Salvage treatment for non-invasive ventilation intolerance in cardiac surgical patients with dexmedetomidine: a pilot feasibility trial

Abstract

Objective To investigate the efficacy of dexmedetomidine on sedation in post-cardiac surgery patients with NIV intolerance. The changes of respiratory function and hemodynamics of the patients as well as non-invasive ventilation (NIV) failure rate were also under evaluation. Methods Thirty-five post-cardiac surgery patients with NIV intolerance and hypoxemia were enrolled in this prospective study. All patients were sedated with dexmedetomidine. NIV was standardized according to the uniform protocol. The main outcome was NIV success (avoiding endotracheal intubation) or NIV failure (requiring endotracheal intubation or die). The cardiorespiratory parameters (BP, HR and RR) and artery blood gas analysis were prospectively recorded before and after sedation. The respiratory function and hemodynamics changes in both groups (NIV success group and NIV failure group ) were then evaluated. Factors independently associated with NIV failure were identified using a logistic regression model. Results Twenty out of 35 patients (57.14%) survived while 15 (42.86%) patients failed NIV. After 1 h and 4 h of NIV with dexmedetomidine sedation, respiratory rate in both groups were decreased compared with baseline, especially in NIV success group. The PaO2/FiO2 was also improved after 1h and 4h of NIV treatment compared with baseline. The improvement was more significantly in NIV success group. The heart rate was decreased compared with baseline with no differences between two groups. There were no significant changes on PaCO2 and mean arterial pressure (MAP) during the treatment. The respiratory and hemodynamics variables identified as predictors of NIV failure were included in a multivariate logistic regression. RR>23 time/min(OR=3.2, 95%CI: 2.043~4.301, P 20 time/min(OR=2.1, 95%CI: 1.659~3.231, P=0.025)4 h after NIV, PaO2/FiO2 <178 mmHg(OR=2.4, 95%CI: 1.892~3.287, P<0.01)1 h after NIV and PaO2/FiO2 <185 mmHg(OR=1.7, 95%CI: 1.243~2.365, P=0.041)4 h after NIV independently predicted NIV failure. Conclusions Dexmedetomidine might be considered as an effective and safe sedative for post-cardiac surgery patients with NIV intolerance. Early identification of predictors of NIV failure may facilitate early intervention. Key words: Non-invasive ventilation; Sedation; Dexmedetomidine; Cardiac surgery