Bulletin europeen de physiopathologie respiratoire最新文献

We have investigated the morphological effects of an intratracheal challenge with 50 micrograms ovalbumin (OA) on sensitized rat tracheas, in vivo. Female Sprague-Dawley rats were primed ten days before challenge with a single i.t. injection of 100 micrograms OA plus Bordetella pertussis (OA-BP). Two additional groups of animals served as controls: primed animals challenged with saline only and non-primed but OA-challenged animals. Sacrifices--and subsequent morphological studies--were performed prior to and 5, 15 and 60 min after challenge. At each time, the total numbers of epithelial nuclei, subepithelial mast cells (SEMC) and intraepithelial mast cells (IEMC) were scored in six non-adjacent cross sections per trachea. We found that: 1) priming with OA-BP alone did not induce any change in the tracheal mucosa with respect to morphological structure and mast cell counts; 2) no morphological change nor significant modification of the cell counts occurred at any time in tracheas from either of the control groups; 3) in contrast, a luminal heterogeneous exudate and a subepithelial oedema developed in 9 of the 15 tracheas of primed animals within 60 min of OA challenge. In those nine tracheas, the scores of intraepithelial nuclei, of IEMC and of SEMC were found to decrease significantly 15 min after challenge as compared with starting values (p less than 0.05 for each score). The decrease in the number of mucosal mast cells is probably related to the damages of the epithelial cells and to the difficulty with which depleted mast cells can be seen by toluidine blue staining.

To establish the clinical feasibility of high frequency body surface oscillation (HFBSO) as a mode of controlled ventilation for infants and to examine its effects on basic haemodynamic parameters, we studied twelve intact rabbits in two groups. The animals were placed in a body chamber with their heads remaining outside through a neck-hole. The mean chamber pressure was maintained at -3 to -4 cmH2O and a piston pump, operating at 3, 6, 9, 12 and 15 Hz, created pressure swings in the chamber, thus generating oscillatory tidal volumes. A fresh-airflow of 2 1.min-1 was used over the mouth. In the first group of six rabbits, we obtained the relationship between tidal volume (VT) and frequency (f) which maintained a normocapnic state (PaCO2 = 40 +/- 2 mmHg) when the animals were paralysed. The average tidal volumes required were between 1.36 and 1.78 ml.kg-1 for the 3-15 Hz frequency range, or about 1/4 of the spontaneous tidal volume. The corresponding mean PaO2 was 66.7 mmHg at 3 Hz and 73.4 mmHg at 9 Hz. These results indicate that adequate ventilation and acceptable gas exchange took place in these experimental animals during HFBSO. In the second group, six rabbits were catheterized with catheter-tip pressure transducers in order to obtain the aortic (ABP), central venous (CVP) and intrathoracic pressures. The arterial pressure profile was severely deranged by HFBSO, but, electronic subtraction of the intrathoracic pressure swings from the ABP signal resulted in the return of the normal pressure profile.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to evaluate the merits of the end expiratory lung volume as an indirect ventilatory index of bronchial obstruction and to show an application of continuous monitoring of lung volume in asthmatic patients. The accuracy of the external measurements (IS) of functional residual capacity (FRC) was controlled by comparing them with the helium measurements (DS) obtained during nine methacholine tests (IS = 0.06 + 1.065 DS in litres: R2 = 0.99). Seven asthmatics (18-48 yr) were monitored by measuring rib cage and abdominal perimeter variations. This was done in basal condition, after methacholine-induced bronchoconstriction and after bronchodilation by either salbutamol or oxytropium bromide inhalation. All the subjects were investigated on two separate days and were their own control. Bronchoconstriction produced a significant increase (p less than 0.01) of tidal volume (VT: + 67%), external minute ventilation (VE: + 58%), mean inspiratory flow (VT/TI: + 78%) and FRC (+ 26.5%) while frequency (f) and fractional inspiratory time (TI/TT) fluctuated non significantly. In the group of seven tested subjects, there was a significant correlation (p less than 0.01) between forced expiratory volume in one second (FEV1) and VE, FEV1 and VT/TI, FEV1 and FRC. However, the individual regression line showed a significant relationship only between FEV1 and FRC (R2 = 0.80 +/- 0.04). We therefore conclude that the variation of the end expiratory level can be chosen as an indirect index of bronchoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty patients with stable COPD (mean age 67.8 yr; mean FEV1 1.08 1), all limited by ventilation at maximum exercise, were randomly allocated after a four week control period, to an eight week programme of either inspiratory resistive training (IRT), with a P Flex device, or conventional breathing retraining (BR). Exercise performance was evaluated every four weeks, using a 12-min walking test, an incremental progressive exercise on a cycle ergometer and a cycle endurance test. Inspiratory muscle endurance was measured as the highest tolerated resistance for 10 min on a P Flex device. IRT produced a significant (p less than 0.05) increase in the highest tolerated resistance, but IRT and BR failed to improve lung function or exercise performance. The present study shows that in COPD patients with ventilatory limitation on exercise an IRT programme may fail to improve exercise performance, in spite of an efficient training effect on the endurance of the inspiratory muscles.