Category Archives: Thorax

Flash Pulmonary Edema After Chest Tube Insertion

You are seeing a young man in the emergency department who gives a history of falling two days ago. He experienced chest pain at the time which has persisted, but he did not immediately seek medical care. He has noticed that he now gets winded when walking quickly or climbing stairs, and describes pleuritic chest pain.

He presents to your emergency room and on exam has a bruise over his left lateral chest wall. Subcutaneous emphysema is present, and breath sounds are absent. Chest x-ray shows a complete pneumothorax on the left.

You carefully prepare and insert a chest tube in the usual position. A significant rush of air occurs, which tapers off over 15 seconds. Here is the followup image:

About 10 minutes later you are called to his room because he is complaining of dyspnea and his oxygen saturation has decreased to 86%. Breath sounds are somewhat decreased and the tube appears to be functioning properly. You immediately obtain another chest x-ray:

What just happened? This is a classic case of unilateral “flash” pulmonary edema after draining the chest cavity. This phenomenon was first described in 1853 in a patient who had just undergone thoracentesis. It is very uncommon, but seems to occur after rapid drainage of air or fluid from the chest cavity.

Here are some interesting factoids from case reports:

  • It occurs more often in young men
  • It is most common when draining large hemo- or pneumothoraces
  • Rapid drainage seems to increase the incidence
  • It is likely due to increased pulmonary capillary permeability from inflammatory mediators or changes in surfactant
  • Symptoms typically develop within an hour after drainage

What should you do? First, if you are draining a large collection of air or blood, do it slowly. Clamp the back end of the chest tube prior to insertion (you should always do this if you value your shoes) and use it to meter the amount of fluid or air released. I typically let out about 300cc of fluid, then wait a minute and repeat until all the blood has been drained. For air, vent it for 10 seconds, then wait a minute and repeat.

In patients at high risk for this condition, apply pulse oximetry and follow for about an hour. If they still look and feel great, nothing more need be done.

References:

  • Fulminant Unilateral Pulmonary Edema After Insertion of a Chest Tube. Dtsch Arztebl Int 105(50):878-881, 2008.
  • Reexpansion pulmonary edema after chest drainage for pneumothorax: A case report and literature overview. Respir Med Case Rep 14:10-12, 2015.
  • Re-expansion pulmonary edema following thoracentesis, Can Med Assn J 182(18):2000-2002, 2010.
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AAST 2019 #8: Timing Of Thoracic Aortic Injury Repair

Over the past two decades, there has been a massive swing from open repair of blunt thoracic aortic injury to thoracic endovascular aortic repair (TEVAR). Although technically a bit more complex, it has decreased both morbidity and mortality significantly. The usual push in fresh trauma patients is to take care of all the life-threatening injuries as soon as possible. And from the days of the open thoracic procedure, this was generally warranted.

However, the optimal timing of repair during the age of TEVAR is not as clear. Is it really necessary to go crashing into the angio or hybrid suite to get this taken care of? Or should it wait until the patient is not as physiologically damaged? The group at University of Texas at San Antonio looked at experience in the National Trauma Databank for some guidance. They reviewed four years of data from 2012 to 2015. Patients who arrested in or prior to arrival in the ED were excluded. Mortality was the primary outcome of interest, but complications and hospital length of stay (LOS) was also noted.

Here are the factoids:

  • Nearly 6,000 patients with blunt thoracic aortic injury were identifed, and 1,930 (33%) underwent TEVAR, 2% were opened, and 65% were managed nonoperatively
  • Looking only at TEVAR patients, 69% underwent the procedure within 24 hours, 24% after 24 hours, and the remainder were not recorded (!)
  • Mortality was significantly higher in the early TEVAR group (6.4% vs 2.1%)
  • Hospital LOS was significantly shorter in the early TEVAR group (18 vs 22 days)
  • Logistic regression controlling for hypotension, severe TBI, ISS and older age confirmed the significantly lower mortality in the delayed group

The authors concluded that delayed (>24 hrs) TEVAR was associated with decreased mortality but longer length of stay.

This is a nice, clean abstract to read. The hypothesis and results are easy to understand and make sense. And it’s exactly the kind of poster that makes you think a bit. 

The only real downside is that it is an NTDB study, so there is very limited ability to go back and tease out why these results should be true. These results should push the authors to set up a more prospective study so they can figure out why this should be true. We can certainly speculate that it helps to temporize with good blood pressure control while cleaning up other major injuries and correcting deranged physiology. But one never knows until the right study is actually done.

Here are my questions for the presenter and authors:

  • Were you able to glean any insights into the associations you identified from the other data in the NTDB records you used? This could help design a really good study to see if your impressions are true.
  • The fact that a quarter of patients had TEVAR at an unknown time throws a big monkey wrench in your results. Can you use any statistical tricks to see if assuming they were either early or late would influence your results. Is it possible that this unknown group could completely neutralized your study?

I’m very excited by this one, and I don’t normally get too excited by posters. Great work!

Reference: Timing of repair of blunt traumatic thoracic aortic injury: results from the National Trauma Databank. AAST 2019, Poster #5.

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Trocar Chest Tubes Or Blunt Technique? Part 2

In my last post on chest tube insertion technique, I reviewed a paper that compared chest tube insertion complications using two different trocar tips, blunt plastic and sharp metal. The sharp tip tubes caused more complications, although the study was weakened by the fact that the physicians inserting the tubes were complete newbies.

Today, I’ll discuss what the authors call a “best evidence topic” that reviewed the safety of the trocar technique. It is similar to a meta-analysis of available literature that attempts to reach a conclusion regarding this type of tube insertion. A literature search from 1946 to 2013 was conducted seeking to pull all papers on trocar chest tube insertion techniqes. A total of 258 papers were identified, but on closer inspection only 7 were identified that “provided the best evidence to answer the question.”

Here are the factoids from some of these papers:

  • Tube malposition occurred significantly more often in a series of 106 trocar tubes inserted into 75 ICU patients
  • In trocar tubes inserted for trauma, CT showed malplacement in 29% vs 19% with non-trocar tubes [This latter number seems very high to me!]
  • A retrospective study of 1249 patients resulted in the trocar technique being abandoned due to severe lung and stomach injuries
  • Use of trocar technique was associated with a significantly higher incidence of re-expansion pulmonary edema in 92 patients with spontaneous pneumothorax
  • A poorly controlled prospective study showed 23 complications with trocar technique and none with blunt dissection. The denominator could not be determined.

Bottom line: Overall, the literature is just not good enough to answer this question. But it does provide some suggestions.

  • Trocar insertion can be done well in experienced hands. Cardiac surgeons use these all the time, although sometimes they have the benefit of already being in the chest so they can visualize the point of entry and control the tip.
  • Any chest tube insertion can go awry.  It’s very important to learn proper technique, and take care to apply it faithfully, even in emergency situations.
  • If you really like trocars and want to improve insertion safety, start with the blunt dissection technique first, sweep a finger inside the chest to ensure there are no adhesions, then insert the trocar tube to guide it into position. Please note that I do not believe that we can control the tube once the instrument (trocar or clamp) are removed from the chest. And the tube will work fine just about anywhere it ends up (unless that’s the spleen).
  • Newbies should be supervised carefully and learn blunt insertion technique first. Be mindful that it is still possible to pass the insertion clamp into the same structures as a trocar if you are not careful. My practice is to place my fingers about 2 cm from the tip of the clamp as I push it through the pleura. If the pleura gives way more easily than anticipated, by fingers will keep the clamp from going too far into the chest. 
  • Always mark your insertion spot before prepping. This will generally be lateral to the nipple in men, so always prep the nipple into your field as a landmark.
  • Always be careful!

Reference: Is the trocar technique for tube thoracostomy safe in the current era? Interactive CV and thoracic surg 19:125-128, 2014.

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Trocar Chest Tubes Or Blunt Technique? Part 1

This is an old question: what is the best way to insert a chest tube? There are several techniques available to us:

  • Blunt dissection and insertion
  • Trocar with a blunt tip (plastic stylet)
  • Trocar with a sharp tip (metal stylet)
  • Seldinger technique for small tubes

Typically, when there are multiple ways to do a thing, then there is no clear choice as to which is better. It then becomes a personal choice, or one driven by the financial considerations of the equipment used, and demonstrates the need for a practice guideline.

There are very few good papers out there that critically compare any of these techniques. Today, I’ll review one cadaver study and tomorrow I’ll tackle one “best evidence” paper that attempt to answer it.

A group in Vienna, Austria performed a cadaver study comparing the use of the two types of trocar tubes:

The top tube is the sharp trocar type, the bottom is the blunt trocar.

The study engaged twenty emergency medicine residents who had little, if any, experience placing chest tubes. Each placed 10 chest tubes (5 of each type) in fresh cadavers after undergoing a one-hour standardized lecture on anatomy, technique, and complications. The authors tabulated insertion times, as well as complication and success rate based on anatomic dissection.

Tube type was randomly assigned for each attempt by each resident. One blunt insertion and one sharp insertion were performed on opposite sides of a cadaver each month for the trainees. Over a period of 5 months, each resident performed 10 total insertions.

Here are the factoids:

  • Mean time to insertion for blunt vs sharp tips was the same, about 60 seconds
  • Insertion time declined by about 20 seconds by the final attempt at 5 months
  • Accurate placement occurred in 94% of blunt tip tubes vs 86% of sharp tip tubes
  • There were significantly more complications with the sharp tip (4 below diaphragm, 5 outside the thorax, 1 in the liver,  and 4 in the spleen) vs the blunt tip (2 below diaphragm, 2 extrathoracic, 2 in the liver, and 2 aborted due to damage to the tube)
  • BMI did not increase complications, but it did increase insertion time significantly

The authors concluded that there is a 6-14% complication rate that is operator related, and that the incidence of complications was increased with the use of a sharp tip tube. They warn against the use of these tubes.

Bottom line: This is certainly an interesting study. The insertion numbers are sort of reasonable, and the use of fresh cadavers is okay. They are not quite as realistic as real living people, but close. The biggest drawback was that they used chest tube newbies, most of whom had never inserted a tube. And they were placed in the unrealistic setting where they had to attend training and watch a video, then insert two tubes per month without coaching or supervision. This is not how we do it in the real world. 

I was impressed with what I consider the high number of complications. I don’t typically see that many, although I work at a blunt dissection institution. However, it does show that any trocar style tube is probably more like a weapon in inexperienced hands. So perhaps, even with supervision, both sharp and blunt trocar types should be avoided in the teaching setting. Sure, blunt dissection may take a bit longer, but the tube is also less likely to end up somewhere it shouldn’t be.

Tomorrow: Review of a “best evidence” review from New York.

Reference: Evaluation of performance of two different chest tubes with either a sharp or a blunt tip for thoracostomy in 100 human cadavers. Scand J Trauma Resus Emerg Med 20:10, 2012.

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Retained Hemothorax: The Practice Guideline

Over the last few days, I’ve reviewed some data on managing hemothorax, as well as the use of lytics. Then I looked at a paper describing one institution’s experience dealing with retained hemothorax, including the use of VATS. But there really isn’t much out there on how to roll all this together.

Until now. The trauma group at Vanderbilt published a paper describing their experience with a home-grown practice guideline for managing retained hemothorax.  Here’s what it looks like:

I know it’s small, so just click it to download a pdf copy. I’ve simplified the flow a little as well.

All stable patients with hemothorax admitted to the trauma service were included over a 2.5 year period. The practice guideline was implemented midway through this study period. Before implementation, patients were treated at the discretion of the surgeon. Afterwards, the practice guideline was followed.

Here are the factoids:

  • There were an equal number of patients pre- and post-guideline implementation (326 vs 316)
  • An equal proportion of each group required an initial intervention, generally a chest tube (69% vs 65%)
  • The number of patients requiring an additional intervention (chest tube, VATS, lytics, etc) decreased significantly from 15% to 9%
  • Empyema rate was unchanged at 2.5%
  • Use of VATS decreased significantly from 8% to 3%
  • Use of catheter guided drainage increased significantly from 0.6% to 3%
  • Hospital length of stay was the same, ranging from 4 to 11 days (much shorter than the lytics studies!)

Bottom line: This is how design of practice guidelines is supposed to work. Identify a problem, typically a clinical issue with a large amount of provider care variability. Look at the literature. In general, find it of little help. Design a practical guideline that covers the major issues. Implement, monitor, and analyze. Tweak as necessary based on lessons learned. If you wait for the definitive study to guide you, you’ll be waiting for a long time.

This study did not significantly change outcomes like hospital stay or complications. But it did decrease the number of more invasive procedures and decreased variability of care, with the attendant benefits from both of these. It also dictates more selective (and intelligent) use of additional tubes, catheters, and lytics. 

I like this so much that I’ve incorporated parts of it into the chest tube guideline at my center!

Download the practice guideline here.

Related posts:

Reference: Use of an evidence-based algorithm for patients with traumatic hemothorax reduces need for additional interventions. J Trauma 82(4):728-732, 2017.

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