The overall goal of this procedure is to enable clinicians to insert a central venous catheter under real-time ultrasound guidance via the right supraclavicular fossa view of the lower part of the superior vena cava. This is accomplished by first obtaining a full longitudinal ultrasound view of the superior vena cava, the adjacent to sending aorta and the right pulmonary artery. The second step is to pre-scan the central venous catheter insertion site, such as the right internal jugular vein.
Next, a venipuncture is performed at that site under ultrasound guidance. The final steps are to obtain the ultrasound window showing the superior vena cava and right pulmonary artery, and ultimately use this view to advance the guide wire into the lower part of the superior vena cava. So the main advantage of our technique over existing methods like chest radiography, for example.
First of all, we can omit any radiation, and secondly, we can get real time information of the Guidewire tip in the central Wier cover. Start by placing the patient in a supine position. If awake, the patient may have their head elevated for comfort.
Then position the ultrasound machine so it is in line with the operator's position and the puncture site on the patient. The operator should be able to see everything at once. Now turn on the ultrasound and connect the micro convex probe.
Then select the preset for deep tissue penetration where the probe is at or below eight megahertz. Before attaching the probe, apply an alcoholic disinfectant to the skin to improve acoustic coupling. Then place the micro convex probe on the puncture site.
Now pre-scan the puncture site using a B mode short axis view for an out of plane puncture technique. Optimize the image by adjusting the gain depth and focus. Confirm the vein by applying pressure on it.
Test it for compressibility and to exclude thrombus at the puncture site. If there's uncertainty about the vein, use color flow doppler and move the probe centrally to detect the possible thrombus to detect a potential thrombus. Probe the right supraclavicular fossa to view the confluence of the internal jugular vein and subclavian vein.
Adjust the gain depth and focus as needed. Set the gain so it is high enough to differentiate between hypoechoic vessel walls and hyper coic vessel lumens. Now increase the depth by four to six centimeters to view the confluence of the brachiocephalic veins.
This will also correspond to the beginning of the upper SVC. Then set the depth to 10 to 12 centimeters and adjust the focus for a full view of the SVC, the adjacent ascending aorta and the right pulmonary artery. Take note that the machine will adjust the probe frequency based on the depth.
Now, evaluate the brachiocephalic veins and the SVC for an intravenous thrombus. Turn the ultrasound probe about 90 degrees clockwise for a sagittal view of the SVC. Now, use a short axis dorsal view of the lower SVC to see the right pulmonary artery and the pulmonary veins distal of the right pulmonary artery.
An optional confirmation of the SVC can be accomplished with doppler. Begin with preparing the CVC kit and putting on sterile protective garments. Next, disinfect the skin with alcohol and apply sterile drapes.
Then insert the ultrasound probe into a sterile cover. Now get a view of the vein to be punctured, holding the probe in the non-dominant hand in the dominant hand grip the needle and syringe and perform a venni puncture under the ultrasound images, guidance out of plane and in plain techniques are both okay to use. Following the venni puncture, insert the guide wire through the needle using a long axis view.
Confirm that the guide wire is within the vein. Begin by transferring the ultrasound probe to the dominant hand and get a view of the SVC. The probe must be in a tight angle relative to the neck.
Now advance the guide wire with the non-dominant hand view. The guide wire's JT tip, especially while it crosses the upper wall of the right pulmonary artery. Do not push the guide wire too far into the SVC.
For the j ttip will become difficult to see. If the ultrasound beam cannot be aligned with the j ttip and the right pulmonary artery, then use the ascending aorta as a landmark and turn the probe 90 degrees clockwise to obtain a sagittal view of the SVC. Then relative to the right pulmonary artery, observed in the short axis, confirmed the guide wire's position.
Now use the central venous catheter to measure the insertion depth of the guide wire. Align the 20 centimeter markings on the CVC and on the guide wire. Then keeping the guide wire still read the marks on it at the venipuncture site.
Chest radiographs were obtained following ultrasound guided CVC placement for every investigated patient. The CVC tip position in relation to the carina on the chest radiographs was confirmed as correct by a radiologist. In 90%of the cases.
The tip was within 35 millimeters of the kina relative to the kina. 17%of the CBC placements were a little high. 19%were on the level and 64%were a little low.
The CVC tip was more than 55 millimeters below the Corina only 4%of the time. Once massed, this technique can be done in 10 minutes if it is performed properly.
