Cardiopulmonary parameters in propofol- or thiopental-anesthetized dogs induced to pulmonary hypertension by serotonin

Abstract

Cardiopulmonary parameters in propofol-or thiopental-anesthetized dogs induced to pulmonary hypertension by serotonin ABSTRACTThe cardiopulmonary changes in propofol-or thiopental-anesthetized dogs induced to pulmonary hypertension (PH) were evaluated. Twenty adult animals were randomly assigned to two groups: propofol group (PG) and thiopental group (TG). In PG, propofol was used for induction (80.03mg.kg -1 ) and anesthesia maintenance (0.8mg.kg -1 .minute -1 ), while, in TG, thiopental was used (22±2.92mg.kg -1 ; 0.5mg.kg -1 .minute -1 , respectively). Mechanical ventilation using time cycle was started. PH was induced by administration of serotonin (5HT) (10µg.kg -1 and 1mg.kg -1 .hour -1 ) through a thermodilution catheter positioned in the pulmonary artery. The measurements were performed before administration of 5HT (T0), after 30 minutes (T30), then at 15-minute intervals (T45, T60, T75 and T90). No differences between groups were registered for systolic (sPAP) and mean pulmonary arterial pressure (mPAP), mean arterial pressure (MAP), total peripheral resistance index (TPRI) and pulmonary vascular resistance index (PVRI). In PG, sPAP and mPAP increased from T30. While in TG, sPAP and mPAP increased from T75. In PG, heart rate (HR) increased from T30, in which PG was higher than TG. The TPRI values decreased from T30 in PG, and in TG, at T45, T60 and T90. In PG, at T0, PVRI was lower than at other times. In PG, arterial partial pressures of oxygen (PaO 2 ) decreased from T60 and alveolar-arterial oxygen gradient (PA-aO 2 ) increased at T60. In TG, at T0 PaO 2 was higher than at T30, T45, T60 and T90, while PA-aO 2 at T0 was lower than at T90. From T30 to T90, TG showed higher PaO 2 means and lower arterial partial pressures of carbon dioxide (PaCO 2 ) values when compared to PG. In PG, from T30, PaCO 2 increased, while in TG this parameter was stable. In conclusion, thiopental anesthesia attenuated the cardiopulmonary changes resulting from serotonin-induced PH, probably by attenuation of vasoconstriction and bronchoconstriction.

The Expression of Proteins Related to Serotonin Pathway in Pulmonary Arteries of Dogs Affected With Pulmonary Hypertension Secondary to Degenerative Mitral Valve Disease

“…Serotonin signaling has been suggested as being involved with the pathogenesis of DMVD in dogs (40)(41)(42)(43)(44) and humans (45,46) but very little is known about its effects on the pathogenesis of PH in dogs with DMVD. Serotonin can be used to induce PH in a canine animal model, suggesting involvement of 5HT in the pathogenesis of PH in dogs (47)(48)(49)(50)(51)(52). However, there is no study of naturally occurring PH in dogs with DMVD.…”