To compare the efficacy and safety of intrathecal Morphine and Fentanyl on intra-operative and post-operative analgesia in patients undergoing hepatobiliary surgeries under general anaesthesia

Hepatobiliary surgeries are more frequently performed nowadays due to a rising incidence of hepatobiliary diseases. Effectively administered analgesia enables greater patient satisfaction by minimising acute postoperative pain, alleviates the acute physiological stress response to surgery, and facilitates enhanced recovery outcomes including early mobilisation and return to normal activity, reduced length of hospital stay, and reduced cardiac, respiratory and gastrointestinal postoperative complications leading to improved long-term patient survival rates. Thoracic epidural analgesia is considered the gold standard analgesic modality for patients undergoing hepatobiliary surgeries as it provides adequate analgesia to support mobilization, with significant reduction in pulmonary, cardiovascular and thromboembolic morbidity in early post-operative period and reduced requirement of additional opioid analgesia. However , there exists high rates of epidural failure and  complications especially since it is an invasive, high-cost, labour-intensive technique. Also , there is increased risk of epidural hematoma formation  due to coagulation abnormalities after hepatobiliary surgeries, even in patients with normal preoperative coagulation profile. Furthermore,  the epidural catheter should be removed in a timely manner to minimize complications due to post-operative coagulation disturbances. In view of the concerns raised with epidural analgesia in hepatobiliary surgeries, intrathecal anaesthesia has emerged as a promising simpler and quicker alternative technique, yielding better patient outcomes with a lower rate of technical failure. Fentanyl is a phenyl piperidine derivative, synthetic opioid agonist which is more potent, more lipid soluble with faster onset of action and relatively shorter duration of action. Morphine is a hydrophilic phenanthrene derivative with comparatively slower onset of action and a significantly longer duration of action. However, it has the potential to cause adverse effects, especially delayed respiratory depression and hence requires more vigilant protocol. Hence this study aims at comparing the efficacy and safety of intrathecal morphine and fentanyl in hepatobiliary surgeries under GA , in terms of intraoperative and post operative analgesia, requirement of rescue analgesics and potential side effects.