Diagnostic accuracy of arterial line blood gas measurements as an estimate of arteriovenous fistula recirculation

Aim We studied the diagnostic accuracy of blood gas determination as a novel method for the estimation of arteriovenous fistula (AVF) recirculation (RC). Methods In 25 patients on chronic haemodialysis, with failure of a previously well functioning native AVF (mean two-needle urea-based RC: 41 ± 10%), arterial line (AL) as well as a peripheral vein (PV) blood samples drawn by the end of a 4 h haemodialysis session, before and after the surgical repair of their AVF. Results Compared to PV samples, patients with RC had significantly higher AL blood pCO2 and pO2 values (P   40 mmHg was shown to have the best sensitivity and AL pH  5.5) making it a powerful diagnostic as well as screening tool. Conclusion We propose the regular AL blood gas measurement as a novel method of AVF function surveillance and RC diagnosis. AL blood pH   40 mmHg and RC index > 5.5, escorted by rather high pO2 and low K+ by the end of dialysis session, but probably earlier as well, signify an important RC (>20%) and warrant further investigation of AVF patency.