Acute Right Ventricular Failure in Cardiac Surgery During Cardiopulmonary Bypass Separation: A Retrospective Case Series of 12 Years' Experience With Intratracheal Milrinone Administration

Abstract

Objective: To report the authors' 12 years of experience with intratracheal milrinone administration and to assess the efficacy and limitations of intratracheal milrinone bolus administration for the treatment of unexpected acute right ventricular (RV) failure in patients undergoing cardiac surgery.

Design: Retrospective analysis.

Setting: Single-center university hospital.

Participants: One hundred seventy-six patients (4.6%) undergoing on-pump cardiac surgery.

Interventions: Endotracheal tube administration of milrinone (5-mg bolus) after unexpected acute RV failure during separation from cardiopulmonary bypass (CPB) weaning. RV failure was defined as the simultaneous presence of all of the following criteria: (1) hemodynamic instability or difficult separation from CPB with associated elevated central venous pressure or abnormal RV pressure waveform, (2) >20% reduction of RV fractional area change from baseline evaluated by transesophageal echocardiography, and (3) anatomical visualization of impaired or absent RV wall motion by direct intraoperative visual inspection.

Measurements and main results: Intratracheal milrinone administration was found to improve RV failure in 109 patients (61.9%) whereas RV failure persisted in 67 patients (38.1%). Using a multiple logistic regression model, severely decreased left ventricular ejection fraction (<35% v >50%) (adjusted odds ratio [OR] 3.72; 95% confidence interval [CI] 1.2-11.3; p = 0.012), longer CPB time (adjusted OR 1.014; CI 1.01-1.02; p = 0.001) and elevated postoperative fluid balance (adjusted OR 1.39; CI 1.1-1.8; p = 0.02) were found to be significant predictors of persistent RV failure.

Conclusion: Intratracheal instillation of milrinone was associated with clinical improvement of RV failure occurring during separation from CPB in almost two-thirds of patients. Factors limiting its therapeutic efficacy include severe left ventricular dysfunction, increased fluid balance, and long CPB time.

Keywords: cardiopulmonary bypass; intratracheal milrinone; right ventricular failure.