During general anesthesia surgery, the role of positive end-expiratory pressure (PEEP) in mechanical ventilation remains uncertain. Pressure levels above 0 cm H₂O can prevent postoperative pulmonary complications but may also cause intraoperative circulatory depression and lung injury due to overdistension. Using very low levels of PEEP may lead to atelectasis. However, high levels of PEEP can not only trigger complications such as intraoperative circulatory depression but also promote hyperinflation. Positive end-expiratory pressure (PEEP) is required to prevent atelectasis during lung-protective ventilation, and different levels of PEEP exhibit varying physiological and clinical effects when used alone or in combination with alveolar recruitment maneuvers (ARM). Alveolar recruitment maneuvers (ARM) are used to open atelectatic lung parenchyma, but the duration of their benefits has not been clearly determined. This study aims to determine the effectiveness of different PEEP levels after ARM in general anesthesia surgery, the duration of their time-dependent responses, and their hemodynamic effects, providing a reference for how often recruitment maneuvers should be performed during general anesthesia and further refining the specific details of lung-protective ventilation strategies.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
101
After the patient enters the operating room, routine monitoring of ECG, non-invasive blood pressure, and SpO₂ is performed. Local anesthesia is used for radial artery puncture and catheterization to monitor invasive blood pressure. After 3 minutes of pre-oxygenation, tracheal intubation is performed with the following ventilation parameters: VT 6-8 ml/kg, FiO₂ 60%, RR 15 breaths/min, I/E 1:2, and PEEP 4 cmH₂O. Ten minutes after the establishment of pneumoperitoneum during surgery, baseline levels of respiratory mechanical parameters and hemodynamic variables are recorded. Subsequently, alveolar recruitment is performed at a pressure of 30 cmH₂O for 30 seconds. Immediately after recruitment, the PEEP level is adjusted according to the group. The changes in respiratory mechanics parameters and hemodynamic variables after recruitment are recorded. After the outcome indicators recover to the new baseline level, the PEEP is readjusted to 4 cmH₂O.
Northern Jiangsu People's Hospital
Yangzhou, Jiangsu, China
the duration of improvement in lung compliance
Time frame: during the surgery
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