Transhepatic insertion of vascular dialysis catheters in children: a safe, life-prolonging procedure.

INTRODUCTION: Central venous catheters (CVC) have been inserted percutaneously since 1989. This technique has been adapted for transhepatic insertion of large-bore catheters in children with occluded central veins. MATERIALS AND METHODS: Three children aged 5, 11, and 12 years required hemodialysis or plasmaphoresis for treatment of life-threatening conditions. All central veins were occluded, thus transhepatic insertion of a large-bore catheter was necessary. All children underwent successful placement using a combination of ultrasound guidance and fluoroscopy. No complications occurred. DISCUSSION: Transhepatic insertion of large-bore catheters can be performed safely in children. Catheter removal should be accompanied by track embolization to prevent exsanguinating hemorrhage. CONCLUSION: Transhepatic insertion of dialysis catheters is a safe alternative in children with occluded central veins.

Percutaneous gastrostomy tube placement in patients with ventriculoperitoneal shunts.

OBJECTIVE: The purpose of this study is to determine the risk of CNS and/or peritoneal infection in children with ventriculoperitoneal shunts in whom a percutaneous gastrostomy tube is placed. MATERIALS AND METHODS: We placed 205 gastrostomy or gastrojejunostomy tubes from January of 1991 to December 1996. Twenty-three patients (10 boys, 13 girls) had ventriculoperitoneal shunts at the time of placement. All shunts were placed at least 1 month prior to placement of the gastrostomy tube. The patients ranged in age from 8 months to 16 years with a mean age of 6 years, 9 months. Patient weight ranged from 2 kg to 60 kg. All 23 children required long-term nutritional support due to severe neurologic impairment. No prophylactic antibiotics were given prior to the procedure. Of the patients, 21/23 had a 14-F Sacks-Vine gastrostomy tube with a fixed terminal retention device inserted, using percutaneous fluoroscopic antegrade technique. Two of the 23 patients had a Ross 14-F Flexi-flo gastrostomy tube which required a retrograde technique due to a small caliber esophagus in these children. RESULTS: All 23 children had technically successful placements of percutaneous gastrostomy (7) or gastrojejunostomy (16) tubes. Of the children, 21/23 (91%) had no complications from the procedure. Two of 23 (9%) patients demonstrated signs of peritonitis after placement of their gastrostomy tubes and subsequently had shunt infections. In both, children CSF culture grew gram-positive cocci. The antegrade technique was used in both children who developed peritonitis. CONCLUSION: Our study indicates children with ventriculoperitoneal shunts who undergo percutaneous gastrostomy are at greater risk for infection and subsequent shunt malfunction. Therefore, we recommend prophylactic antibiotic therapy to cover for skin and oral flora.

Field experiments on interactions between vertebrate predators and larval midges (Diptera: Chironomidae) in the littoral zone of a reservoir.

A field experiment was designed to test a frequent assumption in the literature that vertebrate predators (in this case, fish and turtles) are capable of regulating the seasonal abundance and diversity of benthic communities in the littoral zone of lentic environments. Effects of thermal effluents from a nuclear reactor on predator-prey relationships were also examined. Benthic samples were removed after each of three, 3-month test periods from 36 predator exclusion cages (4m2) and 36 control plots located along a thermal gradient in Par Pond, an 1,100 ha freshwater reservoir in the southeastern United States.Results of our field experiments provide little evidence to suggest that either a single "keystone" species or vertebrate predators as a group were capable of regulating the abundance, diversity or productivity of chironomids in Par Pond. The relationship between predator treatment and community response (changes in density and species richness) was generally unaffected by either plot location or temperature fluctuations. When data from caged and control plots were pooled, however, both location and water temperature individually had significant impacts on the chironomid community. Alternative hypotheses are proposed to explain the lack of regulatory control of the benthic community by individual species or guilds of predators.