Anton F. M. Verbraak

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Objective: In mechanically ventilated patients, the expiratory time constant provides information about the respiratory mechanics and the actual time needed for complete expiration. As an easy method to determine the time constant, the ratio of exhaled tidal volume to peak expiratory flow has been proposed. This assumes a single compartment model for the(More)
The objective of this investigation was to study the relation between size and position of a mask leak on spacer output and lung dose. An upper-airway model (SAINT model, Erasmus MC) was connected to a breathing simulator. Facemasks with leaks ranging between 0 and 1.5 cm(2) were examined. Leaks were located close to the nose or close to the chin. During(More)
The results of monitoring respiratory parameters estimated from flow-pressure-volume measurements can be used to assess patients' pulmonary condition, to detect poor patient-ventilator interaction and consequently to optimize the ventilator settings. A new method is proposed to obtain detailed information about respiratory parameters without interfering(More)
The slope of phase 3 and three noninvasively determined dead space estimates derived from the expiratory carbon dioxide tension (PCO2) versus volume curve, including the Bohr dead space (VD,Bohr), the Fowler dead space (VD,Fowler) and pre-interface expirate (PIE), were investigated in 28 healthy control subjects, 12 asthma and 29 emphysema patients (20(More)
Because myotonic dystrophy patients show marked irregularities of breathing both awake and asleep, variables related to breathing pattern under both conditions were measured in 11 patients, together with pulmonary function indices, ventilatory CO2 response and maximal mouth pressures. The aim of the study was to detect and explain a possible(More)
Methacholine provocation tests are aimed at determining bronchial responsiveness. Recent investigations stress the importance of considering the entire log-dose response curve, yielding not only the provocative dose producing a 20% change in forced expiratory volume in one second (FEV1) (PC20), but also the plateau value and the steepest slope of the curve(More)
The prevalence of abnormalities in lung elasticity in patients with asthma or chronic obstructive pulmonary disease (COPD) is still unclear. This might be due to uncertainties concerning the method of analysis of quasistatic deflation lung pressure-volume curves. Pressure-volume curves were obtained in 99 patients with moderately severe asthma or COPD.(More)
Insufficient cooperation during administration of aerosols by pressurized metered dose inhaler (pMDI)/spacers is a problem in nearly 50% of treated children younger than 2 years. For these children, administration during sleep might be more efficient. However, it is unknown how much aerosol reaches the lungs during sleep. The aim of this study was to(More)
A serial lung model with a compressible segment has been implemented to simulate different types of lung and airway disorders such as asthma, emphysema, fibrosis and upper airway obstruction. The model described can be used during normal breathing, and moreover the compliant segment is structured according to more recent physiological data. A parameter(More)
It has been postulated that serial inhomogeneity of ventilation in the peripheral airways in emphysema is represented by the shape of expiratory carbon dioxide tension versus volume curve. We examined the diagnostic value of this test in patients with various degrees of emphysema. The volumes between 25-50% (V25-50) and 25-75% (V25-75) of the expiratory(More)