"Comparison of of Volume-Controlled Ventilation and Pressure-Controlled Ventilation Modes in Laparoscopic Cholecystectomy"

Laparoscopic cholecystectomy is one of the most commonly performed surgical proceduresunder general anesthesia. Creation of carbon dioxide pneumoperitoneum during laparoscopicsurgery increases intra‐abdominal pressure, resulting in reduced functional residualcapacity, decreased lung compliance, increased airway pressures, and alterations incarbon dioxide elimination. These physiological changes may impair respiratory mechanicsand increase the risk of perioperative pulmonary complications. Therefore, selection ofan appropriate mechanical ventilation strategy is essential to maintain adequateventilation and optimize respiratory function during laparoscopic surgery. The objectiveof this randomized controlled trial is to compare the effects of volume‐controlledventilation and pressure‐controlled ventilation on static lung compliance and end‐tidalcarbon dioxide (EtCO₂) in adult patients undergoing elective laparoscopic cholecystectomyunder general anesthesia. The study aims to determine whether pressure‐controlledventilation provides superior intraoperative respiratory mechanics compared withvolume‐controlled ventilation while maintaining adequate ventilation throughout thesurgical procedure.This is a prospective, single‐center, randomized controlled trial conducted in theDepartment of Anaesthesia, Nishtar Hospital, Multan. A total of 60 adult patients aged25‐50 years, of either sex, classified as American Society of Anesthesiologists (ASA)physical status I or II and scheduled for elective laparoscopic cholecystectomy, will beenrolled after obtaining written informed consent. Patients with uncontrolledcardiopulmonary disease, diabetes mellitus, significant renal or hepatic impairment,chronic systemic illness, body mass index below 18.5 kg/m² or above 24.9 kg/m², or recentrespiratory tract infection within the preceding three weeks will be excluded.Participants will be allocated in a 1:1 ratio using computer‐generated randomization byan independent third party into one of two study groups. Group A will receivevolume‐controlled ventilation, while Group B will receive pressure‐controlledventilation. Allocation concealment will be maintained until initiation of mechanicalventilation. Baseline demographic variables including age, sex, and body mass index willbe recorded before induction of anesthesia.A standardized anesthetic technique will be used for all participants. Mechanicalventilation settings will include a tidal volume of 8 mL/kg (with inspiratory pressureadjusted in the PCV group to achieve the target tidal volume), respiratory rate initiallyset at 12 breaths per minute and subsequently adjusted to maintain an end‐tidal carbondioxide concentration between 32 and 38 mmHg, inspiratory‐to‐expiratory ratio of 1:2,fraction of inspired oxygen (FiO₂) of 0.40, positive end‐expiratory pressure (PEEP) of 5cmH₂O, and oxygen saturation maintained above 95%. Carbon dioxide pneumoperitoneum willbe maintained with an intra‐abdominal pressure of 12‐15 mmHg throughout the procedure.Static lung compliance and end‐tidal carbon dioxide will be recorded at three predefinedintraoperative time points: five minutes after induction of anesthesia, fifteen minutesafter carbon dioxide insufflation in the reverse Trendelenburg position, and ten minutesafter carbon dioxide desufflation. Measurements will be recorded using the integratedmonitoring systems of the anesthesia workstation by a trained anesthesiologist who is notinvolved in group allocation. Blinding of the anesthesia provider is not feasible becauseof the nature of the interventions; however, the primary outcome measures are objectivemonitor‐derived variables, minimizing the risk of measurement bias.The primary outcome measures are static lung compliance and end‐tidal carbon dioxidemeasured at the predefined intraoperative time points. Data will be analyzed using SPSSversion 26. Continuous variables will be summarized as mean ± standard deviation ormedian with interquartile range according to data distribution, while categoricalvariables will be expressed as frequencies and percentages. Between‐group comparisonswill be performed using the independent t‐test or Mann‐Whitney U test as appropriate,with stratification for age, sex, and body mass index where indicated.This study is expected to provide evidence regarding the optimal ventilation strategyduring laparoscopic cholecystectomy and may contribute to improved intraoperativerespiratory management and enhanced patient safety in routine anesthetic practice.