Effects of inhaled nitric oxide on oxygenation and haemodynamic performance during one-lung ventilation in pigs

Objective: To study the effects of 20 ppm inhaled nitric oxide (iNO) on haemodynamics and systemic oxygenation during one-lung ventilation (OLV) in vivo. Design: Prospective animal study with a cross-over design. Setting: Animal laboratory of a university hospital. Subjects: Eight female pigs. Outcome measures: The pigs were anaesthetized, tracheally intubated, and mechanically ventilated. Following placement of femoral arterial and pulmonary artery catheters, a left-sided double-lumen tube (DLT) was placed via tracheotomy. After DLT placement, in each animal OLV was performed during intravenous anaesthesia in a cross-over design with and without iNO (20ppm) in 100% oxygen. After haemodynamic stabilization, haemodynamic measurements and blood gas analyses were made, in addition we measured differential lung perfusion with colored microspheres in three animals. Results and Conclusions: iNO did not improve oxygenation nor did iNO reduce pulmonary arterial pressure in our animal model. Mixed venous PvO 2 and cardiac output were comparable during the study periods.