Awareness Under General Anesthesia

Definition & Incidence - Unwanted Wakefulness

• Definition: Unintended consciousness during general anesthesia (GA) with explicit (conscious) recall of intraoperative events.
  • Perceptions: Auditory (most common), tactile sensations, sense of movement, or pain.
• Incidence:
  • General surgery: 0.1-0.2%.
  • High-risk settings: ↑ up to 1-2% (e.g., cardiac surgery, major trauma, obstetric GA).
  • Awareness with pain: Less common, reported in approx. 1/3 of awareness episodes.

⭐ Modified Brice questionnaire is used for postoperative screening of awareness.

Risk Factors - Danger Zones

• Patient Factors:
  • History of previous AUGA; ASA status III-V
  • Chronic use of opioids, benzodiazepines, or illicit substances
  • Anticipated difficult intubation or mask ventilation; obesity (BMI > 30)
  • Reduced cardiovascular reserve (e.g., shock, trauma); younger age (children)
• Surgical Factors:
  • Cardiac surgery (especially on cardiopulmonary bypass)
  • Emergency surgery (e.g., C-section); major trauma surgery
  • Major orthopedic, neurosurgical, or ENT procedures
• Anesthetic Factors:
  • Use of neuromuscular blocking agents (NMBAs)
  • Inadequate anesthetic delivery: ↓volatile agent concentration, TIVA errors, equipment failure
  • Rapid Sequence Induction (RSI); planned light anesthesia

⭐ NMBAs are a major risk, masking movement, a key awareness sign. Consider BIS/entropy monitoring in high-risk scenarios.

Clinical Features & Diagnosis - Silent Screams

• Intraoperative Signs (often subtle/masked):
  • Autonomic: ↑HR, ↑BP, sweating, tearing (non-specific)
  • Movement (if neuromuscular blockade incomplete)
• Postoperative Recall (Definitive): 📌 Mnemonic: SCREAM
  • Sounds (conversations, noises) - most common
  • Can't move (paralysis, helplessness)
  • Recall of events, tactile sensations (pain, ETT)
  • Emotions (fear, panic, distress)
  • Awake but unable to signal
  • May lead to PTSD, anxiety, nightmares
• Diagnosis:
  • Structured postoperative interview: Modified Brice Questionnaire.

  ⭐ The most common patient recollection is auditory (e.g., hearing conversations).

Management & Sequelae - Healing the Harm

• Immediate: Listen empathetically. If ongoing: deepen anesthesia; consider Midazolam (1-2 mg IV).
• Post-op Protocol:
  • Interview: Modified Brice Questionnaire.
  • Communicate: Apologize, explain.
  • Support: Refer for psychological counseling (CBT).
• Flowchart: Key Management Steps

• Common Sequelae: PTSD, anxiety, nightmares, fear of future anesthesia.

⭐ Post-traumatic stress disorder (PTSD) can occur in up to 70% of patients experiencing definite AUGA.

High‑Yield Points - ⚡ Biggest Takeaways

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