In a 7-month period we studied 38 Hickman central venous catheters (CVCs) positioned in children with hematologic malignancies with the aim of evaluating the incidence and clinical impact of CVC clots. Clots were found in 74% of the CVCs. Three methods of catheter care were developed for flushing the clotted CVCs: (a) use of a heparinized solution (400 IU/mL) on alternate days, (b) use of a heparinized solution (400 IU/mL) and saline solution containing urokinase (10,000 IU/mL) on alternate days, and (c) use of a saline solution containing urokinase (10,000 IU/mL) daily. Only method b decreased clot formation (33% success rate). There were no major mechanical complications in any of the CVCs with clots. Eighteen percent of patients with clots in their CVCs presented with CVC-related infections while no infective complications were observed in the patients without clots in their CVCs. In conclusion, CVC clots may predispose the patient to infections, which must be correctly treated.

The aim of this study was to compare the Hickman and Groshong central venous catheters (CVCs) for incidence and severity of catheter-related complications in children. Seventy-three patients with hematological malignancies were observed, 42 with Groshong CVCs and 31 with Hickman CVCs. The number of infective episodes per 100 CVC-days was not significantly different (0.25 in the Hickman group versus 0.13 in the Groshong group; P = 0.24). The most frequent type of CVC-related infection in both groups was microbiologically documented sepsis; in most cases Gram-positive bacteria were isolated. Neutropenia (P < 0.001 for both CVCs) and hospital CVC management (P = 0.0047 for the Hickman group, P < 0.001 for the Groshong group) emerged as the major risk factors for the outbreak of infections. The rate of mechanical complication episodes per 100 CVC-days was similar in both groups (1.01 in the Hickman group versus 1.1 in the Groshong group: P = 0.58). Some complications (fissures, ruptures, total lumen obstruction by clots) occurred only in the Groshong group. Our study did not demonstrate any statistically significant difference in the incidence of mechanical and infective CVC-related complications between these two types of catheter.

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One hundred fifty-six episodes of fever occurred in 102 children during the first 100 days after bone marrow transplantation (BMT) performed at a single institution: fever of undetermined origin (FUO), 40.3%; septicemia, 7.1%; pneumonia, 19.2%; other infections, 33.4% of cases. The overall incidence of mortality was 22.6% and of mortality due to infections 17.4%. All FUO episodes resolved. Pneumonia was the major cause of death; 60% of recipients who developed pneumonia died, accounting for 90% of deaths attributable to febrile complications. Interstitial pneumonia, occurred rarely, in 3.9% of all febrile episodes. The Cox model showed that the presence of graft-versus-host disease (GVHD) was related to an approximately ninefold increase in the risk of a first episode of FUO (P value .03). The risk of developing pneumonia was fourfold greater in children who received a transplant from a matched unrelated donor or a mismatched family donor (P value .01). Developments in diagnostic tools are needed to diagnose febrile episodes earlier and more precisely with the aim of reducing early mortality after BMT.

Alihough Genetic Algorithms (GAS) are easy to implement and are powerful tools to solve difficult problems featuring huge search spaces, they usually require human supervision to be exploited succesfully.I f seems ihat Furzy Logic techniques can help reduce the amount of human intervention needed to use GAS.This paper concentrates on a particular application to symbolic regression to illustrate how to build a furzy knowledge-based system, or, io use a suggestive term, a fuzzy government, for GA control.

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