Perfusion separation challenge

Separation from cardiopulmonary bypass (CPB) is the most crucial aspect of cardiac procedures, and this chapter aims to summarize the current evidence regarding separation strategies for CPB in patients undergoing cardiac surgery. Difficult CPB weaning is characterized by the use of high doses of inotropes or vasopressors (vasoactive and inotropic score of >10). The most common causes of difficult CPB weaning include left ventricular systolic dysfunction, left ventricular diastolic dysfunction, right ventricular systolic dysfunction, and vasoplegic syndrome. Transesophageal echocardiography plays an important role in the diagnostic setting by helping determine the cause of hemodynamic instability. With regard to treatment, optimization of preload, contractility, afterload, and heart rate is necessary to achieve sufficient oxygen delivery to peripheral tissues. While epinephrine and norepinephrine are considered the first-choice drugs for the management of left ventricular dysfunction, dobutamine and epinephrine are preferred for the treatment of right ventricular dysfunction. Inhalation of nitric oxide or iloprost is indicated in cases of high pulmonary hypertension. Left ventricular diastolic dysfunction is typically managed with volume expansion, norepinephrine, and short-acting beta-blockers. In most severe cases of vasoplegic syndrome, the use of vasopressin, angiotensin II, or methylene blue helps restore normal systemic vascular resistance. In patients with severe hemodynamic depression who are unresponsive to traditional drugs, mechanical circulatory support should be initiated to alleviate the detrimental consequences of systemic hypoperfusion and irreversible organ injury.