Key Facts

ERAS is a paradigm shift in perioperative care, moving from tradition-based practices to evidence-based protocols that address every phase of the surgical journey. First developed by Henrik Kehlet in the 1990s for colorectal surgery, ERAS principles are now applied across virtually all surgical specialties.

Epidemiology

ERAS has been widely adopted in the UK and internationally. Hospitals with mature ERAS programmes report 30-50% reductions in length of stay and 30-40% reductions in complications. Readmission rates are NOT increased. Cost savings of approximately £300-500 per patient have been demonstrated.

Aetiology

Traditional perioperative practices (prolonged fasting, mechanical bowel prep, routine drains and NGTs, bed rest, opioid-heavy analgesia) contribute to the surgical stress response, catabolism, insulin resistance, and delayed recovery. ERAS protocols systematically address each of these factors.

Pathophysiology

Surgery triggers a neuroendocrine stress response (cortisol, catecholamines, growth hormone, glucagon) leading to insulin resistance, catabolism, sodium/water retention, and immunosuppression. ERAS interventions aim to attenuate this response through carbohydrate loading (reduces insulin resistance), regional anaesthesia (blocks afferent stress signals), goal-directed fluid therapy (avoids fluid overload), and early nutrition/mobilisation (promotes anabolism).

Pre-Operative Phase

• Patient education and expectation management
• Prehabilitation (exercise, nutrition, smoking/alcohol cessation)
• Carbohydrate drink 2 hours pre-operatively (reduces thirst, anxiety, insulin resistance)
• Reduced fasting (2h clear fluids, 6h solids)
• No routine mechanical bowel preparation (colorectal)
• Anaemia correction (IV iron if Hb <130g/L)
• DVT risk assessment and prophylaxis planning

Intraoperative Phase

• Minimally invasive surgery where possible
• Regional/neuraxial anaesthesia + multimodal analgesia
• Goal-directed fluid therapy (stroke volume optimisation)
• Active warming (forced-air warmer, warm IV fluids)
• Avoidance of routine drains and nasogastric tubes
• Short-acting anaesthetic agents (TIVA, remifentanil)

Post-Operative Phase

• Early oral intake (fluids day 0, diet day 1)
• Early mobilisation (out of bed day 0, walking day 1)
• Opioid-sparing multimodal analgesia (paracetamol, NSAIDs, regional blocks)
• Early catheter removal (day 1-2)
• Audit of compliance and outcomes

Red Flags

• Non-compliance with ERAS elements — outcomes directly correlate with adherence
• Delayed mobilisation — increases thromboembolic and respiratory risk
• Excessive IV fluid administration — causes oedema, delayed GI recovery, anastomotic complications
• Persistent ileus >day 3 — consider complication (anastomotic leak, electrolyte imbalance)

Bedside

• Pre-operative: Nutritional screening (MUST score), functional capacity assessment, anaemia screening
• Intraoperative: Oesophageal Doppler or non-invasive cardiac output monitoring for goal-directed fluid therapy
• Post-operative: NEWS2 monitoring, fluid balance, pain scores, mobilisation diary

Bloods

• Pre-operative: FBC (Hb target ≥130g/L), HbA1c, U&Es, iron studies
• Post-operative: FBC, CRP (day 3 — early detection of complications)

Imaging

• CT: If post-operative complication suspected (anastomotic leak, collection)

Special Tests

• ERAS audit database: Track compliance with individual protocol elements and outcomes
• Patient-reported outcome measures (PROMs): Quality of life, satisfaction

Non-pharmacological

• Prehabilitation programme: Structured exercise (aerobic + resistance), nutritional counselling, psychological preparation — 4-6 weeks pre-operatively
• Patient education: Detailed information about pathway, expected milestones, discharge criteria
• Early mobilisation: Sit out of bed on day of surgery; walk on POD1; structured mobilisation targets
• Nutrition: Oral nutritional supplements if malnourished; early oral intake post-operatively

Pharmacological

• Carbohydrate loading: Maltodextrin drink (e.g., Preload) 800mL evening before, 400mL 2h before surgery
• Multimodal analgesia: Paracetamol 1g QDS + NSAID (ibuprofen 400mg TDS or diclofenac 50mg TDS) + wound infiltration with LA ± regional block
• VTE prophylaxis: LMWH (enoxaparin 40mg SC OD) + mechanical prophylaxis
• PONV prophylaxis: Dexamethasone 6.6mg IV + ondansetron 4mg IV
• Laxatives: Regular from day 1 post-operatively to prevent opioid-induced constipation
• IV iron: Ferric carboxymaltose 1g if Hb <130g/L and surgery in 2-6 weeks

Surgical/Interventional

• Minimally invasive surgery: Laparoscopic/robotic approach where feasible
• No routine drains: Evidence shows no benefit in most colorectal, gynaecological, and hepatobiliary surgery
• Transversus abdominis plane (TAP) block: For abdominal surgery as part of opioid-sparing strategy

Referral Criteria

• Non-recovery along ERAS pathway — senior surgical and anaesthetic review
• Persistent ileus, rising CRP, or clinical deterioration — exclude surgical complication

• Length of stay reduction: 30-50% across all surgical specialties implementing ERAS
• Complication reduction: 30-40% fewer complications with high compliance
• Readmission rates: NOT increased with early discharge via ERAS
• Cost savings: £300-500 per patient; significant NHS savings with widespread adoption
• Compliance correlation: Outcomes improve linearly with increasing compliance — target >70%

ERAS Society Core Elements (Colorectal)

ERAS Compliance and Outcomes

Key ERAS Evidence