Respiratory and Hemodynamic Management After Cardiac Surgery.

In this new era of managed care, the emphasis has been on the reduction of intensive-care stay after coronary artery bypass surgery. "Fast-track" or rapid weaning protocols have become increasingly popular due to evidence that shows their cost-effectiveness and safety. With new advances in surgical and anesthetic techniques, the goal is often to have patients extubated within 4 to 6 hours upon arrival in the intensive-care unit. Patients who are not candidates for the fast-track protocol are often those who either have poor respiratory function and a large A-a gradient or those who have hemodynamic instability from poor cardiac function after bypass. These patients need more intensive care and more traditional weaning from mechanical ventilation. Those that are not able to wean from the mechanical ventilator within a few weeks are candidates for tracheostomy in order to avoid complications from prolonged endotracheal intubation and to improve pulmonary toilet. The treatment of perioperative low cardiac output syndrome is another goal after bypass surgery. Poor cardiac function can be managed with a variety of vasopressor and inotropic agents based on what the suspected derangement is from clinical examination and hemodynamic measurements (eg, low preload, low cardiac index, high or low systemic vascular resistance). Another modality that has been shown to have benefit on reducing hospital stay and costs is prophylaxis for atrial fibrillation, which may occur in 40% of patients who undergo bypass surgery and in 60% of those who undergo valve replacement surgery. Beta-blockers and amiodarone have both been found to be effective as prophylaxis against postoperative atrial fibrillation.