The average decline in FEV1 over 5 yrs was 200 mL (predicted decline 160 mL). Although most impedance parameters correlated to flow-volume parameters in both years, a rapid 5 year decline of FEV1 (> 330 mL) was only accompanied by a significant decrease in the reactance at 8 Hz (X8) and an increase in the resonance frequency (f0). Interestingly, decline in FEV1 was significantly dependent on age, years of employment, pack-years, FEV1, and all impedance parameters at the start in 1990 (r = 0.35; p = 0.01). Similarly, the increase in f0 was significantly dependent on age, years of employment, pack-years, f0, FEV1, forced vital capacity (FVC), peak expiratory flow (PEF) and maximal mid-expiratory flow (MMEF) at the start (r = 0.56; p < 0.01). Those with a rapid decline in FEV1, were relatively more represented among acid workers (relative risk (RR) = 2.14), maintenance workers (RR = 2.1) and bulk/transport workers (RR = 1.78), but none of these was significant. Lung function, however, was significantly lower in the bulk/transport workers (n = 14) compared to the rest, based both on flow-volume (FEV1, FVC) and impedance (X8, f0) measurements. Smoking had a significant effect on most flow-volume parameters but only for frequency dependence among the impedance outcomes. It is concluded that alterations in impedance parameters do reflect changes in flow-volume curves induced by age. smoking and occupational exposure. Therefore, these data are a valuable extension to current cross-sectional data.
A young woman with cough and chest pain.
Explore the source record for details and available documents.
Nutritional depletion in relation to respiratory and peripheral skeletal muscle function in out-patients with COPD.
Although increasing attention has been paid to nutritional aspects in chronic obstructive pulmonary disease (COPD), limited information is available regarding the prevalence and consequences of nutritional depletion in a random out-patient COPD population. We studied body composition in relation to respiratory and peripheral skeletal muscle function in 72 COPD patients (mean (SD) forced expiratory volume in one second (FEV1) 53 (15) % predicted), who came to the lung function laboratory for routine lung function measurements. Patients were characterized by the degree of body weight loss and fat-free mass depletion. According to this definition, 14% of the group suffered from both loss of body weight and depletion of fat-free mass, whereas 7% had one of these conditions. We found that tissue depletion was concomitant with lower values for respiratory and peripheral skeletal muscle strength (46.0 (27.2) vs 77.1 (29.8) kg), and a significantly lower transfer coefficient for carbon monoxide (KCO 64.9 (16.2) vs 81.9 (24.5) % pred). Stratification by KCO (< 60% vs > 80%) also revealed significantly lower values for fat-free mass and higher values for intrathoracic gas volumes, total lung capacity (TLC) and residual volume (RV) in the group with a KCO < 60% pred. Analysis of covariance, taking fat-free mass as covariate, indicated an independent contribution of KCO on maximal inspiratory mouth pressure (PImax) but not on peripheral skeletal muscle strength. It is concluded that a substantial number of COPD out-patients suffer from nutritional depletion, preferentially affecting peripheral skeletal muscle function.
Asthma-related symptoms and lung function in primary school children.
The aim of the present study was to determine the prevalence of asthma-related symptoms in a group of primary school children, by means of a questionnaire completed by their parents, and their lung function using spirometry and the forced oscillation technique (FOT). Also investigated were diagnostic labeling and medical prescription. We approached 535 children, from two primary schools in Maastricht, the Netherlands. Completed questionnaires were received from 482 children (90%). Valid lung function values were obtained in 470 of these children (98%). The lifetime prevalence of wheeze and attacks of shortness of breath with wheeze was 29% and 19%, respectively. The period prevalence of wheeze was 15%, 13% reported chronic cough, and 10% attacks of shortness of breath with wheeze. The doctor-diagnosed asthma and bronchitis prevalence was 6% and 19%, respectively. Of the children diagnosed as having asthma, 69% used antiasthma medication; none of the children diagnosed as having bronchitis used antiasthma medication. A symptom-based asthma prevalence of 11% was calculated. Statistically significant differences in spirometric and FOT indices were found between the children with and without complaints. In conclusion, among the 482 investigated children a relatively high prevalence of unrecognized or misclassified, and therefore undertreated, asthma-related symptoms was found. These observations were confirmed by the lung function data, in that we found significant differences in spirometric and FOT indices between children with and without complaints.
Forced oscillation technique and spirometry in cold air provocation tests.
BACKGROUND: Impedance measurements by the forced pseudo random noise oscillation technique can be used to study the mechanical characteristics of the respiratory system. The objective of this study was to analyse the changes in impedance to a cold air provocation test in patients with asthma, and to correlate these changes with those in the forced expiratory volume in one second (FEV1). METHODS: The response to isocapnic hyperventilation with cold air was assessed by respiratory impedance measurements and spirometry in 60 patients with bronchial asthma in whom the provocative dose of histamine resulting in a 20% fall in FEV1 (PD20) was < or = 8 mumol. RESULTS: Cold air provocation resulted in a mean(SD) fall in FEV1 from 3.75(0.85) litres to 3.10(0.90) litres. The mean(SD) decrease in FEV1 as a percentage of predicted was 15.4(3.8)%. The oscillatory resistance at 8 Hz increased from a mean(SD) of 0.367(0.108) kPa/l/s to 0.613(0.213) kPa/l/s and at 28 Hz the resistance increased from 0.348(0.089) to 0.403(0.099) kPa/l/s. Frequency dependence of resistance became significantly more negative. The reactance at 8 Hz decreased from a mean(SD) of -0.035 (0.041) kPa/l/s to -0.234(0.199) kPa/l/s, and the resonant frequency increased from 12.5(4.9) Hz to 25.7(9.1) Hz. Significant correlations were calculated between the decrease in FEV1 and changes in the various impedance parameters, especially between the decrease in FEV1 and the increase in resistance at 8 Hz (r = -0.66), and the decrease in FEV1 and the increase in the resonant frequency (r = -0.63). CONCLUSION: Cold air provocation in asthmatic subjects results in changes in the impedance of the respiratory system that correlate well with the changes in FEV1. These changes in impedance reflect ventilatory inhomogeneities in the peripheral compartment of the bronchial tree. These observations show the value of this technique in the evaluation of induced bronchoconstriction, as both a quantitative and a qualitative analysis of the response is possible.
Postoperative pulmonary function abnormalities after coronary artery bypass surgery.
In 18 patients, postoperative effects of coronary bypass surgery were evaluated. Pulmonary function studies were conducted preoperatively, and 1 and 6 weeks postoperatively, by means of spirometry, respiratory pressures, body plethysmography and impedance measurement of the respiratory system using the forced oscillation technique. One week postoperatively, total lung capacity (P less than 0.0001), inspiratory vital capacity (P less than 0.0001) forced expiratory volume (P less than 0.0001) and functional residual capacity (P less than 0.01) decreased significantly, while residual volume remained unchanged. This restrictive respiratory impairment was accompanied by significant decreases in inspiratory (P less than 0.0001) and expiratory (P less than 0.01) mouth pressures and significant decreases in respiratory resistance values (P less than 0.01). Six weeks postoperatively, significant differences in total lung capacity (P less than 0.0001), inspiratory vital capacity (P less than 0.0001) and forced expiratory volume (P less than 0.0001) persisted, while respiratory pressures returned to the preoperative values. It is concluded that respiratory muscle weakness contributes to the immediate postoperative restrictive lung function loss. Furthermore, structural alterations of chest wall mechanics have to be supposed for the persisting late restrictive pulmonary impairment.
Analysis of respiratory impedance characteristics in chronic bronchitis.
Impedance measurements of the respiratory system were performed by means of the technique of forced oscillations to study the mechanical characteristics of the respiratory system in 33 patients with chronic bronchitis without spirometric evidence of airway obstruction (FEV1 greater than or equal to 70% predicted). In 23 patients (69.7%) impedance was found to be abnormal. Inhalation of a beta 2-adrenergic drug (terbutaline) resulted in acute reversibility of these findings. In the 10 patients (30.3%) with a normal baseline respiratory impedance, isocapnic hyperventilation with cold air resulted in impedance characteristics similar to the abnormalities spontaneously occurring in the other group. These changes were found to be completely reversible after the inhalation of terbutaline. On the basis of these findings we conclude that impedance measurements of the respiratory system by means of the technique of forced oscillations allow the determination of mechanical airway abnormalities in patients with chronic bronchitis.
Respiratory impedance measurements in a dose-response study of isocapnic hyperventilation with cold air.
Spirometry and impedance of the respiratory system were compared after increasing rates of isocapnic cold air hyperventilation (IHCA) in 10 asthmatics and 11 healthy nonsmokers. In the control group IHCA at 60% of indirect maximum breathing capacity (IMBC) resulted in a significant, equal increase in resistance at lower and higher frequencies, suggesting central airway constriction. In the asthmatics negative frequency dependence of resistance and a significant increase in resonant frequency and decrease in the reactance at 8 Hz were found at 40 and 60% IMBC. These changes suggest an increase in the resistance of the peripheral airways. The frequency dependence of resistance and resonant frequency were found to be the most sensitive measures to differentiate between normals and asthmatics. It is concluded that impedance measurements provide a suited method to assess the response in cold air provocation tests.
Inhaled budesonide in chronic bronchitis. Effects on respiratory impedance.
In a placebo controlled study the effects of 6 weeks' treatment with inhaled budesonide (1.6 mg daily) on the impedance of the respiratory system, spirometry and symptom scores were evaluated in 35 patients with chronic bronchitis with forced expiratory volume in one second (FEV1) greater than or equal to 70% predicted. Thirty patients completed the study. No statistically significant differences in the changes in morning peak expiratory flow rate (PEFR), symptom scores, use of terbutaline rescue medication and FEV1 were found between the placebo and the active treatment group. Budesonide treatment was found to result in a small decrease in resonant frequency and a less negative frequency dependence of resistance compared with the placebo group.
Dose effects of inhaled ipratropium bromide on the impedance of the respiratory system in normal subjects.
The influence of cholinergic receptor blockade on the impedance of the respiratory system was studied in 10 healthy volunteers in a frequency spectrum between 4 and 52 Hz by means of the forced pseudo random-noise oscillation technique. Ipratropium bromide was used in the inhaled form in two doses (0.040 and 0.200 mg). Both does caused a significant decrease in oscillatory airway resistance, Rrs. No dose effect on Rrs was found. Both doses caused an increase in the reactance of the respiratory system, Xrs. This increase in Xrs was significantly greater after the inhalation of the higher dose. The effect of both doses on the real part of impedance can be explained by a dilation of the central airways. Furthermore, inhaled ipratropium bromide, especially in the higher dose, led to an increase in the imaginary part of impedance suggesting a decrease in the capacitance of pulmonary structures in normal subjects.