Sunday, December 6, 2015

Vascular Access / Arteriotomy Closrue Devices

Any arterial case, whether for a diagnostic 4-vessel angiogram, coronary catheterization, or transarterial chemoembolization, will require access into an artery, most commonly the right common femoral artery. After the case ends, the artery needs to be closed to achieve hemostasis and prevent further bleeding. The most basic closure "device" is manual pressure for 15 minutes. While this is effective, the downsides include no true closure of the wound in the vessel wall, operator dependence, and limited reliability in patients with large body habitus.

Closure devices have been developed to both mitigate the risks of bleeding as well as reduce the suite time required for such cases. Below are step by step instructions (and links to videos) for several common devices:

StarClose

This device functions by placing a metallic clip around the arteriotomy. While effective, the drawback is that a permanent device is left within the patient, potentially limiting future access. 

  1. Prep groin, kit by flushing introducer stylet into hub
  2. Exchange 5/6Fr sheath over wire for introducer
  3. Remove wire and stylet together, leaving stylet. Fix left hand against patient.
  4. Attach StarClose to introducer [#1] and switch left hand to device.
  5. With R hand, push [#2] to break the seal and deploy footplate.
  6. GENTLY RETRACT DEVICE UNTIL TENSION FELT - footplate now against inner wall.
  7. With R#2 above, #3+4 on handle, use R thumb to depress [#3] to fully break seal
  8. Tilt handle straight up, then push [#4] to deploy clip.
  9. Hold manual pressure for 2 minutes.


PerClose

This device is suture mediated. The suture is absorbable, and multiple PerClose's can be used to close larger arteriotomies. 

  1. Prep groin; prep kit with saline into sideport where blood will come, wet introducer part
  2. Exchange 5/6Fr sheath over wire for introducer
  3. Once white triangle reached, remove wire
  4. Advance until *pulsatile* blood return seen - Retract [#1] to deploy footplates
  5. Retract device until blood return disappears
  6. Deploy [#2] to advance suture through wall
  7. Deploy [#3] to loop suture through arteriotomy. Pull out stylet and cut suture
  8. Depress [#4] to close footplate
  9. Pull back device to free both sutures, then pull through. Remove device.
  10. Put knot pusher on LONG thread and push down with LEFT thumb on top of device
  11. Synch down on suture with short thread.
  12. Take knot pusher off long thread and place on both. Repeat motion, but now cut knot.


Mynx GRIP

This device functions by placing an absorbable polyethylene glycol plug in the tissue tract above the arrteriotomy.  


  1. Prep groin; prep kit with saline into sideport where blood will come, wet introducer part
  2. Draw 3 cc NS into syringe
  3. Introduce wire/balloon through existing sheath until white marker.
  4. Inflate balloon until inverse Oreo (white-black-white) seen at back of device. Close stopcock
  5. Grasp black handle and pull back two stops (balloon to sheath tip; balloon-sheath to vessel wall)
  6. Open sheath sidearm to confirm temporary hemostasis
  7. Advance shuttle to definitive stop, then withdraw sheath back to starting position
  8. Grasp the white tube at skin level and advance until green marker fully expose to tamp PEG grip tip onto vessel wall
  9. Hold in place for 30 seconds, then lay down for 90 seconds
  10. WIthdraw syringe to full negative, open stopcock, and withdraw through pusher device.
  11. Withdraw pusher device while holding pressure on vessel up to 60 seconds



To learn more about these closure devices and IR procedures in general, check out the Handbook of Interventional Radiologic Procedures:


Monday, November 23, 2015

Pull Percutaneous Gastrostomy Tube

A prior post detailed how to place a conventional gastrostomy tube as an interventional radiologist. However, a variant based on the approach endoscopists use is the pull percutaneous gastrostomy tube. Other names for this technique are the mushroom or Ponsky gastrostomy tube. The steps are as follows:

  1. Verify an appropriate window for the gastrostomy tube on pre-procedure imaging. In particular, make sure that the transverse colon does not lie between the anterior abdominal wall and the stomach. Alternatively, use ultrasound to check for liver margin and a rectal enema to opacify the transverse colon. 
  2. Check if the patient has a nasogastric tube. If not, using anesthetic gel and a glidewire, a Kumpe catheter can be fluoroscopically guided into the stomach. Have an assistant use the tube to insufflate the stomach. Point the Kumpe straight back with the tip facing down, then flip it 180 degrees to lead away from the trachea.
  3. Once the stomach is sufficiently inflated, anesthetize the skin. A good location is midway along the greater curve as the passes will aim towards the fundus.
  4. Use a 19G Chiba needle to access the stomach. Once intraluminal position confirmed, direct the needle posteriomedially towards the NG tube (ideally, nudge it under fluoro). 
  5. Leading with an 0.035” Amplatz, direct the wire retrograde up the esophagus. 
  6. An assistant will retrieve the wire from the mouth. Once outside, attach a snare (comes in kit) to the back end of the wire near the stomach and pull the snare through to the mouth. 
  7. Release the snare from the wire, then tie a hitch knot to the gastrostomy tube. 
  8. Pull the gastrostomy tube antegrade through the esophagus into the stomach. 
  9. Store a fluoro image with contrast injection to verify location.

Be mindful that a near absolute contraindication to this procedure is any patient with skull base, head and neck, or esophageal cancer / obstruction.

There are several benefits to placing a primary gastrostomy tube in this manner:
  • No T-Tacks to cut
  • 20 Fr instead of 14 Fr, so decreased risk of clogging
  • More durable
  • No pigtail within the gastric lumen, so less concern for gastric outlet obstruction
  • Generally less messy because no dilatation needed, and only one stick into the abdominal wall
Bard's Version of the Pull G-Tube (Copyright Bard)



Monday, June 22, 2015

Lymphangiogram

A lymphangiogram is an uncommon procedure that can be performed by interventional radiologists, typically to identify and potentially treat the source of a chylous leak.

Pre Procedure

  • Indications: Thoracic duct injury, usually from surgery, causing chylous effusion / chylothorax, or recurrent chylous ascites
  • Surgical management (direct fix of the leak intraoperatively if visualized) and medical management should be optimized first. 
  • Specifically, the patient should be on a low fat / medium chain triglyceride diet. Long chain triglycerides are absorbed by the lymphatics, which leads to extra lymph production. Medium chain triglycerides however are absorbed by the portal veins, reducing the production of lymph.  

Procedure

  • Transpedal approach: prep the feet
  • Inject 50/50 mix of isosulfan blue and lidocaine into the webbing between toes and wait 10-15 minutes for dye to be picked up by lymphatics
  • Make incision parallel to lymphatic
  • Strip away fat/tissue parallel to lymphatic
  • Insert backing (cardboard/plastic) underneath lymphatic
  • Insert 30 gauge needle into lymphatic and inject 100% lidocaine
    • Bubble test: watch to see if air goes into lymphatics, or if it fizzes
  • Take serial x-rays of lower extremities and abdomen to see lymphatics and eventually cysterna chyli fill
  • Once filled, can insert 21 gauge needle directly into cisterna chyli and perform embolization, usually with coils and/or N-butyl cyanoacrylate glue

Post Procedure

  • Evaluate for recurrent leak

Monday, June 15, 2015

A Simplified Approach To Spinal Masses

Spinal cord masses can be confusing at times, especially if not encountered routinely. While it may be difficult to arrive at a specific diagnosis, a narrowed differential can often be very helpful to the referring clinician. Clinical history is also quite useful at narrowing the differential.

The first question to ask is where exactly is the tumor located within the spinal canal. The broad categories are: intramedullary, intradural-extramedullary, and extradural. An intramedullary mass will be centered within the substance of the spinal cord itself, which has been described as the claw sign. An intradural-extramedullary mass will form a meniscus with the cord and push it away. An extradural mass will be outside the thecal sac. Vertebral body or clear epidural involvement suggests an extradural location. In cases where the distinction is difficult, assess the cord above and below the mass.

Once that determination has been made, the chart below can help generate a differential by focusing on both the imaging characteristics and clinical context:


The chart is not comprehensive, but it does list the most common primary masses to be found within those locations within the spine. As always, metastases are a consideration in any of these locations. Making the distinction can be challenging at times, especially when the mass is large and distorts normal structures.


References:

Monday, June 8, 2015

Leptomeningeal FLAIR Hyperintensity Differential Diagnosis

Hyper intensity in the subarachnoid space can have a wide range of causes. The finding may be subtle to detect at times. However, identifying it can be crucial in altering a patient's management. The mnemonic FLAIR can be used to recall the common causes of this finding:

DiseaseNotes
FFiO2 highNo contrast enhancement
LLeptomeningeal spread of tumorGEMCLOG: glioblastoma, ependymoma, medulloblastoma, choroid plexus tumor, lymphoma, oligodendroglioma, germinoma
AAneurysmal bleedNo contrast enhancement
IInfection (meningitis)
RpRopofolNo contrast enhancement, may also be due to increased oxygen



Monday, June 1, 2015

Dilated Small Bowel Differential Diagnosis

A common finding in patients with abdominal pain is dilated loops of small bowel. Dilated loops may be noted on plain X-ray, fluoroscopic studies, or CT. The first step to forming a focused differential diagnosis is determining whether the folds are thin, thick (> 3 mm), or thick and nodular.

If the folds are thin, the mnemonic MISS can be used to recall the common diagnoses:

DiseaseNotes
MMechanical obstructionDue to intraluminal impaction (high fiber foods), adhesions post-operatively, or a mass
IIleusPost-operatively, medications
SScleroderma
Systemic sclerosis due to deposition of collagen
Sacculations of anti-mesenteric border
Hidebound bowel (unchanging on dynamic studies)
SSprueVillous atrophy and crypt hypertrophy → chronic fluid overload → ‘congestive gut overload’ → featureless mucosal pattern proximally in small bowel = reversal of jejunal / ileal fold pattern

Moulage sign: moulage means casted or molded structure; the jejunum appears a cast of itself due to featureless appearance because of lack of mucosal folds

Small Bowel Obstruction
Source: Radiology Assistant

If there is segmental thickening of the folds, think of the three Is: ischemia, infection, or idiopathic. Diffuse fold thickening is usually due to systemic processes such as venous congestion or cirrhosis.

Nodular fold thickening is usually due to infiltrative processes of the bowel wall. Common etiologies include Crohn disease, infection, lymphoma, metastases, and Whipple disease.

If the dilatation is thick walled, check out the differential diagnosis for small bowel aneurysmal dilatation.

If you want to learn more about GI imaging, specifically fluoroscopy, the Mayo Clinic Gastrointestinal Imaging book is a wonderful reference with over 500 images:



Monday, May 25, 2015

Will Watson Compete For Radiology Jobs?

IBM recently released an ad from the Ogilvy Group agency currently airing on national TV that directly addresses how Watson, IBM's ongoing supercomputing research project popularized by its star turn on the TV show 'Jeopardy!, may one day play a role in diagnostic imaging:


Is this realistic, or just some far off pipe dream? Technological aspirations often tend to outstrip technical reality. For example, computer-aided diagnosis (CAD) in mammography has not become a panacea for screening mammograms, and ultimately does not appear to have had a significant impact on the labor demand for mammographers. Anecdotally, mammographers I have spoken with regard CAD as too sensitive, and a potential liability. Sure, the software will pick up the subtle lesion occasionally, but it will pick up many more that are merely normal tissue, but nonetheless force the radiologist to make an active decision to dismiss. What happens if the mammographer decides a positive finding on CAD is negative, but cancer develops later anyway? Unless the software can improve both sensitivity *and* specificity, it may create as many problems as it solves.

For argument's sake though, let's say the new technology can improve both sensitivity and specificity.  Several open questions come to mind: will the software aid radiologists? Does it seek to replace radiologists? If it does, who takes on liability if the software 'misses' a lesion, as it inevitably will? And who pays for it all? It is hard to see these questions being answered in the affirmative in the current healthcare system, but after seeing ACA pass, it is clear that the environment is not static. If costs start to rise again, and IBM and similar software vendors market themselves well, one could see hospitals giving such systems a try. The tl;dr - money talks and BS walks: if these systems can do the job better than radiologists, they will be used.

How can radiologists operate under such potential uncertainty? Instead of ducking the issue, radiologists should work towards simultaneously figuring out how best to employ these systems while also demonstrating the value-add of a physician diagnostic imager both to referring clinicians and to patients. If the face of the radiologist is merely the report they generate, very soon that face may take a very Big Blue complexion.

Monday, May 18, 2015

IVC Filter Placement

IVC filters can be placed surgically but the vast majority are placed percutaneously.

Pre Procedure

  • Indications
    • New clot or clot progression on therapeutic anticoagulation.
    • Pre-op for patient who cannot be anticoagulated
  • Can be placed from a transjugular or transfemoral approach.
  • Ideal location is infra-renal.
  • Make sure to check a CT beforehand for variant renal vein anatomy.

Procedure

  • Access the venous system either via a jugular or femoral approach. If femoral, the vein is 1 cm medial to the artery.
  • Insert a Pig cava catheter, and perform an angiogram (Usually 15 ccs / min for 30 cvs)
  • Exchange the catheter for the filter sheath, after dilation of the tract.
  • Gunther-Tulip Jugular
    • Insert the filter until the feet are at the end of the sheath. Unsheath the filter. Press the button to deploy.
  • Gunther-Tulip Femoral
    • Insert the filter until the tip is at the end of the sheet. Unsheath the filter. Bring the red and white torquers together and twist to deploy.
  • Option
    • Make sure the correct end is facing the catheter

Post Procedure


  • If retrievable, can be retrieved up to 3 weeks before the filter epithelializes
  • Complications: fragmentation, migration, perforation


Sunday, May 17, 2015

Radiology Gifts at Raditudes

Ever look for a gift for that special radiologist in your life? Or just the one you want to tease a little? Check out Raditudes! The store is specifically aimed at radiology and diagnostic imaging related gifts, including t-shirts, coffee mugs, and more!

 Raditudes


Have feedback or a design idea you would like to see? Let us know!

Monday, May 11, 2015

IVC Filter Retrieval

Certain types of IVC filters are retrievable within a 3 to 8 week window after placement. Typically, these were placed for a patient who had a short term need for anticoagulation, but could not be medically anti coagulated. For example, a trauma patient with a head bleed and a long bone fracture going to the OR with orthopedics. The procedure is very similar to IVC filter placement.

Procedure

  • Access the venous system via a jugular approach. Filters can only be retrieved via the jugular vein. 
  • Insert a Pig cava catheter, and perform an angiogram (Usually 15 ccs/sec for 30 cvs) 
  • Exchange the catheter for the sheath, after dilation of the tract. 
  • Extend the snare from the tip of the sheath and capture the filter's hook under fluoro.
  • With gentle back tension on the snare, advanced the sheath over the filter so until the filter is fully within the sheath. 
  • Retrieve the entire system and withdraw it from the neck. Be careful as you cross through the right atrium 
  • Hold gentle manual pressure over the neck venotomy site.

Retrievable IVC Filter
Source: Wikipedia

Monday, May 4, 2015

Dynamic MRI of a Knuckle Cracking

From the medical oddities file, researchers from the University of Alberta have *finally* captured a knuckle popping on MRI in order to explain what goes on during when one "pops a knuckle" and where the sound comes from. Per the Wired article:
First, researchers at the University of Alberta found someone who could crack his knuckles over and over again, without the long refractory period most people have. Yup, he was multiply crackasmic. 
Then the scientists put this crack-addict’s fingers into a magnetic resonance imager, watching cracking events as they took place. That’s what’s in the GIF we made you from the researchers’ video. As the bones in the joint separate, negative pressure means gas (likely nitrogen) in the synovial fluid gathers together, resulting in the sudden formation of bubbles—the scientific term for that is tribonucleation. And with that comes the pop.
The GIF of the knuckle pop looks like this:
Source: Gregory Kawchuk, University of Alberta/PLOS Media via Wired

The actual research article has the more staid title of "Real-Time Visualization of Joint Cavitation" but honestly, the authors must have known that is not the source of interest in their work. If you want to know why exactly the sound occurs, the authors state:
Our results offer direct experimental evidence that joint cracking is associated with cavity inception rather than collapse of a pre-existing bubble. These observations are consistent with tribonucleation, a known process where opposing surfaces resist separation until a critical point where they then separate rapidly creating sustained gas cavities.
The work also goes a long way towards explaining this video from the 1980s:


The research leads one to wonder: what other phenomenon have we been missing on MRI? If a patient has vacuum disc phenomenon in their lower lumbar spine, are they simply in need of a good back massage? Speaking of which, why do massages feel good? Clearly, we need to get a metal-free masseuse into a scanner and see what happens!

Monday, April 27, 2015

Bone Tumors

Bone tumors have several features that are characteristic and can be used to narrow a differential diagnosis for a suspicious lesion. This table is by no means comprehensive but it is meant to be a quick reference for various benign and malignant osseous lesions. The following features are relevant: patient age, lesion borders, location within bone, bones, involved, bone matrix changes, periosteal reaction, matrix mineralization, and soft tissue component.

The patients can be divided into two groups based on age: younger than 30 vs older than 30. The lesion borders can be described as a narrow zone of transition (the border is easy to define) vs a broad zone of transition. Periosteal reactions can be described as thin, thick, lamellated, hair-on-end, sunburst, or Codman's triangle. Matrix mineralization is either chondroid (rings and arcs) or osteoid (cloud-like). A soft tissue component is either present or absent.


Diagnoses Age Bones Borders Physis? Cortex? Periosteal Reaction Matrix Mineralization Soft Tissue Mass
Fibrous Dysplasia under 30 Face, ribs, femur Narrow Metadiaphysis No No No No
Eosinophilic granuloma under 30 Face, humerus, ribs, femur Narrow Metadiaphysis Possible Variable No Yes, if fx
Osteoid osteoma under 30 Long bones Narrow Metaphysis Yes No No No
Nonossifying fibroma under 30 Distal femur, distal tibia Narrow Metaphysis Yes No No No
Simple Bone Cyst under 30 Proximal humerus, proximal femur Narrow Metaphysis No No No No
Osteochondroma under 30 Distal femur, proximal tibia Narrow Metaphysis Yes No No No
Ewing Sarcoma under 30 Long bones, ribs Broad Diaphysis Yes Lamellated No Yes
Osteosarcoma under 30 Long bones Broad Metaphysis Yes Sunburst, hair-on-end, Codman's Osteoid Yes
Enchondroma under 30 Small bones Narrow Metadiaphysis Yes No No No
Aneursymal Bone Cyst under 30 Posterior vertebrae, flat bones, long bones Narrow Epiphysis Yes Yes No No
Chondromyxoid fibroma under 30 Long bones Narrow Metaphysis Yes No Chondroid No
Chondroblastoma under 30 Distal femur, proximal humerus Narrow Epiphysis Yes No Chondroid No
Osteomyelitis any age Any Broad Any Yes Thick No No
Myeloma over 30 Any Narrow Metadiaphysis Yes No No No
Geode over 30 Periarticular Narrow Epiphysis Yes No No No
Hyperparathyroidism over 30 Any Narrow Metadiaphysis Thinned No No No
Giant Cell Tumor over 20 Knee, distal radius, sacrum Narrow Epiphysis No No No Eggshell ossification


Bone Tumors By Location
Source: radiologyassistant.nl


References:

Monday, April 20, 2015

How To Place A Percutaneous Gastrostomy Tube

Gastrostomy tubes and their variants can be placed endoscopically, surgically, or percutaneously. The interventional radiologist can help determine which approach is best for patients. In particular, patients with pharyngeal issues, such as head and neck cancers, are good candidates for percutaneous placement. Here is one approach, which utilizes a Wills-Oglesby pigtail gastrostomy tube.

  1. Verify an appropriate window for the gastrostomy tube on pre-procedure imaging. In particular, make sure that the transverse colon does not lie between the anterior abdominal wall and the stomach.
  2. Check if the patient has a nasogastric tube. If not, using anesthetic gel and a glidewire, a Kumpe catheter can be fluoroscopically guided into the stomach. Have an assistant use the tube to insufflate the stomach.
  3. Once the stomach is sufficiently inflated, anesthetize the skin. A good location is midway along the greater curve as the passes will aim towards the fundus.
  4. A fastener is used to enter the stomach and pull it up towards the anterior abdominal wall. The introducer needle is used to initially access the stomach. Attach contrast to the needle and advance the needle under fluoro. Watch it tent the gastric wall, and then enter the gastric lumen. Intraluminal position can be confirmed by seeing the needle tip move freely, aspiration of gas, and injection of contrast outlining gastric rugae.
  5. Once intraluminal position is confirmed, the fastener is advanced through the needle, the needle withdrawn, and the fastener pulled back to lift the stomach up. If additional fasteners are desired, repeat Step 4.
  6. After the stomach is fastened, make a dermatotomy and then pass another needle into the stomach. Confirm intraluminal position as in #4. Pass a 0.035 inch wire into the stomach and watch it coil around the greater curvature past the fasteners.
  7. Withdraw the needle and serially dilate over the wire up to the size of the catheter. Work quickly as the stomach will begin to lose gas and deflate.
  8. Insert the catheter, withdraw the wire, pull the string to pig the catheter, and inject contrast to confirm final position. Suture the catheter into place. 

One protocol to clear the gastrostomy tube is to wait one day, then check the patient. If the patient is afebrile, without leukocytosis, and without peritoneal signs, start trial feeds. If the patient tolerates the trial feeds well after another day, clear the tube for full feeds.



Monday, April 6, 2015

Measurements in Interventional Radiology

Wires, catheters, and devices often have many measurements associated with them. These can often be confusing as each type of device uses its own measurement with its own unit. This post goes over some of the basic measurements one may encounter in the interventional radiology suite.

Needle Measurements

Needles, specifically hypodermic needles, are measured in a unit termed "gauge" (abbreviated G).  Unlike other measurements, a higher gauge number indicates a smaller needle. The gauge refers to the outer diameter. Typical needles encountered in IR include a 21 G needle to do micro puncture access, a 19 G needle to do direct access or transjugular liver biopsies, and 18 G needles to draw up medications. As an example, a 21 G needle has an outer diameter of 0.03225 in (0.8192 mm) and an inner diameter of 0.02025 in (0.514 mm). For more detailed measurements, see this needle gauge chart


Wire Measurements

Guide wires are typically measured in inches of thickness. Using the example above for a 21 G needle, one can see that an 0.018 inch wire can pass through a 21 G needle, because 0.018 inches is less than the inner diameter of 0.02025 inches. Similarly, an 0.035 inch guide wire can pass through a 19 G needle. For more detailed comparisons of wires, use this comparison chart to compare up to 5 wires at a time. 


Catheter Measurements

Catheters are often measured using the French scale, often abbreviated "Fr". A catheter of 1 French has an external diameter of 1/3 millimeter (mm). Therefore, a 3 Fr catheter has an external diameter of 1 mm. 

Source: "French catheter scale" by Glitzy queen00. Licensed under CC BY-SA 3.0 via Wikimedia Commons

Sheath Measurements

A sheath is used to stabilize access within a vessel. While also using the French system for catheters described above, the designation here indicates the largest French catheter the sheath will accept. So, a 6 French sheath will accept up to a 6 French catheter.

Other devices such as coils or TIPS shunts have measurements specific to them, which should be carefully considered before use. 

Monday, March 30, 2015

How to Place a Chest Port

Oncology patients often need long term central venous access for administration of chemotherapeutic drugs. The procedure below utilizes the 8 Fr Bard PowerPort, but the steps are generally the same for any type of port. Before starting the procedure, review the patient's history and recent labs, in particular the type of cancer, and any relevant imaging. If the patient is likely to have radiation to the right chest (for example, with right breast cancer), consider left chest port placement.
  1. Under ultrasound, visualize the right internal jugular vein, which should be compressible (unless thrombosed). The pulsatile carotid should medial/posterior. 
  2. Anesthetize the skin with 1% lidocaine without epinephrine. 
  3. Advance the 21G micropuncture needle into the jugular vein. 
  4. If there is spontaneous venous return, advance the 0.018 inch microwire to the caba-atrial junction under fluoro.  
  5. If no return but likely in vessel, attach connection tubing and aspirate. Dark blood should flow back easily.
  6. If bright red / pulsatile return, the needle is likely within the carotid artery, so withdraw the needle and hold pressure for 2-5 minutes. 
  7. Once access is gained, make a skin incision along the needle and then blunt dissect using the curved Kelly. 
  8. Exchange the needle for the 5 Fr micropuncture sheath and hub it. 
  9. Remove the inner 3 Fr stylet and the micropuncture wire, holding your finger over the 5Fr lumen. 
  10. Insert 0.035 in J wire and advance into the inferior vena cava. If the wire does not go straight down, consider whether it is in the aorta or in the pleural space. Take care not to irriate the atrium (will cause premature ventricular contractions). If difficult, ask patient take deep breath and hold, then advance. Make sure the J is facing right/posterior (take-off of inferior vena cava from right atrium). 
  11. Once the J wire is in the inferior vena cava, ask for the port and catheter. Flush the peel away sheath, and the catheter itself. 
  12. Mark the port pocket on the patient's chest (rule of thumb: 2-3 fingertips below the clavicle). 
  13. Anesthetize the entry point, make an incision using a #15 blade, anesthetize the pocket and tunnel, then blunt dissect both. The incision should be just long enough to fit the port, usually about 3 mm extra on each side. Lidocaine with epinephrine can be utilized to minimize bleeding in the deeper tissues. The pocket should be deep enough so that the port sits on the pectoralis fascia.  
  14. Attach the tunneling device and tunnel to the venotomy site in the neck. Pull the catheter such that about 15 cm are out at the venotomy site. It is easier to pull back the catheter later than to advance it.  Cut the tunneling device and a small amount of attached tubing off, as it is sometimes difficult to manually remove the tunneler. 
  15. Insert the peel away sheath and hub it. 
  16. Pull out the inner obturator and wire. The valve should maintain hemostasis. 
  17. Insert the catheter as far as possible through the peel away, then remove the valve and break the peel away sheath. 
  18. Peel the sheath away while applying pressure to the catheter to keep it subcutaneous. 
  19. Check positioning - pull back slowly until the tip is at the cavo-atrial junction. 
  20. Cut the excess catheter tubing. Carefully attach the proximal catheter to the port and secure it with the fastener. Suture the port in place (optional). 
  21. Attach a Huber needle and check that the port aspirates and flushes appropriately. 
  22. Close the incision using 2-O absorbable suture for the deeper layer using inverted or reverse horizontal mattress knots, and then the skin with 3-O running suture. Use Dermabond at the venotomy site and over the port incision. 
  23. If the patient is going directly to an infusion, leave the Huber needle attached and covered with a dressing. 
Source: Bard


Sunday, March 22, 2015

How To Place A Tunneled Dialysis Catheter (Permcath)

A common request for an interventional radiologist is placement of catheters, in particular a tunneled dialysis catheter (also known as Perm-A-Cath or Permcath). Here is one approach to placing the catheter via the right internal jugular vein. The approach utilizes an AngioDynamics dual lumen central venous catheter that measures 23 cm tip to cuff (28 cm tip to ports).
  1. Check the patient's height. If between 5 ft (150 cm) and 6 ft (180 cm), in general use a 23 cm tip-to-cuff AngioDynamics tunneled hemodialysis catheter. 
  2. Under ultrasound, visualize the right internal jugular vein, which should be compressible (unless thrombosed). The pulsatile carotid should medial/posterior. 
  3. Anesthetize the skin with 1% lidocaine without epinephrine. 
  4. Advance the 21G micropuncture needle into the jugular vein. 
  5. If there is spontaneous venous return, advance the 0.018 inch microwire to the caba-atrial junction under fluoro.  
  6. If no return but likely in vessel, attach connection tubing and aspirate. Dark blood should flow back easily.
  7. If bright red / pulsatile return, the needle is likely within the carotid artery, so withdraw the needle and hold pressure for 2-5 minutes. 
  8. Once access is gained, make a skin incision along the needle and then blunt dissect using the curved Kelly. 
  9. Exchange the needle for the 5 Fr micropuncture sheath and hub it. 
  10. Remove the inner 3 Fr stylet and the micropuncture wire, holding your finger over the 5Fr lumen. 
  11. Insert 0.035 in J wire and advance into the inferior vena cava. If the wire does not go straight down, consider whether it is in the aorta or in the pleural space. Take care not to irriate the atrium (will cause premature ventricular contractions). If difficult, ask patient take deep breath and hold, then advance. Make sure the J is facing right/posterior (take-off of inferior vena cava from right atrium). 
  12. Once J wire in IVC, ask for catheter. Flush dilators, peel away sheath, and both hubs. 
  13. Lay catheter on patient to judge where to make tunnel. The tip should be near the cava-atrial junction. 
  14. Mark the tunnel entry point on the patient's chest (rule of thumb: 2-3 fingertips below the clavicle). 
  15. Anesthetize the entry point, make an incision, anesthetize the tunnel, then blunt dissect the tunnel. 
  16. Attach the tunneling device and tunnel to the venotomy site in the neck. Pull the catheter all the way through to the hub. It is easier to pull back the catheter later than to advance it.  
  17. Dilate the tract (12 Fr blue, then 14 Fr pink) under fluoro until the tip is at the level of the clavicle, then insert the peel away sheath and hub it. 
  18. Pull out the inner obturator and wire. The valve should maintain hemostasis. 
  19. Insert the catheter as far as possible through the peel away, then remove the valve and break the peel away sheath. 
  20. Peel the sheath away while applying pressure to the catheter to keep it subcutaneous. 
  21. Check positioning - if at caba-atrial junction, fix in place. If too distal, pull back slowly while making sure the cuff stays within the tunnel. 
  22. Flush both ports, give heparin (volume to give on hubs), Dermabond venotomy site, place biostatic pad on tunnel entry site, and then suture to skin with 2-0 silk.
  23. Fold a 4x4 and Tegaderm the port to skin.
Variations on this procedure include measuring using the 0.018 inch wire to get an exact length for the catheter to use and how long to make the tunnel. If the hubs do not flush easily, they may be clotted. Aspirate all the clot out first, then flush. The catheter is ready to use at the end of the procedure, but plans should be in place for the patient to receive an AV fistula by vascular surgery.