Postoperative pulmonary dysfunction is frequently observed after laparoscopic abdominal surgery due to the combined effects of general anesthesia, pneumoperitoneum, diaphragmatic dysfunction, and postoperative pain. These factors may impair respiratory mechanics, reduce lung volumes, and negatively affect postoperative recovery. Effective postoperative analgesia plays a crucial role in preserving respiratory function by allowing adequate ventilation and reducing pain-related respiratory limitation.

The erector spinae plane (ESP) block is a relatively novel ultrasound-guided fascial plane block that provides thoracoabdominal analgesia through the spread of local anesthetic along the paraspinal fascial planes. By reducing postoperative pain and opioid consumption, ESP block may contribute to improved respiratory mechanics and preservation of postoperative pulmonary function.

The aim of this prospective randomized controlled study is to evaluate the effect of ultrasound-guided erector spinae plane block on postoperative respiratory function and pain in patients undergoing elective laparoscopic cholecystectomy. Patients will be randomized into two groups: an ESP block group receiving bilateral ultrasound-guided erector spinae plane block and a control group receiving standard analgesic management.

Postoperative respiratory parameters will be evaluated using spirometry measurements including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), the FEV1/FVC ratio, and forced expiratory flow at 25-75% of the pulmonary volume (FEF25-75). In addition, arterial blood gas parameters and postoperative pain scores will be assessed and compared between the groups.

The study aims to determine whether ultrasound-guided erector spinae plane block improves postoperative respiratory function and contributes to better postoperative recovery in patients undergoing laparoscopic cholecystectomy.

Postoperative pulmonary dysfunction is a common complication following laparoscopic abdominal surgery. Several factors contribute to this condition, including the effects of general anesthesia, diaphragmatic dysfunction caused by pneumoperitoneum, decreased functional residual capacity, and postoperative pain that limits effective ventilation and coughing. These mechanisms may lead to reduced lung volumes, impaired respiratory mechanics, and an increased risk of postoperative pulmonary complications.

Adequate postoperative analgesia is a key component of perioperative care because pain following upper abdominal surgery may inhibit deep breathing and reduce chest wall expansion. As a result, insufficient analgesia can further aggravate postoperative respiratory dysfunction. Regional anesthesia techniques have therefore gained increasing interest in multimodal analgesic strategies to improve postoperative outcomes.

The erector spinae plane (ESP) block is a relatively recent ultrasound-guided fascial plane block that involves injection of local anesthetic into the fascial plane deep to the erector spinae muscle. The spread of local anesthetic along the thoracolumbar fascia allows analgesic coverage of multiple thoracic dermatomes and provides effective thoracoabdominal analgesia. Previous studies have demonstrated that ESP block can reduce postoperative pain scores and opioid consumption in various abdominal and thoracic surgical procedures.

Improved postoperative analgesia may also contribute to better preservation of respiratory mechanics. By reducing pain during breathing and coughing, ESP block may facilitate deeper inspiration, improve lung expansion, and support the maintenance of postoperative pulmonary function. However, the effect of ESP block on objective respiratory function parameters following laparoscopic cholecystectomy has not been fully clarified.

This prospective randomized controlled study aims to evaluate the effect of ultrasound-guided erector spinae plane block on postoperative respiratory function and pain in patients undergoing elective laparoscopic cholecystectomy. Patients will be randomly assigned to either an ESP block group or a control group receiving standard analgesic management.

Postoperative respiratory function will be assessed using spirometry measurements, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), the FEV1/FVC ratio, and forced expiratory flow between 25% and 75% of the pulmonary volume (FEF25-75). Arterial blood gas parameters will also be evaluated. Pain intensity will be assessed using the visual analog scale (VAS), and postoperative analgesic consumption will be recorded.

The primary objective of this study is to determine whether ultrasound-guided erector spinae plane block preserves postoperative respiratory function after laparoscopic cholecystectomy. Secondary objectives include evaluation of postoperative pain scores, analgesic requirements, and arterial blood gas parameters.

Inclusion Criteria:

Age between 18 and 65 years ASA physical status I-III-- III Patients scheduled for elective laparoscopic cholecystectomy under general anesthesia Ability to perform spirometry tests Provision of written informed consent

Exclusion Criteria:

Patient refusal to participate Chronic pulmonary disease (e.g., COPD, asthma, restrictive lung disease) Morbid obesity (BMI ≥ 35 kg/m²) Coagulopathy or anticoagulant therapy Local infection at the block site Allergy to local anesthetic agents Pregnancy Previous thoracic surgery Neuromuscular disease affecting respiratory function Conversion from laparoscopic to open surgery Inability to perform postoperative spirometry

Individual participant data will not be publicly shared due to institutional data protection policies and ethical considerations regarding patient confidentiality

Participants and outcome assessors will be blinded to group allocation. The erector spinae plane block will be performed by an anesthesiologist who will not participate in postoperative data collection or outcome assessment.