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Diagnostic accuracy of arterial line blood gas measurements as an estimate of arteriovenous fistula recirculation
Author(s) -
Kirmizis Dimitrios,
Kougioumtzidou Ourania,
Vakianis Pantelis
Publication year - 2013
Publication title -
nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 61
eISSN - 1440-1797
pISSN - 1320-5358
DOI - 10.1111/nep.12117
Subject(s) - medicine , arteriovenous fistula , nuclear medicine , arterial blood , cardiology , urology , surgery
Abstract 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 pCO 2 and pO 2 values ( P < 0.001) and lower AL blood pH and K + values ( P < 0.001), findings that were reversed after the surgical restoration of adequate AVF function. On regression analysis, urea RC values were correlated positively with AL pCO 2 values (r = 0.683, P < 0.001) and negatively with AL pH values (r = 0.896, P < 0.001). AL pCO 2 > 40 mmHg was shown to have the best sensitivity and AL pH < 7.25 the best specificity. RC index, that is, the AL pCO 2 / pH ratio, was found to have superior test characteristics compared to pH and pCO 2 (sensitivity 95% and specificity 88% for values >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 < 7.25, pCO 2 > 40 mmHg and RC index > 5.5, escorted by rather high pO 2 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.