Pulmonary perfusion rate

Pulmonary perfusion rate Volumetric flow rate within the pulmonary veins. 

The rate of pulmonary perfusion (in healthy individuals, essentially equivalent to the cardiac output) also affects the rate of induction of anesthesia. Since more blood will pass through the pulmonary capillary bed when the cardiac output is high, it follows that a greater total transfer of any anesthetic agent across the alveolus will... 

PBPK models have also been used to explain the rate of excretion of inhaled trichloroethylene and its major metabolites (Bogen 1988 Fisher et al. 1989, 1990, 1991 Ikeda et al. 1972 Ramsey and Anderson 1984 Sato et al. 1977). One model was based on the results of trichloroethylene inhalation studies using volunteers who inhaled 100 ppm trichloroethylene for 4 horns (Sato et al. 1977). The model used first-order kinetics to describe the major metabolic pathways for trichloroethylene in vessel-rich tissues (brain, liver, kidney), low perfused muscle tissue, and poorly perfused fat tissue and assumed that the compartments were at equilibrium. A value of 104 L/hour for whole-body metabolic clearance of trichloroethylene was predicted. Another PBPK model was developed to fit human metabolism data to urinary metabolites measured in chronically exposed workers (Bogen 1988). This model assumed that pulmonary uptake is continuous, so that the alveolar concentration is in equilibrium with that in the blood and all tissue compartments, and was an expansion of a model developed to predict the behavior of styrene (another volatile organic compound) in four tissue groups (Ramsey and Andersen 1984). 

Ventilation-perfusion ratio (VA/Q) A comparison of the proportion of lung tissue being ventilated by inhaled air to the rate of oxygenation of pulmonary blood. 

Since Kantrovitz et al. described the concept of counterpulsation in 1968 [3], the lABP has been the mainstay for temporarily augmenting the cardiac output and improving hemodynamics in acutely decompensated refractory HF [4, 5]. lABP use has been shown to reduce heart rate, left ventricular end-diastolic pressure, mean left atrial pressure, afterload, and myocardial oxygen consumption by at least 20-30%. The lABP also modestly increases coronary perfusion pressure and decreases the right atrial pressure, pulmonary artery pressure, and pulmonary vascular resistance [6]. 

Measure the coronary flow rates by timed collections of the coronary venous effluent from the pulmonary artery s cannula. (Discard all perfusates after one passage through the heart.)... 

Carbon dioxide is a rapid, potent stimulus to ventilation. Inhalation of 10% CO can produce minute volumes of 75 L/min in normal individuals. Carbon dioxide acts at multiple sites to stimulate ventilation. Elevated Pco causes bronchodilation, whereas hypocarbia causes constriction of airway smooth muscle these responses may play a role in matching pulmonary ventilation and perfusion. Circulatory effects of CO result from the combination of direct local effects and centrally mediated effects on the autonomic nervous system. The direct effects are diminished contractility of the heart and vascular smooth muscle (vasodilation). The indirect effects result from the capacity of CO to activate the sympathetic nervous system these indirect effects generally oppose the local effects ofCO. Thus, the balance of opposing local and sympathetic effects determines the total circulatory response to CO. The net effect of CO inhalation is an increase in cardiac output, heart rate, and blood pressure. In blood vessels, however, the direct vasodilating actions of carbon dioxide appear more important, and total peripheral resistance decreases when the Pco is increased CO also is a potent coronary vasodilator. Cardiac arrhythmias associated with increased Pco are due to the release of catecholamines. 

Lycorine (1) is an analgesic, more so than aspirin, and a hypotensive (489,490), as are caranine (10) and galanthine (7). The analgesic activity exhibited by the Amaryllidaceae alkaloids is attributed to their resemblance to the morphine and codeine skeletons. Lycorine also has antiarrhythmic action, and lycorine hydrochloride is a strong broneholytic (30). In fact, lycorine shows a relaxant effect on an isolated epinephrine-preeontracted pulmonary artery and increases contractility and the rate of an isolated perfused heart. These effects are mediated by stimulation of S-adrenergic receptors (491). 

Hearts from male, Sprague-Dawley rats (350-400 g) fed ad libitum were perfused without recirculation at 37°C using the Langendorff technique and a perfusion pressure of 95 cm H2O (Pearce etal., 1979). The pulmonary artery was cannulated for measurement of the coronary flow rate and the effluent oxygen tension. All... 

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