Lower PEEP as good as higher PEEP in Non ARDS patients

Marcus J. Schultz, Anna Geke Algera,  Luigi Pisani et el published a trial in JAMA comparing lower versus higher PEEP in Non ARDS patients who needed mechanical ventilation in intensive care unit. 

Background

Higher PEEP has  shown some beneficial  effects in patients with ARDS.  Effect of this observation has resulted in use of  higher PEEP in patients who  do not have ARDS.   On the one hand,  higher PEEP results in better distribution of lung aeration, which improves oxygenation but on the other hand, higher PEEP can cause impaired hemodynamics and increased need for additional fluid administration or vasopressors during surgery.  So far  role of PEEP in  patients who do not have ARDS  has not been well studied.

Where

A randomized clinical trial conducted at the ICUs of 8 hospitals in the Netherlands. 

Who

Adult patients who received mechanical ventilation  and were expected not to be extubated within 24 hours of randomization.  Patients with ARDS were excluded.   Following patients were also excluded

  • pregnancy;
  • ventilation lasting longer than 12 hours before admission to the ICU;
  • COPD GOLD class III/IV; restrictive pulmonary disease;
  • increased and uncontrollable intracranial pressure;
  • delayed cerebral ischemia;
  • ongoing cardiac ischemia;
  • morbid obesity;
  • necrotizing fasciitis;
  • severe untreatable anemia;
  • neurologic diagnosis that could prolong duration of mechanical ventilation;
  • carbon monoxide poisoning;
  • receiving ECMO

Interventions

Lower PEEP, consisting of the lowest PEEP level between 0 and 5 cm H2O , or higher PEEP, consisting of a PEEP level of 8 cm H2O.  In the low PEEP group, after intubation and start of ventilation, every 15 minutes PEEP was down-titrated by 1 cm H2O to a minimum of 0 cm H2O, as long as pulse oximetry–measured oxygen saturation (Spo2) was greater than 92% or Pao2 was greater than 60 mm Hg.

Patients randomized to the higher PEEP strategy started with PEEP at 8 cm H2O.

Main Outcomes and Measures 

Number of ventilator-free days at day 28.

Secondary outcomes- ICU and hospital lengths of stay; ICU, hospital, and 28- and 90-day mortality; development of ARDS, pneumonia, pneumothorax, severe atelectasis, severe hypoxemia, or need for rescue therapies for hypoxemia; and days with use of vasopressors or sedation.

Results

  • 980 randomized patients enrolled in the study, 484 were randomized to the lower PEEP strategy and 496 to the higher PEEP strategy.
  • Lower PEEP strategy had a median of 18 ventilator-free days (IQR, 0-27 days) , higher PEEP strategy had a median of 17 ventilator-free days (IQR, 0-27 days), no statistically significant difference between the randomization groups (P = .22).
  • There was no statistically significant difference in ICU and hospital lengths of stay, mortality rate, or occurrence of pulmonary complications or use of vasopressors or sedatives.

Limitations

  • blinding was not possible.
  • Some patients were not randomized within 1 hour.

Bottomline

Patients without ARDS do not need higher PEEP for mechanical ventilation. 

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