Fresh Gas Flow and Lung Ultrasonography in Laparoscopic Cholecystectomy

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.

Inclusion criteria

• Adults aged 18 years or older.
• American Society of Anesthesiologists (ASA) physical status I-II.
• Scheduled for elective laparoscopic cholecystectomy under general anesthesia.
• Able and willing to provide written informed consent.

Exclusion criteria

• Refusal to participate in the study.
• History of chronic respiratory disease, including severe asthma, chronic obstructive pulmonary disease (COPD), or bronchiolitis.
• History of alcohol or substance abuse.
• Intraoperative airway or respiratory complications during endotracheal intubation or surgery.
• Life-threatening postoperative complications.
• Patients with ASA physical status III or higher.