Tag Archives: chest tube

Does Chest Tube Size Matter? Part 1

Over the next few days I will be reviewing a number of papers that try to determine whether the dogma that bigger chest tube size is better is actually true.

Here are the questions that need to be answered when reading each one to determine if it’s worth its weight:

  • How good is the study design? Obviously, prospective is better than retro. How did the authors decide to put in a small vs a large tube? Were there enough subjects to achieve any meaningful statistical significance?
  • Were the tubes used actually different? If the small bore tubes are 30 – 32 French and the large tubes are 36 – 40 French, would that make a difference?
  • What were the outcomes studied? Mortality and complications like pneumonia and empyema are too crude and uncommon to detect a difference. But what about incidence of retained hemothorax, accidental removal, subjective pain, or clotting?
  • Did the authors identify and acknowledge any limitations in their study?
  • Do the conclusions match up with the actual results?

Let’s kick off the chest tube size debate with an oldie but goodie. The first paper I’ll review was published back in 2012 by a busy LA trauma center.  They performed a prospective, observational study of their experience with two tube size ranges inserted for hemo- and pneumo-thorax over a three year period. The size ranges were 28-32 for small and 36-40 for large. The size selected was based on the discretion of the attending physician.

A total of 353 chest tubes were placed during the study period. This analysis will only dissect the 275 that were inserted for hemothorax.

Here are the factoids:

  • Pertinent demographics were identical for the large and small bore tube patients
  • Pneumonia occurred in about 5% of both groups, and empyema in about 5% of both
  • Retained hemothorax occurred in 12% of small tubes and 11% of large tubes
  • Duration of tube placement was about 6 days in each
  • Additional procedures such as thrombolysis, additional chest tubes, VATS, or thoracotomy were 3-6% in both groups and were not statistically different
  • Pain scores could only be performed on about 45% of patients, and were not different between the two groups

The authors concluded that there were no differences in complications, tube reinsertion, or need for invasive procedures based on tube size. They also concluded that choice of tube size did not impact outcomes.

Bottom line: The authors seem to be saying that the choice of tube size is not important. And if you only read the abstract or conclusions of this study, you might actually believe it. But wait, the authors end the paper with this telltale sentence:

Further evaluation of percutaneously placed drainage systems is warranted”

This is code for: “this paper isn’t very good and shouldn’t change your practice; it needs further verification.”

So what are the issues?

  • There is huge potential for selection bias since the choice of tube size was based on personal preference. For example, the attending could look at the chest x-ray, see a lot of blood, and decide to use a big tube in that patient. No guidelines or randomization were used.
  • The authors did not acknowledge any limitations of the study in their discussion.
  • The only outcomes that really counted in this study were incidence of retained hemothorax (which was not very well defined) and additional procedures required. However, if you take the incidence of retained hemothorax in the large bore tube patients and do an analysis of the statistical power of the study, you run into a major problem. Given the number of patients in each of the two groups, this study would only be able to show statistical significance if the number of retained hemothoraces in the small chest tube group doubled! Anything short of 25% retained hemothorax in the small tube group would not be significant. Thus, the authors’ findings that there was no difference between the groups was entirely expected based on sample size. 

So this paper does not really say that there is no difference in using a small vs a large chest tube. It says that it was not sufficiently powered to detect anything but a massive difference. Many more patients (thousands) were needed to answer the question.

So the question remains, does (chest tube) size matter? More in the next post.

Reference: Does size matter? A prospective analysis of 28-32 versus 36-40 French chest tube size in trauma. J Trauma 72(2):422-427, 2012.

Chest Tube Insertion: Does Size Matter?

I’m old school. I cut my teeth during the days when there were only two sizes of chest tubes for trauma: big and bigger. That meant 36 French or 40 French. Period. I even went as far as adding a chest tube insertion video to my collection of YouTube posts:

But recently, someone posted a comment on that video to the effect that we are moving away from large chest tubes for trauma.

But are we? Really? Am I missing something? I’ve written a few posts in the last two years, examining some of the newer research on this topic. One paper was so-so, one was terrible.

So I’ve decided to really hit this topic hard this week. I want to know what the literature really says on this topic. So I’ve located the best papers I could and I’m going to do a teardown over the next few days. That way I can make sure that my video is up to date, and that my (and your) practice is as well.

Tomorrow, I’ll start with work that compares large and smaller bore tubes. Through the week, I’ll work my way down in size to papers suggesting that pigtail catheters are as good as a chest tube.

Hope you enjoy! We’ll all learn something!

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.

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.

Practice Guideline: Chest Tube Management (Part 2)

Yesterday, I went over the rationale for developing a practice guideline for something as simple and lowly as chest tube management. Today, I’m posting the details of the guideline that’t been in use at my hospital for the past 15 years. I’ve updated it to reflect two lessons learned from actually using it.

Here’s an image of the practice guideline. Click to open a full-size copy in a new window:

Here are some key points:

  • Note the decision tree format. This eliminates uncertainty so that the clinician can stick to the script. There are no hedge words like “consider” used. Just real verbs.
  • We found that hospital length of stay improved when we changed the three parameters from daily monitoring to three consecutive shifts. We are prepared to pull the tube on any shift, not just during the day time. And it also allows this part of the guideline to be nursing driven. They remind the surgeons that criteria are met so we can immediately remove the tube.
  • Water seal is only used if there was an air leak at some point. This allows us to detect a slow ongoing leak that may not be present during our brief inspection of the system on rounds.
  • The American College of Surgeons Committee on Trauma expects trauma centers to monitor compliance with at least some of their guidelines. This one makes it easy for a PI nurse or other personnel to do so.
  • The first of the “new” parts of this guideline is: putting a 7 day cap on failure due to tube output greater than 150cc per three shifts. At that point, the infectious risks of keeping a tube in begin to outweigh its efficacy. Typically, a small effusion may appear the day following removal, then resolves shortly.
  • The second “new” part is moving to VATS early if it is clear that there is visible hemothorax that is not being drained by the system. Some centers may want to try irrigation or lytics, but the data for this is not great. I’ll republish my posts on this over the next two days.

Click here to download a copy of this practice guideline for adults.

Click here to download the pediatric chest tube practice guideline.