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Biomedical subjects

H T Folgering

Publications and source records attributed to H T Folgering.

At least 73 records · Page 4Linked to original sources
PubMed1994

Exercise cardiorespiratory function before and one year after operation for pectus excavatum.

In 35 patients with pectus excavatum (aged 17.9 +/- 5.6 years) pulmonary function and maximal exercise test results were compared before and at 1 year after operation. The lower posteroanterior chest diameter on the lateral x-ray film was significantly smaller than normal (p < 0.0001) and increased significantly after operation (p < 0.0001). Preoperatively, total lung capacity (86.0% +/- 14.4%; p = 0.0001) and inspiratory vital capacity (79.7% +/- 16.2; p = 0.0001) were significantly smaller than predicted and further decreased after operation (-9.2% +/- 9.2%; p = 0.0001 and -6.6% +/- 10.7%; p = 0.0012, respectively). Arterial blood gas values displayed normal patterns with increasing exercise both before and after operation. Only the arterial pH decreased more after operation than before (p = 0.0026). After operation there was a significant increase in maximal oxygen uptake (oxygen uptake; p = 0.0002 and oxygen uptake per kilogram; p = 0.0025) and oxygen pulse (oxygen uptake/heart rate approximates an indirect parameter for stroke volume; p = 0.0333) during exercise, whereas the maximal work performed was unchanged. Efficiency of breathing (ratio of tidal volume/inspiratory vital capacity) at maximal exercise improved significantly after operation (p = 0.0005). Ventilatory limitation of exercise (defined by an increase in carbon dioxide tension during exercise) was found in 43.9% of the patients before operation. A tendency of improvement was noted (not significant) after operation (difference in carbon dioxide tension 0.6 +/- 0.4 kPa before versus 0.3 +/- 0.5 kPa after operation). However, the group with normal preoperative carbon dioxide elimination had a ventilatory limitation of exercise after operation (difference in carbon dioxide tension -0.4 +/- 0.3 kPa before versus -0.1 +/- 0.3 kPa after operation; p = 0.0128) with a significant increase in oxygen consumption (p = 0.0007). In conclusion the subjective physical improvement after operation is not explained by changes in cardiorespiratory function at exercise. The data suggest a higher work of breathing after operation.

Adolescent↗
PubMed1993

Tonic activity in inspiratory muscles during continuous negative airway pressure.

We studied tonic inspiratory activity (TIA) induced by continuous negative airway pressure (CNAP) in anaesthetized, spontaneously breathing cats. TIA in the diaphragm and parasternal intercostal muscles (ICM) was quantified in response to tracheal pressure (PTR) = -0.3 to -1.2 kPa. To differentiate between reflexes from rapidly adapting receptors (RARs), slowly adapting receptors (SARs) and C-fiber endings different temperatures of the vagus nerves (TVG) were used between 4 and 37 degrees C. At PTR = -1.2 kPa mean TIA values were 41% and 62% of peak inspiratory EMG activity of control breaths for the diaphragm and ICM, respectively. After vagotomy and for TVG < 6 degrees C CNAP did not induce TIA anymore. Changes in inspiratory and expiratory time during vagal cooling down to 4 degrees C confirmed the selective block of conductance in vagal afferents of the three types of lung receptors. We conclude that CNAP-induced TIA results from stimulation of RARs. Our data strongly indicate that stimulation of SARs suppresses TIA, whereas C-fiber endings are not involved in TIA at all. The results suggest that part of the hyperinflation in bronchial asthma may be caused by TIA in response to mechanical stimulation of RARs.

Airway Resistance↗
PubMed1993

Nocturnal end-tidal PCO2 to detect apnoeas and hypopnoeas in sleep-disordered breathing.

In this study, the end-tidal PCO2 (PETCO2) during the night was measured. The PETCO2 signal was obtained by introducing a cannula through the nose into the nasopharyngeal cavity. The usefulness of this method to identify nocturnal hypoventilation was studied in 29 patients with chronic obstructive pulmonary disease (COPD) with and without oxygen supplementation. The results showed that 27 patients with COPD developed 67 nocturnal oxygen desaturations which were all accompanied by raised PETCO2. During oxygen therapy in all COPD patients nocturnal episodes with increased PETCO2 occurred. Furthermore, the detection of nocturnal apnoeas and hypopnoeas was assessed in 19 subjects who were referred to the sleep laboratory for snoring and daytime sleepiness. In this group episodes of disordered breathing could easily be assessed. The PETCO2 signal was especially useful to identify hypopnoeas that were accompanied by only small dips in SaO2 (< 3%). It is concluded that PETCO2 measurement is useful in the detection of hypoventilation during sleep in COPD patients, especially when they receive supplemental oxygen. PETCO2 recording detects obstructive apnoeas and hypopnoeas and is especially helpful to identify hypopnoeas which are accompanied by only small dips in oxygen saturation.

Adult↗
PubMed1993

Differences between sniff mouth pressures and static maximal inspiratory mouth pressures.

Measurements of static maximal inspiratory mouth pressure (PImax) and dynamic sniff mouth pressure (Psniff) are frequently used to assess inspiratory muscle strength. The aim of the present study was to examine, in 42 healthy subjects, the equivalence of PImax and Psniff, the influence of body posture on PImax and Psniff, and the effects of nasal patency and repeated manoeuvres on Psniff. PImax was significantly higher than Psniff, 11.05 +/- 0.42 versus 8.53 +/- 0.31 kPa. Because of the low agreement between PImax and Psniff, the two measurement methods were not interchangeable. The limits of agreement were 2.56 +/- 3.92 kPa. Sitting PImax was 11.05 +/- 0.42 kPa, and supine PImax was 9.36 +/- 0.41 kPa. Sitting and supine Psniff were 8.53 +/- 0.31 kPa and 7.52 +/- 0.33 kPa, respectively. Psniff performed with one nostril open instead of two, was higher: 9.67 +/- 0.32 kPa left and 9.62 +/- 0.32 kPa right versus 8.53 +/- 0.31 kPa when both nostrils were open. After 20-28 sniff manoeuvres, Psniff fell from 8.43 +/- 0.31 kPa to 7.83 +/- 0.30 kPa, suggesting some mechanism of inspiratory muscle fatigue. We conclude that measurement of sitting PImax yields the highest values for inspiratory muscle strength. The two measurement methods, Psniff and PImax, are not interchangeable. Measurement of Psniff is affected by nasal patency.

Adult↗
PubMed1992

[Lung function of adult patients with bronchial asthma or chronic obstructive lung disease prior to and following a 3-month-stay in the Dutch Asthma Center in Davos].

The effect of a multidisciplinary treatment for obstructive airway disease at high altitude has not been well established for adult patients. One hundred and fifty patients with obstructive airway disease were examined at admission and at discharge after a 3-month hospitalization period in an Alpine clinic. Body plethysmographic data were collected at admission and at discharge as was medication use. Patients were subdivided into three groups, one group (n = 34) with bronchial asthma, one group (n = 97) with moderately severe chronic obstructive pulmonary disease (COPD) and one group (n = 19) with severe COPD. The greatest improvement in lung function data occurred in the moderately severe COPD group (at discharge before salbutamol administration there was an increase in FEV1 of 6%, after salbutamol administration there was an increase in FEV1 of 7%). When we divided the patient groups into atopic and non-atopic, it appeared that the non-atopic moderately severe COPD group showed the greatest improvement in lung function variables. The histamine threshold (expressed in 10logPC20) improved only in the moderately severe COPD group. There was a reduction from mean 7.5 mg per day in oral corticosteroids use to mean 5.0 mg per day in the moderately severe COPD group. We conclude that after 3 months' multidisciplinary treatment in the Alpine climate there is an improvement in lung function and a reduction in medication use in patients with airflow limitation.

Albuterol↗
PubMed1992

Pectus excavatum. A clinical study with long-term postoperative follow-up.

Between 1972 and 1987, 192 patients have been operated upon for pectus excavatum of which 152 patients were included in the study (79%). Mean age at operation was 15.3 +/- 5.5 years; 117 were male. Mean follow-up was 8.1 +/- 3.6 years. The deformity was noted before the age of 5 in 90%. Type I symmetrical and localized deformity was seen in 33.2%, type II symmetrical but diffuse depression in 23.7% and type III localized or diffuse asymmetrical deformity in 43.1%. It was considered severe in 68.9%, fair in 16.9% and mild in 14.2%. There were significantly more asymmetrical defects in the older age groups. The operation consisted of subperichondral chondrectomy, transverse sternotomy and division of the intercostal bundles at the outer limit of the chondrectomy and suturing the edge of this broad sheet of muscle and perichondrium to the anterior surface of the chest wall more laterally and under tension, elevating and stabilizing the sternum. Results were satisfactory in 83.6% (excellent 44.1%, good 39.5%). Results were not significantly influenced by age, sex, severity, type, symmetry, the extent of cartilage resection or follow-up. Results were inversely influenced by the occurrence of wound problems. The optimal age for operation is considered to be between 5 and 10 years. Both physical as well as psychological cosmetic factors may serve as an indication for operation.

Adolescent↗
PubMed1991

[Mushroom growers' lung; clinical diagnosis and treatment].

The objective of this study was to give a description of the clinical picture, diagnosis and treatment in 19 patients with mushroom grower's lung. Of these patients, six worked at mushroom compost manufacturing, seven were traced by means of a nationwide enquiry among mushroom growers and six were referred by GPs. The following factors were measured after provocation at the worksite: pulmonary function, blood gas values, leukocyte count and body temperature. On the day of the provocation and on a control day chest X-rays were made. The most frequent complaints were dyspnoea and fever (in 15 and 13 patients, respectively). Serological tests in 16 of the 19 patients revealed antibodies against various fungi that occur in locations where mushroom compost is handled. Six to 12 hours after the provocation, all patients showed a rise of the mean body temperature from 37.1 to 38.4 degrees C; the mean leukocyte count rose from 7.7 to 17.0 X 10(9)/l. Lung function studies revealed restrictive disorders: the mean VC fell from 5.15 to 4.50 l, the TLC from 6.80 to 6.18 l. The differences, tested with Wilcoxon's two-sample test were significant (p less than 0.001). Roentgenological abnormalities were seen in two patients (reticular lung image). Treatment consisted of preventive measures, such as improved air conditioning at the worksite, wearing masks, wetting the compost to keep it from flying about, and supplying pretreated compost requiring no personal preparation.

Adult↗
PubMed1991

Effects of hypercapnia and hypocapnia on respiratory resistance in normal and asthmatic subjects.

The effects of hypercapnia and hypocapnia on respiratory resistance were studied in 15 healthy subjects and 30 asthmatic subjects. Respiratory resistance (impedance) was measured with the pseudo-random noise forced oscillation technique while the subjects rebreathed from a wet spirometer in a closed respiratory circuit in which end tidal carbon dioxide tension (PCO2) could be controlled. Hypercapnia was induced by partially short circuiting the carbon dioxide absorber, and hypocapnia by voluntary hyperventilation. The circulating air was saturated with water vapour and kept at body temperature and ambient pressure. A rise of end tidal PCO2 of 1 kPa caused a significant fall in respiratory resistance in both normal and asthmatic subjects (15% and 9% respectively). A fall of PCO2 of 1 kPa did not cause any significant change in impedance in the control group. In the asthmatic patients resistance increased by 13%, reactance fell by 45%, and the frequency dependence of resistance rose 240%. These findings confirm that hypocapnia may contribute to airway obstruction in asthmatic patients, even when water and heat loss are prevented.

Adult↗
PubMed1991

Target-flow inspiratory muscle training during pulmonary rehabilitation in patients with COPD.

The effects of additional target-flow inspiratory muscle training (TF-IMT) on the performance of the inspiratory muscles, on general exercise capacity, and on psychologic parameters during a pulmonary rehabilitation program (PR) were studied in 40 patients with COPD selected for ventilatory limitation during exercise. The mean age of the patients was 59 years, and the mean FEV1 was approximately 50 percent of predicted. All patients participated in a ten-week PR program. They were randomized to receive either additional TF-IMT (PR + IMT) or not (PR). The TF-IMT was performed by means of a target-flow resistive device; the generated mouth pressure and the duration of inspiration and of the respiratory cycle were imposed. After the training period, maximal inspiratory mouth pressure and EMG-fatigability of the diaphragm were significantly better in the PR + IMT group than in the PR group. Maximal work load and psychologic symptoms increased to the same extent in both groups. The 12-minute walking distance also increased in both groups, but it increased significantly more in the PR + IMT group than in the PR group. We believe that additional TF-IMT during PR in a selected group of patients with COPD who have ventilatory limitation has an extra beneficial effect on the performance of the inspiratory muscles and on exercise performance.

Activities of Daily Living↗
PubMed1991

Target-flow inspiratory muscle training: breathing patterns and metabolic costs.

In target-flow inspiratory muscle training (TF-IMT), the generated inspiratory mouth pressure and the duration of the inspiration and expiration are standardized to given an adequate training stimulus to the inspiratory muscles. The acute effects of TF-IMT on the efficiency of breathing were studied in a group of 12 COPD patients with a ventilatory limitation of their exercise capacity (mean age 58, mean FEV1 46.2% of predicted) and in 15 normal subjects (mean age 30). Also, the effect of a 10 week period of TF-IMT on the maximal inspiratory mouth pressure (PImax) in the COPD patients was measured. After an unloaded baseline period, the subjects started to inspire through a target-flow device during 15 min, followed by a recovery phase of 5 min. During TF-IMT minute ventilation (VE) decreased only in the COPD group. The ventilatory equivalent for O2 (VE/VO2) and the dead space to tidal volume ratio (VD/VT) decreased in both groups. During recovery, VE, VE/VO2 and VD/VT remained below baseline values in the COPD group, but not in the control group. PCO2 and lactate concentrations did not change during TF-IMT. After the 10 week training period, PImax [means) (SD] increased from 5.7(2.2) to 8.2(2.7) kPa (p less than 0.05). The results indicate that with standardized TF-IMT, the inspiratory muscles can be trained effectively in COPD patients with a ventilatory limitation. The persistence of the decrease in VE, VE/VO2 and VD/VT after a training session may be an additional beneficial effect of TF-IMT.

Adult↗
PubMed1991

Provocation tests in extrinsic allergic alveolitis in mushroom workers.

The clinical diagnosis of extrinsic allergic alveolitis can be supported by a positive provocation test. Twenty-eight common mushroom (Agaricus bisporus) workers, 4 oyster mushroom (Pleurotus ostreatus) workers and 6 Shii Take mushroom (Lentinus edodes) workers, whose medical history indicated a possible extrinsic allergic alveolitis, were examined. The provocation test consisted of a control day, an exposure day, and half a day of follow-up observation. On the control and exposure days, the body temperature, leucocyte count and lung function were measured every 2 h. The chest X-ray and arterial blood gas sample were taken once. The exposure consisted of a 1-h presence on the common mushroom farm in spawning conditions or inhaling a suspension of spores of Pleurotus or Shii-Take in the laboratory. Eighteen of the 28 people employed on the common mushroom farm, all 4 Pleurotus workers and 4 of the 6 Shii-Take workers were diagnosed as having extrinsic allergic alveolitis, according to the following criteria: a positive history and 2 or more of the following findings: increase in leucocyte count, rise in temperature and decrease in inspiratory vital capacity (IVC) and total lung capacity (TLC).

Adult↗
PubMed1990

Target-flow inspiratory muscle training at home and during pulmonary rehabilitation in COPD patients with a ventilatory limitation during exercise.

The effects of a 10-week inspiratory muscle training (IMT) program at home were compared to IMT during a 10-week pulmonary rehabilitation program (PR) in 40 COPD patients with a ventilatory limitation of the exercise capacity. IMT was performed with a target-flow resistive device; the generated mouth pressure as well as the duty cycle were imposed. The mean age of the patients was 59, the mean FEV1 was 48% of predicted. In the training period the inspiratory muscle strength improved in both groups to the same degree. EMG fatigability of the diaphragm improved in the PR+ IMT group, but not in the IMT group. In the IMT group, the 12-min walking distance increased after the training period, but maximal workload (Wmax), VO2,max, and ADL scores did not change. In the PR + IMT group, however, Wmax, VO2,max, walking distance, and ADL scores improved significantly after the training period. Walking distance and ADL scores showed a significantly greater improvement in the PR + IMT group than in the IMT group. It is concluded that both isolated IMT and PR + IMT in COPD patients with a ventilatory limitation have a beneficial effect on inspiratory muscle strength, but PR + IMT improves the physical exercise capacity significantly more than IMT alone.

Activities of Daily Living↗