[Central venous catheter location by endocavitary ECG: an alternative to chest radiography]

The location of a central venous catheter is checked with a chest radiograph. Right endocavitary electrocardiography (ECG), a technique in which the catheter is connected to the ECG recorder wire to record ECG in DII, might be an alternate method to check the position of the catheter. When the catheter enters the right atrium, there is a large increase in the amplitude of P wave. The aim of this study was to compare the efficacy of endocavitary ECG against the chest radiography as a method to check the position of a central catheter, and to determine whether the ECG method can replace the radiological method.

One-hundred central catheters which location was checked by ECG and by chest X-ray entered the study. Efficacy of endocavitary ECG, delay between catheter insertion and radiological check, and the cost of the two methods were studied.

Endocavitary ECG determined that de catheter was in a correct position in 80 cases and malpositioned in 20 cases. ECG check agreed with radiological check in 93 catheters. There were 4 false-positive and 3 false-negative cases. The efficacy of endocavitary ECG was 93% (sensitivity: 82%; specificity: 81%; positive predictive rate: 95%; negative predictive rate: 85%). Catheter location was checked immediately on insertion by ECG in all cases, while radiological check was delayed 32 +/- 25 min in the emergency department and 68 +/- 206 min in the admitted patients. The cost of the ECG method was less than that of the radiological method.

The check of the position of a central venous catheter by endocavitary ECG is taster, cheaper, and of similar efficacy to the radiological method. Endocavitary ECG can replace chest X-rays to check the position of the catheter in more than 90% of cases.