A percutaneous 27-gauge OD central venous catheter was inserted at 4 +/- 3 (SD) days of age and left in place for up to 2 weeks in 20 neonates with birth weights less than 1200 g and greater than 24 h of age. Parenteral nutritional solutions and medications were administered through these catheters. Twenty neonates matched for birth weight and gestational age served as paired controls. In vitro studies demonstrate that the maximum infusion rate for parenteral nutrition solutions is about 20 ml/hr. Packed red blood cells could not be infused through these catheters. In vivo results demonstrate a significant (p less than 0.05) reduction in number of peripheral iv catheters inserted during study (2 +/- 1 vs 7 +/- 4, SD) with no difference in cost per day of iv access ($79.42 +/- 113.51 vs $43.91 +/- 15.99, SD). Two-dimensional ultrasound assessment of catheter thrombosis was unsuccessful. Moreover, there was no correlation between angiographic and electron microscopic evaluation of catheter tip thrombosis. Electron microscopy of catheter tips revealed 33% with complete, partial and no occlusion, respectively, and 39% with sheath thrombosis. In summary, percutaneous insertion of a 27-gauge OD Vialon central venous catheter is a feasible alternative in providing venous access in very low birth weight infants.