Impact of short term use of interdialytic 60% ethanol lock solution on tunneled silicone catheter dysfunction.

INTRODUCTION: Ethanol lock (EL) is used to reduce catheter infections, but its impact on dialysis catheter dysfunction has not been studied. METHODS: We analyzed the rate of dialysis silicone catheter dysfunction after an interdialytic 60% EL in an open prospective controlled non crossover cohort study, with each patient being his or her own control. The study was divided into three consecutive 2-week periods: the pre- and post-intervention periods, in which interdialytic standard locks (SL) were used, and the intervention period, in which one EL was instilled during the first week, and two consecutively in the second week. We analyzed the rate of catheter dysfunction (exchange, use of fibrinolytic, reversing the lines, difficulty in instilling or withdrawing fluid) after EL or SL. RESULTS: In 30 patients, 90 EL were instilled. The rate of catheter dysfunction increased during the EL period (2 - 13%, p < 0.001), and between the two consecutive dialysis sessions before and after EL (p < 0.05). It decreased between the two consecutive dialysis sessions after EL and the following dialysis session after an SL (p < 0.05). No catheter was removed. The urea reduction ratio did not differ in dialysis after an SL and after an EL (0.77 vs. 0.73, p = 0.17). CONCLUSION: Short term EL is associated with a transient increase in catheter dysfunction, without resulting in catheter removal or decreasing dialysis efficiency.

Comparison of three methods of diagnosis of plasma unmeasured anions in critically ill patients.

BACKGROUND: The measurement of plasma unmeasured anions (PUA) is paramount in assessing metabolic acid base disorders. The aim of this study was to compare the accuracy of three methods in diagnosing abnormal PUA values: standard base excess (SBE), the albumin corrected anion gap (AGc), and the Stewart-Figge approach, based on unidentified anions (XAc-). METHODS: Acid-base variables were prospectively collected in ICU patients admitted January-September 2008. Whatever the method, PUA values measured two standard deviations above or below the mean of those in control subjects were considered as abnormal. RESULTS: Of the 205 consecutives patients included, 179 had an abnormal PUA value. The accuracy of AGc and XAc- in diagnosing abnormal PUA values was comparable (AUC: 0.89±0.03 and 0.89±0.03, P=0.82) but greater than that of SBE (0.67±0.06, P<0.001 and P<0.001, respectively). Of the high PUA values (n=161), 96% were diagnosed by XAc-, 88% by AGc (P<0.01) and 48% by SBE (P<0.001). Hyperlactatemia (n=111) was diagnosed equally by AGc and XAc-, (81% and 86%, P=0.37) but less by SBE (50%, P<0.001 and P<0.001, respectively). High PUA not associated with hyperlactatemia (N.=61) was more frequently diagnosed by XAc- (97%) than by AGc (84%, P=0.03). CONCLUSION: In ICU patients, AGc and the Stewart-Figge approach should be preferred over SBE for diagnosing abnormal PUA values and predicting hyperlactatemia. The Stewart-Figge approach based on unidentified anions, is the most efficient in diagnosing high PUA values not associated with hyperlactatemia.