ESP Block in Pediatric Patients for Postoperative Analgesia

Reducing the pain from surgical procedures performed early in life psychologically reduces the pain experienced by children in subsequent procedures. Pediatric cardiac surgery is associated with moderate to severe postoperative pain that is related to median sternotomy. Pediatric cardiac surgical patients usually undergo multiple surgical interventions and hospital admissions and will benefit from effective pain relief during their initial surgery. In a fast-track protocol, used in modern-day cardiac surgical care, early extubation may be facilitated by executive postoperative pain control, which also helps in maintaining hemodynamic stability.

Neuraxial analgesia techniques are effective for sternotomy pain. However cardiac surgery procedures potentially require cardiopulmonary bypass (CPB) and systemic anticoagulation, thus increasing the epidural hematoma risk. Erector spinae plane (ESP) block appears to provide adequate regional analgesia for multiple dermatomal levels covering the sternum without increasing the risks associated with neuraxial blocks.

This prospective, randomized, and double-blind study is designed to examine the efficacy and safety of the ESP block on the postoperative analgesia in pediatric patients after cardiac surgery. We hypothesized that the ESP block significantly improves pain control, as evidenced by the reduced need for systemic postoperative analgesics.

METHOD After obtaining approval from the Institutional Review Boards at Çukurova University Medical Faculty, 40 pediatric patients aged 2-10 years, undergoing cardiac surgery with median sternotomy will be enrolled. Parental consent and patient assent from patients of an appropriate age will be obtained. Children with a preoperative ejection fraction<35%, a ventricular arrhythmia/dysrhythmia, a low cardiac output syndrome, a redo or an emergency surgery, a scoliosis or other anatomic contraindication to ESPB, a history of bleeding diathesis, an anticoagulant drug use at the time of the block and with known allergies to any of the study drugs will be excluded from the study.

Anesthesia Children received oral premedication of midazolam 0.5 mg/kg. After i.v. access will be obtained, fentanyl 5 µg/kg will be given. Anesthesia will be induced with 2-3 mg/kg propofol and all children will receive rocuronium 0,6 mg/kg for tracheal intubation. After tracheal intubation, an arterial line, central venous catheter, and urinary catheter will be inserted. Subsequently, fentanyl 5 µg/kg will be administered prior to incision and an additional 5 microg/kg of fentanyl given prior to CPB. Anesthesia will be maintained with %2-3 sevoflurane. Fentanyl 1 µg/kg will be given before skin closure at the end of surgery.

Intervention Patients were randomly assigned to a study group by the computer generated number table. Children in group B will be administered bilateral ESPB with 0.25% bupivacaine, while children in group C did not receive any intervention. The anesthesia resident observing the patient in the postperative period and the intensive care unit staff giving postoperative care will be blind to the study protocol.

Following anesthesia induction and endotracheal tube placement, the patient will be turned into a left lateral decubitus position and bilateral ESP block will be performed under aseptic conditions.

ESP block at bilateral side will be performed in the lateral decubitis position and at T5 transverse process level by using 10-MHz liner ultrasound probe. The probe will be located 1 cm lateral to T5 spinous process in longitudinal parasagittal orientation. Simplex A 50mm (B.Braun, Germany) will be inserted by using out of plane technique. The ESP blocks proceed with 0,5 ml/kg of 0,25% bupivacaine (Group B). The injection will be applied after the confirmation of location by hydrodissection developed anterior to erector spinae muscle with 1-2 ml of local anesthetic solution.

Postoperative care All the patients then will be shifted to the intensive care unit (ICU) after the surgery and managed with the institution's ICU protocol for postoperative pain management and ventilation.The postoperative analgesia will be provided with rescue intravenous (IV) morphine 0.05 mg/kg. Both the groups will receive IV paracetamol 15 mg/kg every 6 hours as a component of multimodal analgesia.

Postoperative sternal wound pain will be judged by the Modified Objectice Pain Scale.

Postoperative sedation levels will be evaluated with Ramsay sedation score.