Methodsby an interventional radiology expert. Subclavian vein was not preferred since it complicated the insertion of the catheter into the clavicle under ultrasound guidance. Adequate anesthesia was achieved prior to the procedure (1 μgr/kg fentanyl); sedation was ensured using midazolam (0,1 mg/kg) or ketamine (1-2 mg/kg). During the procedure, the patients were followed under continuous monitoring of the cardiac rate and rhythm, the respiratory rate and oxygen saturation. Except emergency situations, patients with pre-existing thrombocytopenia and abnormal coagulation test results were given supportive treatment and the catheter was inserted in these patients after the test results returned to normal. Central venous catheters were inserted by the pediatricians employed at the intensive care unit or interventional radiology expert at the pediatric intensive care unit. Double-lumen 4-Fr, triple-lumen 5-Fr, triple-lumen 7-Fr polyurethane transient catheters were used for patients with a body weight below 5 kg, between 5 and 20 kg and above 20 kg, respectively (Guangdong Baihe Medical Technology, China).For the purpose to recognize artery and vein; 1-the anatomic positions of internal jugular and femoral veins relative to arteries (internal jugular vein lies on the lateral side of the common carotid artery, femoral vein lies on the medial side of the femoral artery) (figure 1,2), 2-the compressibility of the internal jugular and femoral veins relative to arteries (figure 1,2), 3-in case of difficulty of discriminating the veins and arteries, the shape of the flow was investigated using Doppler mode of ultrasound (Figure 3). While transverse access was mostly used due to the size of the ultrasound probe, CVC was conducted using longitudinal access with real-time images in older patients (figure 4).Hand hygiene and aseptic conditions were ensured to manage infections. The site of administration was sterilized using 10% povidone iodine. A sterile ultrasound gel (Aquatouch Jelly, Turkey) and sterile transducer cover (Medbar Cardboard Camera Cover, Turkey) was used. While inserting the catheter, a "laptop style" ultrasound device and a straight linear probe (7.5 MHz) was used (Mindray-M5 Ultrasound System, China). The catheters were inserted using the Seldinger technique. The location of the catheter was assessed by posterior-anterior chest radiograph for the internal jugular catheters and the localization was deemed appropriate if the tip of the catheter was in the space between the distal part of vena cava superior and the entrance of the right atrium. Dressings were applied once every two days. Patients exhibiting the same microorganism growth in the catheter culture and the peripheral blood culture with accompanying the sepsis clinical findings and signs were diagnosed as central line-associated bloodstream infection while those with erythema, indurations and tenderness within 2 cm distance around the catheter exit were diagnosed with catheter exit-site infection 9 .