These circadian rhythms are self-sustained, endogenous oscillations generated by circadian clocks that persist with a period of around 24 -h under constant conditions. Multiple clinical and foundational science studies report that circadian rhythm disruption can directly alter pain thresholds. Altered circadian pain rhythms manifest inconsistently in various disease states. circadian differences exist in tolerability of administration as well as in effectiveness of analgesia during surgical, obstetric, and dental procedures, with the majority of studies demonstrating highest pain sensitivity during the overnight or early morning hours. Although the relationship between pain states and circadian rhythm has been studied in various surgical procedures and chronic pain syndromes, there is little literature examining the relationship between postoperative pain and circadian rhythm in pediatric surgical procedures. Therefore, it was aimed to evaluate the relationship between postoperative pain and circadian rhythm after pediatric acute appendicitis surgery.

This study will be conducted with the data to be obtained from the Anesthesiology Surgery Form and Pediatric Surgery Service Forms in 200 patients aged 6-18 years, after the approval of the Faculty Local Ethics Committee in the Department of Anesthesiology, Faculty of Medicine, Selcuk University. According to the time the patients were taken into the operation, Group 1; 01:01-07:00, Group 2; 07:01-13:00, Group 3; 13:01-20:00 and Group 4; 20:01-01:00, It will be divided into four groups between. The files of the patients will be examined and demographic data such as age (year), body weight (kg), height (cm), gender, ASA scores (I-III), anesthesia and surgery time, anesthesia and surgery time will be recorded. Intraoperative vital signs; systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR) oxygen saturation (SpO2) Endtidal CO2 and temperature before operation (control) and 5, 10, 15, 20, 25 and 30 minutes (min) and at the end of the process (end) data will also be saved. Perioperative side effects such as nausea-vomiting, hypotension, bradycardia, tremor, respiratory distress, sore throat, headache, and dizziness symptoms will be noted if they occur. The routinely applied analgesic protocol and vital signs in the postoperative pediatric surgery service, the total amount of analgesic administered, the time to first analgesia requirement and VAS scores at 1, 2, 3, 6, 9, 12, 15, 18, 21 and 24th hours will also be recorded. There will be no interference with the routinely applied analgesic protocol.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical condition I-II,
• Undergoing acute appendicitis,
• Patients aged 6-18 years

Exclusion Criteria:

• ASA ≥ III,
• Uncontrolled chronic, metabolic disease,
• Opioid or analgesic use in the last 10 days,
• Acute peritonitis or sepsis
• History of abnormal operation or recovery from anesthesia,
• Patients with parents who are unwilling to give informed consent

Postoperative pain differs in both sexes according to the circadian rhythm.

Pediatric patient population of both sexes aged 6-18 years

I do not have a plan to make individual participant data (IPD) available to other researchers.