Biomedical subjects

Hans Folgering

Publications and source records attributed to Hans Folgering.

7 recordsLinked to original sources

PubMed2005

Flow-volumes indices as means to discriminate between intra- and extrapulmonary restrictive disease.

Restrictive lung disease comes in two major categories: (1) intrapulmonary (= parenchymal) disease caused by fibrotic reactions or (2) extrapulmonary (= compression), like in heart failure. In the first category the conducting airways, tethered in stiffened structures, are less likely to be compressed during forceful expiration and expiratory flows hence are expected to remain high. This could serve as a cheap and easy diagnostic, avoiding more complicated measures. A database was build containing 624 patients suffering from either intra- and extrapulmonary disease. The flow-volume curve indices of restrictive patients (with a total lung capacity < -1.96 sd of reference) were compared and it was shown that in primary fibrotic disease and in leukaemia, indeed, the PEF and MEF(75/50/25) were significantly higher compared to the heart failure group (P < or = 0.001). The diabetes mellitus vs. heart failure differences were much less (P > 0.05). The area under the ROC to discriminate extra- from intrapulmonary disease was a low 0.607 and 0.606 for the PEF and MEF75, respectively. For the peakflow an optimal cut-off point was found at 65.8% of the reference value. The positive/negative predictive value of a peakflow < 65.8% to detect extrapulmonary disease was 30.1% and 82.2%, respectively.

Adult↗

PubMed2005

Impact of a maximal exercise test on symptoms and activity in chronic fatigue syndrome.

OBJECTIVE: This study examined the effects of exercise on symptoms and activity in chronic fatigue syndrome (CFS). METHODS: Twenty CFS patients and 20 neighborhood controls performed an incremental exercise test until exhaustion. Fatigue, muscle pain, minutes spent resting, and the level of physical activity were assessed with a self-observation list. Physical activity was assessed with an actometer as well. Data were obtained 3 days before the maximal exercise test (MET) up to 5 days thereafter. RESULTS: For CFS patients, daily observed fatigue was increased up to 2 days after the exercise test. For controls, self-observed fatigue returned to baseline after 2 h. Both CFS patients and controls spent more minutes resting on the day before and on the day after the MET. For CFS patients, self-observed minutes resting increased on the day of the exercise test. For neither group, a decrease of actometer recorded or self-observed physical activity after exercise was found. CONCLUSION: Fatigue in CFS patients increased after exercise, but the level of actual physical activity remained unchanged.

Adult↗

PubMed2003

Cerebrovascular response to acute metabolic acidosis in humans.

OBJECTIVES: Evaluation of the cerebrovascular response (delta CBV/delta PaCO2) during baseline metabolic conditions and acute metabolic acidosis. METHODS: 15 healthy subjects, 5 m, 10 f, 56 +/- 10 yrs were investigated. For acidification, NH4Cl was given orally. CBV was measured using Near Infrared Spectroscopy (OXYMON) during normo-, hyper- and hypocapnia. RESULTS: Acute metabolic acidosis was realised: mean delta BE -2.7 mEq.L-1 (p < 0.001) with mean delta PaCO2 -0.2 kPa (p < 0.01). During normo-, hyper- and hypocapnia, CBV values of 3.51, 4.82 and 2.55 mL.100 g-1 were calculated during baseline metabolic conditions and 3.70, 4.86 and 2.63 mL.100 g-1 during acute metabolic acidosis. The CBV/PaCO2 response showed a hockeystick configuration with the point of infliction around normocapnia. delta CBV/delta PaCO2 reactivity from normo- to hypercapnia and from normo- to hypocapnia was calculated; no significant differences in delta CBV/delta PaCO2 were found in both metabolic conditions. CONCLUSION: Cerebrovascular reactivity to CO2 does not alter during acute metabolic acidosis.

Acidosis↗

PubMed2003

Comparison of acetazolamide and medroxyprogesterone as respiratory stimulants in hypercapnic patients with COPD.

BACKGROUND: Acetazolamide and medroxyprogesterone acetate (MPA) are two respiratory stimulants that can be used in patients with stable hypercapnic COPD. DESIGN AND METHODS: The effects of acetazolamide, 250 mg bid, and MPA, 30 mg bid, on daytime and nighttime blood gas values and the influences on the hypercapnic and hypoxic ventilatory and mouth occlusion pressure (P(0.1)) at 100 ms response were studied in a crossover design in 12 hypercapnic patients with stable COPD (FEV(1), 33 +/- 4% predicted [mean +/- SEM]). RESULTS: Daytime PaCO(2) decreased from 47.3 +/- 0.8 mm Hg (placebo) to 42.0 +/- 1.5 mm Hg during acetazolamide treatment (p < 0.05) and to 42.8 +/- 1.5 mm Hg during MPA treatment (p < 0.05). Daytime PaO(2) improved with acetazolamide from 65.2 +/- 2.3 to 75.0 +/- 3.0 mm Hg (p < 0.05), whereas no significant changes were seen with MPA. Mean nocturnal end-tidal carbon dioxide tension decreased with both treatments, from 42.0 +/- 2.3 to 35.3 +/- 2.3 mm Hg with acetazolamide (p < 0.05) and to 34.5 +/- 0.8 mm Hg with MPA (p < 0.05). The percentage of time that the nocturnal arterial oxygen saturation was < 90% was reduced significantly with acetazolamide, from 34.9 +/- 10.7% to 16.3 +/- 7.5% (p < 0.05). Mean nocturnal saturation did not change with MPA. Resting minute ventilation increased significantly only with MPA from 9.6 +/- 0.7 to 10.8 +/- 0.8 L/min (p < 0.05). The slope of the hypercapnic ventilatory response did not change during acetazolamide and MPA therapy. The hypoxic ventilatory response increased from - 0.2 +/- 0.05 to - 0.4 +/- 0.1 L/min/% during acetazolamide (p < 0.05) and to - 0.3 +/- 0.1 L/min/% during MPA (p < 0.05). The hypoxic P(0.1) response improved with acetazolamide treatment from - 0.05 +/- 0.008 to - 0.15 +/- 0.02 mm Hg/% (p < 0.05). CONCLUSIONS: This study shows that acetazolamide and MPA both have favorable effects on daytime and nighttime blood gas parameters in ventilatory-limited patients with stable COPD. However, the use of acetazolamide is preferred because of its extra effect on nocturnal saturation.

Acetazolamide↗

PubMed2002

Guidelines for mechanical lung function measurements in psychophysiology.

Studies in psychophysiology and behavioral medicine have uncovered associations among psychological processes, behavior, and lung function. However, methodological issues specific to the measurement of mechanical lung function have rarely been discussed. This report presents an overview of the physiology, techniques, and experimental methods of mechanical lung function measurements relevant to this research context. Techniques to measure lung volumes, airflow, airway resistance, respiratory resistance, and airflow perception are introduced and discussed. Confounding factors such as ventilation, medication, environmental factors, physical activity, and instructional and experimenter effects are outlined, and issues specific to children and clinical groups are discussed. Recommendations are presented to increase the degree of standardization in the research application and publication of mechanical lung function measurements in psychophysiology.

Airway Resistance↗

PubMed2002

Influence of two different inhalation devices on therapy compliance in asthmatic patients.

OBJECTIVE: To examine the influence of inhalation device (Autohaler versus metered dose inhaler) and patients' subjective opinion towards the different devices, as well as daily frequency and duration of treatment on medication compliance. DESIGN: Prospective study measuring compliance in the same patients of the Autohaler twice daily with the metered dose inhaler twice daily, as well the Autohaler twice daily with the Autohaler four times daily. SETTING: Primary health care. SUBJECTS: 34 subjects with asthma. MAIN OUTCOME MEASURES: Patients preference and compliance. RESULTS: Patients preferred the Autohaler. The percentage of patients with a negative opinion towards the metered dose inhaler was 38% compared with 12% towards the Autohaler. The median values of the compliance rate of the Autohaler with twice and four times daily frequency were 90.8% (25-75th percentile 61.6-98.0%) and 78.5% (25-75th percentile 49.0%-91.2%), respectively (p < 0.001). The duration of treatment period had a significant negative influence on compliance when four times daily dosage frequency was prescribed (p = 0.05). CONCLUSION: In conclusion, the devices (metered dose inhaler and Autohaler) and the patients' opinion about the devices did not significantly contribute to the compliance rates. Compliance towards the medication treatment, however, is negatively influenced by a high daily frequency.

Adult↗

PubMed2002

Effects of acetazolamide and furosemide on ventilation and cerebral blood volume in normocapnic and hypercapnic patients with COPD.

STUDY OBJECTIVES: Effects of chronic metabolic alkalosis and acidosis and their relation to central chemoregulation may differ between normocapnic and chronic hypercapnic patients with COPD. The relationship between responses of inspired ventilation (VI), mouth occlusion pressure (P(0.1)), and cerebral blood volume (CBV), to short-term changes in arterial PCO(2) was measured. PATIENTS AND METHODS: Seventeen patients with chronic hypercapnia and COPD (PaCO(2) > 6.0 kPa) and 16 normocapnic patients with COPD (PaCO(2) < or = 6.0 kPa) [FEV(1) 27% predicted] were studied under baseline metabolic conditions and after 1 week of treatment with oral furosemide, 40 mg/d, or acetazolamide, 500 mg/d. Hypercapnia (change in end-tidal carbon dioxide > 1 kPa) was induced by administering adequate amounts of carbon dioxide in the inspired air. CBV was measured using near-infrared spectroscopy. RESULTS: Compared with baseline metabolic condition, chronic metabolic acidosis and alkalosis did not change ventilatory (Delta VI/Delta PaCO(2)) and cerebrovascular (Delta CBV/Delta PaCO(2)) reactivity. Base excess (BE) decreased by 6.8 +/- 1.1 mEq/L and 6.9 +/- 1.6 mEq/L, respectively, in the normocapnic and chronic hypercapnic COPD groups during metabolic acidosis, resulting in a not-quite-significant leftward shift of both the ventilatory and cerebrovascular carbon dioxide response curve. BE increased by 2.3 +/- 1.2 mEq/L and 1.2 +/- 1.3 mEq/L, respectively, during chronic metabolic alkalosis in both COPD groups, without concomitant shift. Poor correlations between ventilatory and cerebrovascular carbon dioxide responsiveness (Delta CBV/Delta PaCO(2) and Delta VI/Delta PaCO(2), Delta CBV/Delta PaCO(2) and Delta P(0.1)/Delta PaCO(2), respectively) were found irrespective of baseline, respiratory condition, and induced metabolic state. CONCLUSIONS: Normocapnic and chronic hypercapnic COPD patients have the same ventilatory and cerebrovascular carbon dioxide responsiveness irrespective of induced metabolic state.

Acetazolamide↗