ECCO₂ removal with a phosphorylcholine-coated membrane oxygenator in difficult respiratory weaning patients

Introduction

ECCO₂ removal may be a useful support in patients with difficult respiratory weaning. The aim of this study is to evaluate a new phosphorylcholine-coated EECO₂ removal system with no thrombogenic activity to assess the clinical safety of the system, the changes of main cardiorespiratory indices and CO₂ removal by the system.

Methods

Ten patients were enrolled. Before starting with ECCO₂ removal all patients were ventilated with TV <6 ml/kg, peak pressure >35 cmH₂O and pH <7.25. ECCO₂ removal was initiated using a modified continuous venovenous hemofiltration system with a membrane oxygenator (ABYLCAP; Bellco, Mirandola, Italy; membrane surface area: 0.67 m², blood flow 280 to 350 ml/minute, phosphorylcholine coated). Femoral vein cannulation with a double-lumen catheter was used to connect the patients to the extracorporeal system. Heparin was infused to maintain ACT <190 to 240 seconds. All patients had ECCO₂ for 4 days. Every 12 hours the pH, PaCO₂, peak pressure and PaO₂ were evaluated. VCO₂ was determined by indirect calorimetry using a gas analyser equipped on an Engstrom Carestation Ventilator. During the ECCO₂ removal the patients were ventilated with TV ≤6 ml/kg and peak pressure <30 cmH₂O. All data are expressed as mean ± SD. One-way ANOVA was used to compare the changes of parameters. P < 0.05 was considered significant.

Results

Table 1 presents the main results. The CO₂ removal by membrane oxygenator ranged from 56 to 37 ml/minute. All patients survived to the treatment and 7/10 were weaned from the ventilator at the end of ECCO₂ removal. Only one oxygenator was used for every patient without clotting of the circuit or any major bleeding problem.

Table 1 (abstract P129)

Conclusion

ECCO₂ removal with a phosphorylcholine-coated membrane oxygenator is clinically safe, avoids clotting of the oxygenator circuit and allows adequate CO₂ removal.