Can nitrous oxide raise blood pressure in some individuals, similar to beet-derived nitrate products?

Nitrous Oxide and Blood Pressure Effects

No, nitrous oxide does not raise blood pressure in the same way as beet-derived nitrate products—in fact, nitrous oxide typically causes either no change or a modest decrease in blood pressure, which is the opposite effect of dietary nitrates that can lower blood pressure through vasodilation. 1, 2

Cardiovascular Effects of Nitrous Oxide

Blood Pressure Response

• Nitrous oxide causes dose-dependent decreases in mean arterial pressure, not increases. 3
• At 10% concentration, blood pressure drops by approximately 6 mmHg (6% decrease). 3
• At 60% concentration, blood pressure drops by approximately 11 mmHg (13% decrease). 3
• These decreases occur without significant changes in cardiac output or pulmonary artery pressure in patients with normal cardiac function. 3

Transient Early Effects

• During the first 15-30 minutes of exposure, nitrous oxide may transiently increase blood pressure, heart rate, and cardiac output through sympathetic nervous system stimulation. 4
• This early stimulation is short-lived and blood pressure returns to baseline or below within 1-2 hours of continuous exposure. 4
• The transient increase appears related to central nervous system excitation and mild increases in PaCO2, not a direct hypertensive effect. 4

Documented Adverse Cardiovascular Effects

Hypertension as a Reported Side Effect

• Hypertension has been reported as an adverse effect in some patients, but this is not the typical or predominant cardiovascular response. 1, 2
• The American Gastroenterological Association notes that hypertension and arrhythmias can occur, though the mechanism and frequency are not well-characterized in the literature. 1, 2
• This contrasts with the more common finding of hypotension, particularly when nitrous oxide is combined with intravenous sedation agents. 1

Sympathetic Activation

• Nitrous oxide produces a 59% increase in baseline muscle sympathetic nerve activity (MSNA), indicating sympathetic nervous system activation. 5
• Despite this sympathetic activation, the net effect on blood pressure is typically neutral or hypotensive due to concurrent vasodilation. 5, 3

Special Populations at Risk

Pulmonary Hypertension

• In patients with pre-existing pulmonary hypertension, nitrous oxide increases pulmonary vascular resistance by approximately 34% (from 159 to 213 dynes·sec·cm⁻⁵). 6
• This increase in pulmonary vascular resistance does not translate to systemic blood pressure elevation and is not associated with changes in systemic vascular pressures. 6, 7
• The effect on pulmonary circulation is clinically modest and does not contraindicate nitrous oxide use in these patients. 6

Clinical Context: Comparison to Beet-Derived Nitrates

Fundamental Difference in Mechanism

• Beet-derived nitrate products (like beet chews) contain dietary nitrates that are converted to nitric oxide, causing vasodilation and typically lowering blood pressure.
• Nitrous oxide is an inhaled anesthetic gas that acts through different mechanisms—it does not function as a nitric oxide donor in the same way.
• The two substances have opposite or unrelated effects on blood pressure despite both containing nitrogen-oxygen compounds. 3, 4

Key Clinical Pitfalls

Avoid Confusing Nitrous Oxide with Nitric Oxide Donors

• Do not assume nitrous oxide will behave like dietary nitrates or nitroglycerin. 1
• Nitrous oxide's primary cardiovascular effect is mild hypotension, not hypertension. 3

Monitor for Rare Hypertensive Responses

• While uncommon, some individuals may experience hypertension with nitrous oxide, particularly during the first 15-30 minutes of exposure. 1, 2, 4
• Co-administer with 30-50% oxygen and use continuous pulse oximetry monitoring to prevent the major risk of hypoxia. 8, 2
• Avoid nitrous oxide in patients with severe uncontrolled hypertension or ischemic heart disease if using ketamine concurrently, as ketamine (not nitrous oxide) produces dose-dependent increases in blood pressure. 1

Arrhythmia Risk

• Arrhythmias have been reported with nitrous oxide administration, though the incidence is low. 1, 2
• This risk appears unrelated to blood pressure changes and may reflect direct cardiac effects or sympathetic activation. 5