Postoperative care of the critically ill endocarditis patient

Introduction

The postoperative course of patients with infective endocarditis is marked by relatively high mortality, with increased risk of severe complications leading to prolonged intensive care unit (ICU) and hospital lengths of stay. Nevertheless, over 90% of endocarditis patients who undergo surgery survive to hospital discharge, but with higher mortality rates among patients with prosthetic infections compared to native valve infections (13% vs. 5.6%) [ ]. 80% of patients are alive at 1 year, irrespective of valve type used [ ]. The average postoperative length of stay among IE patients is 18 ± 2 days [ ]. Overall outcomes of patients with IE who undergo surgery are dependent on existing preoperative risk factors, such as age, persistent bacteremia, embolic strokes, congestive heart failure, cirrhosis, renal insufficiency, and other major comorbidities [ , ].

In addition to preoperative factors, perioperative factors either specific to or more pronounced with surgical repair of IE such as long cardiopulmonary bypass times, operating on septic patients, debriding infected tissue, and major valvular and tissue reconstruction increase the risk and severity of complications such as severe vasoplegia and hypotension, mixed shock, coagulopathy requiring treatment, excessive postoperative bleeding that may require reexploration of the chest for hemostasis, or relief of tamponade [ , ].

Additional complications that carry significant morbidity and mortality in this patient population include cardiac arrhythmias, cerebrovascular accidents (CVAs), acute renal failure, and pneumonia [ ]. Finally, health-care providers need to consider special patient populations, in particular, pain management and relapse prevention, in the intravenous drug user (IVDU) to improve outcomes and reduce recurrence in this vulnerable group.

Postoperative vasoplegia

Cardiac surgery patients are prone to profound vasoplegia postoperatively, occurring in 5%–25% of patients [ , ]. Postoperative vasoplegic syndrome occurs when there is markedly low systemic vascular resistance, frequently associated with lack of volume responsiveness and increased cardiac demand to maintain oxygen delivery [ ]. Patients with infective endocarditis who undergo surgery are at increased risk for vasoplegic syndrome [ ]. This is likely multifactorial, due to long cardiopulmonary bypass runs, preoperative use of vasodilators, endothelial dysregulation, preoperative cardiac dysfunction, in addition to the profound inflammatory response that characterizes IE [ ]. Initial treatments for vasoplegia include the need for high-dose alpha adrenergic agents such as epinephrine, norepinephrine, phenylephrine, and vasopressin. When these first-line measures fail resulting in refractory vasoplegia, methylene blue can be added [ ].

Fluid management

In addition to vasoplegia, marked by distributive shock due to a profound inflammatory state and sepsis, IE patients are at risk of hypotension postoperatively owing to a mixed picture which includes low cardiac output as myocardium recovers. Further, IE patients who undergo surgery are prone to pulmonary edema, especially following operations for tricuspid valve endocarditis. As a result, careful and frequent attention needs to be paid to the patient's fluid and hemodynamic status in the early postoperative period, and intraoperative transesophageal echocardiography in addition to frequent point-of-care ultrasound assessments of fluid status postoperatively can help guide resuscitation [ ].

Although pulmonary artery catheters (PACs) have been associated with right-sided endocarditis, the mixed cardiogenic, distributive, and vasoplegic shock state seen in endocarditis patients often argues in favor of PACs [ , ].