Biomaterial Database

Effects of halothane on hypoxic pulmonary vasoconstriction in canine atelectasis. 1991

D H Johnson, and T S Hurst, and I Mayers

Department of Anaesthesia, University of Saskatchewan, Saskatoon, Canada.

We studied the interactions of atelectasis and halothane on hypoxic pulmonary vasoconstriction using an isolated canine lobe. We divided pulmonary vascular resistance into arterial, venous, and middle segmental resistances by a vascular occlusion technique. We found that middle segmental resistance significantly increased (P less than 0.05) from 0.016 +/- 0.007 cm H2O.mL-1.min-1 during normoxic ventilation to 0.06 +/- 0.007 cm H2O.mL-1.min-1 during hypoxic ventilation. We then produced sublobar atelectasis by introducing 4.5-mm steel ball bearings into the lobar bronchus, which resulted in a significant increase (P less than 0.05) of middle segmental resistance to 0.046 +/- 0.014 cm H2O.mL-1.min-1 during normoxic ventilation and a further significant increase (P less than 0.05) to 0.084 +/- 0.02 cm H2O.mL-1.min-1 during hypoxic ventilation. Ventilation with 2.0% halothane but not 0.5% halothane prevented the increases in middle segmental resistance observed with either atelectasis or hypoxic ventilation. Values of arterial and venous segmental resistances were not similarly affected. We conclude that sublobar atelectasis increases pulmonary vascular resistance by stimulating hypoxic pulmonary vasoconstriction. Both halothane and hypoxia primarily act upon the middle vascular segment, but their effects are in opposite directions and, in the former instance, are concentration-dependent.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D011659	Pulmonary Gas Exchange	The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.	Exchange, Pulmonary Gas,Gas Exchange, Pulmonary
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D006221	Halothane	A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)	1,1,1-Trifluoro-2-Chloro-2-Bromoethane,Fluothane,Ftorotan,Narcotan
D006439	Hemodynamics	The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.	Hemodynamic
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000860	Hypoxia	Sub-optimal OXYGEN levels in the ambient air of living organisms.	Anoxia,Oxygen Deficiency,Anoxemia,Deficiency, Oxygen,Hypoxemia,Deficiencies, Oxygen,Oxygen Deficiencies
D001261	Pulmonary Atelectasis	Absence of air in the entire or part of a lung, such as an incompletely inflated neonate lung or a collapsed adult lung. Pulmonary atelectasis can be caused by airway obstruction, lung compression, fibrotic contraction, or other factors.	Atelectasis, Congestive,Lung Collapse,Atelectasis,Compression Atelectasis,Compression Pulmonary Atelectasis,Congestive Atelectasis,Congestive Pulmonary Atelectasis,Contraction Pulmonary Atelectasis,Postoperative Pulmonary Atelectasis,Resorption Atelectasis,Resorption Pulmonary Atelectasis,Atelectases,Atelectases, Compression,Atelectases, Compression Pulmonary,Atelectases, Congestive,Atelectases, Congestive Pulmonary,Atelectases, Contraction Pulmonary,Atelectases, Postoperative Pulmonary,Atelectases, Pulmonary,Atelectases, Resorption,Atelectases, Resorption Pulmonary,Atelectasis, Compression,Atelectasis, Compression Pulmonary,Atelectasis, Congestive Pulmonary,Atelectasis, Contraction Pulmonary,Atelectasis, Postoperative Pulmonary,Atelectasis, Pulmonary,Atelectasis, Resorption,Atelectasis, Resorption Pulmonary,Collapse, Lung,Compression Atelectases,Compression Pulmonary Atelectases,Congestive Atelectases,Congestive Pulmonary Atelectases,Contraction Pulmonary Atelectases,Postoperative Pulmonary Atelectases,Pulmonary Atelectases,Pulmonary Atelectases, Compression,Pulmonary Atelectases, Congestive,Pulmonary Atelectases, Contraction,Pulmonary Atelectases, Postoperative,Pulmonary Atelectases, Resorption,Pulmonary Atelectasis, Compression,Pulmonary Atelectasis, Congestive,Pulmonary Atelectasis, Contraction,Pulmonary Atelectasis, Postoperative,Pulmonary Atelectasis, Resorption,Resorption Atelectases,Resorption Pulmonary Atelectases
D014655	Vascular Resistance	The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.	Peripheral Resistance,Total Peripheral Resistance,Pulmonary Vascular Resistance,Systemic Vascular Resistance,Peripheral Resistance, Total,Resistance, Peripheral,Resistance, Pulmonary Vascular,Resistance, Systemic Vascular,Resistance, Total Peripheral,Resistance, Vascular,Vascular Resistance, Pulmonary,Vascular Resistance, Systemic