Finally, the central line itself is then passed over the guidewire, which is then removed. All the lumens of the line are aspirated (to ensure that they are all positioned inside the vein) and flushed with either saline or heparin.[1] A chest X-ray is typically performed afterwards to confirm that the line is positioned inside the superior vena cava and no pneumothorax was caused inadvertently. Vascular positioning systems can also be used to verify tip placement during insertion.