Ultrasonographic investigation of the pathogenesis of infusion thrombophlebitis

Background Thrombophlebitis frequently complicates intravenous infusion, but its precise pathogenesis remains unclear. Methods Serial B mode ultrasonographic imaging was used to detect intraluminal thrombosis when intravenous nutrition was delivered via fine-bore catheters inserted into peripheral veins. Results Thrombus was detected in 14 of 22 catheterized veins. There were nine episodes of clinical phlebitis; each was associated with intravenous thrombosis. Venospasm was not observed, The time at which thrombus was first detected varied from within 24 h to more than 15 days after catheterization. Detection of intravenous thrombosis within 24 h of catheter insertion was associated with early catheter complications. Early thrombus tended to be found close to the site of venepuncture, whereas late thrombus was found at the catheter tip, where the hypertonic feed was delivered. Discussion Ultrasonographic imaging was a useful technique for investigation of infusion thrombophlebitis. Two patterns of thrombosis were observed: distal early thrombosis and proximal late thrombosis. Information acquired may help in the design of novel catheters and strategies to reduce the incidence of thrombophlebitis.