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.

Multi-element analysis of the human body using neutron activation.

The calibration described is of the Leeds in vivo neutron activation facility for the simultaneous measurement of total body Na, Cl, P, Ca, N and K. The effects of body size and shape have been incorporated into the calibration using a variable anthropomorphic phantom. The main interfering reactions are considered, and the method by which the results are corrected for these interferences described. The accuracy and precision of the technique have been determined. The procedure is suitable for measuring the critically ill since both irradiation and counting are performed with the patient lying supine. For a whole body dose equivalent of 0.5 mSv nitrogen was measured with a coefficient of variation (CV) of 2.2%; potassium was measured in the same counting period with a CV of 1.6%. Using a dose equivalent of 5 mSv sodium (2.2%), chlorine (1.6%) and phosphorus (2.9%) were also determined; for a 10 mSv dose equivalent calcium was measured with a CV of 3%.