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Time Stamps

• 01:09 Pearl 1 – Nuances of Imaging  
• 14:37 Pearl 2 – Pre procedural planning 
• 25:56 Pearl 3 – Drain placement and removal  
• 29:45 Pearl 4 – Troubleshooting Drains 
• 36:09 Pearl 5 – Outpatient IR  

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Show Notes

Pearl 1: Nuances of Imaging

• Bleeding assessment: use MULTI-phase CT imaging
  • To detect an active bleed you need:
    • Triple-phase CT, i.e. CT
      • Includes a non-contrast phase, an arterial contrast phase, and finally, a venous contrast phase.
      • Radiology tech must time the images so that contrast is expected to be in a patient’s circulatory system at 3 separate points in time:
        • The first, non-contrast phase 
          • Baseline to identify pre-existing artifacts that could be confused with a bleed
            • Example: calcifications, pills, or recent PO contrast lingering in the bowels
        • The second, arterial phase
          • Captures contrast after it is injected and pumped by the heart into systemic arterial circulation.
            • If there is “active extravasation” from a brisk arterial bleed, this is the first time that leakage of contrast outside a vessel can show up.
        • The third, venous phase
          • Captures contrast through the venous system.
            • More delayed in time, so radiologists look for persistent blooming/accumulation of contrast in the same area as the arterial phase,
              • This confirms that the bleeding is still active and ongoing, while giving a sense of bleeding rate. 
  • Patients’ cardiac output affects imaging quality (low ejection fraction = slower contrast distribution).
    • Put the EF in the one-liner to help with timing of IV studies.
• Clot assessment: Use Ultrasound or CT Venography (CTV)
  • Ultrasound
    • Very useful imaging modality because you can directly interact with veins and organs by applying pressure and doppler, while also sparing patients radiation and contrast.
      • However, it can be operator-dependent and not as accurate for deeper vessels!
  • CT venogram
    • More accurate for visualizing deeper vessels
      • Example: In the chest, abdomen/IVC, and pelvis.
    • Can be reviewed by multiple providers
  • Clots
    • Acute clots
      • Much softer!
        • “Jello-like” during thrombectomy, which allows them to be easily removed
    • “Chronic total occlusion” (CTO)
      • Does NOT mean an actual blood clot is sitting in the vessel for months to years
    • The pathophysiology of “chronic DVTs” and CTOs:
      • Acute thrombus formation (e.g. a clump of RBCs, fibrin, and platelets) forms –> Body attempts to break thrombus down –> Triggers cycle of clot breakdown and re-clotting –> Scars the inner vessel wall over months to years and fills it with collagenous material, fibrin, and calcifications –> Chronic vessel narrowing or total occlusion!
        •  Body tries to compensate for reduced blood flow through the occluded vessel by forming collaterals over time!
        • May require mechanical scraping to improve blood flow through the lumen!
    • What are the management implications of acute vs chronic DVT? 
      • Chronic, non-occlusive, wall-adherent DVTs do not respond as well to anticoagulation as acute DVTs.
        • However, if patients are asymptomatic, chronic non-occlusive DVTs do not necessarily require IR intervention.
      • CTOs from chronic DVTs will often require intervention for symptomatic relief, even when collaterals are present.
• Contrast considerations
  • IR will usually ask for IV contrast if possible
    • Understanding the vascularity of/around the structures they’re planning to operate on is important!
  • Recent PO contrast administration complicates IV contrast studies!
    • Makes it hard for radiologists to distinguish whether the contrast in the scan is IV or leftover from PO.
      • The patient’s GI motility determines how long it takes to get rid of PO contrast 
• MRI considerations
  • MRI is the superior imaging modality for detecting edema associated with tissue inflammation.
    • Conversely, it can overcall fluid collections because of how sensitive it is.
    • A follow-up ultrasound can help confirm if these fluid collections are drainable.
  • Use MRI spine to confirm the acuity of acute vertebral fracture!
    • MRI can pick up edema along a new vertebral fracture line

Pearl 2: Pre-procedural Planning

• Patient counseling
  • Should this patient get an IR procedure in the first place?
    • Have clear communication with the patient and specialists!
      • Will procedures such as a percutaneous cholecystostomy or nephrostomy tube are likely to be curative or just temporizing?
• Pre-operative labs and orders
  • Standard pre-operative labs include:
    • PT/INR, PTT, platelets, creatinine
  • IR will often still do procedures on patients who have abnormal coagulation studies that do not correlate with their true bleeding risk (e.g. cirrhosis, hematologic malignancies)
• Perioperative anticoagulation
  • The Society of Interventional Radiology (SIR) has an app that provides general guidelines on whether it is safe to continue anticoagulation/antiplatelet agents for specific procedures
    • In general, aspirin is safe to continue.
    • Stronger antiplatelet agents such as clopidogrel or ticagrelor
      • Discuss the risks vs benefits with the IR team
    • While guidelines state that continuation of DOACs is permitted for port placements, it is still unclear if this increases the risk of pocket hematomas.
      • Check with your IR consultants about what their practice is!
  • Procedures with a high risk of bleeding: anything that requires a new puncture into an organ or highly vascular structure
    • Example: new gastrostomy tube, new percutaneous nephrostomy tube, liver biopsy
  • Procedures with a low risk of bleeding:
    • Example: routine exchange of existing tubes, superficial biopsies (ex. Inguinal lymph nodes)
• NPO and sedation practices
  • Two main levels of sedation for IR procedures (may vary depending on individual patients’ pain tolerance/agitation):
    • Moderate/”Twilight” sedation: VAST majority of all IR procedures, usually involving slightly less sedation than a colonoscopy. 
      • IR will administer their own fentanyl and versed intra-operatively
    • Deep sedation/anesthesia:
      • Required for procedures that are:
        • Very painful (ablations)
        • Requires a high degree of precision due to bleeding risk (e.g. proximity to very vascular structures)
        • Patients who have significant comorbidities/are critically ill. 
      • Anesthesiology is required to assist with the titration of sedation intra-operatively to keep the patient still, and to secure an airway if needed
  • Certain patients may be able to get away with local analgesia or very limited single-agent sedation as needed (i.e. fentanyl OR versed)
    • Procedures such as superficial biopsies, temporary central lines, paracentesis, or lumbar punctures
  • Clear liquids up until 2 hours pre-procedurally per anesthesia guidelines
    • Because inpatient IR procedural timing can be unpredictable, consider local hospital policies for inpatients (e.g., clear liquid diet at 2AM, NPO at 8AM)

Pearl 3: Drain Placement and Removal

• What makes a fluid collection drainable?
  • Must have:
    • Defined walls + Internal liquefaction on imaging
    • Phlegmon = interspersed fluid without walls = NOT drainable 
  • Ultrasound, where possible, is the best for confirming liquefaction/drainability without overcalling fluid collections
• When does a drain get put in?
  • Rule of thumb: is the fluid collection > 3 cm in size?
    • If the fluid collection is <3cm, a one-time aspiration is usually enough
    • If the fluid collection is >3cm, a drain is usually required
  • Cases where a drain isrequired:
    • High likelihood of fluid reaccumulation
      • Ex: collection adjacent to the bowel in diverticulitis
    • Viscous fluid during aspiration
    • High suspicion that the fluid is infected
• When does a drain come out?
  • Usually guided by maximum output per day determined by IR
    • e.g. <10cc/day for 2 consecutive days, but always double check with your IR team
  • Resolved collection on follow-up imaging

Pearl 4: Troubleshooting Drains

• Causes of drain malfunctions
  • Common issues:
    • Inadequate drain care or flushing
    • Occlusion from viscous drainage
    • Drain malpositioning or displacement
• Basic troubleshooting steps
  • Drain care:
    • Ask the patient how often they’re flushing the drain at home 
    • Ask nursing staff how they’ve been doing the daily drain care
  • External inspection:
    • Remove the dressing
    • Check for kinks in tubing
    • Ensure the drain is not clamped
  • Flushing drains
    • Use 10cc saline syringe to flush forward (safe for virtually all drains)
    • If resistance/pain/leakage occurs during flush, inform IR
    • Avoid pulling back with syringe (can create unwanted traction and does not necessarily rule out a distal drain occlusion)
  • Consider imaging:
    • Xray of the drain area (for example, a CXR or KUB) to compare the current drain position to its original placement by IR
• Preventing drain malfunctions
  • Regular flushing is key
    • All drains should typically be flushed at least once per day
    • But for more viscous fluid, such as tube feeds,
      • more frequent and regular flushing may be needed. 
    • Consider preemptively talking with nursing staff about their familiarity with caring for different drain types

Pearl 5: Outpatient IR Follow-up

• Discharge planning for patients with drains
  • Consider sending patients home with extra drain care supplies, especially if they are discharging on a weekend or late in the day:
    • Dressing materials
    • Flushing supplies
• Outpatient IR follow-up 
  • Short-term drains (e.g. for an abscess)
    • Follow-up in 1-2 months
    • Evaluate drain output trends
    • Consider imaging to confirm abscess resolution before removal
  • Long-term drains (e.g. PCN, cholecystostomy):
    • Routine exchanges approximately every 3 months
    • If the patient’s clinical  trajectory allows for removal, a capping trial is considered
      • Repeat imaging to confirm that the original cause for drain placement, ex. obstructive hydronephrosis, has resolved
      • What does a capping trial entail?
        
        • Cap the drain so that it can’t drain externally and must drain internally
        • Monitor the patient for at least a week to check for any red flag symptoms:
          • Fevers or chills
          • Pain
          • Other infectious/SIRS-like symptoms
          • Lack of internal drainage (e.g. low urine output after capping a PCN, rising bilirubin after capping a biliary drain)
        • Sometimes, IR will do one final functional study (ex. a nephrogram) to triple-check that things are flowing well before removing the drain

Youtube Videos:

Y-Flush Drainage System

3-way valve flush drainage system

Transcript

Dr. Jeffrey Weinstein: There is a saying in interventional radiology that IR is like a bank robbery. You have to figure out how to get in, get out, and get away with it. 

Dr. Shreya Trivedi: That was Dr Jeff Weinstein, an interventional radiologist at Beth Israel Deaconess. And today we’re talking about the mysteries of IR and IR drains!   

Dr. Olumide Olulade: I can often sense a certain amount of trepidation and nervousness whenever I get a consult about a malfunctioning drain from IM doctors. Part of why I’m excited for this episode is to help demystify the everyday basics of what we do in IR especially since we collaborate so closely with so many other specialties.

Dr. Shreya Trivedi: And that was Dr Olumide Olulade, an IR fellow at Brigham and Women’s Hospital. Welcome to the CORE IM 5 pearls podcast, bringing you high-yield evidence-based pearls. I am Dr. Shreya Trivedi and I am joined by…

Dr. Antonia Chan: Hi everyone! I am Dr Toni Chan, a resident at BI, and I’m excited to explore some pearls about working with IR today – it’s always been such a black box for me.

Dr. Shreya Trivedi: I hear you on that. Well then, let’s get started on our five questions in IR. Make sure to test yourself by pausing after each of the five questions. And remember, the more you test yourself the deeper your learning gains. 

Dr. Antonia Chan: Pearl 1 – Nuances of Imaging  

Dr. Shreya Trivedi: When is an U/S vs. CT vs. MRI helpful before consulting IR? 

Dr. Antonia Chan: Pearl 2 – Pre procedural planning 

Dr. Shreya Trivedi: What factors go into an IR pre-op evaluation? 

Dr. Antonia Chan: Pearl 3 – Drain placement and removal  

Dr. Shreya Trivedi: When do drains go in, and when do they come out? 

Dr. Antonia Chan: Pearl 4 – Troubleshooting Drains  

Dr. Shreya Trivedi: When a patient has trouble with a drain, what are things you can do before calling IR? 

Dr. Antonia Chan: Pearl 5 – Outpatient IR  

Dr. Shreya Trivedi: What does outpatient IR follow up entail, and what does a capping trial of PCN tubes entail? 

Pearl 1: Naunces of Imaging

Dr. Antonia Chan: So I think the IR consult for us often begins with an abnormal imaging finding. I’ve noticed that sometimes they call back and ask for additional imaging, so I wanted to dig deeper into why IR might ask for one scan vs the other. 

Dr. Shreya Trivedi: Let’s start out with one of the more common scenarios: trying to detect where a bleed is coming from.

Dr. Antonia Chan: We sat down with Dr. Quinn Meisinger, an IR doc at UC San Diego who just happens to be President-elect of the Society of Interventional Radiologists.   

Dr. Quinn Meisinger: So one of the most important things for bleeding assessment if you are trying to identify a bleed is multi-phase, usually CT imaging. 

Dr. Antonia Chan: So when I heard that, I scratched my head. I usually just ordered a CTA for a GI bleed.. so what does multi-phase imaging means? 

Dr. Jeff Weinstein: We also need to have a non-contrast study with no IV contrast and no oral contrast to get a baseline as to either are there pills in there with calcium that are bright spots that are already in the bowel or if there calcifications in diverticula the idea is that there can be things that can sort of fake us out and we don’t want to take someone for a procedure that they really weren’t. And then when we give the dye in the arterial phase, we’ll see it in the arteries and then if we see any dye in the bowel that was not seen before we gave the dye that is now seen, that means in the arterial phase of contrast that there’s an artery that’s contributing to the bleeding that’s going into the bowel. And so then that is highly useful for us and then we can watch the venous phase to see if it continues to grow. The venous phase is more delayed in time a grow or we call it blooming or more accumulate, which will give us a census to the rate and confirm that this bleeding is active and ongoing.  

Dr. Shreya Trivedi: So sounds like with Multi-phase imaging – the 1st phase is the non-contrast CT as a baseline image.  In the second phase, the arterial phase where the contrast gets pumped out of the heart. Without that first non-contrast study as our roadmap, it can be difficult to separate active extravasation of contrast from calcifications or existing dense stuff in the bowels like pills or food. If IR does see the contrast, the third phase, the delayed or venous phase, is helpful to confirm that extravasation continues to grow, which gives IR a sense of bleeding rate and ongoing activity. 

Dr. Antonia Chan: And you know the other thing I didn’t appreciate until this episode was how carefully the radiology technicians need to time giving contrast for these CTs.

Dr. Quinn Meisinger: So the patient gets an injection of IV contrast. The CT technologist times it to say it’s about 40 seconds after the injection in the arm. It can be different if they have a picc because then it’s going immediately to the atrium. So the technologist is usually making an assessment based on when to time the ct. Those of you all read cts. You  will see the diagnostic radiologist say, oh, this was not timed appropriately because of whatever. And that’s generally because there’s some sort of thing that they didn’t suspect the patient had heart failure, they didn’t pump out the contrast.

Dr. Antonia Chan: So, that’s a great teaching that timing the contract injection for a patient’s cardiac output could affect imaging quality. That makes sense though, since if a patient ejection fraction is really low, the heart will take longer to pump out the contrast into the systemic arterial circulation and you wanna capture an image that actually has contrast

Dr. Shreya Trivedi: Okay great! Let’s move now into the nuances of ultrasounds. I’ve always wondered how radiologists know whether a clot is acute or chronic when it’s picked up for the first time on imaging and so we sat down with Dr Oz Ahmed, an IR physician at UChicago. 

Dr. Osman Ahmed: Chronic DVT specifically is a misnomer in the sense that if something is truly chronic, like years long, there’s no DVT, the vein is actually  a trace in the sort of scarred down. And when I say a clot, I mean is it any clot, subacute, acute, chronic versus a truly chronic occlusion like what we call a CTO, those true chronic occlusions. And what you actually do see is a ton of collaterals now as an internist or on the medicine side that may manifest as severe leg swelling collateral. That sort of speaks to a very chronic process.

Dr. Olumide Olulade: So when we say chronic thrombotic occlusion, it’s not like there’s hard chronic clot that has been sitting there for five years and just stayed there. The body doesn’t really. Work that way. It’ll always continuously try to dissolve that clot and get it away. But the constant sort of form continuous formation of clot in that particular area, say your femme pop or like your iio femoral, causes the vein to become scarred down and basically destroys the vein.

And so you basically just have really scarred down, narrowed vein wall, , that has now, that doesn’t allow blood to flow through, and then it feeds on itself, right? Because the more the vein continues to scar, the narrower the lumen becomes.

The slower the blood flows, the more likely your you are to form a acute clot there and then it just kind of feeds on itself as a cycle.

Dr. Antonia Chan: And sometimes I’ve had consultants ask for a CT-V for a clot over doppler ultrasound and never fully understood why.

Dr. Jeff Weinstein: So the very long-winded answer is that Usually CTV is going to be very good for sort of the pelvis and the IVC and things that are too deep for ultrasound. Ultrasound is probably good, cheaper without any radiation penalty. And you can interact with the vein itself, put color doppler on it, squish it, look at things to try to define the clot if there is any with ultrasound with the caveat that it is operator dependent. So if they skipped a segment and didn’t take a picture   and there was a clot in there, it’s theoretically possible there could be a DVT, but the operator missed it and going by it. Whereas a CAT scan, multiple people can scroll through, everything’s been saved and so every image can be scrutinized. 

Dr. Shreya Trivedi: Nice, so CT-V is more helpful for looking at clots deeper in the pelvis and IVC. And CT-V does have contrast.

Dr. Osman Ahmed: There’s almost no other really broad indication that I can think of where I would say I definitely don’t need or want contrast. I’d always welcome IV contrast because it allows us to see the vessels and it also allows us, I’m thinking of now nonvascular interventions, abscess strain placement, things like that. Again, it allows you to sort of see the vascularity that you may need to potentially avoid when you do a needle guided intervention, and it also sort of helps evaluate whether something is a mass versus an abscess. Now do we do, now that means we do every single thing with contrast. If the referring service says, look, we can’t give this person contrast, then we do what we can, whether that’s half dose contrast or sort of just evaluate without, similarly, if it’s just a follow-up scan, we placed an abscess drain, now we just want to see what the collection looks like. 

Dr. Antonia Chan: Great! So basically, IV contrast helps us understand vascular blood flow. One caution with getting an IV contrast study is if they’ve just gotten PO contrast. PO contrast could make interpreting everything we just talked about significantly more complicated. I’m thinking about a situation where patient comes in for abdominal pain, gets PO contrast to evaluate for an obstruction, and later develops a GI bleed. 

Dr. Jeff Weinstein: So if they got a regular CT where they were given PO contrast, the bowels already going to be full with bright stuff from the oral contrast they’ve taken and now it doesn’t even matter the phases, we’re not going to be able tell if more bright stuff is going into bright stuff.  

Dr. Shreya Trivedi: Bright stuff on bright stuff!  That would be a tough situation indeed. Just shifting gears to MRI. Sometimes I really wonder how much more helpful an MRI will be over CT or ultrasound, especially since this is a scan that inpatients often end up  waiting for those 1-2 MRI machines.

Dr. Antonia Chan: Yes! I know MRI is great for evaluating soft tissue changes  that’s why you’ll see, for example, MRIs for ligament injuries or MRCP ordered to evaluate for cholangitis when the CT read isn’t a slam dunk. 

Dr. Shreya Trivedi: And when would we really want to know about soft  changes.

Dr. Antonia Chan: Anytime you really need to have a high-res picture of soft tissue anatomy, or look for more subtle signs of inflammation – MRI is really good at those things. So you might see dilated ducts on CT concerning for cholangitis, but the MRCP, which is basically MRI of abdomen focused on biliary and pancreatic system that helps us see any obstructions in the biliary duct like a mass or inflammation surrounding soft tissue or biliary stone, that might be as well characterized on a CT or RUQ U/S.

Dr. Shreya Trivedi: And then on the flip side, MRI does not mean better! 

Dr. Quinn Meisinger: Believe it or not, MR overcalls fluid all the time. It’s so sensitive for fluid. That’s the point of MR T2-weighted. MR SCLs are really sensitive to fluid, so they will very much overestimate the amount of fluid. You may see an MR report on a lumbar spine that recently had surgery and they’ll say, oh, there’s three big fluid collections. So I usually say to providers, get an ultrasound and that actually tells us if it’s drainable or even big enough too. And it probably happens to me about once a week. 

Dr. Antonia Chan: Wow, that’s a pretty helpful tip!  So CT is like a strong flashlight in the woods at night – it gives you a good sense of the major structures but can miss finer details. Whereas MRI is like night vision goggles – it’s incredibly sensitive and picks up the smallest changes, but in that same vein, can lead to more artifacts, like mistaking a rustling bush for an animal.  

Dr. Shreya Trivedi: On the topic of MRI spine findings, patient comes in with a pathologic fracture or concerning vertebral lesions on CT, sometimes a consulting team will ask for  an MRI, but if MRI is supposed to be better for soft tissue, why are we asking for MRI for bone things? 

Dr. Olumide Olulade: So in that case, the way to know whether a fracture is acute is if there is edema. And the only way to be able to see edema is with an MRI, not with a CT or an ultrasound. Usually something like a kyphoplasty    would work best for acute or subacute fractures. If it’s a chronic fracture, you’re not going to be able to treat that with a kyphoplasty most likely.

Dr. Shreya Trivedi: I see, I see. That makes a lot of sense – so if the radiologist sees a line in a vertebra that’s worrisome for fracture, the next step is to check if there’s edema, which you can only get on MRI and which tells you if this is a fresh fracture with acute edema around it that might warranrt IR intervention like kyphoplasty down the line. 

Dr. Antonia Chan: Totally! Lots of good learning points already. Big picture, it seems like so far, we’ve found that not all imaging is equally helpful before consulting IR, with any concern for bleed requiring multi-phase imaging to avoid false positives. It’s also a good learning point for me for how other factors like cardiac output and prior PO contrast administration can negatively impact the quality of your CT images. 

Dr. Shreya Trivedi: So I guess it is important to put their EF in the one liner when ordering a scan!

Dr. Antonia Chan: Finally, MRI can be useful when you really want to check for inflammation or edema not seen as well on CT or ultrasound, but just be aware of its tendency to overcall fluid collections. 

Pearl 2: Pre-Op Planning

Dr. Shreya Trivedi: So, now that we know how to order scans correctly for our IR colleagues, let’s get into pre-op planning. I think a lot of have been here. Patient is really sick, surgery tells you that they’re actually too sick for surgery or just a poor surgical candidate, so we reach out to  IR instead. 

Dr. Antonia Chan: Even before getting into pre-op planning for IR, Dr. Meisinger brought up a humbling reminder on the counseling to patients or families on whether they should get an IR procedure in the first place? 

Dr. Quinn Meisinger: I have to be honest with them, as I say, “Hey there’s your option. You’re a cholecystostomy tube, you’re an 88-year-old with congestive heart failure and you’ve had a bunch of MIs and you’re on an intense anticoagulant that we can’t take you off for this procedure. So yeah most surgeons wouldn’t want to operate on somebody with that kind of morbidity. But I say, and I have to be honest with them as I say, Hey, this is going to probably save your life in the temporizing, but you may have this tube for life. And so that is something that’s usually lost with patients is that they think that we may be fixed them temporarily, but then comes the issues postoperatively when patients have tubes for the rest of their life. So we do a lot of tube maintenance of course as well, but often that’s something where we tell patients where they show up down in the interventional suite or we see them on the floor and say, Hey, you’ve been sent for a PCN, did you know you’re going to probably have this for the rest of your life? And they say, oh, we’ve never been told that. So that’s part of our informed consent as well is expectations with how patients are going to do. So we tend to have a lot of patients that we’re just delaying potentially death, not necessarily always saving them.

Dr. Antonia Chan: What a good reminder on our part in the expectation-setting. I’d hate the idea of a patient getting all the way down to the IR suite before realizing a drain is going to be permanent, or a procedure is just going to prolong their suffering if that’s not what they want. 

Dr. Shreya Trivedi: And I think some of that comes with IR and tubes being a black box and hopefully this episode will help us with our counseling or anticipate some of these questions and ask for ex. urology if they think the indication for the PCN tube is temporary or more permanent. Will you be talking to the patient about it or should our team? What do you think is the best for this patient?

Dr. Antonia Chan: Let’s say the patient is counseled appropriately,  let’s get into nuances of pre-procedures. Let’s chat about pre-op labs, AAC and NPO/sedation. Obviously grab the things that will affect bleeding risk and renal function, the PT/INR, PTT, platelets, and creatinine. 

Dr. Shreya Trivedi: Speaking of coags, I just want to clarify for patients with advanced cirrhosis or hematologic malignancies, their coags won’t look pretty and thankfully coags may not correlate to actual bleeding risk.  

Dr. Quinn Meisinger: The biggest thing that you’ll see in terms of the change from when the first guidelines came out in 2011 to 2019 updates is really our liver failure patients and our low risk procedures. I’ll do a bone marrow biopsy with a platelet of one because these patients usually have MDS or some sort of leukemia or  something that’s going on with regards to their hematologic malignancy. And so they need to get it. And their bleeding risk is very low. Paracentesis, I really don’t care what their INR platelets are, particularly if they’re cirrhotic. If they need it, they need it.     

Dr. Shreya Trivedi: Of course, at the end of the day, comfort with the pre-op labs is up to the proceduralist and different viewpoints. 

Dr. Jeffrey Weinstein: IR can be wildly different. The complexity, the tools that they use, the approach that they use can have different levels of risk and sophistication. And not every hospital has the same tools and so they may do things differently.  

Dr. Antonia Chan: Now on the do we stop the blood thinner the night or the morning of, of course it is helpful to talk to our IR colleagues what they feel comfortable with. There is a beautiful infographic from the Gray Matters episode on afib that summarizes the 3 helpful branch points to think about 1) how pressing is the indication for the blood thinner 2) what are the suggested days to hold that particular AC and 3rd) how high risk is that procedure.

Dr. Olumide Olulade: So I would say that whenever you’re making a puncture from outside the body and you’re puncturing an organ, that is a high bleeding risk procedure. So any kind of a new gastrostomy tube, a new PCN, new cholecystostomy tube, these are all high bleeding risk procedures that require any kind of percutaneous biopsy. A liver biopsy, for example, is a high bleeding risk procedure, a lymph node biopsy, if it’s very superficial and it’s in the inguinal region, for example, that’s not a high  bleeding risk procedure because lymph nodes are not super vascular. And so in general, yes, any kind of new puncture will be a high bleeding risk procedure. A routine exchange of A PCN or any kind of tube is not a high bleeding risk procedure, and probably anticoagulation does not need to be stopped for those.  

Dr. Antonia Chan: Definitely appreciate that rule of thumb for how high risk is a procedure. 

Dr. Quinn Meisinger: There’s an SIR,  Inter Society of interventional Radiology app for all the guidelines in terms of how we manage anticoagulation. However, we’ve changed one thing, and that’s generally our management of portsThe guidelines say, oh, you can continue DOACs and stuff like that  for ports where we found, a lot of times patients get hematomas within their port site pockets and stuff like that. So we tend to be a little bit more conservative.  

Dr. Antonia Chan: I have the SIR app on my phone and it really does AC for every single IR procedure and more and it even cover abx for some of which is interesting.

Dr. Shreya Trivedi: Yeah, we get no kickbacks for shouting that app out. And I appreciate that point of caution for DOACs in    management of ports. What about antiplatelet meds? Aspirin and say clopidogrel?

Dr. Quinn Meisinger: We pretty much rule platelet inhibition. So like aspirin and Plavix, most of us will do majority of procedures regardless of whether or not they’re on it. Obviously aspirin, much lower risk in terms of that, in terms of Plavix. And then of course we’re getting into the more higher powered platelet inhibitors like Lenta and stuff like that. But there is a risk assessment on us, and most IR providers don’t care about aspirin if they’ve been on it.  

Dr. Shreya Trivedi: Really surprised to hear doing  procedures on plavix. The teaching point is In low-risk procedure, IR guidelines say to not stop of any AC or antiplatelets. Low risk things typically things in the vein like an IVC filter, LN bx, a port placement. But of course, the caveat to this all, regardless of SIR guidelines say about pre-procedural AC, they’ll still be colleagues who might not feel comfortable doing the procedure on Plavix so would just check-in with your local IR team. 

Dr. Antonia Chan: Before we wrap up our second pearl, I feel like we have to talk about making patients NPO. I always feel so terrible for our inpatients, who are starving from midnight to sometimes 4pm, sometimes multiple days in a row while they’re waiting for an IR slot to open up. 

Dr. Shreya Trivedi: Absolutely! I mean, the American Society of Anesthesiologists has guidelines from 1998 saying that  clear liquids up until 2 hours prior to sedation on low aspiration  risk  patients is okay. I think the harder part inpatient is that we can’t always predict when someone is called down.   

Dr. Antonia Chan: One win i’ve seen at some medical centers they’ve updated local policies to say ok for clear liquid diet at 2AM and NPO at 8am for procedures where moderate sedation is required, so patients  can have a clears tray with coffee for breakfast at least. 

Dr. Shreya Trivedi: Speaking of moderate sedation (and some may call it conscious sedation aka twilight sedation), could we talk about the different types of sedation required for IR procedures?  

Dr. Antonia Chan: So let’s start with moderate sedation. We can tell most patients as a  benchmark, it’s a little less  intense than what they’d be getting for a routine colonoscopy. 

Dr. Osman Ahmed: I think our version of moderate sedation may be less than I think a lot of other specialties, because this is just more anecdotally talking to my GI colleagues and stuff. Their version of moderate sedation is five of verse said and 300 of F or something. For us, it’s like one  or two milligrams of  ED and a hundred mics of fentanyl, and that’s sort of a typical patient.

Dr. Shreya Trivedi: So most things in IR are moderate sedation or minimal with one sedative agent usually, then.. Then falls under deep sedation? I feel like I always have patients ask if a procedure will entail tube in their throat? 

Dr. Osman Ahmed: Oh yeah, yeah. Anything where there’s a needle going through an organ, not a biopsy, but we’re connecting a hepatic vein or a portal vein, and it’s in a lot of ways it’s kind of like a blind stick and things like that where you basically need the patient very still, there’s a precision needed there. The ablations tend to hurt, tend to be painful, and you also need patients to be really still. So almost all of our  ablations are done with general anesthesia. And then again, some of this stuff also depends on comorbidities even then for an IR procedure, they may be too sick to get moderate sedation. So those patients a lot of times will also get anesthesia consults for as well. Like portal vein, recanalization, IVC, recanalization, anything near the heart where you’re taking needles, so like SVC sharp recanalization, things like that where there’s a real chance of death” 

Dr. Shreya Trivedi: Yep when there is a real chance, definitely good to have anesthesia on board .

Dr. Antonia Chan: So  just to recap our second pearl: Before your patient goes for an IR procedure, talk with them or other consultants who may be asking for an IR intervention about how the short-term  benefits fit within their long-term goals of care. Ask your consultants around pre-op labs and holding anticoagulation but know that the SIR app can be a useful resource as well. And finally, it never hurts to ask our IR colleagues about what the sedation plan is and how we can avoid unnecessary NPO time, knowing they can be NPO 2 hours before their procedure if it’s moderate sedation.   

Pearl 3: Ins & Outs

Dr. Shreya Trivedi: For our next pearl, we wanted to ask – when do drains go in, and when do they come out? But first things first, how do we even know if something we see on imaging is amenable to drainage in the first place?

Dr. Quinn Meisinger: So yeah, the biggest thing in terms of CT is when you see a fluid collection is there actually a component of walls. So when a lot of radiologists use the term phlegmon, phlegmon usually means just fluid. That’s kind of interspersed. That generally means that there’s not a vocalized collection that allows us to put a drain in or actually say it. I will say, let’s get an ultrasound of that area, we need to see if it’s liquified because you can’t put a drain as things are developing. So the biggest thing is making sure there’s liquefaction and it’s something that’s rounded or walled off.

Dr. Shreya Trivedi: Okay, so the main things to know when we consult IR for a potentially drainable collection are that to be successful, it needs a component of walls with internal liquefaction – otherwise, it’s just phlegmon, or interspersed fluid not amenable to aspiration or drainage. 

Dr. Antonia Chan: Yes, I feel like sometimes we send a patient down to get an abscess aspirated and they come back with a drain we didn’t expect! 

Dr. Quinn Meisinger: Drains generally are left behind when there’s infected fluid or we think the fluid’s going to reaccumulate. I usually if it’s under three centimeters, we’re probably just going to try to aspirate it and just remove the fluid and not leave a drain. However, there’s circumstances where we suspect fluid is going to reaccumulate, so if it’s adjacent to the bowel for diverticulitis and I think that there’s potential leakage coming from the bowel, we generally place a drain regardless of the size […] And so definitely if it’s infected, definitely if it’s large, definitely if it’s viscous, we usually need a drain to do that, so we’ll  place the drains. 

Dr. Shreya Trivedi: Okay less than 3cm or so we can feel more comfortable it will be a one and done aspiration event. 

Dr. Antonia Chan: Yes and typically where those scenarios are happening with a drain being left in when  we didn’t expect that’s because there’s a high chance of reaccumulating infected fluid (i.e. next to the bowel in diverticulitis), or when they’re aspirating they notice very viscous fluid that is harder to drain in one shot and needs a drain in place for a longer time . So that may lead a drain to be placed regardless of abscess size. 

Dr. Shreya Trivedi: But it’s good to leave patients with some room of flexibility. Our reviewer, Dr. Pavlus also memorably said “We often triage by radiology these days. And the read may say one thing but once they get in there, their assessment may be different”. 

Dr. Antonia Chan: And then once they get a drain in, the patient, nurses, CM, etc will be asking when is that drain coming out? Of course that is very dependent on the reason for the drain.  

Dr. Shreya Trivedi: I always like asking IR what we should be shooting for and a lot of times it’s they page us when the drain has, less than 10 ccs per day for 2 days and we will come up and  take the drain out or we need repeat imaging to look at the interval change on this one.

Dr. Antonia Chan: Okay so to recap what I want people to takeaway is that dont be so surprised  when a patient comes back with a drain and be curious if it’s because when IR got the abscess was >3cm or bc it was in an area with a chance reaccumulation or was more viscous fluid that couldn’t be drained out with one aspiration.

Pearl 4: Troubleshooting Drains

Dr. Antonia Chan: Now we get to my favorite part of this episode – troubleshooting drains! I think there is a lot of nervousness around c aring for drains both for the clinicians as well as nurses.

Dr. Shreya Trivedi: Yeah I’ve definitely been there where I feel at a loss when I got a page that a drain is clogged or became painful for the patient and I think a lot of that irritation came from being expected to know about it and having knowledge gaps.

Dr. Antonia Chan: Yes, we are all learning here. Dr Olulade also has a really good summary on how to troubleshoot malfunctioning drains if someone from IR can’t come by immediately to help. 

Dr. Olumide Olulade: So, as an example, I was on rotation at some point, and I got a call mid case about a patient whose PCN was suddenly not draining anymore. And so came out of the case, called back and said, oh, did you flush the tube? I don’t know how to do that. What’s the response that I got back? And I was like, Hmm, okay, sounds good. Did you look at the tube? And they’re like, well, I don’t know how to evaluate a tube. So I would say that that’s something that any clinician really can do is troubleshoot a tube. And I would say when I went to go see that patient finally to go find out what was going on, what had happened was that they had redressed, they had changed the dressings on the tube, and in changing the dressings on the tube, they basically folded the tube onto itself and it was just kinked under the patient. And so all that needed to be done was basically undress it, take off the kink and just dress it back. I think that that’s possibly a delay in patient care, right? Because you have a patient who suddenly doesn’t have any drainage from the tube, and the only reason is because it’s kinked underneath them, or it’s clamped in some kind of way, and they forgot to UN clamp it after flushing it. We as IRs, we may not have the opportunity to get to that patient’s bedside immediately. And I have seen patients come through the emergency room who have clamped drains and are getting septic from that, and it’s sort of like, whoa, all you had to do is just UN-clamp this and it would be fine. And so I think that there is a lot of benefits to any clinician being able to do the basic troubleshooting of an IR drain, which is basically, well, what does the tubing look like? Does it flush well? Is everything kinked? Are there any, is anything clamped in it? 

Dr. Antonia Chan: Say we’ve checked the PCN externally though, and it’s 1) not kinked and 2) already unclamped, but still painful or not draining. How do I know that there isn’t a blockage, or that the drain hasn’t come dislodged? Is it still safe to flush? 

Dr. Olumide Olulade: Flushing really is just take a 10 cc syringe, attach it to whatever flushing mechanism that comes with the drain, and open up the port so that the fluid flows towards the drain and push. And if you get a lot of resistance or if the patient has pain with that, or if it starts to leak from the site where the drain is going into the patient’s body, then you know that something is going wrong. But if it flushes smoothly, everything’s flushing forward, fine, then at least you’ve ruled out certain things, which is very helpful for us to know when we get the consult that, oh, a particular drain is not working well 

Dr. Quinn Meisinger: So most tubes when they come through, particularly for biliary abscess and urinary, it’s usually related because the tube is somewhat occluded from viscous fluid crustaceans, things like that. So usually you need to flush daily to maintain patency. 

Dr. Shreya Trivedi: Yeah i remember this well in the tube feeds episode where the GI doc talked about how patients often get discharged on tube feeds and then come back the next day in the ER bc they were told to flush after the tube feeds went through their G tube or whatever enteral access they have and maybe their Price Is Right or another good show, the feeds kind of get stucky in the tube and by the time they get around flushing, we have a problem

Dr. Olumide Olulade: I would say that a good rule of thumb is if you are draining something that’s very thick, if you’re draining molasses, something that’s a molasses texture that’s more likely to get stuck in your drain and clog up your drain, I would probably flush that more often. If you’re draining urine, then you can probably flush that less often, I would say once a day for something like that. 

Dr. Shreya Trivedi: Okay at least try 10cc flush. But honestly, it can be hard to visualize these things just listening over a podcast, so see the show notes for some pictures on what a clamped vs unclamped PCN looks like.  

Dr. Antonia Chan: We did want to clarify for listeners that aspirating fluid aka pulling back with the syringe to see fluid return is less helpful to IR – just because you get something back doesn’t rule out a blockage further down in the drain, and it can create unwanted traction if there is a malfunction.  So takeaway is to try flushing but less utility to aspirating! 

Dr. Shreya Trivedi: And then what do we do if flushing doesn’t fix things, say for example with a PCN?

Dr. Olumide Olulade: And then at the worst case scenario, then as a first line, you can also get a KUB, which is something that I often will recommend as the first line of imaging, because remember we take a picture of where the tube was at the end of the procedure. And so if you get a KUB and you compare the two and you see that the tube is completely retracted out or something like that, then we know that that’s something that is probably going to require some kind of intervention, whether urgent emergent or routine to be quite fair 

Dr. Shreya Trivedi: Just to recap our 4th pearl: IR may not always be able to see our patients right away, so it’s really helpful to check the basics: make sure the tube isn’t improperly clamped, and have a low threshold to flush it with a 10cc syringe. Then go to imaging where the drain is can also be very helpful for IR, since it allows them to compare with prior imaging and evaluate if the drain has migrated in some way. Finally, be sure to check in with patients and nursing to make sure they feel comfortable with managing drain flushes on their own, to help prevent future clogging of the drain. 

Pearl 5: Outpatient IR

Dr. Shreya Trivedi: While we’re at it, we should touch briefly on outpatient IR follow up as well. What are things we should know when discharging a patient who needs to follow up with IR?  

Dr. Olumide Olulade: So I think it never hurts to give patient supplies when they go home. I think that we never take, or I personally do not take for granted the fact that you’re putting a drain that’s going to be sticking out of somebody’s body and they’re going to have to go home and live with this somehow I think that dressing supplies are always helpful in case the patient wants to change their dressing at some point. Flushes I think are also very helpful because patients do tend to run out of flushes very quickly, or they’re not able to pick up flushes the very same day that they’re going home. Maybe they’re getting discharged at night or something like that.  

Dr. Shreya Trivedi: That’s a really good tip especially given how important regular flushing of drains is. We do our best to set up VNA services and I know IR often leaves detailed drain care instructions in their notes, but things don’t always go exactly as planned once patients leave the hospital or they get discharged on a weekend day.

Dr. Antonia Chan: Especially with discharging patients with drains, I feel better that they will have IR follow up. I’m curious how IR makes that determination of whether and for how long a patient needs outpatient follow up with them.

Dr. Olumide Olulade: As it relates to drains, it really depends on what type of drain it is. Say it’s a short-term drain for an abscess, we would potentially see that patient in clinic after a month or two to say, Hey, what’s your drainage output? Has it gone down? Which would give you a sense that like, oh, this has healed, and then they can come into IR clinic and we can basically maybe you do some imaging to make sure that the abscess is truly gone, or you use your clinical judgment of like, oh yeah, it’s been enough time and we’re fairly sure that this is done and we can just remove the drain in clinic at that point. In terms of drains that are staying in for the medium to long-term, say like percutaneous chole cystostomy tubes or percutaneous nephrostomy tube, those patients, those drains are exchanged with us every three months to sort of reduce the risk of infection and also just to defer the possibility that the drain starts to malfunction or gets moved around and things of that nature.

Dr. Antonia Chan: So then how does IR determine when the drain can come out? I’ve heard IR ask for capping trials for PCNs or biliary drains – but what does that entail?

Dr. Olumide Olulade: But this is a situation where I think that having that sort of multidisciplinary understanding of what’s going on with the patient, especially from an IR perspective, is very important. And so when the patient comes in, you’re always discussing with them, what has your cancer done in the meantime? Has it shrunk? Is there a possibility that we could do what we call a capping trial, which is basically to send you out with the drain capped, basically with a cover on it so it’s not draining outside. If we have a decent sense that things are draining inside, and we do some intraprocedural imaging to sort of evaluate  this first. And so in those kinds of situations, we may initiate a capping trial where the patient goes home for a week or two with the drains capped, and if they do well with that, no fever, chills flank pains or anything like that, then we have, and they’re making very good urine, then we have a good sense that, oh, this is a drain that may be able to come out. And then we bring them back within one or two weeks, we bring them into angio suite, we do a nephrogram to make sure that things are flowing well, and as long as things are flowing well, then we can take up the drain at that point.  

Dr. Antonia Chan: Gotcha – so it’s a combination of imaging to confirm the original problem has resolved, capping the drain and monitoring the patient for at least a week to make sure they can drain internally without issues, and finally a functional IR study like a nephrogram to triple check things are flowing well before taking the drain out permanently.

Dr. Shreya Trivedi: On the flip side, if the reason they had the drain is the first place isn’t resolved, that will certainly declare itself.

Dr. Olumide Olulade: The way that I think about this is anytime there’s fluid in the body that’s not moving, it’s a nidus for infection. There are two things that happen. The body’s reaction to that is the first thing or the organ getting stressed by the fluid, that’s not moving, getting distended, pushing on the parenchyma, and your body’s natural reaction to that is to say, Hey, it’s pain, so flank pain, side pain, whatever the case may be in that particular organ, right? The second thing is if that continues to fester, then you get a local infection in that area and then eventually that infection placed spreads to the bloodstream and then you get your sort of SIRS reaction to that. And so I would say that pain, fever, chills, those are the things with a non draining system, those are the things that usually trigger us to say, Hey, you probably should come into the emergency room to get evaluated.

Dr. Antonia Chan: Okay, so let me take a stab at trying to synthesize everything we’ve learned this episode through a patient case. Let’s say you have an oncology patient who gets admitted for vague symptoms and had a CT that showed pyelonephritis from a new obstructive retroperitoneal mass. The team talks with the patient about a long-term PCN for source control, and they agree that it’s in line with their goals of care. IR does the procedure the following afternoon, and the patient’s able to drink some coffee for breakfast. Fast forward several months, and unfortunately the patient comes back into the ED from home complaining of fever and decreased drainage from their chronic PCN. What next? 

Dr. Olumide Olulade: I would investigate and try to figure out what is causing this patient to have pain? What is this patient causing this patient to have fever? Is the drainage adequate? Do they need a bigger drain in their kidney, for example? Right. Unlikely. Most of the time, whatever drain is put in is usually going to be adequate. In those situations, I will basically check, troubleshoot the drain and make sure that it’s functioning as perfectly as I need it to function, which is, is it flushing very smoothly? Is it getting normal drainage out? I may even get a KUB again, just to sort of look and see is it in the right place? And if all those things check out, then my index of suspicion that the patient’s drain is the culprit for causing the fever, for example, starts to go lower.

Dr. Shreya Trivedi: What a journey, what a great example of being before jumping the gun as to why the patient developed SIRs again, go back to the basics and check the drain.

Dr. Antonia Chan: And that brings us to the end of this episode! 

Dr. Shreya Trivedi: If you have ever gotten any value from the podcast, our ask is to please please please share this with at least one other colleague who might also get something out of the episode

Dr. Antonia Chan: Thanks to Dr. John Pavlus,  Dr. Yan Yepelboym and Dr. Adam Strauss for reviewing this podcast. Thank you to Ivanna Tang for the accompanying graphics. This episode was made as a part of the Digital Education Track at BIDMC.

Dr. Shreya Trivedi: Opinions expressed are our own and do not represent the opinions of any affiliated institutions.