All posts by TheTraumaPro

If A Tree Falls In A Forest…

It’s time for a little philosophy today. There seem to be two camps in the world of initial diagnostic testing for trauma: selective scanning vs pan-scanning. I admit that I am one of the former. Yes, the more tests you do, the more things you will find, and this will make your radiologist happy. Some of these findings will be red herrings. Some may be true positives, but are they important? Here’s the key question:

“If a tree falls in a forest and no one is around, does it make a sound?”

Huh? How does this answer my question? Well, there is a clinical corollary to this question in the field of trauma:

“If an injury exists but no one diagnoses it, does it make a difference (if there would be no change in treatment)?”

Here’s an example. On occasion, my colleagues want to order diagnostic studies that won’t make any clinical difference, in my opinion. A prime example is getting a chest CT after a simple blunt assault. A plain chest xray is routine, and if injuries are seen or the physical exam points to certain diagnoses, appropriate interventions should be taken. But adding a chest CT does not help. Nothing more than the usual pain management, pulmonary toilet, and an occasional chest tube will be needed, and those can be determined without the CT.

Trauma professionals need to realize that we don’t need to know absolutely every diagnosis that a patient has. Ones that need no treatment are of academic interest only, and can lead to accidental injury if we look for them too hard (radiation exposure, contrast reaction, extravasation into soft tissues to name a few). This is how we get started on the path to “defensive medicine.”

Bottom line: Think hard about every test you order. Consider what you are looking for, what you might find, and if it will change your management in any way. If it could, go ahead. But always consider the benefits versus the potential risks, or what I call the “juice to squeeze ratio.”

References:

  • George Berkeley, A Treatise Concerning the Principles of Human Knowledge, 1734, section 45.
  • paraphrased by William Fossett, Natural States, 1754.

Mainstem Intubation In Pediatric Patients: How To Avoid It

In my last post, I reviewed a simple technique utilizing a reminder card and provider feedback loops to reduce deep intubations in pediatric patients. Today, I’ll review three other techniques and discuss a paper that compared their efficacy.

A variety of techniques for determining and/or confirming endotracheal tube position exist. Use of one or more of them is important in children due to their short trachea and increased likelihood of deep intubation. Some, like the confirmatory chest x-ray, are obvious. However, it’s more desirable to apply techniques during the intubation in order to avoid deep intubation in the first place. Hyperinflation of one lung, especially in very small children, can cause a host of impairments and complications that may compound their other injuries.

A paper from the University Hospital Basel in Switzerland evaluated three techniques: bronchoscopic insertion to a specific depth, cuff palpation in the sternal notch, and intentional right mainstem intubation followed by slow withdrawal during auscultation.  Each of 68 children ranging in age from 0 to 4 years were studied using all three techniques.

Each endotracheal tube was marked at the ideal insertion point that would ideally be placed just beyond the vocal cords. The distance from this mark to the mouth end of the tube was measured so actual intubation depths could be compared.

Bronchoscopic insertion was always performed first to obtain a baseline depth measurement, essentially the gold standard. The other two techniques were performed in random order. For the cuff palpation technique, the trachea was palpated while the balloon was intermittently partially inflated until it could be felt at the suprasternal notch. For the mainstem intubation technique, the uninflated tube was advanced until breath sounds in the left axilla disappeared. It was then slowly withdrawn until sounds reappeared.

Distances from the tip of the tube to the carina was calculated using the insertion depth at the incisors and the initial ideal intubation depth mark. Here are the factoids:

  • Insertion to a depth mark on the tube via bronchoscope technique resulted in the highest tube tip with respect to the carina, and also with the greatest depth variability
  • The cuff palpation technique resulted in less distance to the carina (about 19mm vs 36 for the mark technique) and less variability
  • Use of the mainstem intubation with pullback technique resulted in the tube tip resting within just a few mm of the carina, but tube depth was very consistent

Bottom line: What to make of all this? Which technique is “best?” First, it’s not practical or advisable to use a bronchoscope for every pediatric intubation. It’s invasive and adds complexity and time to a critical procedure. The cuff palpation technique also takes additional time due to the repeated cuff inflation/deflation that is required. However, the tube position is fairly accurate and safe.

The intentional right mainstem intubation with pull-back seems a bit sketchy. It requires some type of ongoing ventilation while the tube is being inserted, as well as someone who can listen to the left chest. Additionally, it results in a tube position that is so low that neck positioning may move it into the mainstem bronchus again.

In my mind, estimation of the proper depth pre-intubation is probably the best. Strict attention must be paid to the final depth of the tube once it is inserted, as measured by the distance marker at the incisors. This number must match the one decided upon at the start of the procedure. A good exam of the chest should be carried out to quickly identify an inadvertent mainstem intubation. And finally, a quick confirmatory chest x-ray should always be obtained for objective information on tube position. 

The fancy techniques described in this paper add too much time and complexity for intubation in a trauma situation. They may very well have a place in the OR where the situation is more controlled and there is more advanced equipment and support. But stick to the basics when intubating children in your trauma bay!

Reference: Assessment of three placement techniques for individualized positioning of the tip of the tracheal tube in children under the age of 4 years. Ped Anesthesia 25:379-285, 2014.

Mainstem Intubation In Pediatric Patients: How Common?

Mainstem intubation in the pediatric patient is a common problem. There are two major issues: the trachea is shorter than in an adult, and the angles are different making intubation of the right mainstem bronchus much easier. Frequently, the intubator watches the balloon slide between the cords, then pushes the tube in “just a little further.”

Unfortunately, that “little bit” can vary significantly. An abstract from my hospital was presented at the Pediatric Trauma Society in 2016. Subjectively, we noticed that mainstem intubation was occurring with some regularity in our pediatric trauma patients.  It seemed as though insufficient attention was being paid to the depth of the tube.

A major difference between adult and pediatric intubations is that in adults, optimal tube depth is locked into a relatively narrow range. In children, the depth varies considerably based upon child age and size. And small variances in depth can have major implications for tube position.

We decided to implement a PI project to change our intubation policy. In order to focus the entire team on tube depth, a color coded card was attached to each size of endotracheal tube. This card listed the optimal depth for insertion. Once the provider inserted the tube, the final depth was called out for the team and documentation scribe to hear. This had the added advantage of allowing multiple team members confirm the appropriateness of tube depth. A chest x-ray was immediately obtained to confirm position.

We retrospectively reviewed our seven year experience with pediatric intubations, from 2009-2015. Here are the factoids:

  • Nearly 2,000 pediatric trauma patients were admitted during the study period
  • 94 patients (5%) required intubation in the ED
  • Prior to implementation of the new protocol, 6 of 68 patients (8.8%) had confirmed right mainstem intubation 
  • After the change, only one further mainstem intubation occurred in 26 procedures (3.8%)

Bottom line: Unfortunately, this series is too small to determine statistical significance. There is a definite trend toward fewer mainstem intubations. It appears that by calling more attention to the proper tube depth, fewer deep placements occur. Our numbers  have remained low since this change.

Are there other methods to ensure proper ET tube placement in small patients? In my next post, I’ll review a paper that compares three additional different techniques that can be used.

Reference: Eliminating the Preventable Occurrence of Right Mainstem Intubation in the Pediatric Trauma Patient: A Quality Performance Improvement (PI) Initiative. Pediatric Trauma Society Poster Abstract #1, 2016.

How To Predict Venous Thromboembolism In Pediatric Trauma

As with adults a decade ago, the incidence of venous thromboembolism (VTE) in children is now on the rise. Whereas adult VTE occurs in more than 20% of adult trauma patients without appropriate prophylaxis, it is only about 1% in kids, but increasing. There was a big push in the early 2000′s to develop screening criteria and appropriate methods to prevent VTE. But since the incidence in children was so low, there was no impetus to do the same for children.

The group at OHSU in Portland worked with a number of other US trauma centers, and created some logistic regression equations based on a large dataset from the NTDB. The authors developed and tested 5 different models, each more complex than the last. They ultimately selected a model that provided the best fit with the fewest number of variables.

The tool consists of a list of risk factors, each with an assigned point value. The total point value is then identified on a chart of the regression equation, which shows the risk of VTE in percent.

Here are the factors:

Note that the highest risk factors are age >= 13, ICU admission, and major surgery.

And here is the regression chart:

Bottom line: This is a nice tool, and it’s time for some clinical validation. So now all we have to do is figure out how much risk is too much, and determine which prophylactic tools to use at what level. The key to making this clinically usable is to have a readily available “VTE Risk Calculator” available at your fingertips to do the grunt work. Hmm, maybe I’ll chat with the authors and help develop one!

Reference: A Clinical Tool for the Prediction of Venous Thromboembolism in Pediatric Trauma Patients. JAMA Surg 151(1):50-57, 2016.