P.J. Barnes, London E.D. Bateman, Cape Town E. Brambilla, Grenoble S. Bilaceroglu, Izmir P. Camus, Dijon M. Cazzola, Rome P.N. Chhajed, Mumbai U. Costabel, Essen K. Dorrington, Oxford A. Foresi, Sesto San Giovanni M.E. Froudarakis, Alexandroupolis G. Hoheisel, Leipzig M. Humbert, Clamart M. Kneussl, Vienna J.G. Mastronarde, Columbus, Ohio L.E. Nery, São Paulo A. Palla, Pisa H.-B. Ris, Lausanne J.L. Robotham, Seattle, Wash. F. Rodriguez Panadero, Tomares International Journal of Thoracic Medicine

Backgrounds: The effects of acute blood volume expansion (BVE) on the respiratory mechanics of normal animals have been not extensively studied. The subject is of both theoretical and practical interest since BVE is a frequent medical intervention, and the associated increase in cardiac output may occur in different physiopathological situations. Objectives: To describe the changes in the parameters of respiratory mechanics occurring as an effect of acute BVE and the related increase in cardiac output. Methods: We applied the end-inflation occlusion method in normal, positive pressure-ventilated rats to measure the respiratory mechanics under control and BVE conditions. Results: Under BVE conditions, we found a statistically significant increase in static respiratory system elastance (Est,rs), ohmic airway resistance plus resistance of respiratory system tissues to movement (Rmin,rs), and overall resistance including pendelluft and stress relaxation effects (Rmax,rs). Under BVE conditions, the resistive component due to sole stress relaxation and pendelluft (Rvisc,rs) increased almost significantly while a significant increment in mean respiratory system hysteresis surface area (Hyrs) was also found. Conclusions: Increasing pulmonary blood flow by BVE increases the mechanical work of breathing because of the effects on Est,rs, Rmin,rs and Rmax,rs, and because of the increase in Hyrs.

BACKGROUND:Hypertension occurs in some 10% of pregnancies and its effects on the left ventricular (LV) morphology and systolic function have been well elucidated. Little is known, however, about the changes in LV diastolic function in such a condition. The aim of this study was to evaluate the LV diastolic function in women with pregnancy-induced hypertension (PIH) using new Doppler echocardiographic methods.METHODS:Twenty-two women with PIH (mean age 31.0 +/- 4.1 years) were examined during the third trimester of pregnancy. Other 15 normotensive pregnant women (mean age 31.8 +/- 5.7 years, p = NS) were used as controls. Doppler parameters of diastolic function included: mitral inflow variables, pulmonary venous flow (PVF) variables, M-mode color Doppler of LV inflow and pulsed tissue Doppler of the mitral annulus. Furthermore, patients underwent an echocardiographic evaluation immediately after delivery and 1 month later.RESULTS:PIH women showed an increased E/A ratio and an increase in the diastolic forward components of PVF. The ratio of systolic to diastolic time-velocity integral and the systolic fraction of time-velocity integrals subsequently decreased. Women with PIH also presented a significantly increased velocity of reversal PVF at atrial contraction, a decrease in the ratio between mitral and PVF duration at atrial contraction and a slower flow propagation velocity with M-mode color Doppler. LV wall thickness and mass were significantly higher in hypertensive pregnant women. In women with PIH the abnormal PVF parameters became similar to those of controls immediately after delivery, while the E/A ratio, M-mode flow propagation velocity and LV mass did so after 1 month.CONCLUSIONS:Hypertension complicating pregnancy significantly affects ventricular diastolic filling. These alterations chiefly involve PVF, mitral inflow and intraventricular flow propagation velocities. The LV systolic function is preserved, in the presence of a transient LV remodeling.

To describe the accuracy and the reproducibility of the thermodilution flow measurements obtained using 3 commercially available cardiac output computers commonly used in intensive care units.