Pre-dialysis application of the glucose infusion test for recirculation detection

Vascular access recirculation (R) is a well-known cause of decreased dialysis dose. In this paper a new easy protocol for R detection in pre-dialysis derived from the classic Glucose Infusion Test (GIT) is introduced. The pre-dialysis GIT (GIT-pre) is based on the glucose (5%, 10 ml) bolus injection directly into the venous needle and on a simultaneous withdrawal from the arterial needle. If the glucose value increases during the glucose bolus, R is present. This new protocol was validated on 29 chronic haemodialysis patients (20 AVFs, 7 CVCs, 2 PTFE grafts), comparing the glucose increase with the classic GIT during dialysis. Only one CVC had R with the blood lines in the normal position (deltaglu = 465 mg/dl with GIT-pre and a deltaglu = 186 mg/dl, R = 9.3% with classic GIT) while in the reverse blood line position, all CVCs showed a significant glucose increase (mean GIT-pre deltaglu = 195 mg/dl; mean GIT deltaglu = 140 mg/dl corresponding to a R = 8%). There were 5 AVFs with true R (correct blood lines position) clearly identified by both methods (mean values deltaglu = 316 mg/dl with GIT-pre and a deltaglu = 390 mg/dl, R = 19.5% with classic GIT). Preliminary results show good reliability of the new protocol in identifying VA R caused either by failing VA with stenosis or by reverse blood lines position. The GIT-pre is a simpler application of the classic GIT useful for testing new VA, new needle positions or CVC performance before starting dialysis. A simpler R test could increase the frequency of the measurements and consequently the power of R in early detection of VA problems.