View clinical trials related to Vasoconstriction.
Filter by:The goal of this study is to examine possible mechanisms of heightened vasoconstriction in Black/African American men and women as possible links to the elevated prevalence of cardiovascular dysfunction and disease. The main targets in this study are sources of oxidative stress.
The goal of the study is to examine the possible mechanisms of impaired cutaneous microvascular function through local heating along with administration of vasoconstrictors.
This study aims to evaluate whether dietary supplementation with fish oil can protect against the cardiopulmonary alterations linked to air pollution
This is the second part of a research study in order to determine if using a specialized pulse oximetry probe with external heat pack will help obtain oxygen saturation (SaO2) and heart rate (HR) during monitoring for patients with peripheral vascular disease (PVD), vasoconstriction, and hypothermic extremities. The inability to obtain accurate SaO2 and pulse readings can lead to misdiagnosis, incorrect treatment, or procedures to be canceled. SaO2 and pulse readings are important to maintain patient stability during diagnostic testing, surgical procedures and monitoring while in critical care areas. Changes in SaO2 and pulse are important to monitor in order to be able to compensate for any decrease in patient oxygen saturations during hemodynamic monitoring. The primary aim of this study is to determine if using a specialized pulse oximetry probe with external heat pack will improve oxygenation readings in order to obtain SaO2 and pulse readings in patients with PVD, vasoconstriction, and hypothermic extremities as compared to readings obtained from an arterial blood gas. The hypothesis is using a specialized pulse oximetry probe with external heat pack will help obtain more accurate pulse oximetry readings consistent with values obtained with an arterial blood gas.
Endothelin-1 (ET-1) has been linked to a number of conditions including pulmonary arterial hypertension (PAH). ET-1 acts via 2 receptors, ETA and ETB. The ET-1 receptor blockers bosentan and sitaxsentan have been shown to be beneficial in patients with PAH. Bosentan blocks both ETA and ETB receptors. Sitaxsentan selectively blocks ETA receptors. Theoretically, selective ETA blockade may be associated with greater vasodilation and clearance of ET-1 by leaving the ETB receptor unblocked. This has not been directly studied in humans. We aim to investigate the endothelial ETB-mediated vascular responses between bosentan and sitaxsentan by using a ETB selective agonist (ET-3). We hypothesise that at clinically relevant doses: - Bosentan will show evidence of ETB receptor blockade compared to sitaxsentan and placebo. - These effects will be confirmed by 2 functional markers of ETB receptor antagonism: plasma ET-1 (a very sensitive, but not necessarily clinically relevant marker), and the forearm vasodilator response to ET-3.
The purpose of this study is to compare changes of minimally invasive arterial pulse contour cardiac output with changes of intermittent and continuous thermodilution cardiac output by pulmonary artery catheter in hemodynamic unstable patients with rapid changing vascular tone (changing dosage of vasoactive drugs or inotropics, or volume challenge). Simultaneously, global parameters of oxygen delivery and consumption will be compared with regional flow parameters and tissue oxymetry (near infrared spectrometry and laser-Doppler). While continuous thermodilution cardiac output is used for patient management, pulse contour cardiac output, intermittent thermodilution cardiac output and tissue oxymetry is only used for monitoring.