EFFECT OF A High versus a low PEEP strategy

Christel M.A. Valk, Anissa M. Tsonas, Michela Botta, Lieuwe D.J. Bos, Janesh Pillay, Ary Serpa Neto, Marcus J. Schultz and Frederique Paulus, Writing Committee for the PRoVENT-COVIDM, Collaborative Group

BACKGROUND

There is uncertainty about how much positive end-expiratory pressure (PEEP) should be used in patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19).

OBJECTIVE

To investigate whether a higher PEEP strategy is superior to a lower PEEP strategy regarding the number of ventilator-free days (VFDs).

DESIGN

Multicentre observational study conducted from 1 March to 1 June 2020.

SETTING AND PATIENTS

Twenty-two ICUs in The Netherlands and 933 invasively ventilated COVID-19 ARDS patients

INTERVENTIONS

Patients were categorised retrospectively as having received invasive ventilation with higher (n 259) or lower PEEP (n 674), based on the high and low PEEP/FIO2 tables of the ARDS Network, and using ventilator settings and parameters in the first hour of invasive ventilation, and every 8 h thereafter at fixed time points during the first four calendar days. We also used propensity score matching to control for observed confounding factors that might influence outcomes.

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of VFDs. Secondary outcomes included distant organ failures including acute kidney injury (AKI) and use of renal replacement therapy (RRT), and mortality.

RESULTS

In the unmatched cohort, the higher PEEP strategy had no association with the median [IQR] number of VFDs (2.0 [0.0 to 15.0] vs. 0.0 [0.0 to 16.0] days). The median (95% confidence interval) difference was 0.21 ( 3.34 to 3.78) days, P 0.905. In the matched cohort, the higher PEEP group had an association with a lower median number of VFDs (0.0 [0.0 to 14.0] vs. 6.0 [0.0 to 17.0] days) a median difference of  4.65 ( 8.92 to  0.39) days, P 0.032. The higher PEEP strategy had associations with higher incidence of AKI (in the matched cohort) and more use of RRT (in the unmatched and matched cohorts). The higher PEEP strategy had no association with mortality.

CONCLUSION

In COVID-19 ARDS, use of higher PEEP may be associated with a lower number of VFDs, and may increase the incidence of AKI and need for RRT.

KEY POINTS

In an unmatched cohort of COVID-19 ARDS patients, a higher PEEP strategy did not have an association with the number of VFDs; in a matched cohort a higher PEEP strategy had an association with a lower number of VFDs.

In an unmatched cohort, a higher PEEP strategy had an association with more use of RRT; in a matched cohort, a higher PEEP strategy had an association with a higher incidence of AKI and more use of RRT.

A randomised clinical trial is highly needed to determine the effects of a higher PEEP strategy versus a lower PEEP strategy.