Tips

Management Of Penetrating Neck Trauma: The Way We Were/Are

March 20, 2023 The Trauma Pro Leave a comment

The management of penetrating injuries to the neck has changed very little over the years. Could it be time? Today, I’ll review some of the basics of classic diagnosis and treatment. In my next post, I’ll discuss an alternative way to approach it.

First, lets look at the time-honored zones of the neck. Here’s a nice diagram from EMDocs.net:

The zones are numbered in reverse, from bottom to top, and in Roman numerals.

The area below the cricoid cartilage is considered Zone I and contains many large vascular and aerodigestive structures that are relatively difficult to approach surgically. For this reason, diagnostic testing is recommended to assist in determining if an operation is actually needed and what the best surgical exposure would be. Obviously, this can only be considered in the stable patient. Unstable patients must go straight to the OR and the trauma surgeon will determine the surgical approach on the fly.

Similarly, the area above the angle of the mandible is Zone III, and is also difficult to expose. Injuries to this area may involve the distal carotid and vertebral arteries near the base of the skull, as well as the distal jugular vein. Surgical approach may require dislocation of or fracturing the mandible to get at this area. This is challenging and not that desirable, and few surgeons are familiar with the technique. For this reason, imaging is very desirable and often demonstrates that no significant injury is present. And endovascular / angiographic techniques are now available that may obviate the need for surgery.

Zone II is everything in-between the mandibular angle and cricoid cartilage. This is the surgical Easy Button. Exposure is simple and the operation is fun. In the old days, an injury to this area went straight to the OR regardless of whether there were signs or symptoms of injury. Yes, there were quite a few negative explorations. But we’ve become more selective now with the advent of improved resolution of our CT scans.

Currently, we usually follow a two-step approach to penetrating neck trauma:

Are there hard signs of injury present? These tell us that a structure that absolutely needs to be fixed has been injured. The patient should be taken directly to OR after control of the airway, if appropriate. Typical hard signs are:
1. Airway compromise
2. Active air bubbling from wound
3. Expanding or pulsatile hematoma
4. Active bleeding
5. Hematemesis
What zone is the injury in? And don’t just look at the obvious entry point. Gunshots (and long knives) may enter multiple zones. The zone then determines what happens next:
1. Zone I – CT angio of neck and chest. If positive, proceed to OR for repairs, and perform EGD and/or bronchoscopy as needed
2. Zone II – Old days: proceed to operating room for exploration, or angiogram, EGD, direct laryngoscopy, and bronchoscopy. Most chief residents chose the former. Current day: CTA of neck, followed by OR, EGD, bronchoscopy only if indicated.
3. Zone III – CT angio of the neck. If positive, consider angiography/endovascular consultation vs operation.

Changes from old days to more current thinking have been made possible by improvements in speed and resolution of our CT scanners. But why can’t we take this another step forward and streamline this process even more? I’ll propose some changes in my next post!

Reference: Western Trauma Association Critical Decisions in Trauma:
Penetrating neck trauma. J Trauma 75(6):936-940, 2013.

General

Flying Or Diving After Traumatic Pneumothorax: Part 2

March 17, 2023 The Trauma Pro Leave a comment

In my last post, I wrote about the accepted management of and delay in flying due to traumatic pneumothorax. I republished the post because of the publication of a paper from Oregon Health Science University in Portland. The authors specifically tried to assess timing of chest tube removal and long-distance flight, and to measure the risk of pneumothorax recurrence or other complications.

The authors performed a retrospective review of a series of military patients who had sustained chest injuries that were treated with chest tubes over a 5 year period from 2008 to 2012. After tube removal and a pneumothorax-free period of at least 24 hours (by chest x-ray), the patients were then transported by air from the military theater back to the United States.

Here are the factoids:

Of 517 patients screened in the military trauma registry database, only 73 were available for study after applying exclusion criteria
Subjects were predominantly young and male, as one would expect from the injured military population, and 74% were injured by a penetrating mechanism
Median time that the chest tube was in place was 4 days, and median time from tube removal to flight was 2.5 days
All patients had post-flight documentation available for review, but only half (37) had in-flight documentation available
Nearly half (40%) had positive pressure ventilation in place during the flight
Five patients had “in-flight medical concerns” (4 were ventilated), but none were related to the pneumothorax. The four ventilated patients had ventilator issues, the non-vented patient had “self-limited discomfort without evidence of respiratory distress.”
None of the subjects developed a recurrent pneumothorax, either post-flight or over the following 30 days

The authors conclude that air travel after tube removal and a 24-72 hour observation period “appears safe.”

Bottom line: Not so fast! This is yet another small, retrospective study making grand claims. The study group is a very unique population: healthy, fit young men with penetrating injury. Your average civilian trauma patient is older, less healthy, and usually has a blunt mechanism with multiple rib fractures. In-flight documentation was not available in half of the cases. And a full medical team was present on the aircraft had a problem actually occurred.

Contrast this with a civilian patient on a commercial aircraft with very limited medical equipment and expertise on board. What could go wrong? I definitely do not recommend changing our practice on these patients yet based on this one paper. Until we have better guidance (more good papers) stick to the usual wait time to ensure a safe flight for your patient.

Reference: Trauma patients are safe to fly 72 hours after tube thoracostomy removal. J Trauma, published ahead of print, May 18 2018.

Thorax

Flying Or Diving After Traumatic Pneumothorax: Part 1

March 15, 2023 The Trauma Pro Leave a comment

Today, I’m dusting off an old post on flying and diving after pneumothorax. This shows the thinking up until a few years ago. In my next post, I’ll write about a more recent paper that suggests that we can shorten the “no-fly” time considerably.

Hint: no changes to the diving recommendations. One pneumothorax is likely to ground you forever. (pardon the pun)

Patients who have sustained a traumatic pneumothorax occasionally ask how soon they can fly in an airplane or scuba dive after they are discharged. What’s the right answer?

The basic problem concerns Boyle’s Law (remember that from high school?). The volume of a gas varies inversely with the barometric pressure. So the lower the pressure, the larger the volume of gas becomes. Most of us hang out close to sea level, so this is not an issue. But for flyers or divers, it may be.

Flying

Helicopters typically fly only one to two thousand feet above the ground, so the air pressure is about the same as standing on the earth. However, flying in a commercial airliner is different. Even though the aircraft may cruise at 30,000+ feet, the inside of the cabin remains considerably lower though not at sea level. Typically, the cabin altitude goes up to about 8,000 to 9,000 feet. Using Boyle’s law, any volume of gas (say, a pneumothorax in your chest) will increase by about a third on a commercial flight.

The physiologic effect of this increase depends upon the patient. They may never know anything is happening if they are young and fit. But if they are elderly and/or have a limited pulmonary reserve, it may compromise enough lung function to make them symptomatic. And having a medical problem in an aluminum tube at 30,000 feet is never good.

Commercial guidelines for travel after pneumothorax range from 2-6 weeks. The Aerospace Medical Association published guidelines that state that 2-3 weeks is acceptable. The Orlando Regional Medical Center reviewed the literature and devised a practice guideline with a single Level 2 recommendation that commercial air travel is safe 2 weeks after resolution of the pneumothorax, an that a chest x-ray should be obtained immediately before travel to confirm resolution.

Diving

Diving would seem to be pretty safe, right? Any pneumothorax would just shrink while the diver was at depth, then re-expand to the original size when he or she surfaces, right?

Not so fast. You are forgetting why the pneumothorax was there in the first place. The lung was injured, most likely via tearing it, penetration by something sharp, or popping a bleb. If the injured area has not completely healed, then air may begin to escape through it again. And since the air used in scuba diving is delivered under pressure, this could result in a tension pneumothorax. This is disastrous underwater!

Most injuries leading to pneumothorax heal completely. However, if there are bone spicules stuck in the lung or more complicated parenchymal injuries from penetrating injury, they may never completely heal. This makes the diver susceptible to a tension pneumothorax anytime they use their regulator.

Bottom line: Most patients can safely travel on commercial aircraft 2 weeks after resolution of pneumothorax. Ideally, a chest xray should be obtained shortly before travel to confirm that it is gone. Helicopter travel is okay at any time, since they typically fly at 1,500 feet or less.

Divers should see a physician trained in dive medicine to evaluate their injury and imaging prior to making another dive.

Tomorrow: new info on flying after pneumothorax

References:

Divers Alert Network – Pneumothorax – click to download
Practice Guideline, Orlando Regional Medical Center. Air travel following traumatic pneumothorax. October 2009.
Medical Guidelines for Airline Travel, 2nd edition. Aerospace Medical Association. Aviation, Space, and Environmental Medicine 74(5) Section II Supplement, May 2003.

Complications

Top 10 Worst Complications: #1 Nasocerebral Tube

March 13, 2023 The Trauma Pro Leave a comment

Minor complications from nasogastric tube insertion occur relatively frequently. Emesis is fairly common when the gag reflex is stimulated by the tube in the back of the oropharynx. An infrequent but possibly fatal one is insertion through the cribriform plate.

The cribriform plate is located directly posterior to the nares and is part of the ethmoid bone. It is very porous in nature and weaker than the surrounding portions of the ethmoid. It is easily fractured, and can be seen is association with basilar skull fractures. This is one source for rhinorrhea in patients with these fractures.

Cribriform fracture is a contraindication to unprotected insertion of a nasogastric tube. If you look at the sagittal section below, the plate lies directly behind the nares. When inserting the NG tube, we are usually taught to aim the tube straight back. Unfortunately, this aims it directly at the cribriform. If a fracture is present, it is possible that you may be inserting a nasocerebral tube!

Cribriform plate - sagittal section

The usual symptoms when this occurs consist of immediate neurologic deterioration to coma, and a unilateral or bilateral blown pupil. The tube must not be withdrawn, because it will cause significant injury to the base of the brain. A stat neurosurgical consultation must be obtained, and if the patient is salvageable, the tube must be withdrawn through a craniectomy.

To avoid this dreaded complication, identify patients at risk for cribriform injury. They are:

patients with signs of trauma from eyebrows to zygoma
comatose patients
patients with signs of basilar skull fracture (Battle’s sign, raccoon eyes, oto- or rhinorrhea)

If your patient is at risk, follow these guidelines:

first, does the patient really need a gastric tube?
if comatose, insert an orogastric tube
if awake, don’t put the tube in their mouth, as they will gag continuously. Instead, place a lubricated, curved nasal airway. Then lube up a slightly smaller Salem sump tube and pass it through the airway.

Complications

Nausea In The Trauma Bay: Gastric Tube vs Anti-Emetic Drugs?

March 10, 2023 The Trauma Pro Leave a comment

Nausea and vomiting are common problems in trauma patients, particularly those in a trauma activation. Inciting factors include pain, full stomach from food eaten before the event or blood swallowed after, or reaction to pain medications. For years, trauma professionals reached for the lowly gastric tube to evacuate stomach contents to “solve” the problem.

But how many of you have seen a patient forcefully empty their stomach as soon as the tube touches the oropharynx? And of course, your patient is lying supine, so the vomitus goes straight up, then back down into their airway. And if their mental status is not quite right, they may aspirate, causing even bigger problems.

We’ve had anti-emetic medications for a long time, some more effective than others. Only recently have we begun to rely on these as a first line defense in the trauma resuscitation room. But do they work? Are they safer?

The University Medical Center Utrecht in the Netherlands looked at this problem. They changed their policy from inserting a gastric tube to administering anti-emetics at the beginning of 2014. They studied their experience for the 6 months before and 6 months after the policy change. They inserted an orogastric (OG) tube preferentially before the switch, and used ondansetron and/or metoclopramide after.

Here are the factoids:

A total of 1446 trauma patients were admitted during this period. After excluding patients who were intubated or did not complain of nausea, 453 were analyzed (30%)
20% of patients who had an OG tube placed vomited vs only 3% receiving medication (significant)
After therapy, 14% of patients receiving an OG were still nauseated vs only 2% getting meds (also significant)
3 patients vomited and aspirated after OG placement, and 1 developed a pneumonia. 2 patients became bradycardic and med administration, and one developed QT-prolongation

Bottom line: This is a relatively small, retrospective study. Furthermore, the choice of gastric tube route (oral) is a setup for gagging and vomiting. Nasogastric tubes are a bit less noxious, but can’t be inserted in all patients (see next week’s post). Even so, the use of anti-emetics in trauma patients complaining of nausea seems like the kinder, gentler way to go.

Which drug to use? Previous studies have shown that ondansetron 4mg is as effective as 8mg, and that this drug is about equally as effective as metoclopramide. There is also some evidence that giving both is more effective than just giving one.

Gastric tubes are still important, particularly in the comatose patient. But since these patients are at risk for cribriform plate injury, only the oral route should be used.

Reference: Analysis of two treatment modalities for the prevention of vomiting after trauma: orogastric tube or anti-emetics. Injury (accepted manuscript, in press) online 8 July 2017.

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