Alveolar Recruitment Maneuver, Dynamic Lung Compliance
Conditions
Brief summary
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.
Interventions
BEHAVIORALlung recruitment maneuvre; PEEP
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.
Sponsors
Northern Jiangsu People's Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* ASA physical status classification: Ⅰ or Ⅱ or Ⅲ * Adults aged 18 to 80 years, regardless of gender. * Patients undergoing elective laparoscopic colorectal cancer surgery under general anesthesia. * Patients who have provided written informed consent after understanding the study purpose, procedures, and potential risks.
Exclusion criteria
* Recent thoracic surgery; radiographic evidence of pneumothorax, emphysema, or pulmonary bullae; * Pulmonary diseases: asthma or severe obstructive ventilatory dysfunction; preoperative pulse oxygen saturation (SpO2) \< 90% on room air or \< 95% with supplemental oxygen; contraindications to ARMs (e.g., intracranial hypertension, hypovolemic shock, or right heart failure); * severe cardiac disease (NYHA class III/IV, acute coronary syndrome, sustained ventricular tachycardia); concurrent participation in another trial; or refusal to provide informed consent
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| the duration of improvement in lung compliance | during the surgery |
Countries
China
Outcome results
None listed