Bulletin europeen de physiopathologie respiratoire最新文献

Assessment of respiratory muscle strength is done most directly by measuring maximal static inspiratory and expiratory mouth pressures (MIPS and MEPS, respectively). The available studies that report reference values of MIPS and MEPS, however, show ill-explained wide variability, not only between individuals but also between studies. This study of 106 normal white adults (60 women and 46 males, aged 16 to 79 yr) attempts to identify the anthropometric factors which best predict MIPS and MEPS. It was found that: 1) smoking does not affect MIPS and MEPS; 2) sex is a major determinant of MIPS and MEPS, as women reached 68 and 63%, respectively, of the male values; 3) within each sex, age is the major determinant of MIPS and MEPS, since body size factors such as height, weight and percent ideal body weight do not significantly improve the relationship between age and MIPS or MEPS. In both sexes, the pattern of change in pressures with age is different for MIPS and MEPS, suggesting different maturation processes for MIPS and MEPS. While MIPS is an inverse linear function of age (i.e. MIPS decreases with advancing age from early adulthood on), the relationship between MEPS and age is best described by a second degree polynomial (i.e. MEPS increases towards a peak in mid-life, after which it also decreases with age).(ABSTRACT TRUNCATED AT 250 WORDS)

The automated multilinear regression analysis method (MLRA) was recently proposed to measure respiratory mechanics in mechanically ventilated subjects [11]. The method is applicable whatever the inspiratory flow pattern and without any assumption as to the value of the parameter characterizing the non linear term of flow resistance. It was compared here in ten mechanically ventilated patients to the constant flow inflation (CFIM) method described by Rossi et al. [15]. The non linear term of flow resistance was lower in intubated patients than in corresponding isolated endotracheal tubes. When derived from the MLRA method, the values for the elastance of the respiratory system were significantly higher (p less than 0.01) than with the CFIM method, and those for the system resistance, significantly lower (p less than 0.01). These differences might be due to the recruitment of lung units in the early part of inflation. When additional resistances were inserted into the respiratory circuit, both methods proved able to determine their values accurately. They therefore appear suitable for respiratory resistance monitoring in anaesthetized ventilated patients.

We evaluated the effects of inhomogeneous lung emptying on the relationship of partial to maximal complete expiratory flow by obtaining pre- and post-metaproterenol maximal (MEFV) and partial flow-volume curves in normal subjects and asthmatics. Partial curves were initiated between 65-70% of vital capacity after inspiration from functional residual capacity (PEFV curve) or after deflation from total lung capacity (PEFVDI curve). Since PEFVDI curves were initiated at lower lung volumes than MEFV manoeuvres (but with a similar volume history), non-homogeneous emptying should cause higher flow on PEFVDI than on MEFV manoeuvres. Expiratory flow (Vmax) was highest on MEFV manoeuvres in normals and PEFV curves in asthmatics. Pre- and post-metaproterenol Vmax was very similar on MEFV and PEFVDI manoeuvres in both groups, although Vmax(MEFV) slightly but significantly exceeded Vmax(PEFVDI) in normals and the reverse was true in asthmatics. Lung elastic recoil did not differ significantly on MEFV and PEFVDI manoeuvres in either group. We conclude that asthmatics demonstrate inhomogeneous emptying. However, because flow-volume curves are relatively insensitive to sequences of lung emptying, inhomogeneous emptying during forced expiration only has minor effects on the relationship of partial to maximal expiratory flow.

Maximum voluntary coughing produces a flow-volume profile which incorporates the characteristics of a maximum expiratory flow-volume curve (MEFV). The cough flow-volume curve also has transient spikes of supramaximal flow, interspersed with portions of zero flow when the glottis is closed. The peak flow rates of the supramaximal flow transients during cough decrease in a linear fashion as lung volume goes down from total lung capacity to residual volume. Cough flow-volume curves have been recorded from forty-two subjects between the ages of 7 and 56 yr. The rate of change of cough peak flow shows a positive correlation with airway conductance measured plethysmographically in children. The ratio of forced expiratory flow to cough peak flow (the cough ratio) expresses the maximum expiratory flow rate during forced expiration as a proportion of that which can be achieved with a cough. The cough ratio declines during adult life, because although there is a fall in cough peak flow with age there is a proportionally greater fall in MEFV-equivalent flow. These investigations explore the information to be gained from cough flow-volume curves by examining the cough in a heterogeneous group of individuals.

We studied the acute effect of a single, oral dose of 200 mg almitrine and of placebo on arterial blood gas tensions, ventilation, gas exchange and pulmonary mechanics in 28 patients with chronic obstructive bronchitis and emphysema (COPD), 20 patients with bronchial asthma and 10 patients with interstitial lung disease. Almitrine significantly increased PaO2 in COPD, had a borderline effect in bronchial asthma and no effect in lung fibrosis. In all groups of patients almitrine significantly increased minute ventilation and decreased arterial carbon dioxide tension (PaCO2). Placebo had no effect on arterial oxygen tension (PaO2) and PaCO2 in any of the groups. Therefore, despite similar effects on ventilation, the improvement of arterial PO2 by almitrine depends on the underlying disease.