Critical Illness/Major Surgery
The heterogeneity of patients admitted to the ICU is very high. Therefore, it is not easy to generate evidence for clear guidelines. Existing guidelines should be seen as support to make decisions for each patient on an individual basis. ESPEN recently updated their guidelines for ICU patients (Singer, et al., 2019). Every critically ill patient staying for more than 48 hours in the ICU should be considered at risk for malnutrition. Critical illness is associated with proteolysis and muscle loss to even up to 1 kg per day. A higher protein intake preferable in combination with some physical activity might be needed.
While a too large energy delivery might result in overfeeding and refeeding, and may therefore be deleterious, increased protein delivery may be of benefit for the critically ill patient (Singer, et al., 2019). It was shown that the amount of protein provided to most ICU patients is less than the loss. An oral diet (incl ONS) should be preferred over ETF or PN for patients who are able to eat. If not possible early ETF (within 48 hours) should be initiated. However, early full ETF or PN should be avoided to avoid overfeeding. Since the caloric needs of each patient differs based on their condition, it is advised to calculate the need on an individual basis.
Several studies showed the benefit of high protein in the ICU patient (Weijs, et al., 2012). It was for example shown that in 886 patients who received a protein amount between 1.2 and 1.5 g/ kg body protein/ day had reduced 28-day mortality. In another study, 2824 patients showed an improvement in survival when patients received more than 80% of their protein target. Finally, a significantly higher survival was shown when protein was administered > 1.3 g/kg/d, resulting in a gain of 1% survival for each 1 g of protein (Plauth, et al., 2019).
Home Enteral Nutrition
Prior to discharge from hospital patients at risk of malnutrition (e.g. patients with neurological diseases, head injury, head and neck cancer gastrointestinal diseases including malabsorptive syndromes), either ONS or ETF should be considered (Bisschoff, et al., 2020).
Trauma and Burn
In the last decade, a lot of changes have been included in the guidelines regarding the use of glutamine in the ICU. Hypothetically, glutamine should be beneficial in a large amount of the ICU patients. However, recent evidence showed that the benefit of supplementing with glutamine is mainly seen in certain patient groups and not in other groups.
- In patient with burns (>20% body surface area), additional enteral doses of glutamine (0.3-0.5 g/kg/d) should be administered for 10-15 days as soon as enteral nutrition has been started.
- In critically ill trauma, additional enteral nutrition doses of glutamine (0.2-0.3 g/kg/d) can be administered for the first five days with enteral nutrition. In case of complicated wound healing, it can be administered for a longer period of 10 to 15 days.
- In ICU patients admitted for burn and trauma patients, additional enteral glutamine can be administered.
Glutamine supplementation should be avoided in unstable and complex ICU patients, and should NOT be administered in ICU patients suffering from liver and renal failure (Singer, et al., 2019).
A recent study showed a U-shaped association of plasma glutamine levels and clinical outcome. (Rodas, Rooyackers, Hebert, Norberg, & Wernerman, 2012). Most patients with very high glutamine concentrations suffered from acute liver failure. Glutamine is a very potent gluconeogenic and ureogenic amino acid. Liver failure reduces the clearance of ammonia produced from glutamine metabolism.
Studies in major burns patient, repeatedly demonstrated that glutamine supplementation has a beneficial effect, reducing infectious complications and also mortality. This has been confirmed doing meta-analysis studies (Zanten van, Dhaliwal, Garrel, & Heyland, 2015). It has also been included in the ESPEN guidelines for burn patients (Rousseau, Losser, Ichai, & Berger, 2013). The higher requirement of glutamine can be explained that specifically in burn patients is lost in larger amounts than any other amino acid. A large multi-center trial is running at the moment targeted to enroll 1200 severe burn patients in where enteral glutamine treatment is being studied (Wischmeyer, 2019).
The efficiency of glutamine on infection reduction was also suggested in major trauma (Houdijk, et al., 1998). In a randomized controlled trial, it was shown that a glutamine containing supplement reduced time to wound closure to 22 days versus 35 days in the control group. In another study with patients suffering from head and neck cancer, a significant increase in fat-free mass and quality of life scores was shown.