Effect of Sodium Nitroprusside on Cerebral Blood Flow

• Status: Completed
• Trial end date: 2017-12-04
• Target enrollment: 0
• Participant gender: Male

Summary

The brain has a high energy demand and requires continuous blood flow. The blood flow to the brain appears to be unaffected by small changes in blood pressure, but brain blood flow may be reduced by a large reduction in blood pressure. Large reductions in blood pressure are common during anesthesia or bleeding. It is unclear, however, how a given reduction in blood pressure affects blood flow to the brain.

In this study, medicine called sodium nitroprusside is used to dilate blood vessels and reduce blood pressure in twenty healthy young men. The study will evaluate whether blood flow to the brain is affected when sodium nitroprusside is used to induce a moderate and a large reduction in blood pressure. Blood flow to the brain is evaluated using ultrasound on the neck.

During breathing, oxygen is inhaled and carbon dioxide is exhaled. Carbon dioxide increases brain blood flow whereby changes in respiration can affect the blood flow to the brain. Sodium nitroprusside causes mild hyperventilation, whereby more carbon dioxide is exhaled, which will contribute to a reduction in brain blood flow. Thus, the study will also evaluate how brain blood flow is affected by hyperventilation and by breathing a mix of air and carbon dioxide.

• Phase: N/A
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: Rigshospitalet, Denmark
• Treatments: Nitroprusside

Criteria

Inclusion Criteria:

• Informed consent

• Male

• Age 18-35 years

Exclusion Criteria:

• Alcohol intake ≥ 420 g / week

• Body mass index below 18 kg/m^2 and above 25 kg/m^2

• Smoking

• Beard on the neck

• Chronic cardiac, lung, liver, kidney or metabolic disease that require medication

• Vitamin B12 deficiency

• Anemia

• Leber's hereditary optic neuropathy

• Tobacco-alcohol amblyopia

• Stenosis that obstructs ≥ 16% of the internal carotid artery

• Intake of sildenafil or vardenafil for 24 hours and tadalafil for 48 timer prior to the experiment

• Intake of monoamine oxidase inhibitors

• Neurologic disease considered to affect cerebral blood flow, including epilepsy and multiple sclerosis