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BioSentry Plug vs Blood Patching: Preventing Pneumothorax After Lung Biopsy
Rajat Mohanka • Updated Jul 17, 2023 • 532 hits
CT-guided lung biopsy is used to classify various lung nodules pathologies, which are then used to guide management strategies. While the procedure is relatively safe, complications such as pneumothorax can occur. Interventional radiologists need to understand how to prevent pneumothorax during this very common procedure.
When observing for lung biopsy complications, there are various practices that can be employed. Some practitioners opt for the “wait and watch” approach of observing the patient with multiple chest x-rays to monitor for pneumothorax. Other practitioners observe for air leaks during the procedure itself and use sealant technology to close up the visceral hole created by lung biopsy.
Currently, there are two techniques that can be implemented to close up the visceral hole at the end of a lung biopsy procedure: (1) blood patching and (2) hydrogel plug. According to Dr. Robert Suh, interventional radiologist with the University of California Los Angeles, these methods have similar outcomes in terms of efficacy and safety. Throughout this article, Dr. Robert Suh compares the two methods and how to implement them in practice. This article features excerpts from the BackTable Podcast. You can listen to the full episode below.
The BackTable Brief
• A hydrogel plug is a polymer that fills the visceral hole created by the lung biopsy procedure.
• Dr. Suh recommends monitoring for active air leaks while the patient is on the table and treating leaks as they occur.
• The traditional post-procedure protocol for lung biopsy requires three to four hours of patient observation and multiple chest X-rays to monitor for pneumothorax. Dr. Suh shares his new protocol where he sends patients home within 30 minutes of the lung biopsy procedure.
• According to Dr. Suh, blood patching and hydrogel plug have similar outcomes when it comes to preventing pneumothoraces. The two techniques are equally safe and effective.
Table of Contents
(1) What is the BioSentry Hydrogel Plug?
(2) Indications for the BioSentry Plug
(3) Observing Lung Biopsy Patients For Complications: The Traditional Protocol
(4) Managing Pneumothorax after Lung Biopsy
(5) Parenchymal vs Pleural Blood Patching
What is the BioSentry Hydrogel Plug?
Dr. Robert Suh explains that the BioSentry hydrogel plug is essentially a polymer with a highly desiccated composition. He describes it as a small, straw-like structure measuring about 2.5 centimeters. The hydrogel can be primed by adding saline or lidocaine to the deployment well. Once inserted, it absorbs moisture from the tissues and expands fully within five minutes. Dr. Suh emphasizes that the hydrogel expands in both length and width, effectively sealing the parenchymal and visceral pleura holes. Hydrogel can be introduced through the same needle that’s used for the biopsy, using either a 19-gauge or 17-gauge introducer needle. The plug is pushed down to a depth that spans approximately 2 centimeters within the lung or subpleural lung, with around 5 millimeters extending outside. As the plug grows, it bridges the lung and pleura.
[Dr. Christopher Beck]
Okay, what exactly is the hydrogel? Is that too technical of a question?
[Dr. Robert Suh]
No, it's basically a polymer as anything else and it's really highly desiccated so it's like a little straw about 2.5 centimeters and you can prime it by putting a little saline or lidocaine in the well as you're deploying it but it's supposed to pick up the moisture from the tissues, and within five minutes, it should fully expand. It's about four times the volume, it grows in length as well as in width to plug that parenchymal but more importantly, the hole in the visceral pleura.
[Dr. Christopher Beck]
Does it go through just the introducer needle that you had in for the biopsy?
[Dr. Robert Suh]
Correct. That goes with the 19 gauge introducer but you can also use the 17 gauge introducer. There's a handle that you set the skin to pleural depth and then it pushes the plug down where ideally with a 2.5 centimeter plug, 2 centimeters is within the lung or the subpleural lung and then about 5 millimeters hangs out. As that grows it crosses both the lung and the pleura.
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Indications for the BioSentry Plug
Dr. Christopher Beck and Dr. Robert Suh engage in a discussion regarding the post-biopsy process. Dr. Suh shares a notable shift in his approach, describing his transition from utilizing blood patching to employing the BioSentry hydrogel plug in all of his lung biopsy cases. Notably, Dr. Suh explains that he is now able to discharge patients within 30 minutes of the lung biopsy procedure without the need for an additional X-ray.
[Dr. Christopher Beck]
Once you've taken your samples, you have good tissue, either by pathology or just your Gestalt cases done, pull the needle, blood patch, anything else?
[Dr. Robert Suh]
Well, okay, the blood patch. So, I think majority of people just pull the needle out.
[Dr. Christopher Beck]
I think you're completely right.
[Dr. Robert Suh]
Then they just maybe put the patient to pend-in and hope for the best. Historically, I've used the blood patch and maybe it's because I did my residency and interventional radiology fellowship at Loma Linda, and one of the earliest if not the first papers on blood patching came out of Loma Linda by a guy named Ronald McCartney. But in '74 and '75, he described in two papers the blood patching technique in the first and then I think they ran a series of 50 patients in the second.
For very long, I've used the blood patch just because of how I was trained and my familiarity with it, and that all started to change in the mid-2000s. We participated in a trial for the hydrogel plug called Bio Seal back then. After the trial, the plug disappeared and then eventually resurfaced after it was FDA approved in 2013, and it was called BioSentry, not BioSeal anymore.
And so we did some work with the BioSentry and having some familiarity with it and what I started to do with that was to put it in every biopsy where we crossed lung, and then I kept the same follow-up routine in some patients for the first 50 I think, then I started to ratchet the observation time downwards. Today, I pretty much put the BioSentry in every patient, I keep the patient on the table for 3 to 5 minutes and then we do our posts and if there is no pneumothorax and it was an uncomplicated straightforward biopsy, I just send the patient home within 30 minutes, and I don't even get a chest X-ray.
[Dr. Christopher Beck]
Okay, the other thing I wanted to ask you about and this was what really grabbed my attention, because I'll just tell you in our practice whether we do blood patch routine complicated, it's three hours hold, one hour chest x-ray and then the a three hour chest x-ray and if that one looks good they can go. You're sending some of these patients home 30 minutes after biopsy, basically just enough to let the anesthesia wear off, no x-ray?
[Dr. Robert Suh]
That's correct.
Observing Lung Biopsy Patients For Complications: The Traditional Protocol
Dr. Suh explains that while his approach may differ from others in his group, the typical procedure involves placing the patient in an observation position with the dependent side down for approximately an hour and a half. Following this, a first chest X-ray is performed, followed by a second one at around three to four hours. If the X-rays appear normal, patients are then allowed to be discharged. Dr. Suh notes that this practice is based on literature indicating that most pneumothoraces occur within the first hour after the biopsy, with the second majority appearing in the subsequent three hours. Despite using the blood patch for many years, some cases still experienced delayed pneumothoraces, which were detected on the second chest X-ray or even after the patient had returned home. Dr. Suh mentions that out of 124 consecutive patients, six had delayed pneumothoraces with the blood patch, but only one required a chest tube. In such cases, a follow-up chest X-ray is recommended if the pneumothorax enlarges or persists.
[Dr. Christopher Beck]
…say you didn't have the BioSentry, what's the old school way of y'all's protocol?
[Dr. Robert Suh]
The way I used to practice and still some of us do because not everybody has gone my way. I have to say that this is something I do, but not everybody in the group practices the same way. How we used to do the follow up is like very much like what you've already elucidated. They go back to the observation, but they lay in that position or dependent side down for about an hour and a half, first chest x-ray, then a second chest x-ray at about three hours to four hours, somewhere in that period. Then if that looks okay, then the patients were allowed to go.
I think some of that follow up really harks back to some of the literature on pneumothorax after lung biopsy, given that most of the biopsy that had pneumothoraxes occurred in that first hour, but the far majority happened in the next three hours after that first hour. That's why people generally keep their patients three to four hours in the past. Despite having used the blood patch for so many years, we still had some delayed pneumothoraxes that showed up on that second chest x-ray and a few over the years after they went home. We looked at that as well, with our initial blood patch stuff.
So, I think in 124 consecutive patients, about 6 of them have delayed pneumothoraxes with the blood patch, but only one required a chest tube. If you see I guess the pneumothorax on the second chest x-ray or getting a little bit larger than you just naturally get another one after that.
Managing Pneumothorax after Lung Biopsy
Dr. Suh explains that before removing the needle, it's essential to scan the patient to understand the situation. If there is a pneumothorax, the measurement from the skin to the pleura is adjusted to account for the lung's position. The hydrogel is deployed within the lung but extends into the pleural space where the air is present. Dr. Suh suggests that if the pneumothorax is significant enough, the introducer needle can be reinserted into the pleural space to aspirate the air while the hydrogel is being removed. This step allows for direct confirmation of an active air leak. Dr. Suh emphasizes the importance of addressing a large pneumothorax during the procedure to avoid future complications and reliance on indirect methods of detecting air leaks, such as repetitive chest X-rays. By aspirating the air and observing the lung's response, the presence or absence of an active air leak can be determined. If there is no active air leak, the procedure is considered complete, and the air is mostly removed from the pleural space. On the other hand, if an active air leak persists, further treatment decisions, such as chest tube placement, can be triaged based on the rate of the leak.
[Dr. Christopher Beck]
If you're deploying that hydrogel, can you still do the deployment? Because you mentioned if you have an uncomplicated biopsy, but let's say you have a biopsy where you have a very small pneumothorax that you see during the biopsy so you're getting your needle in position. It's not one of those ones where the lung is just totally deflating that you have to address on the table. This is a little small sliver of a pneumo, same deployment and everything.
[Dr. Robert Suh]
That's a great question. Yes, more or less. What you do is let's say you've taken all your samples and you're about to take the needle out and so before you take the needle out you should always scan the patient so you know what the lay of the land is. Instead of measuring from the skin to the pleura. If you had no pneumothorax what you do is you still measure skin to pleura but you have to measure to the visceral pleura.
If the lung is down 2 centimeters, then you're going to add let's say another 2 centimeters to that length. You'll still deploy it within the lung and it'll be hanging out into the pleural space where the pneumothorax or the air is also there. Then if it's large enough what you do is just put the coaxial needle or the introducer needle back into the plural space and simply aspirate it.
[Dr. Christopher Beck]
Yes, just suck it out as you're pulling it out.
[Dr. Robert Suh]
Right. I think people sometimes don't interpret pneumothorax the right way. They get bothered by the pneumothorax but, having a pneumothorax is relatively inconsequential. It's really whether or not you have an active air leak. By putting the introducer needle back into the pleural space, aspirating on the air, when you feel the lungs sucking up against the needle, you can just wait 30 seconds, a minute, couple minutes, after that if you can't suck any air out, that means that you plugged the hole or the hole is sealed and it's a non-issue at that point.
[Dr. Robert Suh]
I think the biggest thing is when you have a large enough pneumothorax on the table, it's important to do something about it then. It saves you a lot of headache later because that way you don't rely on these indirect methods to ascertain whether or not you have an air leak. Indirect methods would be like repetitive chest x-rays. If you have a large enough pneumothorax on the table, simply put a catheter or put the introducer needle back in aspirate the air.
Like I said, once you get all the air out and the lung is sucking up against the needle, if you wait and observe and maybe scan a little bit if needed, but if you keep the patient on let's say for five minutes, you'll know if you've got an active air leak or not. If you don't have an active air leak, it's done and the air's out of the pleural space for the most part. Again, you're going to get good visceral parietal pleural acquisition when you put that patient dependent.
It's probably going to be a non-issue. If you do have active air leak, then by aspirating it helps you because now you could triage how fast that air leak is going. Now you could say, well, this person we got to put a chest tube in, but they'll do fine with a Heimlich versus I need to admit the patient and put them on wall suction because the air leak is so rapid.
Parenchymal vs Pleural Blood Patching
Dr. Suh elaborates on pleural blood patching. Fundamentally, the technique is to put some of the patient’s blood into the pleural space as another patching method. Dr. Suh reports this method is more effective if there is less air in the pleural space. The goal would be to couple the blood contact with the hydrostatic coupling between the visceral and parietal pleura. Dr. Suh ends the conversation by talking about a study that reports blood patching was non-inferior to hydrogel.
[Dr. Christopher Beck]
Have you guys worked to differentiate the parenchymal, the blood patch from something called the plural blood patch where you do some plural injection with higher volume 50 to 60 ccs of the patient's blood?
[Dr. Robert Suh]
I know that technique was elaborated by the group out at Wisconsin with Fred Lee and I think you try anything that's going to help you in the long run, because we're all very busy and the last thing we want to do is keep adding to the bottom of our to-do list. Sometimes we'll do that. We'll put in 20 to 30 ccs of IV or fresh blood back into the pleural space. Again, I think it works better if you have less air in the plural space because then, of course, if let's say the patient is prone and you have a posterior lung puncture and let's say you got reasonable-size pneumothorax. You could put the blood in and then put the patient supine and get those plural surfaces to touch and so the blood's dependent in there, but you have a better chance of success in my opinion if you take all the air out because now you're coupling the blood plus the hydrostatic coupling between the visceral and parietal pleura. I think in any case, you could put those in or put the pleural blood in, but I would still recommend or advocate for taking the air out first.
[Dr. Christopher Beck]
Like you said, there's probably better opposition of the blood between the visceral and the parietal pleura if you've evacuated that potential space. Yes, completely agree. Is there anything, Rob, that I didn't bring up, as you said earlier like one of the secrets to a good case? Is there anything I didn't ask you about that you need to share with us or our audience?
[Dr. Robert Suh]
I just wanted to circle back to the use of the hydrogel plug because the group at Memorial Sloan, the paper by Maybody, they did look at that and found that the blood patch was non-inferior to the hydrogel plug, but I don't know. I just never felt as comfortable with the blood patching as I do with the hydrogel plug. Probably because the hydrogel stays where you put it, whereas the blood diffuses out of the track potentially. I use the plug on everybody and I think it's a good sauce. You can use it on everything.
Podcast Contributors
Dr. Robert Suh
Dr. Robert Suh is a chest radiologist and interventional radiologist with UCLA in California.
Dr. Christopher Beck
Dr. Chris Beck is a practicing interventional radiologist with Regional Radiology Group in New Orleans.
Cite This Podcast
BackTable, LLC (Producer). (2023, January 3). Ep. 278 – Minimizing Complications for Lung Biopsies [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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