Emergence Delirium and Agitation in an Elderly Patient After General Anesthesia

Differential for post-anesthetic agitation in an elderly patient:

1. Emergence delirium / hypoactive or hyperactive delirium - common in elderly, especially with anticholinergic burden (ondansetron), benzodiazepines (midazolam), and sensory deprivation. Typically fluctuating, with disorientation and inattention. The daughter's report of baseline sharpness supports a new acute change.
2. Hypoxemia / hypercapnia - SpO₂ 94% on 4 L is lower than expected; check ABG or capnography. Hypercapnia from residual anesthetic or opioid-induced hypoventilation can cause agitation.
3. Pain - often overlooked; a Colles fracture fixation is painful. Look for splinting, guarding, and response to analgesia.
4. Urinary retention - common after anesthesia and opioids; check bladder scan. Agitation with a distended bladder is a classic presentation.
5. Hypoglycemia - check point-of-care glucose.
6. Electrolyte disturbance - sodium, calcium; CKD raises concern for hyperkalemia or hyponatremia.
7. Sepsis / infection - check temperature, WBC, source; she is afebrile but early sepsis can present without fever.
8. Anticholinergic toxicity - ondansetron plus possible other agents; dry mouth, flushing, tachycardia.
9. Alcohol or benzodiazepine withdrawal - obtain a careful history.
10. Stroke / intracranial event - focal deficits, new asymmetry; consider if focal findings.
11. Malignant hyperthermia or neuroleptic malignant syndrome - unlikely given normal temperature, but check for rigidity and CK if concerned.

Distinguishing findings: ABG/capnography (hypoxemia/hypercapnia), glucose, electrolytes, bladder scan, pain assessment, focused neuro exam, temperature, and response to small analgesic or antipsychotic doses.

Stepwise management:

1. Safety first - ensure a patent airway, apply oxygen, and have a nurse at the bedside to prevent falls or self-harm. Reorient gently and reduce stimulation (dim lights, minimize noise).
2. Rule out life threats - check SpO₂ and capnography/ABG (hypoxemia/hypercapnia), glucose, electrolytes, and temperature. Obtain an ECG given tachycardia.
3. Assess and treat pain - titrate small doses of opioid (e.g., fentanyl 25 mcg increments) while monitoring ventilation. Untreated pain is a common and fixable driver.
4. Check for urinary retention with a bladder scan; catheterize if distended.
5. Review medications - ondansetron and midazolam are contributors; avoid additional anticholinergics and benzodiazepines.
6. Consider dexmedetomidine - an alpha-2 agonist that provides sedation without respiratory depression and is useful for hyperactive delirium; start low (0.2–0.5 mcg/kg/h) and titrate. Monitor for bradycardia and hypotension.
7. If agitation is severe and dangerous, use the lowest effective dose of an antipsychotic (e.g., haloperidol 0.5–1 mg) - but only after excluding reversible causes and with QT monitoring.
8. Involve family - a familiar face and voice can be calming.
9. Escalate if no improvement: consider ICU transfer, neurology consult, and imaging if focal deficits.

What to avoid:

• Benzodiazepines - they worsen and prolong delirium in elderly patients and are a risk factor for falls and respiratory depression.
• Physical restraints as a first-line measure - they increase agitation and injury risk; use only as a last resort with monitoring.
• Large opioid boluses without titration - risk of respiratory depression and worsening delirium.
• Anticholinergics (e.g., diphenhydramine) - they worsen delirium.
• Assuming it is 'just emergence' - always exclude hypoxia, pain, retention, and metabolic causes first.

• Avoid or minimize benzodiazepines - omit preoperative midazolam or use a very small dose; consider non-pharmacologic anxiolysis.
• Avoid anticholinergic antiemetics where possible (ondansetron is relatively low-risk but contributes to the burden); use multimodal PONV prophylaxis with dexamethasone and non-anticholinergic agents.
• Consider regional anesthesia - a brachial plexus block (e.g., supraclavicular or axillary) for distal radius fixation provides excellent analgesia and avoids general anesthesia, reducing delirium risk. Discuss with the surgeon and patient.
• Opioid-sparing analgesia - multimodal: acetaminophen, NSAIDs if renal function permits (caution with CKD stage 3), regional block, and judicious opioids.
• Depth-of-anesthesia monitoring - consider processed EEG (BIS) to avoid excessive depth, which is associated with postoperative delirium.
• Maintain normothermia, normoglycemia, and normovolemia - all are delirium risk factors.
• Early mobilization, orientation, sleep hygiene, and family involvement - non-pharmacologic delirium prevention is the most effective strategy.
• Preoperative cognitive screening - document baseline cognition; MMSE 26 suggests possible mild cognitive impairment, which raises risk and should be communicated to the patient and family.
• Medication review - minimize anticholinergic and sedative burden; involve pharmacy.
• Follow-up - screen for persistent delirium or cognitive decline after discharge and refer if needed.