In the peri-operative period, the primary nutrition goals are to evaluate the patient for pre-existing malnutrition, treat malnutrition to optimize surgical readiness, minimize starvation, prevent postoperative malnutrition, and support anabolism for recovery
As the role of the anaesthesiologist expands to include perioperative nutrition optimization, dieticians are integral to the perioperative care team. For malnourished patients who cannot meet protein/ calorie requirements via oral nutrition, a dietician should be consulted and home enteral nutrition initiated for a period of at least 7 days preoperatively.
Why pre-operative nutrition is crucial?
- Pre-operative physiological reserve is important to meet the surgical stress response which includes increased cardiac output and delivery of oxygen. At the same time, lean body mass reserve is equally important to support the stress-induced mobilization of reserves so that the physiological integrity and strength are not compromised. Patients who are low on lean body mass reserve have less capacity to respond to the surplus energy demands post-surgery.
- When patients do not meet their energy needs from normal food it is recommended to encourage these patients to take ONS during the preoperative period unrelated to their nutritional status.
- Preoperatively, ONS shall be given to all malnourished cancer and high-risk patients undergoing major abdominal surgery. A special group of high-risk patients is the elderly people with sarcopenia.
Identifying patients at risk
- The use of CT scan and ultrasound in lean body mass (LBM) evaluation to identify sarcopenia associated with surgical risk and aid nutrition intervention is going to support. Recent evidence has demonstrated that several strategies can enhance outcomes in malnourished patients before surgery. These include optimizing nutrition before the operation, implementing immune-boosting nutrition protocols for all major surgeries, avoiding prolonged fasting before surgery, incorporating high-protein nutritional supplements in the postoperative period, and encouraging the early resumption of oral intake after surgery.
The real issue -> A diagnosis of malnutrition rarely leads to adequate intervention. Truly, malnutrition is a silent epidemic occurring daily in our care of patients.
Why nutrition post-surgery is crucial
- Any surgical trauma induces a stress response equivalent to the injury which is characterized by hormonal, hematological, metabolic, and immunological changes. Clinical manifestations of the same would be:
- Salt and water retention to maintain plasma volume.
- Increased cardiac output and oxygen consumption to maintain systemic delivery of nutrient and oxygen-rich blood.
- Mobilisation of energy reserves (glycogen, adipose, lean body mass) to maintain energy processes.
- Repair tissues and synthesize proteins involved in the immune response
Nutritionally-relevant clinical consequences of the surgical stress response include:
- Whole body protein catabolism-post surgery
Catabolism manifests as the wasting of muscle which occurs due to reprioritization. Lean body mass is mobilized releasing amino acids into circulation for preferential uptake by the liver to allow synthesis of acute phase reactions and production of glucose from non -carbohydrate sources via gluconeogenesis.
- Hyperglycaemia – post-surgery
Hyperglycaemia is a result of peripheral and central insulin resistance. Peripheral insulin resistance refers to impaired insulin-mediated glucose uptake, whereas central insulin resistance refers to the inability of insulin to suppress glucose production from the liver.
Why post-operative nutrition is crucial?
- All major surgical patients should consume high protein oral nutrition supplements postoperatively to reduce the length of stay and continue for at least a 1-month post hospital discharge to optimize recovery
- Any patient who cannot achieve more than 50% of protein/calories requirement by ONS or enteral nutrition should receive parenteral nutrition for more than 7 days, in combination with enteral nutrition where feasible.
- There is robust evidence to conclude that allowing food without delay (at will) is safe and effective and that withholding of oral intake (nil-by-mouth) for the first postoperative days is unnecessary in most types of major abdominal operations including surgeries necessitating proximal bowel anastomosis. However, during the first postoperative days, it may be difficult to achieve the full energy and protein requirements exclusively with natural foods. Accordingly, it is recommended to integrate oral nutritional supplements to reach the nutritional target.
- Furthermore, if full tolerance to oral intake (including oral supplements) is not accomplished and the nutritional needs are not covered by per is within 5 to 7 days after the operation, artificial nutrition is recommended to be prescribed at once.
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