Role of Inhaled Nitric Oxide in Vascular Mechanics and Right Ventricular Function

Role of Inhaled Nitric Oxide in Vascular Mechanics and Right Ventricular Function Following Cardiac Surgery

The aim of this study is to evaluate the role of nitric oxide on pulmonary vasculature and right ventricular function in postoperative cardiac surgery patients.

This study will evaluate modifiable pathophysiological treatments for postoperative pulmonary hypertension and right ventricular dysfunction.

One pharmacological, inhaled nitric oxide, and one non-pharmacological, the OLA strategy combining lung recruitment and stabilization with individually optimized positive end-expiratory pressure (PEEP) and the possible synergistic effects of both interventions on right ventricular performance. Apart from acting specifically on the pathophysiological mechanisms described, the combination of an OLA strategy and iNO may be particularly beneficial, as modification of pulmonary status by OLA may, in theory, enhance the effects of iNO by significantly increasing gas exchange area and thus alveolar ventilation.

A number of closely related physiological variables will also be studied to better characterize the effects of both strategies and their combination. This may help to better establish the indication for iNO in cardiac surgery patients and improve our understanding of mechanisms that are also present in ARDS patients, albeit on a different scale.

This is a prospective randomized controlled physiological prospective study to be performed in two hospitals. The intervention period is limited to the first 2 -3 hours postoperatively. A total of 54 patients will be recruited.

• Age > 18 years
• Under controlled mechanical ventilation in passive conditions
• Presence of postoperative lung collapse (confirmed by pulmonary echocardiography and Air test)
• Preoperative left ventricular ejection fraction (LVEF) ≥ 30%.
• Absence of hypovolemia: absence of "kissing" ventricles and/or collapsibility index of the superior vena cava < 20%.
• Stable spontaneous heart rhythm
• Postoperative hemodynamic stability:
• Mean arterial pressure (MAP) ≥ 60 mmHg
• Central venous pressure (CVP) ≥ 10 mmHg
• Heart rate (HR) ≤ 100 bpm without tachyarrhythmias
• Lactic acid ≤ 3 mmol/L
• Single vasopressor treatment
• Norepinephrine dose ≤ 0.2 μg/kg/min, without an increase ≥ 15% in the last 30 -minutes.

Obtained informed consent