The overall goal 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 view is useful for different catheter insertion sites, thrombosis detection before insertion and ultrasound guided correction of misplaced catheters.
The supraclavicular fossa ultrasound view can be useful for central venous catheter (CVC) placement. Venipuncture of the internal jugular veins (IJV) or subclavian veins is performed with a micro-convex ultrasound probe, using a neonatal abdominal preset with a probe frequency of 10 Mhz at a depth of 10-12 cm. Following insertion of the guidewire into the vein, the probe is shifted to the right supraclavicular fossa to obtain a view of the superior vena cava (SVC), right pulmonary artery and ascending aorta. Under real-time ultrasound view, the guidewire and its J-tip is visualized and pushed forward to the lower SVC. Insertion depth is read from guidewire marks using central venous catheter. CVC is then inserted following skin and venous dilation. The supraclavicular fossa view is most suitable for right IJV CVC insertion. If other insertion sites are chosen the right supraclavicular fossa should be within the sterile field. Scanning of the IJVs, brachiocephalic veins and SVC can reveal significant thrombosis before venipuncture. Misplaced CVCs can be corrected with a change over guidewire technique under real-time ultrasound guidance. In conjunction with a diagnostic lung ultrasound scan, this technique has a potential to replace chest radiograph for confirmation of CVC tip position and exclusion of pneumothorax. Moreover, this view is of advantage in patients with a non-p-wave cardiac rhythm were an intra-cardiac electrocardiography (ECG) is not feasible for CVC tip position confirmation. Limitations of the method are lack of availability of a micro-convex probe and the need for training.
Central venous catheter (CVC) tip position has to be confirmed since misplaced catheters can lead to trauma and erosion of endothelium and vessel walls with subsequent potentially fatal pericardial tamponade1. Furthermore, CVC in the upper superior vena cava (SVC) can provoke thrombotic events, especially in cancer patients. The same is true for misplaced CVC in opposite brachiocephalic vein or internal jugular vein (IJV)2.
Several methods have been established to confirm CVC tip position in the lower SVC. Chest radiograph has been performed traditionally as a bedside method to visualize the CVC tip and exclude pneumothorax. However, additionally to exposure to radiation and costs, the accuracy of chest radiograph for tip position and sensitivity for pneumothorax have been questioned, specifically for the patient in a supine position3. Computer tomography is highly accurate and sensitive for both CVC tip position and pneumothorax, respectively. However, the costs and exposure to radiation do not justify this method for the sole indication of CVC tip confirmation. Transesophageal echocardiography (TEE) is highly accurate for tip position, but indication for TEE is limited to patients with cardiac pathology4. Intra-cardiac electrocardiography (ECG) is an accurate method but depends on a p-wave cardiac rhythm5.
Parasternal and subcostal ultrasound view were suggested to verify the CVC tip position, but success depends on deep insertion of the guidewire into the right atrium. A negative result does not exclude misplaced catheters6,7. The right supraclavicular fossa ultrasound view has been solely described for diagnostic purposes in cardiac failure. In a pilot study, we have demonstrated that this view can also be safely used for venipuncture of the right IJV and accurate positioning of the CVC guidewire with subsequent CVC placement in real-time8. The right supraclavicular fossa ultrasound view can be established with a microconvex probe which has the advantage of a small footprint, deep pentetration and, yet a sufficient resolution for venipuncture when compared to a linear probe8-10.
The proposed procedure has the advantage of visualizing venipuncture and guidewire advancement with a single ultrasound probe within the sterile field in real-time. CVCs insertion length does not have to be corrected afterwards and extra manipulations and potential sources of contamination are prevented. In conjunction with lung ultrasound for exclusion of a pneumothorax, the proposed procedure has the potential to replace chest radiograph for CVC tip position confirmation and exclusion of pneumothorax, reducing costs and exposure to radiation and increasing patient comfort in any hospital setting where an ultrasound machine equipped with a microconvex ultrasound probe is available.
NOTE: The following protocol follows our internal guidelines and standard operation procedures approved by the chair of our department. The same protocol was approved by our institutional review board and was used for studies published in a previous paper8.
1. Pre-ultrasound Scan Preparation
2. Ultrasound Scan of the CVC Insertion Site and Superior Vena Cava
3. Supraclavicular Fossa Ultrasound View
4. Ultrasound Guided Venipuncture
5. Ultrasound Guided Guidewire Advancement
6. Measurement of Insertion Depth
7. Lung Ultrasound
8. Central Venous Catheter Change Over Guidewire
NOTE: CVC change over guidewire is a single contributor to catheter-related blood stream infection and should be avoided. In patients with a high risk of mechanical complication related to CVC insertion or limited venous access, CVC change over guidewire still can be considered12.
In a previously published study, chest radiographs were obtained in all patients following ultrasound guided CVC placement8. The CVC tip position in relation to the carina on chest radiographs was analysed by a radiologist who confirmed a correct position of the CVC in the lower SVC in all investigated patients. In 90% of all cases CVC tip was within 35 mm distance of the carina. In 17% the CVC tip was above, in 19% at the level of and in 64% below the carina. In 4% the CVC tip was more than 55 mm below the carina (Figures 1-2).
Figure 1: Distance of CVC tip to carina in mm measured in chest radiographs following ultrasound guided CVC tip positioning. This figure has been modified from Kim et al.8. Chest radiograph confirmed correct position in all patients with 90% of all tips within 35 mm distance of the carina.
Figure 2: Representative chest radiograph following ultrasound-guided CVC tip positioning in supine position and exspiration. The CVC tip (arrow) is in projection of the distal superior vena cava.
Figure 3: (A) Representative ultrasound image of the superior vena cava (SVC), right and left innominate veins (RIV/LIV), ascending aorta (AoAsc) and right pulmonary artery (RPA). (B) Representative ultrasound-guided guidewire advancement. J-tip of the guide wire is visualized in the mid-portion of the SVC. The RPA can be seen as a hypoechoic band in the far field.
This procedure allows for visualization of ultrasound guided venipuncture and central venous catheter tip position in real time via the right supraclaviculare fossa view. In combination with a lung ultrasound scan, this approach could replace chest radiograph for confirmation of catheter tip position and exclusion of a pneumothorax.
It is critical for ultrasound trained operators to become familiar with the ultrasound anatomy provided by the supraclavicular fossa view and correctly identify the anatomical landmarks. Moreover, it is crucial to adjust the angulation of the ultrasound probe with respect to the neck to a very narrow angle which can be best achieved with small probes. Little adjustments need to be performed to achieve an optimal view of the long axis of the SVC. Furthermore, advancing of the guidewire with one hand while performing the ultrasound scan with the other hand, requires training. In some case, it is not possible to align the ultrasound beam with the J-tip and the right pulmonary artery which could be solved by turning the probe into a sagittal view.
Best results will be obtained by micro-convex and similarly by phased array ultrasound probes due to their small contact surfaces and high penetration depth when compared to linear probes9. Curved abdominal ultrasound probes may also be used but may be difficult to handle because of their large surface and body. As with every ultrasound image, settings like gain, depth and focus position have to be modified to achieve optimal results.
A micro-convex probe might not be available at every hospital since it is a pediatric ultrasound probe. Ultrasound presets should allow deep tissue penetration. Other ultrasound probe types are potentially feasible but the results might not be optimal. Currently, there is limited data on the feasibility of this approach in obese patients. In 8% of the study population the J-tip was not visible in proximity of the right pulmonary artery. However, we did not test if a sagittal view would allow a better visualisation8.
Intra-cardiac ECG, transesophageal echocardiography and other transthoracic echocardiographic views have been suggested for confirmation of a central venous catheter tip. However, these approaches have limitations. Intra-cardiac ECG is restricted to patients with a p-wave cardiac rhythm while the incidence of patients with atrial fibrillation and atrial flutter is increasing. It is a highly sensitive, cost-effective method5. Some cases have been reported with intra-aortic central venous catheter tips and positive high p-wave. Furthermore, no change of the p-wave is suggestive for a misplaced catheter which can then only be verified by chest radiograph13. Furthermore, a chest radiograph is still necessary for exclusion of a pneumothorax if venipuncture was not performed with ultrasound. Transesophageal echocardiography is indicated in those patients who have a cardiac pathology and are undergoing cardiac surgery4. At the time of echocardiography, the position of a central venous catheter can only be corrected if the catheter is visualized, and was inserted deep enough to retract for a correct tip position. Catheters in other positions can only be changed over a guidewire under sterile conditions.
Using the right supraclavicular fossa view, chest radiography for confirmation of the correct CVC position may be redundant if in addition a lung ultrasound is performed to exclude a pneumothorax. Furthermore, ultrasound guided change of a misplaced CVC over guidewire is feasible without subsequent chest radiography.
The authors have nothing to disclose.
None
Name of Material/ Equipment | Company | Catalog Number | Comments/Description |
skin desinfection | Ecolab | 2686556 | Skinsept G |
8C-RS microconvex probe | GE Healthcare | 8C-RS | Any ultrasound machine equipped with a microconvex ultrasound probe should be suitable for this method |
Logiq e ultrasound machine | GE Healthcare | Logiq e | |
CVC Kit | Teleflex Medical | OW-15802-E | 8 Fr. 2 Lumen Blue-Flex tip catheter |
Sterile gloves | Protexix | 2D72NT70X | LatexMicro |
Sterile gown | Medline | OP9512CE | OPS Advanced |
sterile ultrasound probe cover | CIVCO | 610-637 | CIV-Fle Transducer Cover; sterile 8.9 x 91.5 cm |
suture | Ethicon | EH7723 | Ethibond |
12L-RS linear ultrasound probe | GE Healthcare | any linear ultrasound probe is suitable for lung ultrasound |