The primary objective of this study is to evaluate the effect of intraoperative salbutamol administration on mechanical power in obese patients undergoing laparoscopic bariatric surgery under general anesthesia. Mechanical power will be measured at predefined intraoperative time points (T0, T1, and T2), and changes over time will be compared to determine the impact of salbutamol on the overall energy delivered to the respiratory system during mechanical ventilation. Secondary objectives include the assessment of intraoperative respiratory mechanics, including peak airway pressure (Ppeak), plateau pressure (Pplat), driving pressure (Pdrive), airway resistance (Raw), and lung compliance, as well as gas exchange parameters (SpO₂, EtCO₂) and hemodynamic variables (mean arterial pressure). Postoperative pulmonary outcomes will be evaluated using the Melbourne Group Scale (MGS), with a score greater than 4 indicating the presence of postoperative pulmonary complications. The study aims to investigate whether improvement in intraoperative mechanical power and respiratory mechanics is associated with a reduction in postoperative pulmonary complications in this high-risk population.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
66
Salbutamol will be administered intraoperatively via the respiratory circuit during mechanical ventilation to assess its effect on mechanical power and respiratory mechanics.
Normal saline will be administered intraoperatively via the respiratory circuit in the same volume and manner as salbutamol to serve as a placebo
Health Sciences University Gazi Yaşargil Training and Research Hospital
Kayapınar, Diyarbakır, Turkey (Türkiye)
Change in intraoperative mechanical power
Mechanical power will be measured directly by the ventilator/respiratory monitoring device using ventilator parameters (tidal volume, respiratory rate, peak and plateau pressures, driving pressure, and compliance) at T0, T1, and T2. The primary outcome is the difference in mechanical power between the Salbutamol and placebo groups over time.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Peak airway pressure (Ppeak)
Peak airway pressure will be measured directly by the ventilator/respiratory monitoring device at T0, T1, and T2 to assess intraoperative respiratory mechanics.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Plateau pressure (Pplat)
Plateau pressure will be measured by the ventilator device at T0, T1, and T2 to evaluate changes in lung mechanics.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Driving pressure (Pdrive)
Driving pressure (Pplat minus PEEP) will be measured via the ventilator device at all intraoperative time points to assess lung stress.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Airway resistance (Raw)
Airway resistance will be recorded from the ventilator/monitoring device at each time point to evaluate intraoperative airway changes.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Lung compliance
Lung compliance will be measured by the ventilator at T0, T1, and T2 to assess changes in respiratory mechanics.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Lung elastance (E)
Lung elastance will be measured directly by the ventilator/monitoring device at each intraoperative time point (T0, T1, T2) to evaluate the stiffness of the respiratory system and its changes due to pneumoperitoneum and Ventolin/SF administration.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Heart rate (HR / Nabız)
Heart rate will be monitored continuously and recorded at T0, T1, and T2 to evaluate intraoperative hemodynamic stability and potential effects of pneumoperitoneum and Ventolin/SF administration.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Mean arterial pressure (MAP)
Mean arterial pressure will be monitored continuously and recorded at T0, T1, and T2 to assess intraoperative hemodynamic stability and the effects of pneumoperitoneum and Ventolin/SF administration.
Time frame: Baseline (intraoperative, after establishment of pneumoperitoneum and before Ventolin or saline administration)
Postoperative pulmonary complications (Melbourne Group Scale >4)
Incidence of postoperative pulmonary complications will be assessed using the Melbourne Group Scale (MGS). A score greater than 4 indicates the presence of a postoperative pulmonary complication. Criteria include: Temperature \>38°C White cell count \>11.2 ×10⁹/L or use of respiratory antibiotics Physician diagnosis of pneumonia or chest infection Chest X-ray findings of atelectasis or consolidation Production of purulent (yellow/green) sputum different from preoperative sputum Positive microbiological analysis of sputum SpO₂ \<90% in ambient air Re-admission to or prolonged stay (\>36 h) in ICU/high dependency unit for respiratory problems Patients meeting ≥4 of these criteria at any assessment point will be recorded as having a postoperative pulmonary complication.
Time frame: First assessment: Within 24 hours postoperatively Second assessment: 48 hours postoperatively Third assessment: Immediately before hospital discharge
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