The addition of clonidine to ropivacaine in rectus sheath nerve blocks for pediatric patients undergoing laparoscopic appendectomy: A double blinded randomized prospective study

Study objective: The primary goal of this study was to determine if the addition of clonidine to ropivacaine prolonged periumbilical numbness compared to ropivacaine alone in pediatric patients receiving ultrasound guided rectus sheath nerve blocks for laparoscopic appendectomy. The secondary goals were to evaluate differences in perioperative pain scores, analgesic consumption, sedation, anxiolysis, and hemodynamic effects from clonidine. Design: This was a single center, randomized, double-blinded prospective study. Setting: This study was conducted within the pediatric operating rooms at the Children's Hospital of Pittsburgh, a large university-based academic medical center. Patients: Fifty pediatric patients (ages 10-17 years old) without pre-existing cognitive impairment, developmental delay or chronic pain undergoing laparoscopic appendectomy during weekday hours were enrolled and randomized to control versus intervention groups. Intervention: Ultrasound guided rectus sheath nerve block injections were performed at the beginning of surgery with either ropivacaine 0.5% plus normal saline or ropivacaine 0.5% plus clonidine (2 mcg/kg, maximum of 100 mcg). Measurements: The duration of periumbilical numbness, Numeric Pain Rating Scale scores, University of Michigan Sedation Scale, State-Trait Anxiety Inventory for Children, analgesic consumption, heart rate, blood pressure, and mean arterial pressures, were recorded for each patient at several time points in the perioperative setting. Main results: There were no significant differences in demographic characteristics between groups. The median duration of periumbilical numbness did not significantly differ between the ropivacaine only and the ropivacaine plus clonidine groups 540.0 minutes [360.0 -1015.0] (median [interquartile range (IQR)]) versus 823.5 minutes [509.5- 1080.0], p = 0.451. There were no significant differences in perioperative analgesic consumption, pain and anxiety scores, PACU sedation, or hemodynamic instability. Conclusions: The addition of clonidine did not significantly prolong rectus sheath nerve block duration and was well tolerated in pediatric patients. Perioperative analgesia, hemodynamics, anxiety, and PACU sedation did not differ between groups.