Anesthesia for Gastrointestinal Endoscopy

Pre-Anesthetic Evaluation - Patient Check-in

• Patient ID & Valid Consent: Verify patient, procedure. Crucial first step.
• Focused History (AMPLE):
  • Allergies.
  • Medications: Note anticoagulants, antiplatelets, hypoglycemics.
  • PMH: Cardiac, respiratory, OSA, GERD, prior anesthesia issues.
  • Last Meal: Confirm NPO.
  • Events leading to procedure.
• Airway Assessment:
  • Mallampati, TMD (> 6 cm), neck mobility, dentition, beard.
• Fasting Guidelines (NPO): 📌 "2-6-8 Rule"
  • Clear liquids: ≥ 2 hrs.
  • Light meal/milk: ≥ 6 hrs.
  • Heavy/fatty meal: ≥ 8 hrs.

  ⭐ Strict NPO adherence is vital to minimize aspiration risk in GI endoscopy.

• ASA Physical Status: Assign (I-VI).
• Baseline Vitals & IV Access: Record HR, BP, SpO2. Secure IV line appropriate for procedure and patient condition.

Sedation & Monitoring - The Anesthesia Dashboard

• Goals: Patient comfort, amnesia, stable cardiorespiratory function, rapid recovery. Target: moderate to deep sedation.
• ASA Standard Monitoring:
  • Oxygenation: Pulse oximetry (SpO₂ > 92%). Supplemental O₂.
  • Ventilation: Capnography (ETCO₂) - vital for early detection of hypoventilation/apnea.
  • Circulation: Continuous ECG, NIBP (q3-5 min), Heart Rate.
  • Depth of Sedation: Clinical scales (e.g., MOAAS/OAA/S).
• Key Vigilance: Shared airway, aspiration risk, intervention readiness.

⭐ Capnography is the cornerstone for detecting respiratory depression during GI endoscopy sedation, often preceding changes in SpO₂.

Pharmacological Agents - The Sedation Cocktail

• Goal: Conscious to deep sedation.
• Common Agents:
  • Benzodiazepines (BZD):
    • Midazolam: 0.02-0.1 mg/kg IV. Anxiolysis, amnesia. Onset 1-3 min.
    • Reversal: Flumazenil (0.2 mg IV, up to 1 mg). 📌 Flumazenil Frees Benzos.
  • Opioids:
    • Fentanyl: 0.5-1 mcg/kg IV. Analgesia, sedation. Onset 1-2 min.
    • Reversal: Naloxone (0.04-0.4 mg IV). 📌 Naloxone Nixes Narcotics.
  • Propofol:
    • 0.5-1 mg/kg IV bolus; inf. 25-75 mcg/kg/min. Rapid onset/recovery, antiemetic.
    • Risk: Apnea, hypotension. No specific reversal agent.
  • Ketamine:
    • 0.25-0.5 mg/kg IV. Dissociative sedation, analgesia, airway preserved.
    • Risk: Emergence phenomena, ↑secretions.
  • Dexmedetomidine:
    • 0.2-0.7 mcg/kg/hr IV. Sedation, minimal respiratory depression.
    • Risk: Bradycardia, hypotension.
• Combinations (Synergistic Effects):
  • BZD + Opioid (e.g., Midazolam + Fentanyl).
  • Propofol ± Opioid/BZD.

⭐ Propofol is favored for its rapid recovery profile, making it ideal for high-turnover endoscopy units, but requires careful cardiorespiratory monitoring due to potential for apnea and hypotension.

Procedural Nuances & Complications - Gut Feelings Gone Wrong

• General Risks: Hypoxemia, hypotension, aspiration (esp. upper GI), arrhythmias.
• Procedure-Specifics:
  • EGD: Shared airway, ↑aspiration risk. Brief.
  • Colonoscopy: Longer, CO2 insufflation preferred (↓distension/pain). Vasovagal common.
  • ERCP/EUS: Prone/left lateral. Prolonged, requires deep sedation/TIVA.
    • Risks: Pancreatitis, cholangitis, bleeding, duodenal perforation.
    • Sphincter of Oddi relaxation: Glucagon, hyoscine.
• Complications Management:
  • Airway: Jaw thrust, O2, LMA/ETT.
  • Hemodynamic: Fluids, vasopressors.
  • Reversal: Naloxone, Flumazenil.
  • Perforation: Surgical consult, antibiotics.
• 📌 PERCS for ERCP Complications: Pancreatitis, Excessive bleeding, Rupture (perforation), Cholangitis, Sepsis.

⭐ Post-ERCP pancreatitis (PEP) is the most common serious complication, incidence 3-5%; up to 15% in high-risk patients.

High‑Yield Points - ⚡ Biggest Takeaways

• Airway management is critical; high aspiration risk with shared airway.
• Monitored Anesthesia Care (MAC) with propofol is standard; General Anesthesia (GA) for complex or prolonged procedures.
• Propofol: rapid onset/offset, antiemetic; risk of apnea, hypotension. Consider etomidate/ketamine in unstable patients.
• Ketamine useful adjunct: preserves airway reflexes, provides analgesia, bronchodilation.
• Monitor for hypoxia, hypercapnia (capnography essential), hypotension, and arrhythmias.
• Difficult airway (e.g., obesity, OSA) and full stomach are major concerns requiring careful planning.
• Barotrauma (perforation) is a rare but serious procedural complication to be aware of during endoscopy.