Sodium thiosulfate pharmacokinetics in hemodialysis patients and healthy volunteers

Vascular calcification is a major cause of morbidity and mortality in dialysis patients. Human and animal studies indicate that sodium thiosulfate (STS) may prevent the progression of vascular calcifications. The pharmacokinetics of STS in hemodialysis patients has not been investigated yet.

Olfactory function improves following hemodialysis

Olfactory function has been shown to be affected in chronic kidney disease; however, studies are contradictory and little is known on the effects of dialysis. To resolve these issues we tested olfactory function in 24 healthy controls and in 28 patients with chronic kidney disease receiving hemodialysis (20 patients) or peritoneal dialysis (the other 8). As assays for olfactory function we measured smell identification, n-butanol and acetic acid thresholds, Kt/V urea, percentage reduced urea, and weights before and after dialysis. Olfactory function was also self-rated by the participants. Compared to healthy controls, predialysis olfactory function was moderately but significantly decreased in the two dialysis groups, with hemodialysis patients being more affected. Patients self-rated olfactory function similar to that of healthy controls, suggesting that patients are unaware of the olfactory decrease. Olfactory function was significantly improved by one hemodialysis session. Neither body mass index, total volume loss, nor any other dialysis parameter correlated with olfactory function or its restitution following hemodialysis. The observed pattern of improvement suggests underlying mixed peripheral and central mechanisms. Thus, olfactory dysfunction in patients with chronic kidney disease is readily reversible by hemodialysis.

Metabolic effects of dialyzate glucose in chronic hemodialysis: results from a prospective, randomized crossover trial

There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD) and 100 and 200 mg/dL (G100 and G200) are frequently used. G200 may result in diffusive glucose flux into the patient, with consequent hyperglycemia and hyperinsulinism, and electrolyte alterations, in particular potassium (K) and phosphorus (P). This trial compared metabolic effects of G100 versus G200.

Polytetrafluoroethylene and bovine mesenterial vein grafts for hemodialysis access: a comparative study

PURPOSE: This study aimed to evaluate the safety and patency rate of bovine mesenterial vein grafts (BMVG) for vascular access (VA) in hemodialysis patients (HDP), compared to expanded polytetrafluorethylene (ePTFE grafts) over a mid- to long-term period. METHODS: Patency and complication rate of 23 consecutive HDP with BMVG for VA were compared to a control group consisting of 23 similar HDP with ePTFE grafts. In both groups, the graft was placed preferably in a forearm loop configuration. The same surgeon performed all procedures. All patients were followed over a period of 4 yrs. RESULTS: Graft placement was successful in all patients. Patency rates did not differ significantly in both groups. However, there were less severe complications in the BMVG group. CONCLUSION: The BMVG is a viable alternative for HD access in patients where autologous construction is not possible, and should be given priority in patients with a failed ePTFE graft or high risk for infection.

Adequacy of an early arterial phase low-volume contrast protocol in 64-detector computed tomography angiography for aortoiliac aneurysms

PURPOSE: This retrospective study was conducted to determine whether a low-volume contrast medium protocol provides sufficient enhancement for 64-detector computed tomography angiography (CTA) in patients with aortoiliac aneurysms. METHODS: Evaluated were 45 consecutive patients (6 women; mean age, 72 +/- 6 years) who were referred for aortoiliac computed tomography angiography between October 2005 and January 2007. Group A (22 patients; creatinine clearance, 64.2 +/- 8.1 mL/min) received 50 mL of the contrast agent. Group B (23 patients; creatinine clearance, 89.4 +/- 7.3 mL/min) received 100 mL of the contrast agent. The injection rate was 3.5 mL/s, followed by 30 mL of saline at 3.5 mL/s. Studies were performed on the same 64-detector computed tomography scanner using a real-time bolus-tracking technique. Quantitative analysis was performed by determination of mean vascular attenuation at 10 regions of interest from the suprarenal aorta to the common femoral artery by one reader blinded to type and amount of contrast agent and compared using the Student t test. Image quality according to a 4-point scale was assessed in consensus by two readers blinded to type and amount of contrast medium and compared using the Mann-Whitney test. Multivariable adjustments were performed using ordinal regression analysis. RESULTS: Mean total attenuation did not differ significantly between both groups (196.5 +/- 33.0 Hounsfield unit [HU] in group A and 203.1 +/- 44.2 HU in group B; P = .57 by univariate and P > .05 by multivariable analysis). Accordingly, attenuation at each region of interest was not significantly different (P > .35). Image quality was excellent or good in all patients. No significant differences in visual assessment were found comparing both contrast medium protocols (P > .05 by univariate and by multivariable analysis). CONCLUSIONS: Aortoiliac aneurysm imaging can be performed with substantially reduced amounts of contrast medium using 64-detector computed tomography angiography technology.

Effect of transcutaneous electrical muscle stimulation and passive cycling movements on blood pressure and removal of urea and phosphate during hemodialysis

BACKGROUND: Intradialytic exercise has been described to improve blood pressure stability and dialysis efficacy. However, comorbid conditions in the dialysis population often preclude the widespread use of active intradialytic exercise. Therefore, we investigated the effect of intradialytic transcutaneous muscle stimulation (TEMS) and passive cycling movements (PCMs) on blood pressure and dialysis efficacy in patients. STUDY DESIGN: Prospective, controlled, randomized, crossover investigation. SETTING ; PARTICIPANTS: Ten patients were randomly allocated to TEMS, PCMs, or no intervention (NI) for 9 consecutive dialysis sessions. INTERVENTION: Participants were studied with NI, PCMs using a motor-driven ergometer, and bilateral TEMS of the leg musculature. Individual dialysis prescriptions were unchanged during the investigation. OUTCOMES ; MEASUREMENTS: The effect of TEMS and PCMs on blood pressure and dialysis efficacy in patients was assessed. RESULTS: Mean blood pressure increased from 121/64 +/- 21/15 mm Hg with NI to 132/69 +/- 21/15 mm Hg (P < 0.001) during sessions with PCMs and 125/66 +/- 22/16 mm Hg (P < 0.05) during sessions with TEMS. Urea and phosphate removal during dialysis were significantly (P < 0.001) greater with TEMS (19.4 +/- 3.7 g/dialysis and 1,197 +/- 265 mg/dialysis) or PCMs (20.1 +/- 3.4 g/dialysis and 1,172 +/- 315 mg/dialysis) than with NI (15.1 +/- 3.9 g/dialysis and 895 +/- 202 mg/dialysis). Body weight, ultrafiltration, Kt/V, and increases in hemoglobin and albumin levels during dialysis did not differ among the NI, PCMs, and TEMS groups. LIMITATIONS: The study design does not allow extension of the findings to prolonged treatment. CONCLUSION: Future studies during longer observation periods will have to prove the persistence of these acute findings. Both TEMS and PCMs deserve future investigations in dialysis patients because they increase intradialytic blood pressure and facilitate urea and phosphate removal when applied short term.

Glycyrrhetinic acid food supplementation lowers serum potassium concentration in chronic hemodialysis patients

Hyperkalemia is a common life-threatening problem in hemodialysis patients. Because glycyrrhetinic acid (GA) inhibits the enzyme 11beta-hydroxy-steroid dehydrogenase II and thereby increases cortisol availability to the colonic mineralocorticoid receptor, it has the potential to lower serum potassium concentrations. To test this, 10 patients in a 6 month prospective, double-blind, placebo-controlled crossover study were given cookies or bread rolls supplemented with glycyrrhetinic acid or placebo. Twenty-four-hour blood pressure measurements were performed at baseline and week 6 and 12 of each treatment period. The ratio of plasma cortisol/cortisone was significantly increased in all patients on GA as compared to baseline or placebo, indicating appropriate enzyme inhibition. Nine of the 10 patients had a persistent decrease in predialysis serum potassium concentration. On GA, mean predialysis serum potassium was significantly lower than at baseline or on placebo. On placebo, serum potassium was significantly elevated above the upper limit of normal in 76% compared to 30% of measurements during GA treatment. Furthermore, on this treatment the frequency of severe hyperkalemia significantly decreased from 9% to 0.6%. No differences were found in parameters reflecting sodium retention. Although these studies show that prolonged GA supplementation persistently lowers serum potassium in dialysis patients, a long-term toxicity study will be mandatory before we recommend the routine use of this treatment.

Intermittent hemodialysis treatment in cefepime-induced neurotoxicity: Case report, pharmacokinetic modeling, and review of the literature

Cefepime is a broad-spectrum cephalosporin indicated for in-hospital treatment of severe infections. Acute neurotoxicity, an increasingly recognized adverse effect of this drug in an overdose, predominantly affects patients with reduced renal function. Although dialytic approaches have been advocated to treat this condition, their role in this indication remains unclear. We report the case of an 88-year-old female patient with impaired renal function who developed life-threatening neurologic symptoms during cefepime therapy. She was treated with two intermittent 3-hour high-flux, high-efficiency hemodialysis sessions. Serial pre-, post-, and peridialytic (pre- and postfilter) serum cefepime concentrations were measured. Pharmacokinetic modeling showed that this dialytic strategy allowed for serum cefepime concentrations to return to the estimated nontoxic range 15 hours earlier than would have been the case without an intervention. The patient made a full clinical recovery over the next 48 hours. We conclude that at least 1 session of intermittent hemodialysis may shorten the time to return to the nontoxic range in severe clinically patent intoxication. It should be considered early in its clinical course pending chemical confirmation, even in frail elderly patients. Careful dosage adjustment and a high index of suspicion are essential in this population.

A novel clinical scoring system for outcome prediction in dogs with acute kidney injury managed by hemodialysis.

BACKGROUND No reliable tool to predict outcome of acute kidney injury (AKI) exists. HYPOTHESIS A statistically derived scoring system can accurately predict outcome in dogs with AKI managed with hemodialysis. ANIMALS One hundred and eighty-two client-owned dogs with AKI. METHODS Logistic regression analyses were performed initially on clinical variables available on the 1st day of hospitalization for relevance to outcome. Variables with P< or = .1 were considered for further analyses. Continuous variables outside the reference range were divided into quartiles to yield quartile-specific odds ratios (ORs) for survival. Models were developed by incorporating weighting factors assigned to each quartile based on the OR, using either the integer value of the OR (Model A) or the exact OR (Models B or C, when the etiology was known). A predictive score for each model was calculated for each dog by summing all weighting factors. In Model D, actual values for continuous variables were used in a logistic regression model. Receiver-operating curve analyses were performed to assess sensitivities, specificities, and optimal cutoff points for all models. RESULTS Higher scores were associated with decreased probability of survival (P < .001). Models A, B, C, and D correctly classified outcomes in 81, 83, 87, and 76% of cases, respectively, and optimal sensitivities/specificities were 77/85, 81/85, 83/90 and 92/61%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The models allowed outcome prediction that corresponded with actual outcome in our cohort. However, each model should be validated further in independent cohorts. The models may also be useful to assess AKI severity.

Veterinary hemodialysis: advances in management and technology.

Hemodialysis (HD) is a renal replacement therapy that can enable recovery of patients in acute kidney failure and prolong survival for patients with end-stage kidney failure. HD is also uniquely suited for management of refractory volume overload and removal of certain toxins from the bloodstream. Over the last decade, veterinary experience with HD has deepened and refined and its geographic availability has increased. As awareness of the usefulness and availability of dialytic therapy increases among veterinarians and pet owners and the number of veterinary dialysis facilities increases, dialytic management will become the standard of advanced care for animals with severe intractable uremia.