Gerard Zasuwa

Clinical experience with short-time hemodialysis.

After at least 6 months on conventional hemodialysis (cellulosic dialyzers, acetate dialysate, and a 3- to 4-hour treatment time), 56 patients were changed to short-time hemodialysis (less than 180 minutes) using polysulfone dialyzers and bicarbonate-containing dialysate. Treatment time decreased (191 +/- 5 v 147 +/- 5 min; P = 0.001), while Kt/V (1.22 +/- 0.04 v 1.29 +/- 0.06; P = NS) and normalized protein catabolic rate (pcr) (1.10 +/- 0.05 v 1.10 +/- 0.07 g/kg/d; P = NS) remained constant. When compared with the conventional period, 30 months of short-time hemodialysis resulted in no changes in predialysis blood pressure (BP) (151 +/- 2/84 +/- 1 v 151 +/- 2/86 +/- 1 mm Hg), postdialysis BP (144 +/- 2/81 +/- 1 v 143 +/- 3/84 +/- 1 mm Hg), interdialytic weight gain (2.4 +/- 0.1 v 2.7 +/- 0.2 kg), or blood urea nitrogen (BUN) (26.1 +/- 0.71 v 25.3 +/- 1.07 mmol/L [73 +/- 2 v 71 +/- 3 mg/dL]). Shorter treatment times were not associated with an increase in intradialytic complications. Actually, the frequency (%) of dialysis treatments associated with nausea (5.94 +/- 1.33 v 2.21 +/- 0.52), vomiting (3.12 +/- 0.87 v 0.54 +/- 0.14; P less than 0.05), headaches (5.60 +/- 1.13 v 2.03 +/- 0.52; P less than 0.05), and back pain (0.91 +/- 0.25 v 0.05 +/- 0.05; P less than 0.05) was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemoglobin Variability and Hyporesponsiveness: Much Ado About Something or Nothing?

Hemoglobin (Hb) variability is considered a discrete clinical entity that when present may presage poor clinical outcomes. However, Hb variability is an intrinsic property of biological systems and is present in all patients, those with and without the anemia of chronic kidney disease. Taken together, variability actually represents the integration of multiple influences at multiple levels in the life of a red cell, namely the summation of positive and negative influences on erythropoiesis. Thus, Hb variability may be interpreted as a mathematic function of time and is the result of a host of influences including definition of the normal Hb range, native erythron responsiveness/hyporesponsiveness, temporal changes in endogenous and exogenous erythropoiesis-stimulating agent (ESA) levels, the algorithms used to dose ESAs and their duration of action, the presence of biologically available iron, red cell turnover, and recyclable and non-recyclable blood loss and gain. When viewed within this construct of matrixed determinants, the source of hemoglobin variability is more readily identified. When variability is present but the etiology is not easily discerned, erythropoietic hyporesponsiveness must be considered and evaluated. Finally, integration of all of these concepts is possible within the context of an anemia management protocol.

Automated Intravascular Access Pressure Surveillance Reduces Thrombosis Rates

Although monitoring of vascular accesses by physical examination is nearly as sensitive as surveillance measurements by vascular access pressure when performed by examiners, the frequency of examinations is limited by time. We developed intravascular access pressure surveillance as a surrogate to physical examination. Using real‐time data from hemodialysis machines, we derived intravascular access pressure ratios for each dialytic procedure. An automated, noninvasive surveillance algorithm that generated a “warning” list of patients at risk for thrombosis was formulated. We hypothesized that this algorithm would reduce access thrombosis frequency. We designed a study comparing thrombosis rates during a baseline 6‐month interval to three subsequent 6‐month periods of active surveillance. Referrals for interventions during this 18‐month period were based on persistently abnormal elevated vascular access pressure ratio tests (VAPRT) >0.55. Thrombosis rates declined progressively for arteriovenous grafts (AVG) during the intervention period compared with the baseline period. Arteriovenous fistula (AVF) thrombosis rates decreased during postintervention months 13–18 during employment of the VAPRT. We conclude that use of VAPRT can reduce thrombosis rates in vascular accesses, and the magnitude of the effect is larger and more consistent in arteriovenous grafts (AVGs) than autologous AVFs.