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Sildenafil modulates hemodynamics and pulmonary gas exchange
A Kleinsasser1, A Loeckinger, C Hoermann
1Department of Anesthesiology and Critical Care Medicine, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria. axel.klleinsasser@uibk.ac.at
American Journal of Respiratory and Critical Care Medicine
|February 17, 2001
Summary
Sildenafil (Viagra) increases intrapulmonary shunt flow, decreasing blood oxygen levels (PaO2) in pigs. This effect occurred despite increased cardiac index (CI) and reduced pulmonary artery pressure with higher doses.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Medicine
- Pharmacology
Background:
- The precise impact of sildenafil on hemodynamics and pulmonary gas exchange is not fully understood.
- Sildenafil is an orally active phosphodiesterase type 5 inhibitor with known vasodilatory effects.
Purpose of the Study:
- To investigate the dose-dependent effects of sildenafil on gas exchange and hemodynamics in an animal model.
- To clarify the relationship between sildenafil administration and changes in pulmonary function and cardiac output.
Main Methods:
- Twenty-four anesthetized pigs were divided into four groups: control, low-dose (25 mg), normal-dose (50 mg), and high-dose (100 mg) sildenafil.
- Hemodynamic and inert gas measurements were taken 30, 60, and 90 minutes post-administration via gastric tube.
Main Results:
- All sildenafil doses significantly increased intrapulmonary shunt flow, leading to decreased PaO2.
- High-dose sildenafil significantly increased cardiac index (CI) but also depressed mean arterial pressure.
- Pulmonary artery pressure decreased with high-dose sildenafil, but no significant differences were observed between treatment groups.
Conclusions:
- Sildenafil administration in pigs leads to increased intrapulmonary shunt and reduced PaO2, even with elevated cardiac output.
- The findings suggest a complex interplay between sildenafil's effects on cardiac function and pulmonary gas exchange.