What is the appropriate workup for a patient 4 days post-Coronary Artery Bypass Grafting (CABG) and Surgical Aortic Valve Replacement (SAVR) presenting with nausea, weakness, poor appetite, and fatigue?

From the Guidelines

The appropriate workup for a patient 4 days post-CABG and SAVR presenting with nausea, weakness, poor appetite, and fatigue should begin with a comprehensive assessment of vital signs, including orthostatic measurements, and a thorough physical examination focusing on cardiac, respiratory, and neurological systems. This is based on the highest quality evidence from the American Heart Association and the American College of Cardiology Foundation 1. The patient's symptoms could be related to various postoperative complications, including arrhythmias, which are common after open heart surgery, with atrial fibrillation (AF) being a common arrhythmia after CABG or surgical valve replacement/repair, occurring in 28% to 33% of patients undergoing CABG and 33% to 49% of patients undergoing surgical valve replacement/repair 1. Given the high incidence of postoperative AF, which most often occurs 2 to 4 days after surgery, continuous telemetric monitoring of cardiac rate and rhythm is recommended for 48 to 72 hours after surgery in all patients 1. Laboratory tests should include a complete blood count to assess for anemia or infection, comprehensive metabolic panel to evaluate electrolyte abnormalities and renal function, cardiac enzymes to rule out perioperative myocardial infarction, and brain natriuretic peptide (BNP) to assess for heart failure. An electrocardiogram should be performed to evaluate for arrhythmias or ischemic changes, and a chest X-ray to assess for pleural effusions, pulmonary edema, or pneumonia. Echocardiography may be necessary to evaluate prosthetic valve function, ventricular function, and to rule out pericardial effusion or tamponade. Medication reconciliation is essential, as many post-cardiac surgery medications (particularly beta-blockers, angiotensin-converting enzyme inhibitors, and pain medications) can cause similar symptoms, and beta blockers should be administered for at least 24 hours before CABG to all patients without contraindications to reduce the incidence or clinical sequelae of postoperative AF, and should be reinstituted as soon as possible after CABG in all patients without contraindications to reduce the incidence or clinical sequelae of AF 1. Particular attention should be paid to fluid status, as both volume overload and depletion can cause these symptoms. The patient's symptoms could represent normal post-operative recovery, but could also indicate serious complications such as infection, valve dysfunction, heart failure, or medication side effects. Cardiac rehabilitation is recommended for all eligible patients after CABG, including early ambulation during hospitalization, outpatient prescriptive exercise training, and education, which reduces risk of death in survivors of MI 1.

Some key points to consider in the workup include:

• Comprehensive assessment of vital signs and physical examination
• Laboratory tests, including complete blood count, comprehensive metabolic panel, cardiac enzymes, and BNP
• Electrocardiogram and chest X-ray
• Echocardiography as needed
• Medication reconciliation
• Fluid status evaluation
• Consideration of cardiac rehabilitation.

It is essential to prioritize the patient's morbidity, mortality, and quality of life when determining the appropriate workup and treatment plan, and to consider the latest evidence-based guidelines and recommendations from reputable sources, such as the American Heart Association and the American College of Cardiology Foundation 1.

From the Research

Post-CABG and SAVR Workup

Presentation

The patient is 4 days post-Coronary Artery Bypass Grafting (CABG) and Surgical Aortic Valve Replacement (SAVR) presenting with nausea, weakness, poor appetite, and fatigue.

Differential Diagnosis

• The symptoms of nausea and vomiting can be associated with high morbidity and poor quality of life, particularly in those with chronic symptoms 2.
• The clinical approach to nausea and vomiting can be challenging, given the numerous possible underlying causes as well as the vast array of diagnostic and therapeutic options 2.
• Typical causes of acute nausea and vomiting include gastroenteritis or other viral syndromes, foodborne illness, acute migraine headaches, vestibular disturbances, early pregnancy, and adverse effects of medication 3.
• Chronic nausea and vomiting have a broad differential diagnosis, including gastrointestinal, infectious, metabolic, neurologic, psychiatric, or related to medications and toxins 3.

Evaluation

• A careful history of related factors is essential to guide the initial evaluation and narrow the differential diagnosis, including associated symptoms, timing of onset and duration of symptoms, exacerbating or relieving factors, alarm symptoms, medication and substance use, relationship with recent food ingestion, and comorbidities 3.
• The 5-step approach to the clinical evaluation and treatment of nausea and vomiting includes defining what the patient means by nausea and vomiting, determining whether symptoms are acute or chronic, considering medication or toxin adverse effects, using the patient's presentation, severity of symptoms, and physical examination findings to formulate a differential diagnosis and to guide evaluation, and directing treatment on the basis of knowledge of neurotransmitters and receptors involved in the emetic pathways 2.

Management

• Nonpharmacologic management options include fluid and electrolyte replacement; small, frequent meals; and avoidance of trigger foods 3.
• Antiemetic drugs effectively reduce symptoms of acute nausea and vomiting, but chronic symptoms are often more challenging to treat 3.
• When a specific etiology is not identified, a serotonin antagonist or dopamine antagonist can be used 3.
• Medications may also target the suspected cause of symptoms and the neurotransmitters involved in central and peripheral pathways of nausea and vomiting 3.
• In cardiac surgery, ondansetron and metoclopramide can be used for prevention of postoperative nausea and vomiting, with ondansetron having a higher incidence of nausea and vomiting compared to metoclopramide 4.

Considerations

• The proportion of patients receiving multiple-valve procedures is increasing, and concomitant CABG moderately increases in-hospital mortality, while multiple-valve procedures dramatically increase in-hospital mortality and complications 5.
• The choice of antiemetic drug should be guided by the cause of nausea and vomiting, with serotonin and neurokinin antagonists being highly effective in treating chemotherapy-induced nausea and vomiting, and metoclopramide and antihistamines being first-line options for nausea and vomiting in pregnancy 6.