Extracorporeal carbon dioxide removal may be used to manage hypercapnia, but compared to dialysis, it’s not widely available. A recent in vitro study showed that dialysis with low bicarbonate dialysates removes CO2.
To show that bicarbonate dialysis removes CO2 in an animal model to validate in-vitro findings and quantify the effect on arterial pH.
Male Sprague-Dawley hypercapnic rats were dialyzed with either a conventional dialysate (PrismasolTM) or a bicarbonate-free dialysate (Bicarb0). The effect of dialysis on standard blood gases and electrolytes was measured.
Partial pressure of CO2 and bicarbonate concentration in blood decreased significantly after exposure to Bicarb0 compared to PrismasolTM (filter outflow values 12.8 vs 81.1 mmHg; p < 0.01 for CO2 and 3.5 vs 22.0 mmol/L; p < 0.01 for bicarbonate). Total CO2 content of blood was reduced by 459 mL/L during dialysis with Bicarb0 (filter inflow 546 ± 91 vs filter outflow 87 ± 52 mL/L; p < 0.01), but was not significantly reduced with PrismasolTM.
Bicarbonate dialysis removes CO2 at rates comparable to existing low-flow ECCO2R.