The error of estimated GFR in predialysis care.

The error of estimated glomerular filtration rate (eGFR) and its consequences in predialysis are unknown. In this prospective multicentre study, 315 predialysis patients underwent measured GFR (mGFR) by the clearance of iohexol and eGFR by 52 formulas. Agreement between eGFR and mGFR was evaluated by concordance correlation coefficient (CCC), total deviation index (TDI) and coverage probability (CP). In a sub-analysis we assessed the impact of eGFR error on decision-making as (i) initiating dialysis, (ii) preparation for renal replacement therapy (RRT) and (iii) continuing clinical follow-up. For this sub-analysis, patients who started RRT due to clinical indications (uremia, fluid overload, etc.) were excluded. eGFR had scarce precision and accuracy in reflecting mGFR (average CCC 0.6, TDI 70% and cp 22%) both in creatinine- and cystatin-based formulas. Variations -larger than 10 ml/min- between mGFR and eGFR were frequent. The error of formulas would have suggested (a) premature preparation for RTT in 14% of stable patients evaluated by mGFR; (b) to continue clinical follow-up in 59% of subjects with indication for RTT preparation due to low GFRm and (c) to delay dialysis in all asymptomatic patients (n = 6) in whom RRT was indicated based on very low mGFR. The error of formulas in predialysis was frequent and large and may have consequences in clinical care.

¿Es necesario heparinizar el suero de cebado del dializador? / Do we need heparin in the dialyser priming solution?

Introducción: El cebado de las líneas de hemodiálisis (HD) se realiza de forma tradicional con heparina sódica y suero salino, lo que conlleva el riesgo hemorrágico que supone el paso de heparina a la sangre. Objetivo: Comparar el cebado del dializador de HD con o sin heparina sódica, en términos de coagulación, eficacia dialítica y eficacia económica. Material y métodos: Estudio prospectivo y randomizado de 3482 sesiones de 109 pacientes en HD (X 66,8±15 años, 40% mujeres, 44% diabéticos, 45% con catéter tunelizado de alto flujo, 50% FAVi nativa, 5% FAVi protésica). 1827 sesiones realizadas a cincuenta y nueve pacientes se incluyeron en el grupo control (cebado con suero fisiológico+heparina sódica) y 1455 de cincuenta pacientes en el grupo estudio (cebado con suero fisiológico). El periodo de seguimiento fue de 5 meses. Se analizaron variables relacionadas con la coagulación del circuito y la eficacia de la diálisis: Flujo de sangre (Qb) seleccionado y Qb efectivo, estado final del dializador, nº de cambios de dializador, nº de cambios de línea arterial, nº de cambios de línea venosa, Kt/hora medido por dialisancia iónica y heparinización del circuito. También se estudió la eficacia en términos económicos. Resultados: No existen diferencias significativas en los resultados relacionados con la coagulación y la eficacia de la diálisis obtenidos en ambos grupos, salvo la X de heparina de bajo peso molecular (2476±1089 Ui grupo estudio vs 2854±1414 Ui grupo control). El cebado sin heparina supone un ahorro de 0,5 e por sesión. Conclusiones: El cebado con suero fisiológico no influye en la dosis de HD, ni implica mayor riesgo de coagulación del sistema en comparación al cebado que añade heparina, evita el riesgo de paso de heparina a la circulación, disminuye la manipulación en los protocolos de conexión y reduce costes (AU)

Introduction: Haemodialysis (HD) lines are traditionally primed with sodium heparin and saline solution, which entails the haemorrhagic risk associated to the passing of heparin into the blood. Aim: To compare HD dialyser priming with and without sodium heparin, in terms of coagulation, dialytic efficacy, and economic efficacy. Material and Method: A randomized, prospective studio of 3482 sessions with 109 HD patients (X 66.8±15 years, 40% women, 44% diabetic, 45% with high-flow tunnelled catheter, 50% native IAF, 5% prosthetic IAF). 1827 sessions carried out with fifty-nine patients were included in the control group (primed with saline solution + sodium heparin) and 1455 sessions with patients in the study group (primed with saline solution). The monitoring period was 5 months. Variables related to the coagulation of the circuit and the efficacy of the dialysis were analysed: Selected blood flow (Qb) and effective Qb, final status of the dialyser, number of changes of dialyser, number of changes of the arterial line, number of changes of the venous, average Kt/hour measured by ionic dialysance and heparinization of the circuit. The efficacy in economic terms was also studied. Results: There are no significant differences in the results related to coagulation and efficacy of the dialysis obtained in both groups, except X of heparin with low molecular weight (2476±1089 IU in the study group compared to 2854±1414 IU in the control group). Priming without heparin represents a saving of 0.50 € per session. Conclusions: Priming with saline solution does not affect the HD dose, and does not entail a greater risk of coagulation of the system compared to a priming solution to which heparin has been added, avoids the risk of heparin passing into the bloodstream, reduces handling in the connection protocols and reduces costs (AU)