The Role of Periodic Alveolar Recruitment Maneuvers in Intraoperative Protective Ventilation

Effects of Three Open-lung Strategies on Respiratory Function and Lung Injury in Protective Ventilation for Laparoscopic Anterior Resection: a Randomized Controlled Trial

The goal of this clinical trial is to compare three open-lung strategies on respiratory function and lung injury in protective ventilation for laparoscopic anterior resection. It aims to answer whether a periodic alveolar recruitment maneuvers (PARM) strategy alone was an appropriate open-lung strategy in intraoperative protective ventilation. Patients were randomly assigned (1:1:1) to receive one of three open-lung strategies in protective ventilation: PARM alone (alveolar recruitment maneuvers [ARM] repeated every 30 min), positive end-expiratory pressure (PEEP) alone (a PEEP of 6 to 8 cm H2O), or a combination of PEEP and PARM (a PEEP of 6 to 8 cm H2O combined with ARM repeated every 30 min). The primary outcome is the mechanical power before the end of intraoperative mechanical ventilation. Secondary outcomes included the accumulative intraoperative mechanical power, an arterial partial pressure of oxygen (PaO2) / inhaled oxygen concentration (FiO2) ratio (P/F ratio) before the end of intraoperative mechanical ventilation, the rates of respiratory failure at post-anesthesia care unit (PACU) and three postoperative days, the concentration of soluble advanced glycation end products receptor (sRAGE) and Clara cell protein 16 (CC16) at the end of surgery, postoperative pulmonary complications score, postoperative hospitalization days and so on.

Inclusion Criteria:

1. Undergoing elective laparoscopic anterior resection and expected duration of mechanical ventilation 2 to 5 h.
2. Had an intermediate risk of developing postoperative pulmonary complications.
3. Pulse oxygen saturation in room air ≥ 94%.
4. Aged 60 to 80 years.

Exclusion Criteria:

• 1. Had received invasive mechanical ventilation for longer than 1 h within the last 2 weeks prior to surgery.

  2. Had a history of pneumonia within 1 month prior to surgery. 3. Had severe chronic obstructive pulmonary disease or pulmonary bullae. 4. Had a progressive neuromuscular illness. 5. With an American Society of Anesthesiologists (ASA) physical status of IV or higher.

  6. Intracranial hypertension. 7. Body mass index (BMI) ≥30 kg/m2. 8. Were involved in other interventional studies.