High fluid volume removal with continuous renal replacement therapy as a therapeutic option for early posttraumatic acute respiratory distress syndrome

Introduction

The increase in vascular permeability, due to capillary leakage, seems to be responsible for high density on CT lung examination and worsening of gas exchange in acute respiratory distress syndrome (ARDS) patients. An improvement of the PaO₂/FiO₂ ratio and ARDS reversal following lung water removal has been shown. The aim of our study was to investigate whether hourly depletion of high fluid volume through continuous renal replacement therapy (CRRT) could reverse posttraumatic ARDS. The body water redistribution in different compartments can lead to a rapid decrease in extravascular lung water (EVLW).

Methods

Three trauma patients, fulfilling ARDS criteria within 48 hours since traumatic nonbrain injury (early posttraumatic ARDS), underwent protective lung ventilation with moderate to high positive end-expiratory pressure, maintaining end-tidal CO₂ < 60 mmHg. All patients developed acute renal failure. The patients were treated with CRRT with 45 ml/kg/hour ultrafiltration and 500 ml/hour fluid volume removal. Modified Swan–Ganz and arterial catheters (Picco) were inserted for cardiovascular and EVLW index (EVLWI) monitoring.

Results

The haemodynamic variables, the gas exchange values and the fluid balance are reported in Figures 1 and 2. Rapid high fluid volume depletion decreased the EVLWI, providing a complete resolution of ARDS and leading to extubation of all three patients within 72 hours from the beginning of CRRT. The treatment was uneventful and all the patients showed haemodynamic stability.

Figure 1

PaO₂/FiO₂ ratio and extravascular lung water index (EVLWI).

Figure 2

Water balance and cardiac index (CI).

Conclusion

This approach seems to be a possible treatment option for early posttraumatic ARDS. In our opinion this study could introduce a new therapeutic choice that might decrease days of mechanical ventilation.