Intrathecal opioids for the management of post-operative pain

Intrathecal opioids are highly effective in the management of postoperative pain. The technique is simple with very low risk of technical failure or complications, it does not require additional training or expensive equipment such as ultrasound machines and therefore widely practiced around the world. The high-quality pain relief is not associated with sensory, motor, or autonomic deficits. This chapter focuses on intrathecal morphine (ITM) which is the only FDA-approved opioid for intrathecal administration and remains the most commonly used as well as extensively studied. The use of ITM is associated with prolonged analgesia lasting 20-48 hours after a variety of surgical procedures. ITM has a well-established role in thoracic, abdominal, spinal, urological and orthopaedic surgery. It is considered the 'gold standard' analgesia technique for caesarean delivery which is generally performed under spinal anaesthesia. As the role of epidural technique in postoperative pain management continues to decrease, ITM has emerged as the neuraxial technique of choice for pain management after major surgery as a component of multimodal analgesia in ERAS protocols. ITM is recommended by many scientific groups and societies such as ERAS, PROSPECT, NICE and SOAP. The doses of ITM have decreased successively, today they are a fraction of those used in the early 80s. With these dose reductions the risks have decreased, current evidence shows that the risk of the much-feared respiratory depression with low-dose ITM (up to 150 mcg) is no greater than that with systemic opioids used in routine clinical practice. Patients receiving low-dose ITM can be nursed on regular surgical wards. The monitoring recommendations from societies such as ESRA, ASRA and ASA need to be updated so that the requirements for extended or continuous monitoring at PACUs, step-down units, High-Dependency Units (HDUs) and ICUs can be eliminated thus reducing additional costs and inconvenience and making this simple, versatile and highly effective analgesia technique available to a wider patient population in resource-limited settings.