Nutritional Therapy for Critically Ill Patients in the ICU – Current Recommendations
Critically ill patients hospitalized in the intensive care unit (ICU) require nutritional support to maintain adequate energy intake. Only by doing so can their clinical condition be prevented from worsening. Therefore, we summarize the current recommendations regarding nutritional therapy as part of care in the ICU in the following text.
Introduction to the Issue
Clinical improvement is usually observed after 3–7 days in the ICU. It has been proven that after trauma or infection, there is a short-term decrease in cardiac output and body temperature (first phase). The second phase is characterized by hypercatabolism. Its early period lasts 48 hours, with the late period following for the next 5–7 days. If the patient does not recover during the second phase, there is a transition to the critical phase (persistent inflammation and catabolism syndrome – PICS), which can last for weeks. There is an increase in energy expenditure, insulin resistance, hyperglycemia, and proteolysis. This can reach 12–16 g of nitrogen per day over several days, potentially increasing up to 30 g per day. Loss of muscle mass, patient frailty, and sarcopenia are inherently linked with a reduced quality of life for the next 6–12 months. The risk of organ failure or death is also increased.
Not only malnutrition but also overfeeding of the patient prolongs hospitalization and increases the risk of artificial lung ventilation, infection, morbidity, and mortality. Therefore, adequate nutritional support and rehabilitation are necessary not only in the ICU but also in the standard department.
Current Recommendations
The measurement of resting energy expenditure (REE) is preferred using indirect calorimetry. It can also be derived from VCO2 on the ventilator according to the following formula:
- REE = 8.2 × VCO2
The optimal daily caloric intake should correspond to 70–100% of REE. In a retrospective observational study, patients with a caloric intake > 100% REE surprisingly showed higher mortality due to overfeeding.
Enteral nutrition is recommended to start soon after the patient is admitted to the ICU. The caloric target should ideally be achieved within 3 days. If enteral nutrition is not sufficient, parenteral nutrition can be initiated between the 3rd and 7th day of ICU stay. The recommended protein intake is 1.3 g/kg/day. Observational (but not prospective randomized controlled) studies indicate a reduction in mortality for patients with higher protein intake. However, this should also depend on the overall condition. For example, in patients with sarcopenia, increased protein intake may improve prognosis, whereas this trend has not been observed in patients in septic conditions.
During the patient's ICU stay, it is advisable to monitor (among other things) the concentration of potassium, phosphates, and magnesium in the blood. In the case of electrolyte imbalance, its correction and reduction of energy intake by 50% the following day are necessary.
For critically ill patients, rehabilitation has been proven to have a positive impact not only on shortening the duration of artificial ventilation. It is appropriate to consider exercise even in the early hours. Early initiation of rehabilitation (in the first week of ICU admission) also helps to preserve muscle fiber cross-section in patients with septic shock. Physical activity (e.g., cycling on an ergometer) subsequently speeds up recovery and improves quality of life.
After extubating the patient, oral intake must always be assessed. In the case of dysphagia (which threatens 3–60% of cases), the patient should be switched to enteral (nasogastric tube) or parenteral nutrition. Reducing energy intake increases the risk of pneumonia, reintubation, and death.
Conclusion
Critically ill patients in the ICU are at risk not only of malnutrition but also overfeeding. Adequate nutritional therapy and rehabilitation are required to reduce morbidity and mortality, both during the patient's ICU stay and after their transfer to the standard department and possible discharge from the healthcare facility.
(mafi)
Source: Singer P. Preserving the quality of life: nutrition in the ICU. Crit Care 2019; 23 (1): 139, doi: 10.1186/s13054-019-2415-8.
Did you like this article? Would you like to comment on it? Write to us. We are interested in your opinion. We will not publish it, but we will gladly answer you.
