Clinical trials

The investigators are interested in whether discrete counterpressure maneuvers, or muscle movements in the lower body, will boost blood pressure and cardiovascular control in children who faint. We will record cardiovascular responses to maneuvers of exaggerated sway, leg crossing, crouching, and gluteal muscle tensing in children who faint (N=20), as well as their height, weight, muscularity, and pubertal (Tanner) stage. Autonomic cardiovascular control will be measured using a Valsalva manoeuvre (expiration against a closed airway for 20 seconds) and a supine-stand test. The primary outcomes are noninvasive measures of cardiovascular responses to the maneuvers (blood pressure, cerebral blood flow, and stroke volume (volume of blood pumped per heartbeat). Comparisons will be made across levels of sex, diagnosis, Tanner stage, muscularity, height, and degree of autonomic control.

This project aims to evaluate the safety and efficacy of using a short-acting drug to reduce the maximal blood pressure during dangerous blood pressure spikes that happen during bowel care in individuals with spinal cord injury. the investigators will monitor the physiological effects of this drug during at-home bowel care to best understand the drug's effects in typical use.

The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes. Drinking water can boost blood pressure and making fainting episodes less likely. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.

The primary purpose of this study is to characterize cardiovascular autonomic function to emotional stimuli (blood-injection-injury phobia \[needle phobia\]) during an orthostatic (upright) challenge in individuals with and without known needle phobia. It is well established that emotional stress can produce hypotensive (low blood pressure) reactions. Interestingly, these hypotensive reactions to venipuncture (even with minimal blood drawn), insulin injections, finger sticks for blood sugar monitoring, dental care, and vaccinations can affect up to a quarter of adults and appear to be uniquely associated with blood-injection-injury phobia rather than other phobias. These hypotensive reactions can ultimately lead to a vasovagal syncope (fainting) response, and lead to increased avoidance of medical and dental procedures as a result of this phobia. Ultimately, this has severe implications on public health and places additional strain on the Canadian healthcare system. Currently, there is limited understanding surrounding the initiation of this response. Additionally, a comprehensive profile of cardiovascular autonomic function during exposure to provoking stimuli during orthostatic stress has not been captured in the literature. We will test individuals with and without blood-injection-injury phobia using our standard approach while exposing them to emotional stimuli.

The main purpose of this study is to test the feasibility of a larger scale interventional study. The investigators want to understand whether data can be reliably collected data various different streams while participants follow a standard 12-week half-marathon training program, and whether participants follow training recommendations.