Umbilical vein catheterization under electrocardiogram guidance.

BACKGROUND

In the neonate, umbilical venous catheters (UVC) are inserted and advanced blindly to a predetermined length from the umbilicus. The reported rates for UVC misplacement into the liver (and occasionally the spleen) range from 20 to 37%. Radiographs are routinely used to confirm the positioning of UVCs. This involves movement of often critically ill infants, as well as radiation exposure. This pilot study examines the potential value of confirming UVC placement in neonates using ECG.

METHODS

In critically ill neonates, a conductive Johans ECG adapter was connected to a UVC. A satisfactory tracing (lead II) was obtained (right arm lead connected to the adapter) when the UVC was filled with saline solution allowing the catheter tip to become a unipolar ECG electrode. The UVC was then advanced from the umbilicus until the tip reached the inferior vena cava (IVC) within the thoracic region, as demonstrated by appearance of normal sized QRS complexes with small P-waves. A small QRS indicated the catheter was below the diaphragm. The appearance of a tall positive P-wave indicated the tip was at the right atrium level. The UVC was then withdrawn until the P-wave size returned to normal. The final UVC position was later confirmed by X-ray.

RESULTS

Eight neonates were studied. The figure shows typical ECG tracings when the UVC was placed in the liver, IVC, and right atrium, respectively. Three malpositioned catheters were detected (2 into liver and 1 into spleen).

CONCLUSIONS

Based on these cases, the insertion of UVCs in neonates can be guided with ECG by observing sequential and characteristic alterations in P-waves and QRS complexes, thereby reducing the use of X-rays. In addition, this technique could prove to be beneficial in remote healthcare facilities where X-ray machines may not be readily available and quick intravenous access is required to transport sick neonates to major centers.