[Quality in dialysis]. / La qualità in dialisi.

BACKGROUND: Several clinical and laboratory dialysis parameters have been suggested by national and international guidelines. Our study aimed to evaluate a series of quality indicators in the dialytic treatment of a group of patients in our two dialytic centers. PATIENTS AND METHODS: In a population of 159 patients on renal replacement therapy (RDT) we performed a 1-yr prospective observational study, with common parameters to indicate cardiovascular pathologies (PAS, LVMI), calcium-phosphorous metabolism (Ca, PO 4 , Ca x PO 4 ), dialytic adequacy (Kt/V, URR%), nutritional status (nPCR, Alb, K), and anemia (hemoglobin (Hb)). For each parameter we evaluated the mean average with the standard deviation and the score percentages below and above the acceptable range (AR). RESULTS: The results demonstrated a substantial stability, with a gradual improvement, in dialytic adequacy, in anemic status and in PAS. The LVMI, calculated at the beginning and at the end of the period, did not demonstrate any significant changes. No significant changes were observed in the calcium-phosphorous metabolism parameters. Serum albumin and nPCR demonstrated the presence of malnutrition in 15-20% of patients. CONCLUSIONS: There was a more than adequate correlation between the target guidelines and that concerning the dialytic adequacy and the corrected anemic status. The improvement in parameters related to cardiovascular pathology, the risk of ectopic calcifications and malnutrition status, represented an achievable target.

In vivo versus simulation training: an interactional analysis of range and type of training exemplars.

We analyzed the role of the range of variation in training exemplars as a contextual variable influencing the effects of in vivo versus simulation training in producing generalized responding. Four mentally retarded adults received single case instruction, followed by general case instruction, on washing machine and dryer use; one task was taught using actual appliances (in vivo) and the other using simulation. In vivo and simulation training were counterbalanced across the two tasks for the 2 subject pairs, using a within-subjects Latin square design. With both paradigms, more errors were made after single case than after general case instruction during probe sessions with untrained washing machines and dryers. These results suggest that generalization errors were affected by the range of training exemplars and not by the use of simulated versus natural training stimuli. Although both general case simulation and general case in vivo training facilitated generalized performance of laundry skills, an analysis of training time and costs indicated that the former approach was more efficient. The study illustrates a methodology for studying complex interactions and guiding decisions on the optimal use of instructional alternatives.

Human platelet spreading on substrata of known surface chemistry.

Using platelet-rich plasma freshly obtained by plasmapheresis, the spread areas of human platelets settled onto substrata of different surface energies were measured to evaluate the hypothesis that initial platelet spreading response is surface dependent. At 37 degrees C, minimal platelet spread areas were found on substrata with critical surface tension between 20 and 30 mN/m (dynes/cm), and increased spreading and morphologic changes occurred on substrata of both higher and lower critical surface tension. This differential response was absent at 25 degrees C. Therefore, measurement of spread platelet area at physiologic temperature rather than number of attached cells is proposed as a superior method of estimating apparent blood compatibility of new biomaterials.

Thromboresistance of glass after glow discharge treatment in argon.

Glow discharge treated (GDT) inorganic materials are sterile and free of all organic contaminants. Such materials implanted in the canine inferior vena cava often demonstrate significant thromboresistance. Standard Pyrex glass tubing was GDT in argon to provide a surface free energy above 70 dynes/cm, slight surface negativity, and other surface-physical modifications of its interface. Chromic acid cleaned lengths of the same tubing, and short segments whose edges were not fire-polished were used as controls. Upon canine implantation, the in vivo results were similar in independent surgical laboratories. The glass was implanted as 1.4 cm long rings or as 5 cm long tubes in separate medical centers according to different protocols. GDT specimens remained patent; all controls accumulated thrombi. A remarkably pure, low critical surface tension, labile protein coating covered all cylindrical lumens after 2 hr in vivo. This coating diminished within 2 weeks and was essentially absent after 480 days, eeven though scanning EM showed evidence of a micron thick luminal film, probably eroding glass. No emboli were found in the implant animal's kidney or lungs at any stage.