Background and Goal of Study: Aim of this study is to determine the sensitivity and specificity of previously reported “saline flush test” (SFT) (1,2) in showing the misplacement of subclavian vein (SCV) catheter to the ipsilateral internal jugular vein (IJV) in patients undergoing neurosurgery. Materials and Methods: Patients scheduled for neurosurgery and to require subclavian vein catheterization were enrolled into this study. After insertion of the central venous catheter through the right SCV using seldinger technique, 10 ml of saline was injected from the distal port of the catheter while an independant observer put the palm of his hand on the patient's ipsilateral sternocleidomastoid muscle to experience wether a thrill is sensed during the injection or not. The thrill sensation was recorded as “positive” and a precursor of misplacement to the IJV. Confirmation was made by chest radiography for correct placement.
Results and Discussion: ASA II-III, 16-68 year old 83 patients were evaluated and only 1 patient (1,20%) had positive saline test and this was the only patient who had misplacement of the SCV catheter into the ipsilateral IJV which was also confirmed by the chest radiograph. The chest radiographs of the remaining 82 patients showed SCV catheter in the right place and had a negative saline flush test. Although more patients are needed to be observed, this test seems highly sensitive and specific for patients with misplaced SCV catheter into the ipsilateral IJV.
Conclusion(s): Misplacement of the SCV catheter to the IJV is a common error of placement with possible side effecs such as thromboflebitis, clot formation, impaired CVP measurement and catheter erosion. Early diagnosis is important and chest radiograph is stil the gold standard. SFT is a simple and costless test with no side effects but high sensitivity and specificity which can be a good alternative for diagnosing misplacement of SCV catheter into the ipsilateral IJV.
1. Toshniwal GR, Rath GP, Bithal PK. Flush test—a new technique to assess the malposition of subclavian vein catheter position in the internal jugular vein. J Neurosurg Anesthesiol 2006; 18: 268-9.
2. Rath GP, Bithal PK, Toshniwal GR, Prabhakar H, Dash HH. Saline flush test for bedside detection of misplaced subclavian vein catheter into ipsilateral internal jugular vein. BJA 2009; 102(4): 499-502.