Postoperative Analgesia in Thoracic Surgery

The gold standard for managing pain after thoracic surgery is the administration of local anesthetics, with or without opioids, through a catheter placed in the epidural space during the 48-hour postoperative period. However, there are instances in which the placement of this catheter is contraindicated (due to patient refusal, coagulation disorders, spinal pathology, etc.) or in which the risk-benefit assessment necessitates the consideration of alternatives (it may lead to hypotension or bradycardia that compromises patients with cardiovascular disease, urinary retention, nerve injury, or spinal hematoma). This has prompted anesthesiologists to explore alternative options, including paravertebral block, which has shown promising results. However, it is important to note that paravertebral block is not entirely risk-free and has contraindications similar to those of epidural analgesia. When epidural catheter placement is not feasible, erector spinae plane block is a safe alternative. The ultrasound target is easily visualized, and the injection site is far from the neuraxis, pleura, and major vascular structures. Consequently, this block has been incorporated into standard clinical practice as a treatment option for patients with complex cases or as an alternative approach when epidural catheter placement is not feasible. The primary objective of this study is to assess the effectiveness of postoperative analgesia in patients undergoing elective thoracic surgery.

Design and Study Population A prospective observational cohort study will be conducted. Patients will be followed from the day of hospital admission (usually 24 hours before surgery, when informed consent will be requested) until hospital discharge.

The management of perioperative analgesia will adhere to standard clinical protocols, following a comprehensive evaluation by the anesthesiologist responsible for intraoperative anesthesia management.

Patients with ASA I-III classification who have scheduled thoracic surgery at the Doctor Negrín University Hospital of Gran Canaria between November 1 and December 31, 2025, will be included in the study. It is estimated that 80 patients will be included in this prospective, observational study.

On the day of the procedure, analgesic management will be administered according to the standard clinical practice of the anesthesiologist responsible for the patient's clinical management. The anesthesiologist will be unaware that the patient's perioperative analgesic management will be evaluated by this study. For all patients undergoing a regional procedure (epidural catheter or erector spinae plane block), standard aseptic measures will be followed during the procedure.

The epidural catheter will be placed according to standard clinical practice using the loss-of-resistance technique in the space between the dorsal spinous processes corresponding to the surgical wound site, prior to the patient's anesthesia induction. The anesthesiologist responsible for the patient's perioperative management will decide whether or not to use this catheter to administer analgesics during the intraoperative period or whether to administer intraoperative analgesics with or without the administration of intravenous opioids in combination with non-opioid analgesics.

For patients undergoing an erector spinae plane block, the procedure will be performed using ultrasound with a high-frequency linear ultrasound probe. The puncture point will be located 3 cm lateral to the spinous process. The puncture is made at the level of T5, in the craniocaudal plane, using a 50 mm EchoPlex needle, until the needle bevel is seen at the level of the transverse process, immediately anterior to the erector spinae muscle group. At this point, 3 ml of the local anesthetic selected by the anesthesiologist in charge of perioperative management of the patient is injected, allowing for the visualization of the dissection of the interfascial plane. If adequate dissection of this plane is confirmed during the injection of these 3 ml, the remaining local anesthetic will be injected until the target volume is reached, without exceeding the toxic dose for each patient. 7) Intraoperative anesthetic management will be carried out in accordance with standard clinical practice. Following the completion of the procedure and extubation, the patient will be transferred to the Post-Anesthesia Care Unit. Pain will be assessed using a numerical pain scale at 1, 3, 6, 24, and 48 hours postoperatively. Postoperative management will be carried out according to standard clinical practice. The patient's postoperative progress will also be assessed until hospital discharge.

• Postoperative analgesics consumption [Time frame: 24 postoperative hours.]
• Postoperative complications [Time frame: First postoperative week.]