The STOP-Bang score is used perioperatively to screen for obstructive sleep apnoea (OSA). A patient with a score of 5 is considered high risk. In the anaesthetic management of such a patient, postoperative opioid use should be minimised because:
- A Opioids decrease REM sleep rebound, reducing the severity of OSA during NREM stages
- B Opioids cause systemic vasodilation, exacerbating OSA-related pulmonary hypertension
- C Opioids suppress the hypercapnic arousal response and reduce upper airway muscle tone, potentiating obstructive events ✓
- D Opioids accelerate the return of REM sleep, during which upper airway tone is highest
Explanation
In OSA patients, respiratory arousal from hypercapnia and hypoxia is the critical protective reflex that terminates obstructive apnoea. Opioids suppress the CO2-mediated ventilatory drive and reduce hypercapnic arousal sensitivity. Simultaneously, mu-receptor activation on hypoglossal motor neurons reduces genioglossus (tongue base) activity, further narrowing the already compromised upper airway. These combined effects prolong apnoeic episodes and reduce oxygen saturation nadir, making postoperative opioid-sparing multimodal analgesia essential in high-risk OSA patients.
Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.