title: Lung microvascular pressure profile measured by micropuncture in anesthetized dogs.
abstract: We have micropunctured the lung in the open thorax of 17 anesthetized dogs to measure microvascular pressure. After intravenous pentobarbital sodium (25 mg/kg), we exposed the left lung through a wide left thoracotomy, which required rib excision. Through a double-lumen endotracheal tube, we ventilated the right lung to maintain normal blood gases and pH while we held the left lung motionless at an inflation pressure of 5 cmH2O. To reduce motion on the surface of the left lower lobe, we resected the left upper lobe, placed a Plexiglas baffle between the lobe and the heart, and held the lobe surface in a suction ring. In accordance with procedures we have previously described, we micropunctured subpleural vessels to measure microvascular pressure. At base line when alveolar pressure exceeded left atrial pressure (zone 2 conditions), 21, 38, and 41% of the total pressure drop occurred, respectively, in the arterial, microvascular, and venous segments. When we raised left atrial pressure above alveolar pressure (zone 3 conditions), the corresponding pressure drops were 30, 55, and 20% of total. The blood flow in the superficial layer of the lung averaged 15% less than the flow in the deeper layers as measured by distribution of 99mTc-albumin macroaggregates. We conclude that the intact and the isolated lung preparations in dog exhibit similar distributions of subpleural microvascular pressure.
authors: Cardiovascular Research Institute, University of California, San Francisco 94143.
authors: J M
authors: JM
authors: Shepard
authors: M A
authors: MA
authors: Gropper
authors: G
authors: G
authors: Nicolaysen
authors: N C
authors: NC
authors: Staub
authors: J
authors: J
authors: Bhattacharya
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D008168:Lung / Q000098:blood supply*; D008833:Microcirculation; D011652:Pulmonary Circulation; D011677:Punctures