Study Title:
Comparison of the Analgesic Efficacy of Caudal and Quadratus Lumborum Blocks Using a Pain Monitor in Children Undergoing Lower Abdominal Surgery
Study Objectives
Primary Objective:
To compare the analgesic efficacy of caudal block and quadratus lumborum block (QLB) using an objective pain monitoring device (Pain Monitor; PAM).
Secondary Objectives:
To evaluate the postoperative analgesic efficacy of caudal block and QLB in lower abdominal surgeries.
To compare postoperative analgesia duration and analgesic requirements between the two groups.
To assess postoperative side effects associated with each regional anesthesia technique.
To evaluate postoperative parental satisfaction.
Materials and Methods
Children aged 2 months to 6 years with ASA physical status I-II, scheduled for elective lower abdominal surgeries (e.g., inguinal hernia repair, orchiopexy, hydrocele) performed by the pediatric surgery unit at Etlik City Hospital, will be included.
Participants will be randomized using the Research Randomizer program (https://www.randomizer.org/
) into either the caudal block group or the quadratus lumborum block group. A total of 68 participants will be enrolled, with 34 participants in each group.
Both regional anesthesia techniques and the use of the PAM device for intraoperative nociception monitoring are established components of standard clinical practice at the study institution. Therefore, all participants will receive these interventions as part of routine perioperative care, independent of study participation. The study design is prospective and observational, with no deviation from standard anesthetic management.
Demographic data, anesthesia duration, and surgical duration will be recorded. Written informed consent will be obtained from parents or legal guardians preoperatively.
Participants may receive routine oral premedication with midazolam (0.5 mg/kg) in the preoperative area. In the operating room, standard monitoring (SpO₂, ECG, non-invasive blood pressure) will be applied, followed by placement of the PAM monitor. A pediatric probe will be placed on the foot in children younger than 3 years, and an adult probe will be placed on the hand in children aged 3 years or older.
Standard anesthesia induction and maintenance will be performed (oxygen/air mixture, sevoflurane, propofol, laryngeal mask airway). Under ultrasound guidance, either a caudal block with 1 mL/kg of 0.125% bupivacaine (maximum 20 mL) or a bilateral quadratus lumborum block with 0.5 mL/kg of 0.25% bupivacaine (maximum 20 mL) will be administered.
Intraoperative PAM index values will be recorded at five predefined time points:
During laryngeal mask airway insertion
During block performance
At the first surgical incision
20 minutes after block performance
During extubation
Following emergence from anesthesia, the PAM monitor will be removed, and participants will be observed for up to 4 hours postoperatively.
Postoperative assessments will include:
FLACC pain scores
PONV scores
Steward recovery scores
Parental satisfaction scores (PPPS)
These assessments will be performed at 1, 2, and 4 hours postoperatively.
Rescue analgesia with intravenous paracetamol (15 mg/kg) will be administered if the FLACC score is ≥4, and the time to first administration will be recorded. Postoperative complications will also be documented.
