Vasodilation

Definition

Vasodilation is the widening of blood vessels due to relaxation of vascular smooth muscle, increasing vessel diameter, blood flow, and lowering blood pressure.

Triggers

• Heat, inflammation, histamine
• Medications: nitroglycerin, hydralazine, calcium channel blockers, ACE inhibitors, alpha-blockers
• Parasympathetic nervous system
• Nitric oxide

Clinical Uses

Treatment of angina (nitroglycerin), hypertension, heart failure (reduces preload and afterload), hypertensive crisis. Warming measures rely on cutaneous vasodilation for heat loss.

Nursing Considerations

Monitor BP closely during vasodilator therapy (risk of hypotension). Nitroglycerin: expect headache and flushing. Teach slow position changes. Avoid alcohol with nitrates (synergistic vasodilation and severe hypotension). Avoid sildenafil (Viagra) with nitrates (severe hypotension).

NCLEX Relevance

Nitroglycerin + Viagra = contraindicated. Monitor BP with vasodilators.