Objective:To determine the application efficacy of the self-made converter displaying the intravenous electrocardiogram combined with ultrasonic test and to explore the possibility of P waves positioning instead of X-ray test in determining terminal tip location when inserting a peripherally inserted central catheter(PICC). Methods:Totally 1 028 patients inserted with PICCs were assigned to the experimental group(n=513) and control group(n=515) according to the admission number. In experiment group

surface electrocardiogram was converted to endocaridal electrogram by the self-made converter;then the tip location was determined by P wave changes and ultrasonography examination. In control group

the tip location was determined by ultrasonography examination. Finally

X-ray was used to confirm the tip location of all the patients. The tip location

ectopic situation

as well as the congruence of P wave prediction and X-ray test were recorded. Results:Tip in-place rate of the experimental group was significantly higher than that of control group(χ~2=20.475

P=0.000). There was no significant difference in ectopic rate of subclavian vein reflexion and the axillary vein between the two group(χ~2=0.140

P=0.708;χ~2=2.997

P=0.083). The congruence rate of P waves prediction and the results of Xray test were good(κ=0.877

P=0.000). Conclusion:Application of self-made converter displaying the intravenous electrocardiogram combined with ultrasonic test can increase the success rate of PICC catheterization

therefore worth clinical promotion. For patients with characteristic P wave

P wave positioning can replace X-ray test in determining terminal tip location during inserting PICC.