The goal of this clinical trial is to evaluate the postoperative analgesic effects of caudal Ropivacaine with or without Dexmedetomidine in pediatric infraumbilical surgery. The main question[s] it aims to answer are:

• if Caudal Dexmedetomidine with Ropivacaine would prolong the duration of analgesia in children undergoing infraumbilical surgery.

Participants will receive ropivacaine with dexmedetomidine in infraumbilical surgery.

If there is a comparison group: Investigators will compare this with ropivacaine with a placebo to see if the duration of analgesia differs.

Children have significant pain following surgery. It has been under-managed most of the time. Poorly controlled post-operative pain increases the morbidity. It leads to post-operative agitation, urinary retention, nausea and vomiting, hypoxia, pulmonary edema, cardiovascular and temperature instability. So, postoperative pain management is an essential and important component of pediatric postoperative care. Adequate pain control after surgery permits early mobilization, reduces postoperative complication, prevents development of fear and anxiety and allows early hospital discharge.

Caudal block is one of the modality of multimodal analgesia. It is a well-established, effective and relatively safe technique used for intra and post-operative analgesia in children undergoing abdominal and lower limb surgery. It provides excellent analgesia, reduces intra-operative anesthetics drug requirements, ensures pain free recovery from anesthesia, decreases stress response and avoids deleterious adverse effects of narcotic drugs.

However, the main disadvantage of caudal block is being its short duration of action with sole local anesthetics. Even long-acting local anesthetic drugs such as bupivacaine provides only 4-8 hours of analgesia. The insertion of catheter in caudal space to administer repeated doses or continuous infusions of local anesthetic drug is not popular because of concerns of infection. So, various adjuvants like Fentanyl, Morphine, Ketamine, clonidine, Dexmeditomidine etc. have been used to prolong the duration of analgesia.

Morphine and Fentanyl are opioids that have been used traditionally in combination with a local anesthetic to achieve prolonged anesthetic effect. The addition of opioid does provide better analgesia but there is a possibility of an increased incidence of pruritus, urinary retention, nausea, vomiting and respiratory depression. Similarly, Ketamine and Clonidine are the widely preferred adjuvant to caudal block but have their own number of unpleasant adverse effects8.

Hence, there is still ongoing investigations to find for an adjuvant that can safely prolong caudal analgesia. Recently, Dexmedetomidine has been used for this purpose. Various studies have described the use of Dexmedetomidine with local anesthetic drugs in caudal block for the management of postoperative pain in children. Saadawy et al. found that 1μg/kg caudal dexmedetomidine with bupivacaine was associated with an extended duration of postoperative analgesia while in other studies 2μg/kg Dexmedetomidine was used with caudal Bupivacaine or Ropivacaine for providing postoperative analgesia in children undergoing lower abdominal and perineal surgeries.

Dexmedetomidine is a highly specific and selective α2-adrenoceptor agonist that has been described as a safe and effective additive in many anesthetic procedures. In contrast to other agents, it has a sympatholytic, analgesic and sedative effects. It is remarkably free from side effects except for hypotension and bradycardia. But studies investigating its analgesic property in our population are limited.

Ropivacaine is a long-acting amino amide local anesthetic drug and was the first to be formulated as a pure S-enantiomer. It is reported to have a better safety profile than Bupivacaine with less risk for central nervous system and cardiac toxicity 10. It also decreases unwanted motor block than Bupivacaine, which makes it a more suitable agent for caudal epidural analgesia6.

Dexmedetomidine with Ropivacaine is commonly used to prolong the caudal analgesia in western population but have not been well studied in our pediatric population. So investigators designed this study to determine analgesic effect of caudal Dexmedetomidine with Ropivacaine in pediatric infraumbilical surgeries.

HYPOTHESIS Caudal Dexmedetomidine with Ropivacaine would not prolong the duration of analgesia in children undergoing infraumbilical surgery.

GENERAL OBJECTIVES To evaluate the postoperative analgesic effects of caudal Ropivacaine with or without Dexmedetomidine in pediatric infraumbilical surgery SPECIFIC OBJECTIVES

1. To compare rFLACC score (revised Face, Legs, Activity, Cry, and Consolability)in 24 hours of postoperative period.
2. To compare the time for first rescue analgesia.
3. To evaluate the total analgesics consumption in 24 hours of postoperative period.
4. To observe the side effects of study drugs (vomiting and bradycardia).

Inclusion Criteria:

• Children of either sex aged 2-7 years
• ASA (American Society of Anesthesiologist) physical status I or II
• Patients undergoing elective infraumbilical surgeries

Exclusion Criteria:

• History of neuromuscular or psychiatric disease
• Coagulation disorders
• Skin lesion at the site of injection
• Spine deformity
• History of developmental delay
• Allergy to study drugs

Children were randomly assigned to two groups having 31 children in each, by using a computer-generated table of random numbers which was enclosed in a sealed envelope and was opened by an anesthesiologist who were not involved in the study.