SHOW NOTES
What impact does surgery have on the body?
- Intentional trauma
- Physiological response
- Psychosocial impact
- Stress
When we think about surgery, it's essential to understand that it triggers a significant reaction in the body known as the 'stress response.' This response is a complex interplay of hormonal and metabolic changes directly linked to the degree of tissue damage during surgery. It can intensify if there are any complications after the operation.
Let's break it down: The whole process starts when the hypothalamic-pituitary-adrenal axis, or HPA axis, kicks into gear. This leads to a surge in hormones like cortisol, growth hormone, glucagon and catecholamines. These hormones are important because they help the body cope with stress by boosting energy availability and adjusting other bodily functions.
- Ebb phase (0-48hrs)
- Increased catabolism of stored glycogen (glycogenolysis)
- Suppression of insulin secretion → transient hyperglycemia
- Increased catecholamines, cortisol, and inflammatory cytokines (IL-6, TNF-α)
- Flow phase (3-10 days)
- Hypermetabolism (increased BMR)
- Increased protein catabolism → muscle breakdown (to provide amino acids for tissue repair and immune function)
- Increased lipolysis (fat breakdown) for energy
- Sustained insulin resistance → continued hyperglycemia
- Enhanced GNG
- Pro-inflammatory response → increased cytokines and acute-phase protein production
In the initial stages after surgery, the body releases a wave of pro-inflammatory cytokines. These cytokines jumpstart the healing process by promoting inflammation, which is important for healing surgical wounds. However, to keep this inflammation from going overboard, the body soon follows up with anti-inflammatory cytokines.
These inflammatory processes have widespread effects across the body. For example, they can influence how the hypothalamus regulates body temperature or how the liver produces certain proteins that help fight infection and aid in wound healing.
But here’s where it gets even more interesting: other hormones like glucagon, cortisol, and adrenaline also play a role in modulating these responses. They can affect everything from your blood sugar levels to how your cardiovascular system handles the stress.
So, why is all this important? Well, by understanding and managing these responses effectively, we can significantly improve how patients recover from surgery. It’s all about helping the body maintain balance during a time when it’s incredibly vulnerable
Disruption of Metabolic Homeostasis: Surgery often disrupts the body's normal metabolic balance, notably through insulin resistance, where cells fail to respond effectively to insulin, leading to 'diabetes of the injury.'
Insulin Resistance and Hyperglycemia: Insulin resistance can cause high blood sugar levels, significantly increasing the risk of surgical complications and mortality. Post-surgery, the body may enter a catabolic state, breaking down muscle instead of fat, which impairs wound healing, weakens the immune system, and reduces muscle strength.
Increased Risks for Vulnerable Groups: Elderly, diabetics, and cancer patients are particularly at risk due to their compromised metabolic and inflammatory states. These groups have less physiological reserve, leading to pronounced catabolic states and increased risk of severe post-operative complications.
Impact on Recovery and Outcomes: The metabolic chaos from insulin resistance to protein loss not only delays recovery but also exacerbates risks of infection and other complications. Effective management of these changes is crucial for improving surgical outcomes and ensuring that patients thrive post-surgery.
ERAS helps to mitigate these by
Surgery isn't just about the physical repair or removal of tissue; it triggers a cascade of stress responses in the body that can complicate recovery. These include everything from the psychological impacts of anxiety and the physiological effects of fasting to direct tissue damage and the systemic reactions to it, such as fluid shifts and hormonal imbalances.
Key Components of ERAS:
Comprehensive Care: ERAS isn't just a single technique but a suite of practices designed to address every aspect of the patient's journey — before, during, and after surgery. This approach aims to minimise the stress responses by controlling pain, reducing fasting times, optimising fluid management, and promoting early mobility.
Minimising Fasting: One traditional practice that ERAS revises significantly is the preoperative fasting rule. Old guidelines that required fasting from midnight before surgery are now replaced with more lenient, evidence-based practices that allow intake of clear fluids up to two hours and solids up to six hours before surgery. This change helps maintain normal blood glucose levels, reduces stress, and decreases the body's shift into a catabolic (muscle-degrading) state.
Nutritional Optimisation: ERAS protocols emphasise the importance of not entering surgery in a depleted state. By allowing a carbohydrate-rich drink shortly before surgery, patients are better hydrated and less anxious, which in turn reduces insulin resistance and preserves muscle mass — critical factors in speeding up recovery post-surgery. Post-operatively, oral nutrition may be delayed by the medical team until bowel function returns, typically taking close to a week. This delay is stated to reduce postoperative complications such as abdominal distension and nausea/vomiting.For the first several days post surgery fluids of limited nutritional value such as water are provided to patient until tolerance is established leading to insufficient nutrition intake during this time increasing the risk of malnutrition. The ERAS protocol promotes early oral intake within 24 hours post surgery departing from traditional fasting practices. Research suggests that between 40-50% of surgical patients have some degree of malnutrition. Pre-operative malnutrition is an independent predictor of poor post-operative outcomes. Therefore addressing malnutrition is a key component of the ERAS protocol.
Immune-Enhancing Diets: Post-surgery nutrition is just as crucial. ERAS encourages diets rich in nutrients that bolster the immune system and enhance wound healing. This includes omega-3 fatty acids, which help modulate the inflammatory response; arginine, which supports protein synthesis and tissue growth; glutamine, which is vital for cellular health and recovery; and nucleotides, which are essential for rapid cell division and immune function .Immuno-nutrition is a specialised medical nutrition therapy that has been shown to adjust the body's inflammatory response: It incorporates specific nutrients like omega-3 fatty acids, arginine, polyunsaturated fatty acids, and nucleotides. It's typically recommended starting 5-7 days before surgery and continuing post-operatively for over 7 days or until oral intake meets at least 60% of the patient's nutritional requirements.
How can we use this info to optimize surgical outcomes?
Patient education
Early nutrition pre and post surgery - Minimise fasting time
What is ERAS? How does it differ from traditional care/practice?
- Introduced by Henrik Kehlet in 1997, the Enhanced Recovery After Surgery (ERAS) protocol has revolutionised surgical practices by optimising perioperative care.
- A key aspect of ERAS is its interdisciplinary approach, involving healthcare professionals from various specialties to minimise surgical stress and facilitate recovery.
What is malnutrition?
Malnutrition, is defined as an involuntary reduction in body weight, muscle mass and physical capabilities, affects up to 65% of surgical patients and can worsen during hospital stays. Enhancing nutritional status and promoting functional nutrition therapy is essential, even for
patients without evident malnutrition, particularly when prolonged perioperative oral intake challenges arise. Addressing malnutrition is essential for preventing surgical complications, prolonged
hospital stays and higher healthcare costs.
What are the benefits of ERAS for the patient?
It has been shown that the key physiological benefits include:
-enhances the body’s anabolic processes
-promotes wound healing, which is critical for patient recovery.
-Reduces the risk of nutritional depletion
-Minimises insulin resistance, a common issue post-surgery, allowing for better blood sugar control and improved metabolic function.
-Reduce protein catabolism
-And lowers the risk of pressure injuries, which can develop due to extended immobility after surgery.
What are the benefits of ERAS from a healthcare perspective?
From a healthcare perspective, ERAS has been shown to
-shorter length of hospital stay for patients,
-Lower risk of ICU transfer rates
-reduce readmission rates
-And all of these improvements lead to lower healthcare costs, not just for the hospital but for the overall healthcare system, as fewer complications and shorter stays reduce the financial strain.
Step 1: Screen & Strengthen
- If you’ve lost any weight unintentionally in the lead up to surgery, or been eating poorly because of a reduced appetite, you may be at risk of malnutrition and it’s really important to address this prior to surgery.
- Research suggests that between 40-50% of surgical patients have some degree of malnutrition. Pre-operative malnutrition is an independent predictor of poor post-operative outcomes. Addressing malnutrition is a key component of the ERAS protocol and why it’s effective in improving surgical outcomes for patients.
- Book an appointment with a dietitian who can guide you on appropriate dietary changes to minimise muscle loss, build you up and optimise nutritional status and stores pre-op.
- A well-nourished body tolerates surgery better, heals faster, has a stronger immune system to fight infection, and experiences fewer complications.
Step 2: Consider Immunonutrition
- If you’re planned for major surgery, especially certain cancer and abdominal surgeries, consider the use of an immunonutrition supplement in the 5-7 days pre op. These are the supplements loaded with arginine, n3s, glutamine and nucleotides to support the immune system and reduce inflammatory responses, potentially leading to fewer infections and better recovery.
Step 3: Build Your Strength & Energy Stores prior to surgery
- Carb load with food in the days leading up to surgery - think that big bowl of pasta a footy player would have the night before the grand final.
- ERAS protocols have significantly reduced or eliminated long periods of "nil by mouth" (NBM) before surgery.
- Ask your surgical team exactly when you need to stop eating solid food – it might be much later than you think, often around 6 hours before surgery for a light meal. For clear fluids, it could be as little as 2 hours before!
- We’ll make the most of every second to prevent unnecessary dehydration, hunger, anxiety, and preserve your body's energy
Step 4: The Pre-Surgery Carb Load using clear fluids
- Many ERAS protocols include a special carbohydrate-rich drink taken a few hours before surgery. Your hospital may provide this, but if they don’t, we can organise orders for you or point you in the right direction. It’s usually a clear, sweet drink. Think of it as topping off your fuel tank right before the 'race'."
- These have been shown to reduce post-operative insulin resistance (which can slow healing), help maintain muscle strength, can reduce nausea, and improve overall wellbeing. It basically tells your body it's in a 'fed' state, not a 'starvation' state, heading into surgery.
- This is best done with tailor made medical nutrition drinks as they come prepped with the correct doses of maltodextrin-polymer carbs and a lower osmolality than other solutions, which essentially means they gentler on your gut and better for gastric emptying so they don’t linger in your gut during surgery.
- Always follow surgical instructions, but ideally we’re aiming for 100 grams of carbohydrate the night before surgery and about 50 grams of carbohydrate in clear fluids approximately 2 hours before anesthesia. This might look like 4 x 200ml drinks the night before, and 2 the morning of surgery
- If you can’t access these drinks, apple or cranberry juice are reasonable replacements.
- Drop us an email or message or give us a call if you’d like advice on where to get pre-op and immunonutrition supplement drinks.
Then we move on to post op and
Step 5 which is aiming to eat early.
- ERAS encourages starting to eat and drink as soon as it's safe after surgery – often within hours, not days!
- As soon as your team says it's okay, try sipping water, then progress to other clear fluids, and then light foods as tolerated. Even small, frequent amounts help. This helps to stimulates your gut to start working again, reducing the risk of ileus – a slow, sleepy bowel, provides energy for healing, and can help you feel more normal, faster.
- If you haven’t been told you can eat or drink, keep asking the question! You are your best advocate!
Another tip that can help here is step 6: Chew Gum
- If your team allows it, start chewing sugar-free gum several times a day once you're able. It sounds simple, but it can be surprisingly helpful in mimicking eating even when you’re not allowed to, and can stimulate your digestive system to return to usual function sooner and reduce the risk of ileus.
Step 7 is to Nourish to Heal
- This is where we bring in our good friend protein to optimise tissue repair and recovery
- Include protein rich food at each meal, and chat to us if you’re finding this difficult because there are plenty of hacks if you’re not feeling up to chicken breast and steak!
And finally step 8 is to Listen to Your Body
- While ERAS encourages early eating, we always want you to be tuned in to your body’s cues and speaking up to your medical team and us if something doesn’t feel right.
- There are plenty of interventions that can be used to keep you comfortable while still optimising your nutrition to get the best outcomes from surgery.
- Weimann, A., Braga, M., Carli, F., Higashiguchi, T., Hübner, M., Klek, S., et al. (2021). ESPEN practical guideline: Clinical nutrition in surgery. Clinical Nutrition, 40(7), 4745-4761.
- Weimann, A., Braga, M., Carli, F., Higashiguchi, T., Laviano, A., Ljungqvist, O., et al. (2017). ESPEN guideline: Clinical nutrition in surgery. Clinical Nutrition, 36(3), 623-650.
- Gustafsson, U. O., Scott, M. J., Schwenk, W., Demartines, N., Roulin, D., Francis, N., et al. (2019). Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations: 2018. Clinical Nutrition, 38(2), 576-586. (Note: The ERAS® Society website, erassociety.org, is the primary source for the most current and comprehensive suite of procedure-specific guidelines.)
- Ljungqvist, O., Scott, M., & Fearon, K. C. (2017). Enhanced Recovery After Surgery: A review. JAMA Surgery, 152(3), 292-298.
- Thiele, R. H., Raghunathan, K., Brudney, C. S., Campos, S., Candiotti, K., Chaves, S., et al. (2016). American Society for Enhanced Recovery (ASER) and Perioperative Quality Initiative (POQI) joint consensus statement on perioperative fluid management in adults. Perioperative Medicine, 5, 26. (Note: This is an example of ASER/POQI consensus; look for other relevant POQI statements on specific surgical procedures and their nutritional components.)
- Soon, K., Levy, G. M., Cusack, L. A., Varma, S., & Nicholson, G. A. (2020). The effect of preoperative carbohydrate loading on patient outcomes in elective surgery: A systematic review and meta-analysis. Systematic Reviews, 9(1), 254.
- Lewis, S. J., Egger, M., Sylvester, P. A., & Thomas, S. (2001). Early enteral feeding versus "nil by mouth" after gastrointestinal surgery: systematic review and meta-analysis of controlled trials. BMJ, 323(7316), 773-776.
- Osland, E. J., Hossain, M. A., Khan, S., & Memon, M. A. (2014). Effect of timing of oral feeding on patient outcomes after elective colorectal surgery: A systematic review and meta-analysis. Journal of Gastrointestinal Surgery, 18(5), 1039-1051.
- Braga, M., Gianotti, L., Nespoli, L., Radaelli, G., & Di Carlo, V. (2002). Nutritional approach in malnourished surgical patients: a prospective randomized study. Archives of Surgery, 137(2), 174-180.
Marimuthu, K., Varadhan, K. K., Ljungqvist, O., & Lobo, D. N. (2012). A meta-analysis of the effect of combinations of enhanced recovery after surgery (ERAS) interventions on postoperative outcomes.
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