Evaluation of the influence of age on pulmonary arterial pressure by use of right ventricular catheterization, pulsed-wave Doppler echocardiography, and pulsed-wave tissue Doppler imaging in healthy Beagles.

OBJECTIVE: To assess the influence of age on pulmonary hemodynamics and hemorheological properties in healthy dogs. ANIMALS: 14 healthy Beagles. PROCEDURES: Dogs were placed in 2 age groups as follows: young dogs (or= 8 years old; 6). Hematologic characteristics, plasma total protein and fibrinogen concentrations, and blood viscosity were measured. Systolic time intervals of pulmonary blood flow were recorded by pulsed-wave Doppler echocardiography. Early (E') and late (A') diastolic myocardial velocities, isovolumic contraction velocity, and systolic myocardial velocity of the free tricuspid annulus were recorded by pulsed-wave tissue Doppler imaging (TDI). Dogs were anesthetized and pulmonary arterial pressures (PAP) and cardiac output were recorded with a pediatric thermodilution Swan-Ganz catheter. RESULTS: Hemorheological measurements were not different between the 2 groups. Systolic, mean, and diastolic PAP were higher in old dogs, compared with values in young dogs; this difference was attributed to a high pulmonary vascular resistance and low arterial compliance in old dogs. Systolic time intervals of pulmonary blood flow stayed unchanged. The A' wave of the free tricuspid annulus was increased in old, compared with that young dogs, and the E':A' ratio was decreased. Pulmonary vascular resistance was inversely correlated with compliance. CONCLUSIONS AND CLINICAL RELEVANCE: The age of dogs should be taken into account when interpreting pulmonary hemodynamic results and TDI variables of right ventricular diastolic function.

Whole body barometric plethysmography: a screening method to investigate airway reactivity and acute lung injuries in freely moving pigs.

The aim of this work was to investigate whether the Penh index, measured using whole body barometric plethysmography, can be used as a screening parameter to evaluate the airway reactivity and the intensity of the pulmonary response to endotoxins. Penh was firstly recorded in non-sedated freely moving piglets exposed (1) to a nebulized acetylcholine (Ach) pre-treated or not with clenbuterol, or (2) to endotoxin challenge. To measure Penh simultaneously with total pulmonary resistance (R(L)), dynamic compliance (C(dyn)) and intrapleural pressure changes (Max Delta Ppl), an oesophageal balloon catheter technique was used and the piglets were anaesthetised. The recordings were performed during (1) an intravenous metacholine (Mch) challenge and (2) in endotoxin-exposed animals. In freely moving animals, Ach induced a significant dose-dependent increase in Penh, which was significantly blocked by clenbuterol. Endotoxin instillation also resulted in a significant rise in Penh while the corresponding response measured under anaesthesia was significantly and positively correlated with R(L) and Max Delta Ppl. Similar results were obtained during Mch challenge but the Penh was negatively correlated with C(dyn). We conclude that Penh could be used in freely moving piglets as a screening index for airway reactivity and pulmonary functional changes in cholinergic and endotoxin challenges.