Sodium bicarbonate buffer for weaning from venovenous extracorporeal membrane oxygenation in patients with hypercapnic respiratory failure and acute renal failure

Although the routine use of alkali buffer is not recommended in patients with respiratory acidosis, some patients may benefit from its administration. A 42-year-old man was treated with venovenous extracorporeal membrane oxygenation (VV-ECMO) and continuous venovenous hemodiafiltration (CVVHDF) due to necrotizing pneumonia and emphysematous cystitis with Klebsiella pneumoniae. Although the sweep gas flow rate of the VV-ECMO was gradually reduced, he failed to wean off VV-ECMO due to respiratory acidosis, followed by tachycardia and tachypnea on the 63rd day of VV-ECMO. Therefore, we mixed sodium bicarbonate in the replacement fluid of CVVHDF for 5 days to avoid an intolerable decrease in blood pH after discontinuing the VV-ECMO sweep gas. When the serum bicarbonate concentration was >30 mmol/L and pH was maintained at >7.30 with a PCO2 of >60 mmHg, VV-ECMO was finally decannulated. Sodium bicarbonate buffer through the replacement of CVVHDF fluid facilitated VV-ECMO weaning in a patient with hypercapnic respiratory failure.