Establishment of a novel miniature veno-venous extracorporeal membrane oxygenation model in the rat.

Recently, veno-venous extracorporeal membrane oxygenation (V-V ECMO) has been commonly used in the world to support patients with severe respiratory failure. However, V-V ECMO is a new technology compared to veno-arterial extracorporeal membrane oxygenation and cardiopulmonary bypass, and there are few reports of basic research. Although continuing research is desired, clinical research that standardizes conditions such as patients' background characteristics is difficult. The purpose of this study was to establish a simple and stably maintainable miniature V-V ECMO model to study the mechanisms of the biological reactions in circulation during V-V ECMO. The V-V ECMO system consisted of an original miniature membrane oxygenator, polyvinyl chloride tubing line, and roller pump. The priming volume of this system was only 8 mL. Polyethylene tubing was used to cannulate the right femoral vein as the venous return cannula for the V-V ECMO system. A 16-G cannula was passed through the right internal jugular vein and advanced into the right atrium as the conduit for venous uptake. The animals were divided into 2 groups: SHAM group and V-V ECMO group. V-V ECMO was initiated and maintained at 50-60 mL/kg/min, and oxygen was added into the oxygenator during V-V ECMO at a concentration of 100% (pump flow:oxygen = 1:10). Blood pressure was measured continuously, and blood cells were measured by blood collection. During V-V ECMO, the blood pressure and hemodilution rate were maintained around 80 mm Hg and 20%, respectively. Hb was kept at >10 g/dL, and V-V ECMO could be maintained without blood transfusion. It was possible to confirm oxygenation of and carbon dioxide removal from the blood. Likewise, the pH was adequately maintained. There were no problems with this miniature V-V ECMO system, and extracorporeal circulation progressed safely. In this study, a novel miniature V-V ECMO model was established in the rat. A miniature V-V ECMO model appears to be very useful for studying the mechanisms of the biological reactions during V-V ECMO and to perform basic studies of circulation assist devices.

A useful new classification of dysmorphic urinary erythrocytes.

BACKGROUND: Among dysmorphic urinary erythrocytes (D cells), G1 cells or doughnut-shaped erythrocytes with one or more blebs are considered to be reliable markers for glomerular diseases. However, although there are many D cells with cytoplasmic color loss and without blebs in the urinary sediment, the significance of these cells is not clear. In this study, we devised a classification system for D cells and examined the relation between these cell types and urinalysis data. METHODS: We classified D cells into three types (D1, D2, and D3 cells): D1 cells showed a ring-like shape and severe loss of cytoplasmic color with protrusions or blebs; D2 cells showed a doughnut-like shape and moderate cytoplasmic color loss with protrusions or blebs; and D3 cells showed a doughnut-like shape and mild cytoplasmic color loss without protrusions or blebs. We calculated the numbers of D cells of each type in 45 patients with glomerular diseases and in 303 general outpatients. This was done by bright-field microscopy modified for the analysis of urinary sediment, and we also examined the significance of these cell types. RESULTS: In the 45 patients with glomerular diseases, the numbers of D1, D2, and D3 cells correlated with urine levels of proteinuria and hematuria and numbers of cellular and fatty casts. Numbers of D1 and D2 cells correlated with urine concentrations of albumin and N-acetyl-beta-D-glucosaminidase, and the proportions of D1 and D2 cells in D cells increased with the activity of glomerular diseases classified by urinalysis data. Only the number of D1 cells correlated with the urine concentration of potassium, which may increase in hemolysis. In the 303 outpatients, the sensitivity of D3 cells and D1 and/or D2 cells (G1 cells) was 73% and 46%, respectively, for the detection of glomerular diseases and the specificity was 93% and 99%, respectively. CONCLUSIONS: These data indicate that the D3 cell is a sensitive marker for glomerular diseases, and that D1 and/or D2 cells are markers for severe glomerular diseases.