Biomedical subjects
Volker Wizemann
Publications and source records attributed to Volker Wizemann.
Dialysis Outcomes and Practice Patterns Study (DOPPS) data on medications in hemodialysis patients.
BACKGROUND: Medications affect many measures of hemodialysis patients' well-being. METHODS: The Dialysis Outcomes and Practice Patterns Study (DOPPS) has evaluated the use of hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins), analgesics, antidepressants, and multivitamins. Additionally, DOPPS has reported on the associations between vascular access outcomes and related medications. RESULTS: Prescription of statins varied widely across countries, with the highest use in the United States. Patients prescribed statins had lower risk of cardiac and noncardiac causes of mortality than those who were not prescribed statins. DOPPS data also show that statins are underprescribed relative to recent Kidney Disease Outcomes Quality Initiative guidelines. No guidelines have been established for analgesic use, but high pain levels self-reported by hemodialysis patients suggest opportunities for improved pain management strategies. Guidelines for analgesic use in dialysis patients may help balance improved quality of life against potential side effects of analgesics. Medical and patient questionnaires show that depression in hemodialysis patients is common, frequently underdiagnosed, usually untreated, and associated with increased rates of mortality and hospitalization. Calcium channel blockers were associated with improved primary graft patency, aspirin with improved secondary graft patency, and angiotensin-converting enzyme inhibitors with improved secondary fistula patency. All 3 medications were associated with significantly decreased relative risk for access failure. There is large country variation in multivitamin use, with significantly higher use in the United States compared with Europe and Japan. Patients taking multivitamins had lower mortality risk than patients not taking multivitamins. CONCLUSION: DOPPS findings on medications indicate that prospective trials are needed before guidelines can be developed for appropriate medication use in these different therapeutic categories.
Infective tricuspid valve endocarditis with septic pulmonary emboli due to puncture of an endogenous arteriovenous fistula in a chronic hemodialysis patient.
BACKGROUND: Patients on chronic hemodialysis are at high risk for infectious endocarditis due to prosthetic access devices such as cuffed venous catheters and polytetrafluoroethylene grafts. Right-sided endocarditis without any predisposing factors is rare in dialysed patients. CASE REPORT: A 42-year-old man with chronic renal failure was referred to hospital due to febrile temperatures. Hemodialysis was performed via an autogenous arteriovenous fistula. He had neither any recognized underlying valve disease nor any percutaneous interventions previously. Chest radiography and computed-tomography revealed numerous lung abscesses caused by tricuspid endocarditis detected by transesophageal echocardiography. Antibiotics were given for 5 weeks curing the infection without necessity of surgical treatment. CONCLUSIONS: Primary arteriovenous fistulas have the lowest rates of infections and are the access of choice for chronic hemodialysis patients. However, repeated vascular punctures even of autogenous grafts expose dialysis patients to bacteremia and imply a higher risk of infectious endocarditis.
A new technique for establishing dry weight in hemodialysis patients via whole body bioimpedance.
BACKGROUND: Quantitative techniques are necessary to achieve dry weight (DW) in patients with kidney failure. Bioimpedance spectroscopy (BIS) is a non-invasive method that determines the volume of body fluid compartments. The current work evaluates the use of BIS data in hemodialysis patients for the prediction of DW. METHODS: A new technique has been devised for the estimation of DW that involves the intersection of two slopes, slope normovolemia (SNV) and slope hypervolemia (SHV). These slopes characterize the variation in extracellular water (ECW) with body weight (BW) in the states of normovolemia and hypervolemia, respectively. SNV was established via measurements of ECW and BW in 30 healthy subjects. In a longitudinal study in new hemodialysis patients, successive reduction of post-dialysis weight (PDW) was attempted until clinical signs of normovolemia were presented. Measurements of ECW and BW that were acquired at the beginning of each treatment were used to determine SHV. RESULTS: SNV was found to be 0.239 L/kg and 0.214 L/kg for male and female healthy subjects, respectively. A significant DeltaPDW predicted by the new method (-4.98 kg) was highly correlated to the DeltaPDW achieved in the study (-5.85 kg, R = 0.839). Blood pressure was reduced (P < 0.001) and an 86% decrease in antihypertensive agents was achieved. CONCLUSION: The method of intersecting slopes (SHV with SNV) via BIS is a new method for the prediction DW. This approach will offer considerable improvement for the routine management of DW in the dialysis setting.
Thoracic impedance measurements during orthostatic change test and during hemodialysis in hemodialyzed patients.
Measurements were performed before and after hemodialysis (HD) in the supine and upright positions (orthostatic change test) and during HD session every 30 minutes in recumbent position on 11 HD patients. Two hydration states were compared: hyperhydration and normal hydration. Each patient served as his own control. Blood pressure and total body bioimpedance were obtained simultaneously. Thoracic impedance values (Zo) obtained during HD were significantly greater in the normal hydration state. There was strong correlation between Zo gain and total ultrafiltration; however, Zo gain divided through total ultrafiltration (calculated for every 100 ml) was also higher in this state. The ratio Zo/R (where R is resistance of total body bioimpedance) was stable during HD but was significantly higher in the normal hydration state. Zo gain during the orthostatic change test was significantly higher after HD than before HD in both hydration states. The anticipated difference in Zo gains between both hydration states was not significant. After echocardiographic analysis of patients, we determined that cardiac dysfunction or valvular defects in four patients were likely responsible for opposite reaction on orthostatic change test. During our measurements, we observed the influence of Zo changes on episodes such as intradialytic hypotension or acute atrial fibrillation. Thoracic impedance is an intriguing method for controlling pathophysiology of fluid distribution, but it requires the accurate definition of a patient's hemodynamics and strong conditions during measurement. During our measurements, we observed the influence of such episodes as intradialytic hypotension or acute atrial fibrillation on Zo changes.