Low tidal volume ventilation during anaesthesia for major surgery: protocol and statistical analysis plan

Area of Science:

• Anesthesiology
• Respiratory Medicine
• Critical Care Medicine

Background:

• Mechanical ventilation is standard during general anesthesia for major surgery.
• While higher tidal volumes were previously advocated, emerging evidence suggests low tidal volumes may benefit surgical patients.
• Previous studies on low tidal volume ventilation during surgery were confounded by varying positive end-expiratory pressure (PEEP) levels.

Purpose of the Study:

• To evaluate the impact of low tidal volume ventilation versus conventional tidal volume ventilation on postoperative respiratory complications.
• To assess these effects in adult patients undergoing surgery with moderate PEEP levels.
• To provide robust evidence for intraoperative ventilation strategies.

Main Methods:

• A single-centre, two-arm, randomized clinical trial involving 1240 adult patients over 40 years old.
• Patients received intraoperative ventilation with a moderate PEEP of 5 cmH2O.
• Participants were randomized to receive either low tidal volume (6 mL/kg predicted body weight) or conventional tidal volume (10 mL/kg predicted body weight).

Main Results:

• The study assessed the incidence of postoperative respiratory complications as a composite endpoint within the first 7 postoperative days.
• This is the first well-powered study to compare low versus high tidal volume ventilation during surgery with moderate PEEP.
• Results are pending for the primary outcome analysis.

Conclusions:

• This study provides a direct comparison of low versus conventional tidal volume ventilation during surgery in patients receiving moderate PEEP.
• The findings will inform best practices for mechanical ventilation strategies during general anesthesia.
• Further research may elucidate the optimal tidal volume settings to minimize respiratory complications in surgical patients.