View clinical trials related to Vasoconstriction.
Filter by:The main purpose of this interventional study is to examine differences in resting blood pressure control between healthy males and females. The main questions it aims to answer are: 1. Are there sex differences in the communication between the sympathetic nervous system (also known as the "fight or flight" response) and peripheral blood vessels (which influence systemic blood pressure)? 2. What is the role of specific vascular receptors that respond to sympathetic signals, and is it different between males and females? Participants will complete one study visit of approximately 3 hours where they will: - Have a blood sample taken to measure circulating sex hormone and sympathetic transmitters. - Receive very small doses of medications commonly used to adjust blood pressure through an artery in their arm. The effects of these medications will be short-acting and localized to the forearm. - Have their sympathetic nervous activity directly measured through two very small needles (similar to acupuncture needles) in the side of their leg. - Have their blood pressure and heart rate recorded, and forearm blood flow measured using ultrasound.
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
The purpose of this project is to determine if hyperinsulinemia attenuates sympathetic nervous system-mediated vasoconstriction in the human leg.
In septic shock there is growing evidence of a state of hemodynamic "disconnection" with seemingly adequate macrocirculatory values despite actual microcirculation failing to meet cellular demand. Norepinephrine (NE) is recommended as first choice vasoactive agent for the treatment of septic shock. However, the dynamic effects of NE on macro- and microcirculation and perfusion parameters has not been described in detail in the context of septic shock, precluding rational individualized titration of NE and fluids, as recommended recently. In the present prospective observational multicenter study in adult septic shock patients, we intend to explore the effects of NE on preload dependency and tissue perfusion by evaluating the correlation and potential discrepancies between macro- and microcirculation both during titration of NE and after fluid resuscitation. The conclusions drawn from our study will contribute to the physiological knowledge necessary for establishing individualized evidence-based bedside management of hemodynamics in the setting of septic shock.
The overall goal of this project is to better understand the effect of intermittent hypoxia (IH) on sympathetic neuronal discharge patterns in humans, as well as mechanisms that mediate persistent sympathoexcitation with IH.
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
The CarMA (Carbon Monoxide and Altitude) Study aims to observe the vascular effects of carbon monoxide exposure at low and high altitudes.
Patients with sleep apnea are at increased risk of developing cardiovascular disease - with women at potentially greater risk than men. Contributing mechanisms are not well understood, but may be related to how women respond to low oxygen and, given over 70% of patients with sleep apnea are obese, the impact of obesity. This project seeks to increase our understanding of mechanisms that may contribute to sex differences in the cardiovascular response to low oxygen with the hope that this knowledge will improve the efficacy of current therapies and support the discovery of novel therapeutics.
This will be a randomized study aiming at investigating the combination of a norepinephrine infusion and colloid preloading versus the combination of a norepinephrine infusion and crystalloid co-loading for the prevention of maternal hypotension during elective cesarean section
This will be a double-blind randomized study, aiming at investigating a fixed rate phenylephrine infusion versus a fixed rate norepinephrine infusion versus placebo in combination with co-hydration with colloids for the prevention of maternal hypotension in elective cesarean section