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Biomedical subjects

R Gosselink

Publications and source records attributed to R Gosselink.

9 recordsLinked to original sources
PubMed1999

Respiratory muscle involvement in multiple sclerosis.

Respiratory complications are common in the terminal stages of multiple sclerosis and contribute to mortality in these patients. When respiratory motor pathways are involved, respiratory muscle weakness frequently occurs. Although it is well established that weakness of the respiratory muscles produces a restrictive ventilatory defect, the degree of muscle weakness and pulmonary function are poorly related. Respiratory muscle weakness was observed in patients with normal or near normal pulmonary function. Expiratory muscle weakness is more prominent than inspiratory muscle weakness and may impair performance of coughing. Subsequently, in addition to bulbar dysfunction, respiratory muscle weakness may contribute to ineffective coughing, pneumonia, and sometimes even acute ventilatory failure may ensue. Respiratory muscle weakness may also occur early in the course of the disease. Recent studies suggest that the respiratory muscles can be trained for both strength and endurance in multiple sclerosis patients. Whether respiratory muscle training delays the development of respiratory dysfunction and subsequently improves exercise capacity and cough efficacy, prevents pulmonary complications or prolongs survival in the long-term remains to be determined.

Humans↗
PubMed1998

Low load inspiratory muscle training increases diaphragmatic fiber dimensions in rats.

The effects of 8 wk of inspiratory resistive loading (30 min/d, 3 x/wk) on diaphragm mass, contractile properties, fatigue, and fiber dimensions were studied in 10 male Wistar rats. They were conditioned to breathe through a Hans-Rudolph device. Half of them had to overcome a moderate inspiratory resistance (MR; n = 5), whereas the others only had to overcome the small resistance (SR; n = 5) of the inspiratory valve of the device. Results were compared with control rats (C; n = 5) moving and breathing freely. At the end of training, animals submitted to MR and SR generated mean inspiratory pressures of -2.5 +/- 1.1 and -0.2 +/- 0.05 cm H2O, respectively. TI/Ttot was 0.60 +/- 0.06 and 0.57 +/- 0.05, respectively. Body and diaphragm weight were unaffected by loading. Little or no change in in vitro diaphragmatic twitch kinetics, force generation, and fatigability was found between the three groups. Nevertheless, cross-sectional area of all fiber types increased in the two loaded groups compared with control animals. This increase reached statistical significance for type I fibers in the MR group (846 +/- 74 microm2) compared with the C and SR groups (589 +/- 32 and 683 +/- 96 microm2, respectively, p < 0.05). For IIa fibers both training groups were significantly different from the control group (SR: 768 +/- 99 and MR: 790 +/- 108 versus C: 592 +/- 37 microm2, p < 0.05). A hypertrophy of type IIx/b fibers was seen in MR compared with control animals (C: 1,555 +/- 136, SR: 1,845 +/- 338, MR: 2,053 +/- 326 microm2, p < 0.05). No differences were present in fiber type proportions between the three groups. We conclude that in our training setup, 8 wk of intermittent long-term inspiratory loading stressed the diaphragm already with a small resistance resulting in hypertrophy of predominantly type IIa fibers. A higher resistance resulted in hypertrophy of all fiber types.

Animals↗
PubMed1998

Peripheral skeletal muscles and exercise performance in patients with chronic obstructive pulmonary disease.

Impaired exercise capacity is a common finding in chronic obstructive pulmonary disease (COPD) patients. This reduction is not a simple consequence of airflow limitation. Peripheral muscle weakness, deconditioning and impaired gas exchange, were recognized as important contributors to exercise intolerance. In this overview, the contribution of peripheral muscle function and muscle training to exercise performance is discussed by means of three questions: 1) Is peripheral muscle dysfunction contributing to exercise limitation in COPD? 2) How do we measure peripheral muscle function? 3) Are peripheral muscle training modalities effective? At present, there is substantial evidence for peripheral muscle dysfunction. Both reduced force generating capacity as well as impaired muscle metabolism were observed and these findings contributed substantially to the reduced exercise capacity in COPD. Peripheral muscle strength measurements are feasible with mechanical or electronic devices and revealed muscle weakness in COPD patients. However, this weakness is not uniform for all muscle groups. Upper arm and leg muscles were more affected than hand muscles. This may, at least in part, be related to differences in the levels of inactivity between leg and hand muscles. In addition, muscle weakness is associated with impaired exercise capacity and symptoms of increased exertion during exercise. Endurance exercise training, i.e. cycling and treadmill walking, improved exercise capacity and was associated with alterations in muscle metabolism. Strength training of peripheral muscles showed increases in submaximal exercise performance and quality of life measures. These improvements were observed independently of the degree of airflow obstruction. The optimal training regimen (strength or endurance), and the muscle groups to be trained, remain to be determined.

Exercise↗
PubMed1997

Intermittent inspiratory muscle training induces fiber hypertrophy in rat diaphragm.

The effects of 8 wk of moderate load intermittent inspiratory resistive loading on diaphragm contractility, and histochemistry of the diaphragm, scalenes, and gastrocnemius were studied in rats. A resistance was placed in the inspiratory port of a Hans-Rudolph valve, through which each animal breathed during 30 min/d, 5 times/wk (loaded group, n = 10). These rats were compared with animals breathing through the same device without inspiratory resistance (control group, n = 10). During loading, animals generated mean inspiratory pressures of -3.2 +/- 1.7 cm H2O with a TI/Ttot of 0.69 +/- 0.06, resulting in a tension-time index of 0.050. At the end of training, the diaphragm mass increased in loaded animals (0.17 +/- 0.01% body mass) compared with control animals (0.15 +/- 0.01%, p < 0.01), while scalene and gastrocnemius mass remained unchanged. Diaphragmatic force as well as fatigue resistance were similar in both groups, whereas time to peak tension was significantly (p < 0.01) shorter in loaded rats (18.8 +/- 1.7 ms) compared with control rats (21.2 +/- 1.8 ms), half-relaxation time remaining unchanged. Finally, hypertrophy of diaphragmatic type IIa (+19%, p < 0.01) and IIx/b (+12%, p < 0.05) was present in the loaded group. Histochemistry of the scalenes remained unchanged, whereas type IIx/b hypertrophy (+12%, p < 0.001) was observed in the gastrocnemius internus. We speculate that the latter was due to multiple escape maneuvers. We conclude that intermittent inspiratory muscle training: (1) caused fast twitch fiber hypertrophy in the diaphragm; (2) did not produce any effect in the scalenes.

Adaptation, Physiological↗
PubMed1997

Muscle weakness is related to utilization of health care resources in COPD patients.

The factors determining utilization of health care resources in patients with chronic obstructive pulmonary disease (COPD) are poorly understood. In order to obtain insight into these factors, we studied the utilization of health care resources in 57 stable COPD patients with a forced expiratory volume in one second (FEV1) of 36 +/- 9% predicted. Patients were divided into two groups: admitted at least twice in the last year (high medical consumption; n = 23) or not admitted in the last year (low medical consumption; n = 34). Other variables related to utilization of health care resources studied were; the number of hospital days; the number of out-patient visits to a pulmonary department in the last year; and the average daily dose (ADD) of corticosteroids taken in the last 6 months. The actual cost of utilization of health care resources, however, was not studied. In addition, pulmonary function, serum electrolytes, blood gas values, 6 min walking distance, respiratory and peripheral muscle force, and appraisal of self-care agency (ASA score) were studied. Pulmonary function, serum electrolytes, blood gas values, ASA score and walking distance were not different between the two groups (e.g. FEV1 36 +/- 8 vs 36 +/- 10% pred). Respiratory muscle forces tended to be lower in the high medical consumption group, this tendency almost reaching statistical significance for maximal expiratory pressure (PE,max) (p = 0.08). Peripheral muscle force, however, was clearly reduced in the high medical consumption group (quadriceps force 63 +/- 20 vs 82 +/- 26% pred; p < 0.05). The number of admissions, the number of hospital days, the number of out-patient visits, and ADD were interrelated and also related to ventilatory and peripheral muscle force (r -0.18 to -0.38). This relationship was statistically significant for PE,max, whilst a similar tendency was present for maximal inspiratory pressure (PI,max). In stepwise multiple regression analysis, only quadriceps force was a significant determinant of utilization of health care services. We conclude that utilization of health care services in patients with chronic obstructive pulmonary disease is related to ventilatory and peripheral muscle force. Whether or not reduced muscle force is simply an expression of disease severity remains to be determined.

Activities of Daily Living↗
PubMed1997

Exercise training in COPD patients: the basic questions.

Pulmonary rehabilitation programmes aim at improving exercise capacity, activities of daily living, quality of life and perhaps survival in patients with chronic obstructive pulmonary disease (COPD). Recently, well-designed studies investigated and confirmed the efficacy of comprehensive pulmonary rehabilitation programmes, including exercise training, breathing exercises, optimal medical treatment, psychosocial support and health education. In the present overview, the contribution of exercise training in clinical practice to the demonstrated effects of pulmonary rehabilitation is discussed by means of six basic questions. These include: 1) the significance of exercise training; 2) the optimal intensity for exercise training; 3) prescribing training modalities; 4) the effects of exercise training combined with medication, nutrition or oxygen; 5) how training effects should be maintained; and 6) where the rehabilitation programme should be performed: in-patient, out-patient or homecare? First, exercise training has been proven to be an essential component of pulmonary rehabilitation. Training intensity is of key importance. High-intensity training (>70% maximal workload) is feasible even in patients with more advanced COPD. In addition, the effects on peripheral muscle function and ventilatory adaptations are superior to low-intensity training. There is, however, no consensus on the optimal training modalities. Both walking and cycling improved exercise performance. Since peripheral muscle function has been recognized as an important contributor to exercise performance, specific peripheral muscle training recently gained interest. Improved submaximal exercise performance and increased quality of life were found after muscle training. The optimal training regimen (strength or endurance) and the muscle groups to be trained, remain to be determined. Training of respiratory muscles is recommended in patients with ventilatory limitation during exercise. The additional effects of anabolic-androgenic drugs, oxygen and nutrition are not well-established in COPD patients and need further research. In order to maintain training effects, close attention of the rehabilitation team is required. The continuous training frequency necessary to maintain training effects remains to be defined. At this point in time, out-patient-based programmes show the best results and guarantee the best supervision and a multidisciplinary approach. Future research should focus on the role of homecare programmes to maintain improvements.

Exercise↗
PubMed1996

Reliability of a commercially available threshold loading device in healthy subjects and in patients with chronic obstructive pulmonary disease.

BACKGROUND: Threshold loading with the Nickerson and Keens' device is frequently applied in the training and assessment of inspiratory muscles. However, this equipment is not easily applied in clinical practice and training. A study was therefore designed to investigate the accuracy and reliability of the Threshold, a commercially available threshold loading device. METHODS: The resolution (accuracy) of the system was determined by measuring variation of pressure and flow during one minute in an experimental setup. The reproducibility and flow independence were then determined during threshold loading at six different inspiratory loads between 25% and 50% maximal inspiratory pressure (PImax) in 10 patients with chronic obstructive pulmonary disease (COPD) and eight healthy subjects. RESULTS: In the first experiment the mean variation of the sustained pressure for all loads was 1.7%. The mean coefficients of variation for pressure and flow measurements were 0.2% and 3%, respectively. In the second experiment the healthy subjects showed mean coefficients of variation for pressure and flow of 0.8% and 20.5%, respectively, and the patients showed mean coefficients of variation of 0.6% and 14.5%, respectively. CONCLUSIONS: During the in vitro experiment as well as during the experiments in patients with COPD and in healthy subjects only small variations in pressure were observed despite large variations in flow. The Threshold is a reliable and reproducible device for loading inspiratory muscles in patients with COPD as well as in healthy subjects.

Aged↗
PubMed1996

Peripheral muscle weakness contributes to exercise limitation in COPD.

Recently, it was suggested that fatigue of peripheral muscles could contribute to exercise limitation in patients with chronic obstructive pulmonary disease (COPD). In order to quantify the role of peripheral muscle force, we restudied potential determinants of exercise capacity (6-min walking distance [6 MWD] and maximal oxygen consumption [V02max]) in 41 consecutive COPD patients (FEV1, 43 +/- 19% of predicted, TLCO, 56 +/- 25% of predicted) admitted to our pulmonary rehabilitation program. VO2max (incremental cycle ergometer test), 6 MWD (best of three), lung function (FEV1, FVC, TLC, FRC), diffusing capacity (TLCO), isometric quadriceps force (QF), hand grip force (HF), and maximal inspiratory (PImax) and expiratory (PEmax) pressures were measured. Patients had a poor 6 MWD (372 +/- 136 m) and VO2max (1.35 +/- 0.60 L, 71%), reduced respiratory (PImax 65 +/- 27%) and peripheral muscle force (QF 74 +/- 27%, HF 82 +/- 23%). In single regression analysis, significant correlations (r) were found for VO2max and TLCO (0.68), FEV1 (0.64), QF (0.55), HF (0.53), and body weight (0.49). Walking distance was significantly correlated with QF (0.63), HF (0.61), PImax (0.49), and TLCO (0.38). In stepwise multiple regression analysis, the variables significantly contributing to 6 MWD were QF and Plmax. For VO2max, variables significantly contributing were TLCO, QF, and FEV1. We conclude that lung function and peripheral muscle force are important determinants of exercise capacity in COPD.

Body Weight↗