ERAS Protocol - An Anaesthesia-Focused Guide

What is ERAS?

• Attenuate the surgical stress response and catabolism
• Minimize opioid consumption and opioid-related complications
• Prevent PONV, ileus, hypothermia, and fluid imbalance
• Enable early oral intake and early ambulation
• Shorten length of stay (LOS) without increasing readmissions

The Anaesthesiologist's Role in ERAS

ERAS Framework: Three Phases

PHASE 1 - PREOPERATIVE

1. Prehabilitation and Optimization

• Identify and optimize comorbidities (HTN, DM, anaemia, COPD) ideally 4-6 weeks preoperatively
• Smoking cessation (at least 4 weeks before surgery - reduces pulmonary complications)
• Alcohol cessation (reduces surgical site infection and bleeding risk)
• Nutritional screening: oral nutritional supplements for malnourished patients; consider immunonutrition for major GI surgery
• Frailty and functional capacity assessment
• Anaemia treatment (iron supplementation, EPO where indicated) to reduce transfusion need

2. Patient Education and Counselling

• Structured preoperative education about the entire perioperative pathway
• Set expectations for pain, diet, mobilisation targets, and discharge criteria
• Reduces anxiety, improves adherence, improves satisfaction
• From an anaesthesia perspective: consent for regional techniques, discuss anaesthetic plan

3. Fasting and Oral Carbohydrate Loading

• Traditional "nil by mouth from midnight" is obsolete in ERAS
• Clear fluids: allow up to 2 hours before surgery
• Solid food: allow up to 6 hours before surgery
• Oral carbohydrate loading (CHO drink 400 mL the night before, 200 mL 2 hours preoperatively): attenuates insulin resistance, reduces preoperative hunger and thirst, improves patient well-being and reduces postoperative catabolism
• Contraindicated in patients with: gastroparesis, bowel obstruction, emergency surgery, severe GERD

4. Premedication

• Anxiolytics: use with caution - benzodiazepines (e.g., midazolam) may cause sedation, cognitive impairment, delayed recovery; avoid routinely especially in elderly
• Gabapentinoids (pregabalin, gabapentin): controversial - limited analgesic benefit, significant risk of sedation, dizziness, falls; use only in high-risk persistent pain cases at lowest possible dose
• Preoperative analgesia: paracetamol 1g PO + COX-2 inhibitor (e.g., celecoxib) or NSAID as part of multimodal preemptive analgesia - Current Surgical Therapy 14e
• Antiemetic prophylaxis initiation where indicated
• VTE prophylaxis: LMWH +/- TED stockings as per risk stratification; pharmacological prophylaxis is standard

5. Bowel Preparation (Surgery-Specific)

• Mechanical bowel preparation (MBP) alone is not recommended routinely
• Combined oral antibiotics + MBP is preferred for colorectal surgery
• Avoidance of MBP reduces fluid/electrolyte disturbances preoperatively

PHASE 2 - INTRAOPERATIVE

1. Anaesthetic Technique

• Minimise opioids intraoperatively - use opioid-free or opioid-sparing total IV anaesthesia (TIVA) or balanced anaesthesia
• TIVA with propofol preferred over volatile agents in patients with high PONV risk (reduces baseline PONV risk ~50%)
• Short-acting agents preferred: remifentanil infusion during procedure, desflurane/sevoflurane with BIS monitoring for adequate depth without overdose
• Depth of anaesthesia monitoring (BIS/entropy): avoid overly deep anaesthesia; reduces POCD risk, especially in elderly
• Avoid nitrous oxide in abdominal/bowel surgery (increases risk of PONV, bowel distension)

2. Multimodal Opioid-Sparing Analgesia (Intraoperative)

3. Regional Anaesthesia - The Core of ERAS Analgesia

4. Intraoperative Fluid Management - Goal-Directed Fluid Therapy (GDFT)

• Avoid both over- and under-resuscitation
• Traditional "liberal" fluids cause: oedema, delayed bowel return, anastomotic complications, pulmonary complications
• Traditional "restrictive" fluids cause: organ hypoperfusion, AKI, ileus
• GDFT is the ERAS standard: use dynamic haemodynamic parameters (stroke volume variation [SVV], pulse pressure variation [PPV], stroke volume optimisation) to guide fluid boluses
• Tools: oesophageal Doppler, FloTrac, arterial line-based pulse contour analysis
• Target: slightly positive fluid balance; avoid large boluses of crystalloid
• Vasopressors: use noradrenaline/phenylephrine to maintain MAP, rather than large fluid volumes, especially in neuraxial-induced vasodilation
• Balanced crystalloids preferred over normal saline (avoid hyperchloraemic acidosis): Lactated Ringer's or Plasma-Lyte

5. Normothermia Maintenance

• Active warming is mandatory: forced-air warming blankets, fluid warmers, warmed irrigation
• Intraoperative hypothermia (<36°C) causes: coagulopathy, surgical site infection, cardiac events, increased blood loss, shivering, delayed recovery
• Temperature monitoring is mandatory

6. PONV Prophylaxis

• Apfel score 0-1: Ondansetron 4mg IV alone
• Apfel score 2: Dual therapy - ondansetron 4mg + dexamethasone 8mg
• Apfel score 3-4: Triple therapy - ondansetron + dexamethasone + droperidol (0.625-1.25mg) or haloperidol
• TIVA with propofol as anaesthetic technique reduces PONV risk further
• Avoid nitrous oxide; minimise intraoperative opioids
• PONV rescue: ondansetron (if not already used), haloperidol, metoclopramide

7. Minimally Invasive Surgery

• Laparoscopic/robotic approach preferred over open wherever feasible
• Reduces systemic inflammatory response, pain, ileus, wound complications
• Shortened LOS: strongest evidence base in colorectal and upper GI surgery

8. Surgical Drains and Tubes

• Nasogastric tubes (NGT): avoid routine postoperative NGT; if used intraoperatively, remove before reversal of anaesthesia
• Abdominal drains: routine intra-abdominal drains are not recommended (no benefit in elective colorectal surgery)
• Urinary catheter: remove early (by POD1-2) to facilitate mobilisation

PHASE 3 - POSTOPERATIVE

1. Postoperative Analgesia (Multimodal, Opioid-Sparing)

• Continue paracetamol + NSAID/COX-2 on a scheduled "round-the-clock" basis
• Opioids as rescue only (as-needed basis); prefer oxycodone or tramadol (not combined formulations with paracetamol to avoid overdose)
• Ongoing regional analgesia (epidural infusion, continuous peripheral nerve block) where appropriate
• Patient education: ice packs, elevation, cognitive behavioural modalities

2. Early Oral Feeding

• Oral fluids immediately postoperatively (within 2-4 hours of surgery where tolerated)
• Solid diet by POD1 in most ERAS patients
• Early oral nutrition reduces catabolism, reduces LOS, does NOT increase anastomotic leak rates
• Meta-analysis of 7 RCTs (587 patients) confirmed: early feeding significantly reduces LOS without increasing complications - Current Surgical Therapy 14e

3. Early Mobilisation

• Mobilise on day of surgery or POD1 at minimum
• Key to preventing VTE, pneumonia, muscle deconditioning, ileus
• Anaesthesia contribution: adequate analgesia that permits movement (not bed-bound by pain or regional block side effects)

4. Prevention of Postoperative Ileus

• Minimise opioids, avoid excess IV fluids, encourage early feeding and ambulation
• Chewing gum (stimulates cephalic phase of digestion) - evidence for faster return of bowel function
• Alvimopan (peripheral mu-opioid receptor antagonist) - accelerates GI recovery after open bowel surgery where opioids are unavoidable

5. VTE Prophylaxis

• Mechanical (TED stockings, pneumatic compression devices) from induction
• Pharmacological (LMWH): commence within 12-24 hours postoperatively; balance with epidural removal timing (follow ASRA/ESA neuraxial guidelines)
• High-risk patients: extended prophylaxis (28 days) especially after cancer colorectal surgery

6. Glycaemic Control

• Target glucose 6-10 mmol/L (140-180 mg/dL) perioperatively
• Stress hyperglycaemia increases wound infection, anastomotic complications, mortality
• Carbohydrate loading preoperatively helps reduce insulin resistance

7. Audit and Compliance Tracking

• ERAS only works when compliance exceeds 70% of protocol elements
• Regular audit and feedback loops are mandatory for sustained outcomes

ERAS Outcomes Data

• LOS reduction: 2-3 days in colorectal surgery
• Morbidity reduction: ~48% vs conventional care (ERAS Society)
• Opioid consumption: significantly reduced
• Same-day discharge rates in ambulatory settings increased from 7.2% to 58.6% in one breast cancer series - Miller's Anesthesia 10e
• Readmission rates comparable to conventional care

ERAS for COLORECTAL SURGERY - Specialty-Specific

Preoperative - Colorectal Specific

Intraoperative - Colorectal Specific

• Laparoscopic/robotic approach strongly preferred (strong evidence for reduced morbidity and LOS)
• TIVA vs volatile: TIVA preferred in high PONV-risk patients; if volatile used, desflurane or sevoflurane with BIS guidance
• Avoid N₂O - bowel distension, PONV risk
• Short-acting neuromuscular blockade with sugammadex reversal to prevent residual paralysis

• Open colorectal surgery: Thoracic epidural analgesia (T8-T10) is the gold standard; provides visceral and somatic coverage; reduces ileus by sympathetic blockade
• Laparoscopic colorectal surgery: Epidural NOT recommended routinely (limited benefit for laparoscopic port sites, impairs ambulation); TAP block + multimodal analgesia preferred
  • Bilateral posterior TAP block (ultrasound-guided): reduces opioid use for somatic abdominal wall pain
  • Does NOT cover visceral/mesenteric pain (epidural or intrathecal morphine needed for visceral component)
  • 2024 Korean ERAS Guidelines recommend TAP block as standard for laparoscopic colorectal cancer surgery
• IV lidocaine infusion: strong evidence in colorectal surgery specifically - reduces pain, opioid use, hastens return of bowel function; use in open and laparoscopic cases

• GDFT standard for colorectal surgery
• Avoid excessive crystalloid (delays bowel function return, increases risk of anastomotic complications)
• Target euvolaemia with vasopressor support where needed
• In laparoscopic colorectal: even more restrictive fluid approach appropriate given pneumoperitoneum

• PONV is particularly problematic post-colorectal surgery (opioid use, bowel manipulation, patient demographics)
• Triple therapy for high Apfel scores is standard: ondansetron + dexamethasone + droperidol/haloperidol
• Dexamethasone 8mg IV intraoperatively: PONV prophylaxis + analgesic + anti-inflammatory (avoid in poorly controlled DM)

Postoperative - Colorectal Specific

PONV in Colorectal Surgery - Special Emphasis

• Combination of dexamethasone + serotonin receptor antagonist (5-HT3 antagonist like ondansetron) is preferred over monotherapy
• This is preferred specifically because opioids reduce GI motility, and PONV compounds this by further delaying oral intake and mobilisation

Discharge Criteria (Colorectal ERAS)

• Adequate oral intake (tolerating solid diet)
• Controlled pain on oral analgesics
• Return of bowel function (flatus or stool)
• Able to mobilise independently
• Apyrexial, haemodynamically stable
• Wound satisfactory
• Adequate social support and patient/carer education complete

Quick Summary Table: ERAS Elements by Phase

• Miller's Anesthesia, 10th Edition (Elsevier)
• Current Surgical Therapy, 14th Edition
• Fuster & Hurst's The Heart, 15th Edition
• 2024 Korean ERAS Guidelines for Colorectal Cancer (Annals of Coloproctology, 2025)
• ASCRS/SAGES 2023 Clinical Practice Guideline - Enhanced Recovery for Colorectal Surgery
• ERAS Society Guidelines (erassociety.org)