[Body weight telemetry in patients with endstage renal failure on hemodialysis: preliminary data]. / Körpergewichts-Telemetrie bei Hämodialysepatienten--vorläufige Daten.

BACKGROUND AND OBJECTIVE: Non-adherence to fluid intake restrictions is one of the leading problems in hemodialysis patients. The consequences of chronic volume overload and massive hypotensive episodes resulting from enhanced ultrafiltration lead to an increased mortality and incidence of vascular events. Telemetric body weight monitoring (TBWM) suggests itself as a successful way to reduce daily fluid intake PATIENTS AND METHODS: This monocentric, prospective, randomized open study includes 120 patients with end-stage renal failure undergoing chronic hemodialysis (for at least two months) three times a week. The mean interdialytic weight gain (IWG) was more than 1.5 kg/2 days over the four weeks immediately before start of the study. The effect of daily body weight telemonitoring on IWG, blood pressure, haemoglobin variability, hospital stay, vascular events and mortality were observed for three months. All monitored patients (group 1, n = 60) received a weekly report of their weight changes, the number of alarms (automatically sent by email to the study center when daily IWG was greater than 0.75 kg/d) and of the interventions by phone (conducted by the responsible nephrologist when IWG was > 2 kg/day). Hemodynamics (each hemodialysis procedure) and weekly laboratory data were recorded for all patients. RESULTS: Preliminary data of 44 patients showed a significant reduction of daily IWG (weekly average, p = 0.0187) and a smaller number of alarm reports after the whole study period in group 1. Blood pressure monitoring during hemodialysis showed less hyper- and hypotensive episodes in patients with an IWG of less than 1.5 kg/2 days. In the control group there have so far been no changes of the analysed parameters. CONCLUSIONS: TBWM seems to be an effective method for optimizing adherence to fluid intake restrictions in patients on hemodialysis. Hemoglobin variability, mortality rates and the number of vascular events will still have to be analysed in detail for all patients once the entire study period has been completed.

Cardiac troponin I and cardiac troponin T increases in pigs during ischemia-reperfusion damage.

In this study we addressed the question of whether the measurement of cardiac Troponin T (cTnT) and cardiac Troponin I (cTnI) is able to detect myocardial cell damage in an ischemia-reperfusion model in pigs. To answer the question 3 pigs were anaesthesized and a cardiac arrest was induced by electric fibrillation. After 5 minutes of global ischemia the cardiac arrest was reversed by electric defibrillation until normal perfusion was restored. We could clearly demonstrate an increase of cTnT and cTnI 30 minutes after reperfusion indicating myocardial injury during ischemia and subsequent reperfusion. The cTnT as well as the cTnI serum levels increased till 180 minutes after reperfusion. This ischemia-reperfusion injury is likely induced by oxygen radicals generated during hypoxia and subsequent reperfusion We conclude from our first results that troponin measurements with commercial available test kits may also reflect myocardial cell damage in pigs as it was recently demonstrated in rats. Further studies are needed for correlation of troponin serum levels and histopathological damage in this model especially if it is used to test beneficial or toxicological effects of radical neutralizing drugs.

Tourniquet-induced changes of energy metabolism in human skeletal muscle monitored by microdialysis.

BACKGROUND: Tourniquets are often used as part of orthopedic surgery but may cause local and remote organ injury. The authors hypothesized that the procedures used to induce ischemia (circulatory occlusion or exsanguination) may have differential effects on the metabolic state of the muscle that should be reflected in the interstitial levels of metabolites. METHODS: Microdialysis probes were implanted in both quadriceps femoris muscles of 18 patients. Interstitial fluid was obtained during tourniquet-induced ischemia and reperfusion and was analyzed for glucose, lactate, choline, and purines by high-performance liquid chromatography. RESULTS: At a flow rate of 2 microl/min, the average baseline concentrations in the dialysate were 2.5 mM for glucose, 1.7 mM for lactate, 5.2 microM for choline, and 14.3 microM for hypoxanthine. Circulatory occlusion by tourniquet caused a 40% decrease of the extracellular glucose concentration within 30 min. Concomitantly, the interstitial levels of lactate and hypoxanthine increased in a linear fashion to 206% (lactate) and 241% (hypoxanthine) of basal values. The extracellular concentration of choline was also significantly elevated. After exsanguination, the glucose levels were significantly more reduced (by 65%), and the levels of lactate (to 268%) and hypoxanthine (to 286%) were more increased than after circulatory occlusion alone. CONCLUSION: Our microdialysis results demonstrate that the interstitial concentrations of glucose, lactate, and hypoxanthine, which are indicators of tissue ischemia, change more prominently after exsanguination than after circulatory occlusion alone.