A comparative study of intrathecal (0.75%) ropivacaine with fentanyl and intrathecal (0.75%) ropivacaine with morphine in day care perianal surgeries.

Subarachnoid block is a popular anaesthesia procedure practiced worldwide. It is a standard procedure for lower abdominal, lower limb and perianal surgeries. It is a more reliable, quick procedure, applicable in emergency surgeries. An ideal anaesthetic for spinal anaesthesia in ambulatory surgery should provide rapid onset, adequate potency, predictable duration, decreased neurotoxicity along with minimal systemic side effects.

Ropivacaine has high pKa , low lipid solubility, it has great degree of sensory blockade and lesser duration of motor blockade compared to Bupivacaine. It also provides rapid sensorimotor dissociation. It is a favorable drug for day care surgeries. Adjuvants like Opioids when added to Ropivacaine have shown to prolong the duration analgesia after surgery.

Subarachnoid fentanyl is known to provide rapid onset of analgesia, improve surgical blockade quality and enhance the effect of small doses of subarachnoid local anaesthetic. Intrathecal morphine used as a ‘one-shot’ method provides several advantages as it is easy, cost-effective, and reliable, and technical failures are rare. The analgesic effects last for 20–48 h. Morphine results in cephalad spread, thereby increasing the area of analgesia.