Inhaled nitric oxide (40 ppm) during one-lung ventilation, in the lateral decubitus position, does not decrease...

Area of Science:

• Anesthesiology
• Cardiovascular Physiology
• Respiratory Physiology

Background:

• One-lung ventilation (1LV) can lead to ventilation-perfusion mismatch, increasing venous admixture (Qs/Qt) and pulmonary artery pressure (PAP).
• Inhaled nitric oxide (NO) is a selective pulmonary vasodilator, but its efficacy during 1LV remains unclear.
• Understanding interventions to manage hemodynamic and oxygenation changes during 1LV is crucial for patient outcomes.

Purpose of the Study:

• To investigate the effects of inhaled nitric oxide (NO) on venous admixture (Qs/Qt), mean pulmonary artery pressure (MPAP), and pulmonary vascular resistance (PVR).
• To assess the impact of NO during one-lung ventilation (1LV) in the lateral decubitus position.
• To determine if NO can mitigate adverse hemodynamic and oxygenation changes associated with 1LV.

Main Methods:

• Prospective, blinded, crossover study design.
• Six adult patients undergoing thoracotomy with 1LV in the lateral decubitus position.
• Administration of inhaled NO (40 ppm) or control gas to the dependent lung, with alternating conditions.

Main Results:

• Inhaled NO at 40 ppm did not significantly alter mean pulmonary artery pressure (MPAP), pulmonary vascular resistance (PVR), or venous admixture (Qs/Qt).
• No significant changes in oxygenation were observed with inhaled NO administration.
• Pulmonary and systemic hemodynamics remained unaffected by inhaled NO during 1LV.

Conclusions:

• Inhaled NO (40 ppm) is not effective in reducing MPAP or improving Qs/Qt in patients with normal baseline PVR during 1LV.
• Current interventions should focus on alternatives to inhaled NO for managing hypoxia in patients undergoing 1LV.
• Further investigation into alternative therapeutic strategies for hypoxia during 1LV is warranted.