Effect of Low-Flow Anesthesia on Perioperative Atelectasis in Patients Undergoing Laparoscopic Bariatric Surgery: A Randomized Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 60
- 试验地点
- 1
- 主要终点
- Change in modified Lung Ultrasound Score from baseline to postoperative hour 1 (ΔmLUSS₁ₕ)
研究概览
简要总结
The goal of this clinical trial is to learn whether low-flow anesthesia reduces perioperative atelectasis compared to normal-flow anesthesia in adults undergoing laparoscopic bariatric surgery. The main questions it aims to answer are:
Does low-flow anesthesia result in a smaller increase in lung ultrasound score from baseline to postoperative hour 1? Does low-flow anesthesia result in better preservation of pulmonary function at postoperative hour 48?
Researchers will compare low-flow anesthesia (fresh gas flow 0.5 L/min) to normal-flow anesthesia (fresh gas flow 2 L/min) to see if low-flow anesthesia reduces the extent of perioperative atelectasis as measured by lung ultrasound.
Participants will:
Be randomly assigned to receive either low-flow or normal-flow inhalational anesthesia with sevoflurane during surgery Undergo lung ultrasound assessments before surgery and at postoperative hours 1 and 24 Undergo spirometric testing one day before surgery and at postoperative hour 48
详细描述
This prospective, single-center, randomized controlled trial investigates the effect of low-flow anesthesia on perioperative atelectasis in patients undergoing elective laparoscopic sleeve gastrectomy. Morbidly obese patients are at increased risk of perioperative atelectasis due to reduced functional residual capacity, diaphragmatic elevation, and the additional physiological burden of pneumoperitoneum and reverse Trendelenburg positioning during laparoscopic surgery.
Eligible patients are randomized in a 1:1 ratio to one of two groups. In the normal-flow group (Group N), anesthesia is maintained with sevoflurane at a fresh gas flow of 2 L/min. In the low-flow group (Group D), anesthesia is initiated at 4 L/min to achieve rapid equilibration and then reduced to 0.5 L/min once 1.0 minimum alveolar concentration (MAC) is reached. All patients receive standardized lung-protective mechanical ventilation and an identical anesthetic protocol otherwise.
Atelectasis is quantified using the modified Lung Ultrasound Scoring System (mLUSS), in which each of 12 lung zones is scored 0-3 based on aeration loss, yielding a total score of 0-36. Assessments are performed preoperatively, at postoperative hour 1, and at postoperative hour 24 by a single investigator blinded to group allocation. Pulmonary function tests (FVC, FEV₁, FEV₁/FVC, PEF, FEF₂₅-₇₅) are performed preoperatively and at postoperative hour 48 by a separate blinded investigator.
Secondary outcomes include changes in spirometric parameters, intraoperative hemodynamic event incidences, mean intraoperative FiO₂ and plateau pressure, sevoflurane and remifentanil consumption, postoperative nausea and vomiting incidence, and postoperative analgesic requirements.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Triple (Participant, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age 18-65 years ASA physical status III Scheduled for elective laparoscopic sleeve gastrectomy under general anesthesia Able to provide written informed consent and cooperate with study procedures
排除标准
- •Severe respiratory comorbidities (advanced COPD, restrictive lung disease, or severe obstructive sleep apnea syndrome) Advanced heart failure (ejection fraction < 20%) Chronic renal failure Hepatic insufficiency Uncontrolled diabetes mellitus Uncontrolled hypertension Limited capacity to cooperate with study procedures
研究组 & 干预措施
Normal-Flow Anesthesia Group (Group N)
Patients receive normal-flow inhalational anesthesia with sevoflurane throughout surgery. Fresh gas flow (FGF) is maintained at 2 L/min with the sevoflurane vaporizer set to 2.5%. Lung-protective mechanical ventilation is applied uniformly.
干预措施: Sevoflurane with normal-flow anesthesia (Drug)
Low-Flow Anesthesia Group (Group D)
Patients receive low-flow inhalational anesthesia with sevoflurane. Anesthesia is initiated at FGF 4 L/min with sevoflurane at 6% for rapid equilibration; once end-tidal sevoflurane reaches 1.0 MAC, FGF is reduced to 0.5 L/min and titrated to maintain 1.0 MAC throughout surgery.
干预措施: Sevoflurane with low-flow anesthesia (Drug)
结局指标
主要结局
Change in modified Lung Ultrasound Score from baseline to postoperative hour 1 (ΔmLUSS₁ₕ)
时间窗: 1 hour after arrival to the post-anesthesia care unit (PACU)
The mLUSS is calculated by scoring 12 lung zones (0-3 per zone) based on aeration loss on lung ultrasound, yielding a total score of 0-36. The primary outcome is the between-group difference in the change from preoperative baseline to postoperative hour 1.
the atelectasis rate with the Lung Ultrasound score (AUS score).
时间窗: 8 months
次要结局
- Change in modified Lung Ultrasound Score from baseline to postoperative hour 24 (ΔmLUSS₂₄ₕ)(24 hours postoperatively)
- Changes in spirometric parameters from baseline to postoperative hour 48(48 hours postoperatively)
- Intraoperative hemodynamic event incidences(Intraoperatively)
研究者
Dunyakhanim Farzaliyeva
RESIDENT DOCTOR
Goztepe Prof Dr Suleyman Yalcın City Hospital