Targeting arterial partial pressure of carbon dioxide in acute respiratory distress syndrome patients using extracorporeal carbon dioxide removal.

BACKGROUND

A retrospective analysis of SUPERNOVA trial data showed that reductions in tidal volume to ultraprotective levels without significant increases in arterial partial pressure of carbon dioxide (PaCO ) for critically ill, mechanically ventilated patients with acute respiratory distress syndrome (ARDS) depends on the rate of extracorporeal carbon dioxide removal (ECCO R).

METHODS

We used a whole-body mathematical model of acid-base balance to quantify the effect of altering carbon dioxide (CO ) removal rates using different ECCO R devices to achieve target PaCO levels in ARDS patients. Specifically, we predicted the effect of using a new, larger surface area PrismaLung+ device instead of the original PrismaLung device on the results from two multicenter clinical studies in critically ill, mechanically ventilated ARDS patients.

RESULTS

After calibrating model parameters to the clinical study data using the PrismaLung device, model predictions determined optimal extracorporeal blood flow rates for the PrismaLung+ and mechanical ventilation frequencies to obtain target PaCO levels of 45 and 50 mm Hg in mild and moderate ARDS patients treated at a tidal volume of 3.98 ml/kg predicted body weight (PW). Comparable model predictions showed that reductions in tidal volumes below 6 ml/kg PBW may be difficult for acidotic highly severe ARDS patients with acute kidney injury and high CO production rates using a PrismaLung+ device in-series with a continuous venovenous hemofiltration device.

CONCLUSIONS

The described model provides guidance on achieving target PaCO levels in mechanically ventilated ARDS patients using protective and ultraprotective tidal volumes when increasing CO removal rates from ECCO R devices.