Neuraxial opioids: Monitoring

When using neuraxial opioids for postoperative analgesia,

A. There is no increased risk of respiratory depression in patients with OSA
B. Neuraxial opioid can be used safely in combination with other sedatives, such as benzodiazepines or systemic opioids
C. The use of a bolus of extended release neuraxial morphine does not require any further monitoring beyond the first 24 hours
D. The use of lipophilic agents (fentanyl, sufentanil) would result in greater systemic absorption compared to hydrophilic opioids (morphine, hydromorphone).

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Correct Answer: D


The ASA and ASRA has updated practice guidelines for the prevention, detection and management of respiratory depression associated with neuraxial opioid administration since death and persistent vegetative states have occurred as a result of respiratory depression due to opioid use. Specifically, a history of sleep apnea and concurrent use of systemic opioids or other sedatives/hypnotics can place patients at risk for respiratory depression and requires increased monitoring. For single bolus neuraxial lipophilic agents (fentanyl, sufentanil), monitoring for adequate oxygenation, ventilation and level of consciousness should be continual for the first 20 minutes followed by once hourly monitoring for 2 hours. For a single bolus of neuraxial morphine, monitoring should be a minimum of 24 hours after administration (hourly for first 12 hours and every 2 hours for second 12 hours). For extended release neuraxial morphine, monitoring should be a minimum of 48 hours (once hourly first 12 hours, every 2 hours from 12h-24h, and every 4 hours from 24h-48h). The use of lipophilic agents (fentanyl, sufentanil) results in greater systemic absorption of the opioids as compared to hydrophilic agents (morphine, hydromorphone).


American Society of Anesthesiologists Task Force on Neuraxial Opioids and the American Society of Regional Anesthesia and Pain Medicine. “Practice Guidelines for the Prevention, Detection and Management of Respiratory Depression Associated with Neuraxial Opioid Administration.” Anesthesiology 2016;124:535-52.

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