After pectus excavatum is done, intravenous patient controlled analgesia device with fentanyl is connected. Then, regional analgesia is performed for additional analgesia; ultrasound guided erector spinae plane block is performed using 0.25% ropivacaine (total 1 ml/kg) bilaterally. Plasma concentration of ropivacaine at baseline, and 5, 10, 20, 30, 60, 120 minutes after ropivacaine injection will be measured.

After pectus excavatum is done, intravenous patient controlled analgesia device with fentanyl is connected. No regional block is performed.

Using ultrasound, place the needle in the erector spinae fascia plane at T7-8 level. Then, 0.25% ropivacaine 0.5 ml is injected to confirm the needle location. After checking the location, 0.25% ropivacaine 0.5 ml/kg is administered. This procedure is repeated at contralateral side.

The Face, Legs, Activity, Cry, Consolability (FLACC) scale is used. FLACC scale is a measurement used to assess pain for children between the ages of 2 months and 7 years or individuals that are unable to communicate their pain. The scale is scored in a range of 0-10 with 0 representing no pain. The scale has five criteria, which are each assigned a score of 0, 1 or 2.

Total dosage of fentanyl used postoperatively via patient controlled analgesia (mcg/kg)