This prospective randomized clinical trial aims to evaluate the effects of different fresh gas flow rates on postoperative pulmonary aeration using lung ultrasonography in patients undergoing elective laparoscopic cholecystectomy. Patients will be randomly assigned to receive either low-flow anesthesia (0.5 L/min) or high-flow anesthesia (4 L/min) during maintenance of general anesthesia. The primary objective is to compare postoperative lung ultrasound scores and the incidence of atelectasis between the two groups.
Pulmonary atelectasis is one of the most common postoperative pulmonary complications following general anesthesia. Fresh gas flow is an important component of inhalational anesthesia and may influence airway humidity, gas exchange, respiratory mechanics, and pulmonary physiology. Although low-flow anesthesia has recognized economic, environmental, and physiological advantages, the effect of different fresh gas flow rates on postoperative lung aeration has not been adequately investigated. This prospective, randomized, parallel-group clinical trial will be conducted at Adıyaman University Training and Research Hospital. Adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia will be randomly allocated to either a low-flow group (0.5 L/min) or a high-flow group (4 L/min) after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation. Standardized anesthesia management will be applied to all participants. Postoperative lung ultrasonography will be performed 30 minutes after extubation in the post-anesthesia care unit. Lung Ultrasound Score (LUS) and the incidence of postoperative atelectasis will be compared between the study groups. The findings are expected to provide evidence regarding the effects of different fresh gas flow strategies on postoperative pulmonary outcomes and may contribute to optimizing intraoperative anesthesia management.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
General anesthesia will be maintained using a fresh gas flow rate of 0.5 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation.
General anesthesia will be maintained using a fresh gas flow rate of 4 L/min after an initial fresh gas flow of 4 L/min for 8 minutes following endotracheal intubation.
Adıyaman Training and Research Hospital
Adıyaman, Turkey (Türkiye)
Postoperative Lung Ultrasound Score
Lung ultrasonography will be performed 30 minutes after extubation. Both lungs will be divided into 12 regions, with 6 regions assessed in each lung. Each region will be scored from 0 to 3: 0 indicates normal aeration with A-lines or fewer than three B-lines; 1 indicates at least three well-spaced B-lines; 2 indicates coalescent B-lines; and 3 indicates lung consolidation. The scores from all regions will be summed, resulting in a total score ranging from 0 to 36. Higher scores indicate greater loss of lung aeration.
Time frame: 30 minutes after extubation
Incidence of postoperative atelectasis
Atelectasis will be defined as a consolidation score ≥2 in any lung region assessed by lung ultrasonography
Time frame: 30 minutes after extubation
Peripheral oxygen saturation (SpO₂)
Time frame: During surgery
Mean arterial pressure
Time frame: During surgery
Heart rate
Time frame: During surgery
Peak airway pressure
Peak airway pressure will be recorded during general anesthesia and compared between the low and high fresh gas flow groups.
Time frame: Throughout the intraoperative period
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Enrollment
120