Nutritional Support Therapy
Currently, there is a lack of highly effective antiviral drugs for COVID-19 patients. In addition to effective respiratory and circulatory support for severe and critically severe patients, nutritional support treatment is of great significance for improving patients’ immune function, shortening the course of the disease, and reducing the mortality of patients. Based on the Rapid Recommended Guideline for COVID-19 Diagnosis and Treatment (Standard Edition), Dynamic assessment of patients' nutritional risks and timely nutritional support. Those who can eat by mouth recommend a diet with high protein and carbohydrate. Enteral nutrition should be opened as soon as possible for those who can't eat orally and have no contraindication of enteral nutrition. Those who cannot open enteral nutrition should be given parenteral nutrition in time, and strive to reach the target energy as soon as possible.
After the patient’s nutritional status is fully assessed, a nutritional plan should be formulated for the patient’s nutritional needs to maintain the patient’s nutritional status at a normal level. Nutritional support includes enteral nutrition and parenteral nutrition, and the main nutrients used in nutritional therapy include carbohydrates, proteins, fats, electrolytes, vitamins, water, etc.
Medical and Nutritional Treatment Recommendations for COVID-19 Patients
The expert group of Enteral and Parenteral Nutrition Society, Chinese Medical Association has made the following recommendations regarding the medical and nutritional treatment of COVID-19 patients:
- 1) Principles: Nutritional therapy is a necessary treatment method and one of the core components of comprehensive treatment measures for COVID-19 patients. Nutritional therapy should be based on the nutritional diagnosis.
- 2) Methods: Nutrition treatment, dietary and nutrition education, oral nutrition supplement (ONS), tube feeding, supplementary parenteral nutrition (SPN), and total parenteral nutrition (TPN) are carried out according to the five-step method.
- 3) Energy: A supply of 20-30 kcal/ (kgd) is recommended, according to the disease’s severity.
- 4) Protein: Patients’ demand for protein increases. It is recommended to increase the supply of branched-chain amino acids according to the supply of 1.0-2.0g/ (kg d).
- 5) Fat: Prioritize medium and long-chain fatty acids, and increase the proportion of n-3 fatty acids and n-9 fatty acids.
- 6) Nonprotein energy supply ratio: The ratio of glucose to fat milk is (50-70)%: (30-50)%. The ratio of nonprotein thermal calorie (kcal) to nitrogen content (g) is (100-150): 1.
- 7) Fluid volume: Pay attention to maintaining fluid balance. For patients with a large area of lung consolidation and elderly patients, it is recommended to control the volume of intravenous infusion.
- 8) Micronutrients: Supplements, such as multivitamins and minerals, should be given regularly.
- 9) Immunonutrients: Pay attention to weighing the advantages and disadvantages and master the indications.
- 10) Monitoring: Closely observe the adverse reactions, assess the therapeutic effect, dynamically adjust the treatment plan, and pay attention to individual differences.
Nutritional Treatment Plan for COVID-19 Patients
Purpose of Nutritional Therapy
Nutritional therapy aims to reduce the weight loss of patients and the decomposition of body protein and increase body weight and body protein. For patients with chronic respiratory insufficiency, nutritional therapy aims to gradually correct their malnutrition and negative nitrogen balance, improve muscle protein synthesis, and reduce respiratory muscle fatigue.
General Principles of Nutritional Therapy
For most COVID-19 patients, the general principles of nutritional therapy are recommended as follows:
- 1) Give a high-protein, high-fat, low-carbohydrate diet or parenteral nutrition.
- 2) The proportion of calories of protein, fat, and carbohydrates is 20%, 20%-30%, 50%-60%.
- 3) The daily protein supply should be 1.0-1.5 g/kg, and for critically severe patients, it should be increased to 1.5-2.0 g/kg.
- 4) Supplement various vitamins and trace elements in appropriate amounts every day, adjust the number of electrolytes according to the clinical situations, and especially supplement potassium, magnesium, phosphorus, and other trace elements that affect respiratory muscle function.
Nutritional Treatment Approaches for COVID-19 Patients
According to the Expert Recommendations on Medical Nutrition Therapy for Patients with COVID-19 by Enteral and Parenteral Nutrition Society, Chinese Medical Association, the five-step method is recommended for nutritional therapy: dietary and nutrition education, ONS, tube feeding, enteral nutrition, SPN, and TPN. Patients with COVID-19 should choose a proper nutritional feeding route based on the diseases severity, gastrointestinal function, and respiratory support.
- 1) Oral intake or oral enteral nutrition is preferred for patients with mild symptoms who can eat autonomously. If they cannot eat on their own, it is recommended to activate enteral nutrition within 48 hours.
- 2) Severe patients are often in a state of high catabolism due to severe infections, and together with weakened anabolism, low immune function, and insufficient intake, they are prone to malnutrition. If nutrition is not supplemented in time, it will increase protein consumption and affect the organs’ structure and function, resulting in organ failure and increased mortality. Enteral nutrition is preferred if the structure and function of the patient’s gastrointestinal tract are not damaged. Because food stimulates the intestinal nerve, it can activate the intestinal neuroendocrine-immune system, which helps maintain the intestinal immune function and prevent intestinal infection. If patients cannot eat after endotracheal intubation, food can be given through the nasogastric tube. Enteral nutrition should be postponed in severe patients with uncontrolled shock, severe hypoxemia, severe acidosis, upper gastrointestinal bleeding, gastric residual volume > 500 mL/6 h, intestinal ischemia, intestinal obstruction, and abdominal compartment syndrome. For patients with oral or enteral nutrition contraindications, parenteral nutrition should be activated within 3-7 days. Combining parenteral nutrition in the case of insufficient enteral nutrition intake can avoid the risk of increased blood sugar and blood lipid, which may result from insufficient energy intake and total parenteral nutrition. At the same time, to avoid overfeeding, enteral nutrition, and parenteral nutrition of critically severe patients should gradually reach the target amount of feeding within 3-7 days.
- 3) Patients with noninvasive ventilation are recommended to change to a nasal mask or temporarily switch to transnasal hyperflow oxygen therapy when eating to reduce the risk of hypoxemia during eating. The “button-type” mask is preferred for patients with noninvasive ventilation because the gastric tube outlet is installed on the mask, which does not affect the efficiency of noninvasive ventilation and is more conducive to the smooth implementation of enteral nutrition. Postpyloric feeding is recommended in patients with severe gastric bloating.
- 4) For patients with invasive mechanical ventilation or patients receiving extracorporeal membrane oxygenation (ECMO), if there is no contraindicated enteral nutrition, it is recommended to use tube feeding enteral nutrition as soon as possible. Transgastric tube feeding is the preferred feeding channel. In case of gastric retention, erythromycin (100-250mg) can be used three times a day to promote gastrointestinal motility or metoclopramide (10 mg) three times a day, and the amount should be reduced to one-third after 72 hours. If it still cannot be relieved, postpyloric feeding can be selected. If the patient has high aspiration risk, such as loss of airway protection ability, age > 70 years old, decreased level of consciousness, poor oral care, prone position, gastroesophageal reflux, and single load, postpyloric feeding can be the first choice for enteral nutrition. In view of the pandemic’s current severity and the relatively insufficient nursing power, postpyloric feeding may be a better way of providing nutrition.