Experts argue for earlier nutritional aid for patients
April 1, 1999 5 minutes read
Experts argue for earlier nutritional aid for patients
Extubated cases should be fed within 36 hours
Patients who get insufficient amounts of protein and other nutrients while in the ICU can suffer severe physical problems. Research indicates that critically ill patients in general should be given well-planned nutritional support sooner rather than later.
There are evidence-based reasons for earlier feeding. Patients who receive insufficient protein while in the ICU are three times more likely to suffer from systemic disorders including severe skin and muscle tissue breakdown compared with patients who receive appropriate levels of enteral nutrition. The presence of bacteria in the intestinal lining and the incidence of gastrointestinal infection also run high.
These patients generally take longer to be weaned from intubation; their overall recovery is much slower, and they are likely to remain in the ICU much longer, according to Ann-Marie Hedberg, DrPH, RD, assistant director for nutritional services at St. Luke’s Episcopal Hospital in Houston.
But in setting proper nutritional support standards, how can nurses make appropriate assessments? How can they ensure that patients are not being overfed or underfed? And in the absence of good assessment tools, which condition — overfeeding or underfeeding — carries more serious medical implications for the patient?
Experts recommend early patient feeding
In the ICU, there is a tendency either to overfeed or underfeed patients, particularly those who are on ventilator support, are extremely weak, or suffer from severe trauma or post-operative complications. As a general rule, these patients normally require high caloric intake. And they require that feeding begin as early as possible to prevent muscle catabolism, says Elaine B. Trujillo, MS, RD, senior clinical dietitian at Brigham and Women’s Hospital in Boston.
It’s better to begin feeding early rather than late. Nurses should encourage physicians to begin writing nutrition orders as part of a formal enteral feeding protocol as soon as it is deemed that the patient either needs the nutritional support or can tolerate it, says Hedberg.
With extubated patients feeding should begin within 36 hours. If nurses wait a day or longer, the patient’s intestinal tract may begin to suffer, which may then require the less-favored TPN (total parenteral nutrition) feeding, says Hedberg. As an alternative, TPN always carries the risk of higher infection rates in the digestive tract because of disuse.
TPN easier but not as beneficial
Many nurses prefer TPN partly because of the messiness associated with using fluids and disposing of waste materials in enteral feeding. But TPN, while convenient, isn’t as beneficial to the patient because enteral feeding more closely approximates real food in nutritional content, Trujillo adds.
An internal study conducted at St. Luke’s found that pulmonologists in general were delaying enteral feeding to extubated patients by as long as two weeks out of concern for potential formula reflux, or backing up of fluid into the lungs. But part of the reason that the delay went unchanged was that no one individual established consistent practice parameters on tube feeding, Hedberg recalls.
Today, the hospital requires that all new critical care nurses and medical residents get training in departmental TPN and enteral feeding standards.
Most hospitals do a good job of monitoring patients’ nutritional needs in the ICU. But assessment standards and criteria vary widely from hospital to hospital. And national guidelines, while readily available in the medical literature, aren’t always followed uniformly by physicians. (A Medline or Index Medicus search can lead to recent research-based nutritional guidelines.)
Unit nurses should work with the department’s dietitian in monitoring patients’ daily nutritional needs and communicating those needs to the attending physician. Verbal communication is always better than looking for information in the patient’s record because the dietitian may not always make notations about daily changes in the chart, Trujillo says.
In a week, the changes may amount to something significant. Furthermore, the mode of feeding required also can change from one day to the next, says Trujillo, It can go from intravenous feeding, or TPN to the much-preferred enteral, or tube feeding. If so, physiologically the patient’s responses will probably change noticeably too, Trujillo adds.
At Brigham and Women’s, a software algorithm is used by nurses and physicians to determine the appropriate nutritional support plan for a given patient via a series of questions that helps them select the appropriate nutrient mix and their levels. Presented in a decision-tree form, physicians can go through the algorithms and execute an order on the same program.
Any hospital can develop a similar set of algorithms with information obtained from various Web sites on the Internet. But the process requires the help of an information specialist, and the facility needs to have a sufficiently sophisticated information system infrastructure to create such a program, according to Rita Zielstorff, corporate manager for information systems research and development at Partners HealthCare System, which owns Brigham.
Indeed, technology can help match a patient to a proper feeding regimen. Calorimetry monitors, considered the gold standard by critical care dietitians, have been used for years.1 But the equipment is expensive to buy (at an average cost of $20,000) and maintain. As a result, they are only available at the largest institutions.
The machines are usually used only for the most seriously ill patients. They determine a patient’s energy expenditure and therefore his or her caloric need by measuring the amount of oxygen the patient takes in and the expended carbon dioxide level. Dietitians use the tool to make accurate nutritional assessments.
But with experience, a medical team can approximate the work of calorimetry, says Hedburg. The margin of difference, according to some research, is about 200 or better calories, she states. By applying their medical knowledge and experience, nurses can make reasonable assessments on patients. Discerning subtle changes in the patient’s condition provide clues, she adds.
Changes in blood pressure, for example, respiratory rate, skin color, or oxygen levels may denote certain activities in the body. But they also could mean the nutritional regimen needs adjustment. Check with the dietitian and physician on these changes as part of a visual assessment, Hedberg advises.
Is continual feeding a good idea?
Monitor the patient hourly if necessary and recheck not only the amount but the composition of the formula. Trujillo advises that nurses use a subjective assessment tool to track patient responses to nutrient support. (See subject assessment chart on p. 43.)
Finally, determine whether continual feeding is a good idea. An intermittent enteral flow may help provide the amount the patient needs and prevent overfeeding compared to a continuous flow. As a general rule, however, it is safer to overfeed than underfeed an unstable patient, says Trujillo.
But each condition carries consequences. Overfeeding can increase carbon dioxide production and slow ventilator weaning. It can also result in metabolic complications such as hyperglycemia, which can lead to nosocomial infections.1 Underfeeding will inevitably lead to starvation, increased morbidity, and death.
Experts don’t know exactly how vitamins, minerals, and other nutrients act in various disease states. But they do know that proteins are essential in preventing hypercatabolism in critically ill patients. They also know that vitamin and mineral requirements are often overlooked in the critically ill.
The goal, according to researchers, should always be to achieve nutritional support that comes as close to the patient’s actual metabolic requirements as possible.1
Reference
1. Trujillo EB, Robinson MK, Jacobs DO. Nutritional assessment in the critically ill. Crit Care Nurs 1999; 19:67-78.
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