A ventilation strategy during general anaesthesia to reduce postoperative atelectasis

Area of Science:

• Anesthesiology
• Respiratory Physiology
• Critical Care Medicine

Background:

• Postoperative atelectasis is a frequent complication following general anesthesia.
• Conventional ventilation strategies may not adequately prevent lung collapse.
• A novel approach combining positive airway pressure and reduced oxygen may mitigate this issue.

Purpose of the Study:

• To investigate the efficacy of a ventilation strategy using continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP) combined with a reduced end-expiratory oxygen fraction (FETO2) in minimizing postoperative atelectasis.
• To compare this strategy against conventional ventilation without recruitment maneuvers.

Main Methods:

• Thirty patients were randomized into three groups receiving different fractions of inspired oxygen (FIO2) and positive airway pressure (CPAP/PEEP).
• The intervention groups received CPAP/PEEP of 6 cmH2O and a reduced FIO2 post-extubation, aiming for FETO2 < 0.30.
• Postoperative atelectasis was quantified using computed tomography 25 minutes after surgery.

Main Results:

• The median area of atelectasis was significantly smaller in the group receiving FIO2 1.0 with CPAP/PEEP compared to the control group (5.2 cm² vs. 8.5 cm², p=0.04), even after adjusting for body mass index.
• The group receiving FIO2 0.8 with CPAP/PEEP showed a median atelectasis area of 8.2 cm², with a higher proportion of smokers in this group.
• The ventilation strategy demonstrated a reduction in postoperative atelectasis in one intervention group.

Conclusions:

• The tested ventilation strategy, incorporating CPAP/PEEP and reduced FETO2, effectively reduced postoperative atelectasis in one of the intervention groups.
• The presence of smokers in one group may have influenced the outcomes, suggesting potential confounding factors.
• Further research is warranted to optimize this ventilation strategy for diverse patient populations, considering factors like smoking status.