Tag Archives: mechanism

Mechanism

Falling Bullets: What Goes Up…

I recently reviewed a case of a person walking outside during fireworks who experienced something strike the top of his head. He could feel something solid stuck in his scalp and thought a piece of a firework had hit him. But then he noticed that people nearby were shooting guns into the air. He also noted a slight weakness and numbness in his upper extremity.

He rapidly proceeded to his local emergency department. Sure enough, physical exam and CT scan revealed a small caliber bullet partially embedded in the top of his skull, with a small contusion in the frontoparietal area. Neurosurgery removed the projectile without incident, and the dura was intact. His neurologic symptoms improved but did not fully disappear before discharge.

This whole situation made me curious. How big a problem is this? How dangerous are bullets fired in the air? The first paper I could find in the trauma literature dates back to 1994 in the Journal of Trauma. The authors presented a series of 118 patients struck by falling projectiles over 10 years. The majority of patients were struck in the head (77%), and the mortality was 32%!

An interesting case report described a male who was watching fireworks who presented to the ED with chest pain and dyspnea.

The terminal velocity of bullets varies based on their size and shape. It ranges from 200-300 ft/sec, or 140-200 mph! Although these numbers are lower than the initial muzzle velocity, they are quite high and comparable to the velocity of a high-powered pellet gun. But with a much heavier projectile. On exam, a penetrating injury was seen above the nipple on the left chest. The abdominal x-ray showed this:

He was taken for laparotomy, and injuries to the splenic hilum, stomach, and diaphragm were identified. Two ventricular injuries were also found and were successfully repaired.

Bottom line: Bullets fired into the air can reach high altitudes and attain high terminal velocities on their descent. The speeds involved can easily pierce bone (e.g., the cranium) and traverse multiple body cavities. Although this activity is universally illegal, it still occurs. Always be wary of this issue during public fireworks celebrations and large family celebrations. Perform a thorough exam of all the nooks and crannies so that these sometimes subtle injuries are identified quickly.

References:

  • Spent bullets and their injuries: the result of firing weapons into the sky. J Trauma. 1994 Dec;37(6):1003-6. PMID: 7996596.
  • Cardiac injury caused by a celebratory bullet. Ann Thorac Surg. 2007 Jan;83(1):283-4. doi: 10.1016/j.athoracsur.2006.04.046. PMID: 17184680.
General, Mechanism

Trauma Activation For Hanging: Yes or No?

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In my last post, I discussed a little-reviewed topic, strangulation. I recommended activating your trauma team only for patients who met the physiologic criteria for it.

But now, what about hangings? There are basically two types. The judicial hanging is something most of you will never see. This is a precisely executed technique that involves falling from a certain height while a professionally crafted noose arrests the fall. This results in a fairly predictable set of cervical spine/cord, airway, and vascular injuries. Death is rapid.

Suicidal hangings are far different. They involve some type of ligature around the neck, but rarely include a fall from any distance. This causes slow asphyxiation and death, sometimes. The literature dealing with near hangings is a potpourri of case reports, speculation, and very few actual studies. So once again, we are left with little guidance.

What type of workup should occur? Should the trauma team be called? A very busy Level I trauma center reviewed its registry for adult near-hangings over a 19-year period. Hanging was strictly defined as a ligature around the neck with only the body weight used for suspension. A total of 125 patients were analyzed and grouped into those with a normal GCS (15) and those with an abnormal GCS (<15).

Here are the factoids:

  • Two-thirds of patients presented with normal GCS, and one-third were impaired
  • Most occurred at home (64%), and jail hangings occurred in 6%
  • Only 13% actually fell some distance before the ligature tightened
  • If there was no fall, 32% had full weight on the ligature, 28% had no weight on it,  and 40% had partial weight
  • Patients with decreased GCS tended to have full weight on suspension (76%), were much more likely to be intubated prior to arrival (83% vs 0% for GCS 15), had loss of consciousness (77% vs 35%), and had dysphonia and/or dysphagia (30% vs 8%)
  • Other than a ligature mark, physical findings were rare, especially in the normal GCS group. Subq air was found in only 12% and stridor in 18%.
  • No patients had physical findings associated with vascular injury (thrill, bruit)
  • Injuries were only found in 4 patients: 1 cervical spine fracture, 2 vascular injuries, and 1 pneumothorax
  • 10 patients died and 8 suffered permanent disability, all in the low GCS group

Bottom line: It is obvious that patients with normal GCS after attempted hanging are very different from those who are impaired. The authors developed an algorithm based on the initial GCS, which I agree with. Here is what I recommend:

  • Do not activate the trauma team, even for low GCS. This mechanism seldom produces injuries that require any surgical specialist. This is an exception to the usual GCS criterion.
  • The emergency physician should direct the initial diagnosis and management. This includes airway, selection of imaging, and directing disposition. A good physical exam, including auscultation (remember that?) is essential.
  • Patients with normal GCS and minimal neck tenderness or other symptoms do not need imaging of any kind.
  • Patients with abnormal GCS should undergo CT scanning, consisting of a CT angiogram of the neck and brain with soft tissue images of the neck and cervical spine recons.
  • Based on final diagnoses, the patient can be admitted to an appropriate medical service or mental health. In the very rare case of a spine, airway, or vascular injury, the appropriate service can be consulted.

Reference: A case for less workup in near hanging. J Trauma 81(5):925-930, 2016.

Mechanism, Trauma Center

Trauma Activation For Strangulation: Yes or No?

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Trauma activation criteria generally fall into four broad categories: physiology, anatomy, mechanism of injury, and cofactors. Of these, the first two are the best predictors of patients who require assessment by the full trauma team. Many trauma centers employ mechanistic criteria, often to their chagrin. They typically end up with frequent team activations, and the patient usually ends up having only trivial injuries.

However, there are some mechanisms that just seem like they demand additional attention. Death of another occupant in the vehicle. Fall from a significant height. But what about a patient who has been strangled?

Unfortunately, the published literature gives us little guidance. This usually means that trauma centers will then just do what seems to “make sense.” And unfortunately, this frequently results in significant overtriage, with many patients going home from the emergency department.

Since there is little to no research to show us the way, I’d like to share my thoughts:

  • As a guiding principle, the trauma team should be activated when the patient will derive significant benefit from it. The primary benefit the team provides is speed. The team approach results in a quicker diagnosis based on physical examination and FAST. It enables patients to undergo diagnostic imaging more quickly, if appropriate. And gets them to the OR more quickly when it’s not appropriate to proceed to CT.
  • Activating for a strangulation mechanism alone is probably a waste of time.
  • Look at the patient’s physiology first. Are the vital signs normal? What is the GCS? If either is abnormal, activate.
  • Then check out the anatomy. If the patient has any voice changes or has obvious discoloration from bruising, crepitus, or subcutaneous emphysema, call the team. They may suffer a deteriorating airway at any moment.

If physiologic and anatomic findings don’t trigger activation, then standard evaluation is warranted. Here are some things to think about:

  • A complete physical exam is mandatory. This not only includes the neck, but the rest of the body. Strangulation is a common injury from domestic violence, and other injuries are frequently present.
  • If there are any marks on the neck, CT evaluation is required. This includes soft tissue, CT angiography, and cervical spine evaluation. All three can be done with a single contrast-enhanced scan. The incidence of spine injury is extremely low with strangulation, but the spine images are part of the set anyway.
  • CT of the chest is never indicated. There is no possibility of aortic injury with this mechanism, and all the other stuff will show up on the chest x-ray, if significant enough for treatment.
  • Even if there are no abnormalities, your patient may need admission while social services arranges a safe place for their discharge. Don’t forget the social and forensic aspects of this injury. Law enforcement may need photographic evidence or statements from the patient so this event can’t happen again.

Next post: Trauma Activation for Hanging: Yes or No?

Reference: Strangulation forensic examination: best practice for health care providers. Adv Emerg Nurs J 35(4):314-327, 2013.

Mechanism, Trauma Center

Trauma Activation For Hanging: Yes or No?

Leave a comment

In my last post, I discussed a little-reviewed topic, that of strangulation. I recommended activating your trauma team only for patients who met the physiologic criteria for it.

But now, what about hangings? There are basically two types. The judicial hanging is something most of you will never see. This is a precisely carried out technique for execution and involves falling a certain height while a professionally fashioned noose arrests the fall. This results in a fairly predictable set of cervical spine/cord, airway, and vascular injuries. Death is rapid.

Suicidal hangings are far different. They involve some type of ligature around the neck, but rarely and fall. This causes slow asphyxiation and death, sometimes. The literature dealing with near hangings is a potpourri of case reports, speculation, and very few actual studies. So once again, we are left with little guidance.

What type of workup should occur? Does the trauma team need to be called? A very busy Level I trauma center reviewed their registry for adult near-hangings over a 19 year period. Hanging was strictly defined as a ligature around the neck with only the body weight for suspension. A total of 125 patients were analyzed, and were grouped into patients presenting with a normal GCS (15), and those who were abnormal (<15).

Here are the factoids:

  • Two thirds of patients presented with normal GCS, and one third were impaired
  • Most occurred at home (64%), and jail hangings occurred in 6%
  • Only 13% actually fell some distance before the ligature tightened
  • If there was no fall, 32% had full weight on the ligature, 28% had no weight on it,  and 40% had partial weight
  • Patients with decreased GCS tended to have full weight on suspension (76%), were much more likely to be intubated prior to arrival (83% vs 0% for GCS 15), had loss of consciousness (77% vs 35%) and had dysphonia and/or dysphagia (30% vs 8%)
  • Other than a ligature mark, physical findings were rare, especially in the normal GCS group. Subq air was found in only 12% and stridor in 18%.
  • No patients had physical findings associated with vascular injury (thrill, bruit)
  • Injuries were only found in 4 patients: 1 cervical spine fracture, 2 vascular injuries, and 1 pneumothorax
  • 10 patients died and 8 suffered permanent disability, all in the low GCS group

Bottom line: It is obvious that patients with normal GCS after attempted hanging are very different from those who are impaired. The authors developed an algorithm based on the initial GCS, which I agree with. Here is what I recommend:

  • Do not activate the trauma team, even for low GCS. This mechanism seldom produces injuries that require any surgical specialist. This is an exception to the usual GCS criterion.
  • The emergency physician should direct the initial diagnosis and management. This includes airway, selection of imaging, and directing disposition. A good physical exam, including auscultation (remember that?) is essential.
  • Patients with normal GCS and minimal neck tenderness or other symptoms do not need imaging of any kind.
  • Patients with abnormal GCS should undergo CT scanning, consisting of a CT angiogram of the neck and brain with soft tissue images of the neck and cervical spine recons.
  • Based on final diagnoses, the patient can be admitted to an appropriate medical service or mental health. In the very rare case of a spine, airway, or vascular injury, the appropriate service can be consulted.

Reference: A case for less workup in near hanging. J Trauma 81(5):925-930, 2016.

Mechanism, Trauma Center

Trauma Activation For Strangulation: Yes or No?

Leave a comment

Trauma activation criteria generally fall into four broad categories: physiology, anatomy, mechanism of injury, and co-factors. Of these, the first two are the best predictors of patients who actually need to be assessed by the full trauma team. Many trauma centers include a number of mechanistic criteria, usually much to their chagrin. They typically end up with frequent team activations and the patient usually ends up have trivial injuries.

However, there are some mechanisms that just seem like they demand additional attention. Death of another occupant in the vehicle. Fall from a significant height. But what about a patient who has been strangled?

Unfortunately, the published literature gives us little guidance. This usually means that trauma centers will then just do what seems to “make sense.” And unfortunately, this frequently results in significant overtriage, with many patients going home from the emergency department.

Since there is little to know research to show us the way, I’d like to share my thoughts:

  • As a guiding principle, the trauma  team should be activated when the patient will derive significant benefit from it. And the benefit that the team really provides is speed. The team approach results in quicker diagnosis from physical exam and FAST. It gets patients to diagnostic imaging quicker, if appropriate. And gets them to the OR faster when it’s not appropriate to go to CT.
  • Activating for a strangulation mechanism alone is probably a waste of time.
  • Look at the patient’s physiology first. Are the vital signs normal? What is the GCS? If either are abnormal, activate.
  • Then check out the anatomy. If the patient has any voice changes, or has obvious discoloration from bruising, crepitus, or subcutaneous emphysema, call the team. They may suffer a deteriorating airway at any moment.

If physiologic and anatomic findings don’t trigger an activation, then standard evaluation is in order. Here are some things to think about:

  • A complete physical exam is mandatory. This not only includes the neck, but the rest of the body. Strangulation is a common injury from domestic violence, and other injuries are frequently present.
  • If there are any marks on the neck, CT evaluation is required. This includes soft tissue, CT angiography, and cervical spine evaluation. All three can be done with a single contrast-enhanced scan. The incidence of spine injury is extremely low with strangulation, but the spine images are part of the set anyway.
  • CT of the chest is never indicated. There is no possibility of aortic injury with this mechanism, and all the other stuff will show up on the chest x-ray, if significant enough for treatment.
  • Even if there are no abnormalities, your patient may need admission while social services arranges a safe place for their discharge. Don’t forget the social and forensic aspects of this injury. Law enforcement may need photographic evidence or statements from the patient so this event can’t happen again.

Next post: Trauma Activation for Hanging: Yes or No?

Reference: Strangulation forensic examination: best practice for health care providers. Adv Emerg Nurs J 35(4):314-327, 2013.