Physiological response following inhaled nitric oxide administration during one-lung ventilation in minimally invasive cardiac surgery: an exploratory prospective cohort study.

Abstract

Objective: This study aimed to evaluate the physiological responses following inhaled nitric oxide (iNO) administration in patients with one-lung ventilation (OLV)-related hypoxemia accompanied by pulmonary hypertension in minimally invasive cardiac surgery (MICS).

Methods: This exploratory prospective cohort study enrolled 63 consecutive patients who underwent MICS. Patients who developed post-cardiopulmonary bypass (CPB) OLV-related hypoxemia with pulmonary hypertension received iNO. The evaluation included changes in PaO₂/FiO₂ and mean pulmonary artery pressure (mPAP). Additionally, multivariable logistic regression analysis was performed to examine clinical factors associated with iNO initiation.

Results: Overall, 30 patients (47.6%) received iNO. PaO₂/FiO₂ significantly increased following iNO administration (70 [61-80] to 85 [72-102], P = 0.011), while mPAP remained unchanged (24 [23-26] to 25 [22-28] mmHg, P = 0.564). Multivariable analysis identified female sex (odds ratio [OR]: 5.00), higher body mass index (OR: 1.36), and prolonged CPB time (OR: 1.03) as associated factors for iNO initiation (area under the curve: 0.822). All patients with a second aortic clamp or pre-CPB hypoxemia met the initiation criteria and received iNO.

Conclusions: Post-CPB OLV-related hypoxemia accompanied by pulmonary hypertension occurs frequently during MICS. The observed increase in oxygenation following iNO administration suggests its potential utility for respiratory management in MICS, warranting future large-scale, multicenter investigations.