Positive tip cultures and related risk factors associated with intravascular catheterization in pediatric cardiac patients.

The incidence and risk factors of positive catheter tip cultures were studied prospectively in 392 consecutive children undergoing cardiac surgery under cover of cephalothin prophylaxis. A total of 1649 catheter tips were cultured and 58 (3.5%) yielded positive cultures. Specifically, the incidence of positive catheter tip cultures for iv, central venous, arterial and pulmonary arterial (PA) catheters was 0.9%, 5.9%, 3.9% and 10.6%, respectively, whereas one of the six surgically placed venous and arterial catheters had a positive tip culture and none of the 279 transthoracic catheters. Staphylococcus epidermidis was isolated from 79% of the positive tip cultures. Ten percent of the children had one or more positive tip cultures but none developed catheter-related septicemia or endocarditis. Stepwise logistic regression analysis revealed that longer in situ time (p less than .001), younger age (p less than .001), and inotropic support (p = .003) were significant independent predictors of risk for children developing positive catheter tip cultures. The safe in situ period for arterial, central venous, and PA catheters is 3 days in infants under 1 yr and 4 and 6 days for arterial and central venous catheters, respectively, in older children, if 0.95 cumulative probability of remaining free of a positive tip culture is accepted. The data generally support the bacteriologic safety of invasive hemodynamic monitoring in infants and children undergoing cardiac surgery.