Phrenic artery blood flow under loaded respiration

Acute experiments on anesthetized cats with additional resistive loads to inspiration and/ or expiration revealed adequate changes in vascular bed resistance and blood flow rate in the phrenic artery. The increase in the phrenic artery blood flow during airflow resistive loading by 30-40 mm H2O was similar to the changes previously found for inspiration of gas mixtures containing 5% O-2 and 5% CO2. Minute ventilation increased 2 times under hypoxia and 3.5 times under hypercapnia. This index did not change under additional loading.