How should patients be monitored while receiving nutritional support?
If a patient is severely malnourished and refeeding is initiated, serious complications can occur, which are summarized in Table 1; these complications can include severe electrolyte disorders, fluid shifts, and even death.12 Refeeding syndrome occurs in the first few days of initiating a diet in severely malnourished patients, and its severity is directly related to the severity of malnutrition prior to refeeding. The National Institute of Health and Clinical Excellence created criteria to identify patients at risk for refeeding syndrome; these criteria include having a BMI less than 18.5 kg/m29
The general rule in initiating nutritional support for severely undernourished patients is to start low and go slow. Patients less than 30% below ideal body weight should be hospitalized for refeeding and monitoring by a licensed dietician.12 Electrolytes should be repleted prior to the initiation of feeding, and serum electrolytes should be checked every 24-48 hours in the initial refeeding process. Patients should be monitored for signs of volume overload – lung exam for rales, cardiovascular exam for edema, and exams for elevated jugular venous pressure. Heart rate tends to be bradycardic in anorexic patients; therefore, if a patient becomes tachycardic this could represent volume overload. Thiamine deficiency can also occur and present as wet beriberi (heart failure) or dry beriberi (Wernicke’s encephalopathy). Neurologic exams should be conducted because sodium shifts can cause central pontine myelinolysis. Gastrointestinal symptoms of refeeding include bloating or constipation caused by prolonged transit time and delayed gastric emptying, or they can include diarrhea caused by intestinal atrophy.9,12
Aspiration is a risk with enteral feeding – the risk factors include being older than 70 years, altered mental status, supine position, and bolus rather than continuous infusion.4 Postpyloric feeding may reduce the risk of aspiration. Expert consensus suggests elevating the head of the bed by 30°-40° for all intubated patients receiving EN, as well as administering chlorhexidine mouthwash twice daily.6
Diarrhea is very common in patients receiving EN. After evaluating for other etiologies of diarrhea, tube feeding–associated diarrhea may be managed first by using a fiber-containing formulation. Fiber should be avoided in patients at risk for bowel ischemia or severe dysmotility. If diarrhea persists despite fiber, small peptide formulations, also known as elemental tube feeds, may be used.4,6