PubMed · 15008617
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Håvar Knutsen. 2004. Polycythemia vera evaluation algorithm revisited.. https://doi.org/10.4065/79.3.430
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AIM/BACKGROUND: The aim of this study was to evaluate the residual blood loss in new type single use dialyzers under the usually prevailing conditions during hemodialysis and to investigate whether or not this loss is dependent on dialyzer membrane composition or flux characteristics. MATERIALS AND METHODS: In 158 hemodialysis (HD) patients, 158 single used dialyzers were studied in corresponding HD sessions. 52/158 dialyzers were made from modified cellulose (acetate, CA or triacetate, CTA) membrane and 106 from synthetic ones (58 with ethyl-vinyl-alcohol (EVAL), 48 with polyacrilonitrile (AN69)). Of those dialyzers 85/158 (58 EVAL+27CA) were low flux (LF) while the other 73 were high flux (HF). Patients underwent 4 hour HD sessions and at the end of the session blood was drawn for the measurement of hematocrit (Ht) and hemoglobin (Hb). Additionally, after the end of dialysis the used dialyzers were rinsed with 1000 mL of 0.05% NH(3) solution in distilled water. The wash was collected and subsequently Hb was measured using the benzidine method. From the volume of the solution and its concentration of Hb, total Hb of the solution was measured and blood loss in terms of red blood cell (RBC) volume was estimated by the use of the formula: RBC (mL) = Total Hb (g) in the solution x patient's Ht (ml/dL) / Patient's Hb (g/dL). For results to be comparable between dialyzers, RBC volume/m(2) of dialyzer membrane was expressed. In 5/158 patients blood loss was also estimated in 6 consecutive HD sessions using the same type of dialyzer. RESULTS: For the sum of the dialyzers, blood loss / dialyzer in terms of RBC volume, expressed as median (range), was 0.978 mL (0.01-23.9). There was statistically significant (p<0.001 or p<0.05) higher blood loss with the use of AN69 dialyzer than with the other three. RBC HF >RBC LF (p<0.001) constrained the first group of patients to use a 6% higher dosage of ferrum and 3.5% higher dosage of erythropoietin than the other group to achieve the optimal hemoglobulin values. No difference existed regarding RBC between CA, CTA and EVAL membranes. RBC measured in the small group of 5/158 patients for 6 consecutive HD sessions with the same dialyzer showed a wide range of RBC loss indicating an effect of the human factor. CONCLUSIONS: Blood loss during HD sessions due to residual blood cell volume inside dialyzers is usually slight using new type single use dialyzers but, sometimes, it can be significant and may contribute to the development or deterioration of preexisting iron deficiency anemia. The results of this study indicated that this loss can be attributed to the membrane composition of the dialyzer or to the human factor and has nothing to do with the ultrafiltration coefficient of the dialyzer.
BACKGROUND: Measurement of the hematocrit (HCT) and total protein (TP) of pericardial fluid can be of critical importance in the management of pericardial effusion (PE) but requires pericardiocentesis. There has been no systematic study of computed tomography (ct) hounsfield density (hd) measurement for the noninvasive evaluation of pe composition. METHODS: We performed CT-guided pericardiocentesis in 53 patients to obtain simultaneous measurement of the PE HD, HCT, and TP. We determined the relationship of PE HCT to the following variables: (1) the average of the mean HD in 5 regions of interest (ROIs) within the PE; (2) the maximum PE HD; (3) the difference between the average effusion region of interest HD and the ventricular blood pool HD. We also correlated PE HD with PE HCT and TP to assess their contribution to the PE CT HD. RESULTS: The average of the HD measured in up to 5 regions within the PE was the best predictor of PE HCT ( r = 0.84). Addition of ventricular blood pool HD and venous HCT to the regression did not improve prediction of PE HCT over average PE HD alone. Pericardial effusion HD was unrelated to PE TP. There was a statistically significant difference in the PE HD among 8 categories of underlying disease etiology in the population. Excluding postcardiotomy cases (n = 22) in which PE etiology is known before pericardiocentesis, visceral or vascular rupture was associated with the highest HD values. Hounsfield density >30 HU had a sensitivity of 100%, specificity 70%, and predictive value 33% for this condition in the remaining cases (n = 31). CONCLUSIONS: Computed tomography is a rapid and accurate method for noninvasive estimation of pericardial fluid HCT and may be helpful in guiding both the acute management and differential diagnosis of PE.
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