True about nitric oxide
a. Formed from L-Arginine by NO synthaseb. Causes vasodilation in all vessels
c. Used in portal hypertension
d. Interacts with Hb
e. Used in erectile dysfunction
Ans. (B)
Dilates pulmonary arteries; (B) Least systemic effects; (E) Better
ventilation perfusion match
•Nitric oxide (NO) is a colorless, odorless gas that is used
extensively in inhaled form. It is mainly used extensively in inhaled form for
its selective pulmonary vasodilator property.
• Inhaled NO diffuses rapidly across the alveolar-capillary
membrane into the subjacent smooth muscle of pulmonary vessels to activate soluble Guanylate Cyclase.
Increased intracellular concentration of cGMPrelaxes smooth muscls.
• Indications: used mainly fOr its selective pulmonary
vasodilator property & consequent
intrapulmonary distribution of ventilation & blood flow (V/Q distribution) & thus improves partial pressure of Oxygen in ystemic
arterial blood (Pa02).
Used in:
- Pulmonary hypertension
- Treatment of pulmonary hypertension & hypoxia following cardio pulmonary
bypass or use of ventricular assist devices, for mitral valve replacement, coronary artey bypass
grafting, Heart & Lung
transplant & Pulmonary
embolism.
- Asthma, COPD, & bronchitis
- One lung ventilation to reduce the shunt fraction
- Sickle cell disease.
- Prevention of chronic lung disease in newborn.
- Ischemia reperfusion injury.
- ARDS by producing selective pulmonary vasodilatation,
pulmonary capillary pressure is reduced, which decreases pulmonary
transvascular Albumin flux & thus improves Oxygenation.
Toxicity of NO:
- Production of N02 & Methemoglobinemia
- Rebound pulmonary hypertension following sudden
withdrawal.
- LV filling pressure & worsening pulmonary edema in
patients with CHF.
• Other side effect of treatment is the coagulation
disorders by inhibition of platelet aggregation
