Measurements of pulmonary arterial pressure in anesthetized male broilers at two to seven weeks of age

Pulmonary hypertension (an elevated pulmonary arterial pressure) is the defining symptom of the pathophysiological progression leading to pulmonary hypertension syndrome (ascites) in broilers. Previously, closed-thorax techniques had not been reported for measuring the pulmonary arterial pressure in young (<5 wk of age) broilers. The objective of this research was to evaluate continuous pulmonary arterial pressure in anesthetized male broilers at weekly intervals (2 to 7 wk of age) by inserting a cannula directly into the pulmonary artery. Body weights, heart rates, and the right:total ventricular weight ratio were also recorded. Clinically healthy individuals were selected from two separate hatches without prior assessment of electrocardiograms or the percentage of saturation of hemoglobin with oxygen. The pulmonary arterial pressure increased (P < or = 0.05) from 20 to 25 mm Hg between Weeks 2 and 3, remained at approximately 25 mm Hg during Weeks 4 and 5, and then returned to 19 mm Hg during Weeks 6 to 7. Body weight increased with age, the heart rate and body weight-normalized right and total ventricular weights remained constant through Week 5, and the right:total ventricular weight ratio remained constant through Week 7. This technique is useful for determining age-related changes in pulmonary arterial pressure that may contribute to a mismatch between pulmonary vascular capacity and cardiac output in apparently healthy broilers during the pathogenesis of pulmonary hypertension syndrome.