Lower Ventilation Pressure Sufficient for Healthy Lungs

Low positive end-expiratory pressure (PEEP) protocols for ICU patients without acute respiratory distress syndrome (ARDS) are no worse than higher levels, according to a new study.

Researchers at Amsterdam University Medical Centers (AMC; The Netherlands), Hospital Israelita Albert Einstein (São Paulo, Brazil), and other institutions conducted a study involving 980 patients (median age 66, 36% women) in eight ICUs in the Netherlands to determine if a lower PEEP strategy (0-5 cm H₂O) was non-inferior to a higher PEEP strategy (8 cm H₂O). All patients were without ARDS, and were not expected to be extubated within 24 hours of ventilation initiation. The primary outcome was the number of ventilator-free days at day 28.

The results showed that at day 28, patients in the lower PEEP group had a median of 18 ventilator-free days, while those in the higher PEEP group had a median of 17 ventilator-free days. Mortality was 38.4% versus 42%, occurrence of severe hypoxemia was 20.6% versus 17.6%, and need for rescue strategy was 19.7% versus 14.6%, respectively. In addition, there were no major differences in duration of ventilation, ICU, or hospital lengths of stay, pulmonary complications, and the other secondary endpoints. The study was published on December 9, 2020, in JAMA.

“There has been a gradual and noticeable increase in use of higher PEEP in patients without ARDS in ICUs worldwide,” concluded senior author Marcus Schultz, MD, PhD, of AMC, and colleagues. “It may not be better to use a lower PEEP strategy, but it could be as good as higher PEEP. These findings support the use of lower PEEP in patients without ARDS.”

Ventilation with higher PEEP may lead to a better distribution of lung aeration, improving oxygenation, and could even prevent ARDS. However, it could also worsen existing or cause new lung injuries, since ventilation with higher PEEP impairs blood hemodynamics and increases the need for additional fluid administration or vasopressors. And because it is common practice to extubate at lower PEEP, use of higher PEEP could also delay weaning in some settings. The study was concluded before the onset of the COVID-19 pandemic.

Related Links:
Amsterdam University Medical Centers
Hospital Israelita Albert Einstein