RT Journal Article SR Electronic T1 Doppler echocardiography was not accurate for diagnosing asymptomatic thrombosis associated with an umbilical venous catheter in infants JF Evidence Based Nursing JO Evid Based Nurs FD BMJ Publishing Group Ltd and RCN Publishing Company Ltd SP 22 OP 22 DO 10.1136/ebn.6.1.22 VO 6 IS 1 YR 2003 UL http://ebn.bmj.com/content/6/1/22.abstract AB