Effect of acute hypoxia on the bovine ventilatory mechanics

in Archives Internationales de Physiologie et de Biochimie (1989)

Maximal diaphragmatic strength measurement in healthy unsedated calves

in Archives Internationales de Physiologie et de Biochimie (1989)

Inertial pressures in exercising ponies

in Archives Internationales de Physiologie et de Biochimie (1989)

Effect of acute hypoxia on the pulmonary haemodynamics in two different breeds of cattle

in Archives Internationales de Physiologie et de Biochimie (1989)

Inertance of the Respiratory System in Ponies

in Journal of Applied Physiology (Bethesda, Md. : 1985) (1989), 67(2), 534-540

The purpose of the present work was to measure the pulmonary inertance (IL) in ponies and to analyze its potential influence on the mechanics of breathing and on their aptitude to increase ventilation ... [more ▼]

The purpose of the present work was to measure the pulmonary inertance (IL) in ponies and to analyze its potential influence on the mechanics of breathing and on their aptitude to increase ventilation during exercise. Five healthy ponies 2.4-4 yr old [mean wt 255 +/- 15 (SE) kg] were used. On the one hand, inertance of the respiratory system (Irs) was computed from the value of the resonant frequency (fr) measured by the forced oscillation technique. On the other hand, respiratory airflow, tidal volume (VT), and transpulmonary pressure (PL) changes were recorded while the ponies were performing a light treadmill exercise, and IL was calculated as the ratio of the associated differences in inertial pressure (delta Pin) to volume acceleration (delta V). Respiratory airflow and VT were measured with a Fleisch pneumotachograph (no. 5) and PL with an intraesophageal balloon catheter. First, the protocol was carried out with the ponies breathing air and He-O2, second, while the ponies breathed through two additional tubes (100 cm long, 3 cm ID), then one, and finally none, fixed on the Fleisch pneumotachograph. Finally, the contribution of the extra- vs. the intrathoracic airways to IL was estimated by measuring the lateral midtracheal pressure recorded simultaneously with the aforementioned parameters. The values of Irs calculated with fr and of IL calculated on the basis of the delta Pin-delta V ratio were 29.8 +/- 0.4 and 19.8 +/- 1.0.10(-4) kPa.l-1.s-2, respectively. During He-O2 breathing IL decreased about three times; this result was similar to the predicted decrease based on gas density only.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

Effets physiologiques de différents types de stress chez le chien avant et après blocage de stress chez le chien avant et après blocage beta-adrénergique par le carzolol

in Annales de Médecine Vétérinaire (1989), 133

The purpose of this experiment was to study (1) some cardio-vascular and metabolic effects of two different stress and (2) the modifications of these stress responses induced by a preventive ... [more ▼]

The purpose of this experiment was to study (1) some cardio-vascular and metabolic effects of two different stress and (2) the modifications of these stress responses induced by a preventive administration of carazolol. Five healthy beagle dogs were used. Firstly, a pharmacological stress was induced by an intravenous (IV) administration of epinephrine tartrate (1 ug/kg). The (3 adrenergic blockade was realised by an administration of carazolol (10ug/kg, IV). The changes in heart rate (HR), haematocrit, glycemia and blood gases were studied (1) to assess the stress-induced adjustements, (2) to study the effect of a R-adrenergic blockade on quiet resting dogs and (3) to estimate the efficiency of this blockade on the stress responses. Secondly, the dogs performed a standardized treadmill exercise, in order to produce a physiological stress. The adjustements to exercise on the one hand and the changes in these adjustements induced by a preventive administration of carazolol (10 ug/kg, I.M.) on the other hand were measured by the recording of the HR before, during and after the exercise. Epinephrine tartrate induced significant changes of HR, haematocrit and glycemia. The Beta-blockade reduced significantly these changes (P < 0,01). The exercise-induced increase of HR was also significantly reduced by the (beta-blockade (P < 0,01). On the oher hand, this blockade has no effects on the resting measured parameters. This study suggests that Beta-blockade by the carazolol has no indesirable effects on resting dogs and that it prevents the cardio-vascular and metabolic effects of stress. [less ▲]

Pulmonary Function Values and Growth in Belgian White and Blue Double-Muscled Cattle

in Research in Veterinary Science (1988), 45(3), 405-410

Seventy-five double-muscled cattle of the Belgian white and blue breed, two days to 50 months old and weighing 45 to 680 kg, were investigated. Transpulmonary pressure changes, measured with an ... [more ▼]

Seventy-five double-muscled cattle of the Belgian white and blue breed, two days to 50 months old and weighing 45 to 680 kg, were investigated. Transpulmonary pressure changes, measured with an oesophageal balloon, variations of air flow and volume at the mouth were obtained during spontaneous breathing to calculate pulmonary function data. Oxygen and carbon dioxide tensions in arterial blood were also recorded. Growth related changes of the pulmonary function values were similar to those observed in other bovine breeds. Total pulmonary resistance, specific total pulmonary resistance, viscous work, power of breathing, specific viscous work, respiratory frequency and peak-to-peak change in transpulmonary pressure were greater in Belgian white and blue cattle than in Friesian cattle. In the former, tidal volume, specific tidal volume, lowest transpulmonary pressure during expiration, transpulmonary pressure at the functional residual capacity level, dynamic lung compliance and oxygen tension in arterial blood were smaller. Airflow, minute volume and carbon dioxide tension in arterial blood were similar in the Belgian white and blue and Friesian cattle. These results were related to the great sensitivity of double-muscled cattle of the Belgian white and blue breed to laryngitis and bronchopneumonia. [less ▲]

Effect of Exercise on the Partitioning of Equine Respiratory Resistance

in Equine Veterinary Journal (1988), 20(4), 268-73

Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting ... [more ▼]

Pleural, tracheal, pharyngeal and mask pressures as well as airflow and tidal volume of five ponies on a treadmill (incline 8.3 degrees) were recorded simultaneously while resting, walking, trotting slowly, trotting fast, after standing for 30 secs and 5 mins after the end of the exercise. The curves obtained were used to calculate total pulmonary resistance (RL), lower airway resistance (RLA) and upper airway resistance (RUA). The latter was also divided into nasal resistance (Rnas) and laryngeal plus extrathoracic tracheal resistance (Retr + lar). Furthermore, the inspiratory and expiratory components of each of these R values were estimated. Levels of RL, RLA and RUA were increased significantly during exercise but, during the recovery period, the values were significantly lower than those pre-exercise. RUA represented 82 per cent of RL at rest and this percentage did not change significantly during and after exercise. The nasal resistance to RUA ratio was always higher than 0.5. The fact that RL increased with exercise intensity was due to the increase of RUA during inspiration, and mainly a result of the increase of RLA during expiration. At fast trot, RLA represented 5 and 50 per cent of RL during inspiration and expiration respectively. It was concluded that heavy exercise induces in ponies an increase of RL, one reason for which could be the partial collapse of the extrathoracic and intrathoracic airways during inspiration and expiration respectively. [less ▲]

Could pulmonary inertance be a limiting factor of ventilation during exercise in the equine species ?

in Proceedings of the 7th Comparative Respiratory Society Meeting (1988)

Influence of the intrapleural pressure on the variability of the pulmonary arterial pressures measurements in calves

in Proceedings of 7th comparative Respiratory Society Meeting, Chicago (USA) (1988)