Summary of "Ventilation during Lung Resection and Critical Care: Comparative Clinical Outcomes"

Summary published October 13, 2022

Summary by Jan Ehrenwerth, MD

Anesthesiology | October 2022

Walsh SP, Shaz D, Amar D. Ventilation during Lung Resection and Critical Care: Comparative Clinical Outcomes. Anesthesiology. 2022 Oct 1;137(4):473-483.

doi: https://doi.org/10.1097/aln.0000000000004325

  • In 2000, the ARDS Network study showed a significant reduction in mortality and ventilator free days when ICU patients with ARDS were ventilated with a Tidal Volume (VT) of 6ml/kg verses patients ventilated with a VT of 12 ml/kg (and modest PEEP). Additional studies with varying degrees of PEEP failed to show any additional benefits. Similar studies in ICU patients without ARDS (i.e., healthy lungs) failed to show significant differences in various outcomes.
  • The authors then analyzed 10 retrospective studies of one-lung ventilation. Here the results were mixed. Two studies of patients having a pneumonectomy demonstrated benefits from protective lung ventilation with low VT. However, another study did not demonstrate any measurable benefit with low VT To confuse matters even more, another study showed slightly higher complications rates with low VT ventilation. The authors noted that study was flawed by the absence of sufficient levels of PEEP. This emphasizes the difficulty in interpreting studies where there is more than one different parameter between the control and study group.
  • Finally, the authors examined eight randomized controlled trials of aspects of protective ventilation during one-lung ventilation. One study showed a significant decrease in post operative complications in the low VT Again, the study was flawed because the high VT did not receive PEEP. Another study also found a benefit to protective lung ventilation; however, the investigators used different ventilation modes between the control and intervention groups.
  • In conclusion, there is no overall definitive proof that protective lung ventilation with low VT will be beneficial to the patient. Interpretation of studies is complicated by poor design and different outcome parameters. The authors conclude “Although it can be hypothesized that protective lung ventilation during one-lung ventilation is a prudent strategy to reduce postoperative pulmonary complications, there is little evidence to support this, and data from both observational and randomized studies are conflicting.” Hopefully, the results from some ongoing studies will resolve this important patient safety issue.