Anaesthesia · Preoperative Assessment (PAC) and Special Conditions

A patient with severe obstructive sleep apnoea (OSA, AHI 52) requires post-operative opioid analgesia. Continuous pulse oximetry shows intermittent desaturations to 82% in the PACU. The MOST effective intervention to reduce perioperative respiratory complications in this patient is:

  • A Supplemental nasal cannula oxygen at 4 L/min
  • B Prophylactic naloxone infusion to counter opioid-induced respiratory depression
  • C Application of the patient's home CPAP device at prescribed settings
  • D Oral doxapram to stimulate respiratory drive
Correct answer: C. Application of the patient's home CPAP device at prescribed settings

Explanation

In patients with established OSA, the primary mechanism of post-operative hypoxaemia is upper airway collapse and obstructive apnoeas — identical to their baseline pathophysiology, worsened by anaesthetic residuals and opioids. CPAP directly stents the upper airway with positive pressure, preventing collapse and is the most effective intervention. Supplemental oxygen corrects desaturation but does NOT prevent obstructive events and may dangerously blunt the arousal response by maintaining SpO2 during prolonged apnoeic episodes. Naloxone would precipitate pain crisis and is reserved for opioid overdose management. CPAP/NIPPV at the prescribed home settings is the standard SAMBA and ASA recommendation for OSA patients postoperatively.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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