RESUMO
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 < 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 pCO2 values (r = 0.683, P < 0.001) and negatively with AL pH values (r = 0.896, P < 0.001). AL pCO2 > 40 mmHg was shown to have the best sensitivity and AL pH < 7.25 the best specificity. RC index, that is, the AL pCO2 /pH ratio, was found to have superior test characteristics compared to pH and pCO2 (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, pCO2 > 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.
Assuntos
Derivação Arteriovenosa Cirúrgica , Dióxido de Carbono/sangue , Oxigênio/sangue , Diálise Renal , Idoso , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-IdadeRESUMO
PURPOSE: Scientific data regarding intravenous iron supplementation in peritoneal dialysis (PD) patients are scarce. In attempting to administer the minimum monthly IV iron dose that could improve erythropoiesis, we wanted to assess the safety and efficacy of monthly maintenance intravenous administration of 100 mg iron sucrose in PD patients. METHODS: In a 9-month prospective study, all clinically stable PD patients received intravenously 200 mg of iron sucrose as a loading dose, followed by monthly doses of 100 mg for five consecutive months. Levels of hemoglobin (Hb), ferritin, transferrin saturation (TSAT), reticulocyte hemoglobin content (CHr) and C-reactive protein (CRP) were measured before each administration and 3 months after the last iron infusion. Also, doses of concurrent erythropoietin administration were recorded. RESULTS: Eighteen patients were eligible for the study. Mean levels of Hb and ferritin increased significantly (from 10.0 to 10.9 mg/dL, p = 0.01 and from 143 to 260 ng/mL, p = 0.005), as well as the increase in TSAT levels approached borderline significance (from 26.2 to 33.1%, p = 0.07). During the 6 months of iron administration, the erythropoietin dose was reduced in five patients and discontinued in one. During the 3 months following the last iron infusion, three of them again raised the erythropoietin dose to previous levels. None of the patients experienced any side effects related to IV iron administration. CONCLUSIONS: A monthly maintenance intravenous dose of 100 mg iron sucrose may be a practical, effective, and safe in the short term, treatment of anemia in PD patients resulting in improved hemoglobin levels, iron indices, and erythropoietin response.