Can local nitroglycerin (glyceryl trinitrate) application facilitate easier arterial puncture?

Local Nitroglycerin Application for Arterial Puncture

Local nitroglycerin application can facilitate easier arterial puncture by dilating the target artery and improving first-attempt success rates, with the strongest evidence supporting subcutaneous injection rather than topical application.

Evidence for Subcutaneous Nitroglycerin

Subcutaneous nitroglycerin injection at the arterial puncture site is effective and should be the preferred method of local application:

• In pediatric patients (age <2 years), subcutaneous nitroglycerin (5 μg/kg in 0.5 ml) injected 3 minutes before radial artery cannulation increased first-attempt success rates from 66.1% to 91.2% (absolute risk reduction 25.2%, P=0.002) 1
• The same pediatric study demonstrated that subcutaneous nitroglycerin increased radial artery diameter by 25.0% compared to only 1.9% with saline (P<0.001), and reduced overall complication rates from 31.2% to 3.5% (P=0.001) 1
• In adults undergoing transradial coronary catheterization, subcutaneous injection of 0.5 mL of 0.1% nitroglycerin at the radial artery puncture site significantly increased radial artery diameter (2.48±0.45 mm vs 2.45±0.46 mm pre-procedure, P=0.003) and reduced early radial artery occlusion from 14.4% to 5.4% (P=0.04) 2

Evidence for Topical/Transdermal Nitroglycerin

Topical nitroglycerin spray shows vasodilation effects but has less robust clinical evidence:

• Transdermal nitroglycerin spray (0.3 mg) applied to skin over the brachial artery in healthy volunteers produced peak vasodilation of 23.6% at 10 minutes (P<0.001 vs control), with effects lasting up to 20 minutes 3
• However, topical nitroglycerin ointment showed no statistically significant improvement in perfusion in an animal model of vascular occlusion and may theoretically worsen ischemia by propagating embolic material into smaller vessels 4

Intra-arterial Nitroglycerin (Post-Access Context)

While not for facilitating initial puncture, intra-arterial nitroglycerin is well-established for preventing vasospasm after arterial access:

• The American Heart Association recommends intra-arterial nitroglycerin (100-200 μg) after sheath insertion during transradial procedures to reduce radial artery spasm, though its short half-life necessitates coadministration with calcium channel blockers 5
• Intra-arterial nitroglycerin can prevent vasospasm during catheter manipulation, which is especially useful during infusion of particulate embolic materials, with doses ≤100 μg per tumor-feeding artery considered safe 5

Practical Algorithm for Use

For arterial puncture facilitation, follow this approach:

1. Preferred method: Inject subcutaneous nitroglycerin (5 μg/kg up to 0.5 mL of 0.1% solution) with ultrasound guidance directly above the target artery 2, 1
2. Timing: Wait 3 minutes after injection before attempting arterial puncture to allow maximal vasodilation 1
3. Alternative: If subcutaneous injection is not feasible, transdermal nitroglycerin spray (0.3 mg) may be applied, with optimal effect at 10 minutes 3
4. Post-access: After successful arterial access and sheath insertion, administer intra-arterial nitroglycerin (100-200 μg) to prevent vasospasm 5

Critical Safety Considerations

Monitor for hypotension and avoid use in specific contraindications:

• Nitroglycerin can cause significant hypotension and cardiovascular decompensation, particularly when combined with other vasodilators or in hypovolemic patients 5, 6
• Avoid in patients with systolic blood pressure <90 mmHg, as vasodilators may reduce central organ perfusion 5
• Exercise caution in patients with cardiogenic shock, severely reduced ejection fraction, or severe aortic stenosis 5
• Do not use in patients who have taken phosphodiesterase inhibitors (sildenafil within 24 hours, tadalafil within 48 hours) 6
• Excessive nitroglycerin (>100 μg intra-arterially) may cause serious adverse events including hypotension 5

Common Pitfalls to Avoid

• Do not rely on topical ointment alone for arterial puncture facilitation, as evidence shows minimal benefit and potential for worsening perfusion in ischemic conditions 4
• Do not assume immediate effect: subcutaneous nitroglycerin requires 3 minutes for optimal vasodilation, while transdermal spray peaks at 10 minutes 3, 1
• Do not use prophylactically in hemodynamically unstable patients, as the venodilating effects can lead to cardiovascular decompensation through decreased preload 5
• Do not administer without considering intravascular volume status and hemodynamic effects of concurrent medications 5