Risk factors for umbilical venous catheter-associated thrombosis in very low birth weight infants.

Background: Thrombosis in neonates is a rare but serious occurrence, usually associated with central catheterization. The objective of this study was to investigate the risk factors associated with catheter related thrombosis in very low birth weight (VLBW) infants.

Procedure: The present retrospective study was performed using data from a randomized trial of duration of umbilical venous catheters (UVC) placement among infants <1,250 g birth weight. Twenty-two cases of UVC-associated thrombosis were identified in this sample. The remaining study sample (n = 188) served as the comparison group. Data on thrombosis, platelets, gestational age, birth weight, hematocrit, serum sodium, maternal preeclampsia, blood group, infant of diabetic mother (IDM) and demographic factors were collected using database and record review.

Results: Among the total subjects (n = 210), 112 (53%) were males and 126 (60%) were Caucasians, with mean gestational age of 27.7 +/- 2.1 weeks (standard deviation) and mean birth weight of 923 +/- 195 g. Bivariate analysis revealed significant association of thrombosis with hematocrit >55% in the first week (odds ratio [OR] 5.4; 95% confidence interval [CI] 2.0-14.6; P = 0.0003), being small for gestational age (SGA) (OR, 2.9; 95% CI, 1.2-7.4; P = 0.02) and maternal preeclampsia (OR, 3.97; 95% CI, 1.6-9.84; P = 0.0017). In multivariate logistic regression analysis, only hematocrit >55% was independently associated with thrombus (OR, 3.7; 95% CI 1.1-11.8; P = 0.03).

Conclusions: This study demonstrates a significant, independent association between elevated hematocrit and development of UVC-associated thrombosis. Careful monitoring for catheter-associated thrombosis may be indicated in VLBW infants who have hematocrit >55% in the first week of life.