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Biomedical subjects

H T Folgering

Publications and source records attributed to H T Folgering.

At least 19 recordsLinked to original sources
PubMed1995

Nocturnal saturation and respiratory muscle function in patients with chronic obstructive pulmonary disease.

BACKGROUND: Nocturnal desaturations, mainly caused by hypoventilation, occur frequently in patients with chronic obstructive pulmonary disease (COPD). Daytime arterial oxygen and carbon dioxide tensions (PaO2 and PaCO2) appear to predict which patients will desaturate at night. It is unknown if respiratory muscle strength, which may be decreased in these patients, plays an additional part. METHODS: Polysomnography, maximal respiratory pressures, lung function, and arterial blood gas tensions were measured in 34 patients with COPD (mean (SD) forced expiratory volume in one second (FEV1) 41.7 (19.9)% pred). RESULTS: Significant correlations were found between the mean nocturnal arterial oxygen saturation and maximal inspiratory mouth pressure (r = 0.65), maximal inspiratory transdiaphragmatic pressure (r = 0.53), FEV1 (r = 0.61), transfer coefficient (KCO) (r = 0.38), arterial oxygen saturation (SaO2) (r = 0.75), and PaCO2 (r = -0.44). Multiple regression analysis showed that 75% of the variance in nocturnal SaO2 (70%) and FEV1 (5%). CONCLUSION: Inspiratory muscle strength and nocturnal saturation data are correlated, but daytime SaO2 and FEV1 remain the most important predictors of nocturnal saturation.

Aged↗
PubMed1995

Predictors for nocturnal hypoxaemia (mean SaO2 < 90%) in normoxic and mildly hypoxic patients with COPD.

Detection of nocturnal hypoxaemia, defined as a mean arterial oxygen saturation below 90%, in normoxic or mildly hypoxic chronic obstructive pulmonary disease (COPD) patients seems clinically relevant, since this feature may precede pulmonary hypertension. Nocturnal studies are expensive and time-consuming procedures. The current study investigates to what extent it is possible to predict nocturnal hypoxaemia from daytime parameters. Forty two COPD patients with a daytime arterial oxygen tension (PaO2) above 8 kPa participated. Nocturnal oxygenation, daytime blood gas values, and ventilatory responses to hypercapnia were measured. In 10 patients, enough desaturations occurred to qualify as nocturnal hypoxaemia. They had a significantly lower daytime PaO2 value, and a lower steady-state hypercapnic ventilatory response. They also smoked more often, and complained about daytime sleepiness. Multiple linear regression analysis demonstrated that daytime PaO2 (32%) was the best independent predictor. Sleepiness (12%), and number of cigarettes smoked (5%) also contributed independently, but in a minor way. Patients with a high daytime PaO2 (> 11 kPa) did not develop nocturnal hypoxaemia. The hypercapnic ventilatory response was used to distinguish nocturnal hypoxaemic from normoxaemic patients. Only patients with a low response (< 3.5 l.min-1.kPa-1) appeared to run a risk of developing nocturnal hypoxaemia. The sensitivity of this test was 80%, and the specificity 70%. It is concluded that daytime PaO2, hypercapnic ventilatory response and sleepiness are helpful in predicting nocturnal hypoxaemia.

Aged↗
PubMed1994

Continuous negative airway pressure increases tonic activity in diaphragm and intercostal muscles in humans.

The main objective of the present study was to quantify the increase in tonic inspiratory activity (delta TIA) in response to continuous negative airway pressure (CNAP) in humans. TIA represents the activity in inspiratory muscles at the end of expiration. In 20 subjects, electromyograms (EMGs) were recorded from the diaphragm and parasternal intercostal muscles (ICM) with surface electrodes during control and at three different levels of CNAP (-0.3, -0.6, and -0.9 kPa; 1 kPa approximately 10 cmH2O). From these recordings we determined delta TIA and the amplitudes of phasic EMG activities (EMGphas) during CNAP and control. To evaluate the effects of CNAP on functional residual capacity (FRC), respiratory frequency, tidal volume, and minute ventilation, the subjects were connected to a closed breathing circuit. When the pressure at the airway opening was -0.9 kPa, mean values of delta TIA were 53 and 49% of control EMGphas for the diaphragm and ICM, respectively. In addition, EMGphas at airway opening pressure of -0.9 kPa had increased to 195 and 162% of control EMGphas for the diaphragm and ICM, respectively. The concomitant decrease in FRC was on average 18.7% of predicted FRC. Minute ventilation had increased significantly (P < 0.05) at all levels of CNAP compared with control. We conclude that CNAP is a forceful stimulus to increase TIA in humans in both the diaphragm and the ICM.

Adolescent↗
PubMed1994

Effects of chlormadinone acetate, acetazolamide and oxygen on awake and asleep gas exchange in patients with chronic obstructive pulmonary disease (COPD).

The purpose of this study was to assess the short-term effects of chlormadinone acetate (CMA), a synthetic progestogen, acetazolamide (ACET) and oxygen on awake and asleep blood gas values. The study was conducted according to a randomized, double-blind and placebo-controlled design in 53 hypoxaemic patients with chronic obstructive pulmonary disease. On the first two consecutive nights, all patients received either room air or oxygen, via a nasal cannula, in random order. They then received either CMA (25 mg), ACET (250 mg) or placebo twice a day, all in identical capsules. On the third study night, after one week of drug treatment, the patients were tested breathing room air. CMA and ACET therapy decreased mean daytime arterial carbon dioxide tension (PaCO2) by 0.7 and 0.5 kPa, respectively, and night-time end-tidal carbon dioxide tension (PETCO2) by 0.5 and 0.3 kPa, respectively. Supplemental oxygen caused increased CO2 retention during the day and night (0.6 and 0.3 kPa, respectively. Daytime arterial oxygen tension (PaO2) increased to the same extent during ACET (1.9 kPa) and oxygen (2.5 kPa). Asleep oxygen saturation improved most with oxygen supplementation (7%), although ACET also caused significant improvement (4%). CMA administration had virtually no effect on mean awake and asleep hypoxaemia. ACET therapy significantly improved subjective sleep quality. On CMA, minute ventilation increased in association with an augmentation of the hypercapnic ventilatory response. ACET treatment increased both hypercapnic and hypoxic ventilatory responses. We conclude from the group of patients with COPD studied, that the short-term effects of ACET treatment on gas exchange compare favourably with those of CMA. Oxygen therapy improves oxygenation slightly more than ACET, but aggravates CO2 retention.

Acetazolamide↗
PubMed1994

Pulmonary rehabilitation at moderate altitude: a 1-year follow-up.

BACKGROUND: In order to evaluate a pulmonary rehabilitation program (PRP) at moderate altitude (1560 m) 62 patients with obstructive lung disease were asked to participate; 37 patients completed a 1-year follow-up at sea level, and 25 patients dropped out. The exercise training program lasted for 10 weeks and consisted of a cycling and running program of 20 min daily, 5 days a week. METHODS: Incremental exercise testing, spirometry and histamine provocation tests were performed at sea level before the PRP, on admission to the Dutch Asthma Centre, Davos, after 5 weeks of exercise training, at discharge from the Centre and 6 and 12 months after discharge at sea level. RESULTS: The PRP led to an increase in exercise capacity of the 37 patients who also completed the follow-up as reflected by an increase in Wmax (from 104 +/- 44 watt on admission to 150 +/- 8 at discharge, p < 0.001). HRmax (145 +/- 19/min to 151 +/- 21, p < 0.001), Wmax/HR (0.71 +/- 0.26 watt/beat/min to 0.99 +/- 0.29, p < 0.001), VO2max (1.4 +/- 0.4 l/min to 1.9 +/- 0.6, p < 0.001) and VEmax (49 +/- 18 l/min to 78 +/- 24, p < 0.001) measured at discharge from the Dutch Asthma Centre after the PRP were significantly higher than before the PRP at incremental exercise testing. The group of 25 patients who dropped out showed corresponding improvements in these parameters after the PRP in Davos. The 37 patients who completed the follow-up showed at incremental exercise testing 1 year after the PRP that only two of these parameters were still significantly elevated: VO2max 1.8 +/- 0.6 (p < 0.001) and VEmax 61 +/- 21 (p < 0.001). One year after the PRP arterial PCO2 values at maximum exercise were significantly lower (5.2 +/- 0.8 kPa, p < 0.05) than the baseline values (5.5 +/- 0.9 kPa). CONCLUSIONS: PRP at moderate altitude results in an increase of exercise tolerance in patients with asthma or COPD, but significant long-term effects are few.

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↗