‘Refeeding syndrome’ can be lethal to anorexics
Refeeding syndrome’ can be lethal to anorexics
Nurse managers should be on alert
Although the number of anorexic and bulimic patients admitted to ICUs each year is relatively small, they nonetheless pose significant challenges to bedside nurses.
The area of biggest concern is reversing the patient’s severe protein-calorie malnutrition without overdoing the refeeding process to the point of endangering the patient’s life.
Striking that balance and preventing overfeeding, or so-called "refeeding syndrome," makes working with anorexic patients in the ICU a special challenge, says Elaine Trujillo, MS, RD, a senior clinical dietitian at Brigham and Women’s Hospital in Boston.
Input from a multidisciplinary team that includes the hospital’s dietician, pharmacist, psychiatrist, internist, eating disorder specialist, and social worker can be valuable, even in determining the safe and proper levels of parenteral nutrition. That’s because anorexic and bulimic patients present a complex set of clinical issues both medical and psychiatric that fall outside the norm for ICUs, Trujillo says. On admission, they also present a range of acutely serious medical problems.
Cardiovascular complications run high
Together these conditions affect, and often are the underlying cause of, the patient’s severe malnourishment, adds Trujillo. These aren’t your conventional patients.
"When these patients go bad, they go into acute clinical distress," adds Richard C. Hall, MD, an eating disorder specialist at Florida Hospital-Altamonte in Gainesville. ICU managers should be on alert to special problems presented by those patients.
Severe cardiovascular complications run high in this population, especially if they are diuretic or laxative abusers, Hall notes. A mixed history of severe anorexia nervosa alternating with periods of bulimia is likely to lead to a range of life-threatening illnesses. More than a third of bulimics admitted to hospitals suffer from a range of medical disorders such as cardiac arrhythmia, esophageal tears, bone marrow failures, gastric ruptures, and hypovolemic shock.1
About 10% of severe anorexics who alternate between binging and purging require ICU treatment. "Those percentages have remained fairly constant for over a decade," Hall observes. (See charts, p. 101.)
Furthermore, more than one in 10 of anorexic/ bulimic patients — 16%, according to one study — have an alcohol or drug abuse problem, and many have ailments such as seizure disorder and pelvic inflammatory disease that may escape detection by nurses during the initial admissions assessment.
The effectiveness of nutritional support to self-starving patients can be a lifesaver. But if performed incorrectly, the effort can backfire and can endanger the patient’s life, says Caroline M. Apovian, MD, an attending physician in the metabolic support service at Brigham and Women’s Hospital.
Anorexic semistarvation is unique
The nutritional support team should follow specific guidelines to avoid pitfalls, Apovian says. Facets of the guidelines include:
• Understanding the patient’s malnutrition
In the marasmic (starving) patient, the body adapts to the chronic semi-starvation by decreasing its basal metabolic rate by as much as 25%. The body relies less on protein and more on existing fat stores for fuel.
This type of malnutrition is different from the type that involves the body’s metabolic response to an injury. So, there is likely not to be many of the usual signs and symptoms such as fever, leukocystosis, or elevated acute-phase reactive proteins, Apovian says.
The distinction is important, because a weight loss of 25% or more in an anorexic that presents to an ICU with injuries can be fatal. Anorexics often present with fractures and other injuries. Mortality rates in an uncomplicated case of semi-starvation don’t increase until weight loss of more than 40%. Also, nurses should assume that the anorexic patient’s immune function already is impaired.
• Striking a nutritional balance
The goal is to ensure the patient gets a reasonable rate of refeeding while avoiding any overfeeding, Apovian says. Estimating the caloric needs of marasmic patients is difficult; initially, it is important to restrict the amount of support to the level of need and not more.
In a 1990 paper, Apovian and her colleagues proposed using a formula called the Harris-Benedict Equation to predict basal energy expenditure (BEE).
Once the BEE is estimated, nurses should start feeding to not more than 20% above the BEE level at a resting metabolic rate. The patient’s glucose intake should also be monitored carefully to avoid excess. But a positive protein intake will work immediately on restoring lean body mass as long as the patient’s kidneys are functional.2
| Frequency of Medical Disorders Anorexia Nervosa (n=31) | ||
| Disorder | Number | Ratios |
| Hypoproteinemia | 23 | 74% |
| Iron deficiency/anemia | 18 | 58% |
| Clinical malnutrition | 13 | 42% |
| Hypocalcemia | 12 | 38% |
| Cardiac arrhythmia | 10 | 32% |
| Nutritional hepatitis | 10 | 32% |
| Irritable bowel syndrome | 9 | 29% |
| Peptic ulcer | 6 | 19% |
| Hypokalemia with cardiac irregularities | 5 | 16% |
• Exercising caution
In Apovian’s report, she says that carbohydrates given too soon can increase insulin and fluid levels that can stress the heart and over-stimulate the nervous system. These conditions increase the likelihood of cardiac arrhythmia, which already affects many anorexics. Therefore, fluid retention should be avoided, especially in the first few days of treatment.
High fluid levels can affect the heart, but it can also falsely suggest weight gain and mislead nurses and physicians about the effectiveness of the nutritional support, Apovian says.
Many physicians aren’t familiar with those caveats, says Trujillo. Therefore, ICU nurses should exercise caution and seek expert advice about all phases of the nutritional regimen.
In fact, Apovian indicates that ICUs are not a good first option for hospital-admitted anorexics. "If cleared of congestive heart failure or cardiomyopathy, the patient would probably be better served in an inpatient psychiatric unit where the staff is specially trained in refeeding syndrome," Apovian says.
Frequency of Medical Disorders Anorexia/bulimia with purging (n=19) |
||
| Disorder | Number | Ratios |
| Iron deficiency/anemia | 8 | 42% |
| Hypoproteinemia | 6 | 32% |
| Hypomagnesemia | 5 | 26% |
| Hypokalemia | 4 | 21% |
| Gastritis | 3 | 16% |
| Granulocytopenia | 2 | 11% |
| Leukopenia with white blood count below 3500 | 2 | 11% |
| Nutritional bone marrow suppression | 2 | 11% |
| Cardiac arrhythmia | 1 | 5% |
| Frequency of Medical Disorders Anorexia/bulimia with purging (n=19) | ||
• Being fully informed
Halls says the more you know about the patient during admission, the better you can help implement a treatment protocol that includes appropriate nutritional support.
If the patient is admitted through the emergency department, but has been previously treated in an eating disorders unit, it’s likely that he or she has a detailed history and eating disorders questionnaire in the medial record. The patient’s internist or primary care physician can also provide input.
The bedside nurse and clinical nurse specialist should study the internist’s evaluations, especially the physical exam notes. There also should be information from a psychiatrist that will provide a broader picture of the patient’s condition.
• Anticipating surprises
In Hall’s research, he found that nearly three-fourths of patients admitted to a hospital were unaware that they had serious secondary problems related to the anorexia. Nearly one in five anorexics admitted to ICUs were also laxative abusers, meaning that they used them up to four times a week, and some were physiologically dependent on them. "Anorexics admitted to hospitals are actually more seriously ill than previously thought, and the supporting data in 10 years hasn’t changed," he concludes.
References
1. Hall RC, Hoffman RS, Beresford TP, et al. Physical illness encountered in patients with eating disorders. Psychosomatics 1989; 30:174-191.
2. Apovian CM, McMahon MM, Bistrian BR. Guidelines for refeeding the marasmic patient. Crit Care Med 1990; 18:1,030-1,033.
[Editor’s note: Clinicians can read about the Harris-Benedict Equation to predict basal energy expenditure in the book, Nutritional Assessment of the Hospitalized Patient: A Practical Approach, pp. 183-205, copyright 1984, published by Blackwell’s Scientific Publications, 100 University Ct, Blackwood, NJ 08012. Telephone: (609) 228-8900. On-line order inquiries: [email protected].]
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