Trauma professionals worry about radiation exposure in our patients. A lot. There are a growing number of papers dealing with this topic in the journals every month. The risk of dying from cancer due to CT scanning is negligible compared to the risk from acute injuries in severely injured patients. However, it gets a bit fuzzier when you are looking at risk vs benefit in patients with less severe injuries. Is it possible to quantify this risk to help guide our use of CT scanning in trauma?
A nice paper from the Mayo clinic looked at their scan practices in 642 adult patients (age > 14) over a one year period. They developed dose estimates using a detailed algorithm, and combined them with data from the Biological Effects of Ionizing Radiation VII data. The risk level for injury was estimated using their trauma team activation criteria. High risk patients met their highest level activation criteria, and intermediate risk patients met their intermediate level activation criteria.
Key points in this article were:
Average radiation dose was fairly consistent across all age groups (~25mSv)
High ISS patients had a significantly higher dose
Cumulative risk of cancer death from CT radiation averaged 0.1%
This risk decreased with age. It was highest in young patients (< 20 yrs) at 0.2%, and decreased to 0.05% in the elderly (> 60 yrs)
Bottom line: Appropriate CT scan use in trauma evaluation is challenging. It’s use is widespread, and although it changes management it has not decreased trauma mortality. This paper shows that the risk of death from trauma in the elderly outweighs the risk of death from CT scan radiation. However, this gap narrows in younger patients with less serious injuries because of their very low mortality rates. Therefore, we need to focus our efforts to reduce radiation exposure on our young patients with minor injuries.
Many patients are intubated in the emergency department who need brief control of their airway or behavior. In some cases, the condition requiring intubation resolves while they are still in the department. Most of the time these patients are admitted, typically to an ICU bed, for extubation. This is expensive and uses valuable resources. Is it possible to safely extubate these patients and possibly send them home?
Maryland Shock Trauma and Mount Sinai Medical Center looked at their experience in extubating selected patients in the ED. They looked at a series of 50 patients who were intubated for combativeness, sedation, or seizures. A specific protocol was followed to gauge whether or not extubation should be attempted.
None of the patients who were extubated per protocol required unplanned reintubation. One patient underwent planned reintubation when taken to the OR for an orthopedic procedure. 16% of patients were able to be discharged home from the ED.
Bottom line: A subset of patients who are intubated in the emergency department can be extubated once the inciting factor has resolved. These factors include sedation for painful procedures and combativeness. Following this protocol can reduce admission rates and reduce the use of scarce intensive care unit resources.
Reference: Trauma patients can be safely extubated in the emergency department. J Emerg Med 40(2):235-239, 2011.
NOTE: The EMCrit blog, written by Scott Weingart, covered this topic last November. He is the first author on the paper and has created a nice podcast on the topic. You can find his blog here, and you can download the podcast here.
Coagulopathy is a frequent occurrence after severe traumatic brain injury (TBI). There are high levels of tissue factor (TF) in the brain, which can be released with severe injury. This in turn triggers a cascade which can lead to generalized coagulopathy.
The trauma group at LAC+USC looked at the time course of coagulopathy after isolated severe TBI. They identified 278 patients over a 1.5 year period and retrospectively review a number of demographic and outcome variables. Coagulopathy was defined as a platelet count < 100,000/mm3, INR > 1.4, or PTT > 36 sec.
They found the following:
46% with blunt trauma and 82% with penetrating injury developed a coagulopathy
Presence of coagulopathy increased with increasing head injury severity
Thromobocytopenia as a cause of coagulopathy was less common (17%) than clotting factor problems
As brain injury severity increased from AIS=3 to AIS=5, median onset of coagulopathy became increasingly earlier (26 hrs, 22 hrs, 10 hrs)
Mortality increased with earlier coagulopathy (23% after 24 hrs, 39% between 12 and 24 hrs, 56% less than 12 hrs)
Prehospital: Coagulopathy should be suspected if the patient is bleeding profusely from multiple sites, including your IV needle sticks. This indicates severe brain injury and demands triage to a trauma center with immediate neurosurgical support.
In-hospital: Coagulopathy that is noted in the ED portends severe injury and poor prognosis. Rapid access to CT scan and your neurosurgical consultant is critical.
Yesterday I wrote about using an intraosseous line (IO) to administer contrast for CT scanning. The authors of the paper I cited prefer using humeral head access for their IO device. I wanted to share a nice video illustrating the technique, especially for those of you who use the tibia.
The technique is simple, and better tolerated in awake, unanesthetized patients than leg access. However, I believe it’s easier to find the insertion landmarks for the tibia in obese patients.
The standard of care in vascular access in trauma patients is the intravenous route. Unfortunately, not all patients have veins that can be quickly accessed by prehospital providers. Introduction of the intraosseous device (IO) has made vascular access in the field much more achievable. And it appears that most fluids and medications can be administered via this route. But what about iodinated contrast agents via IO for CT scanning?
Physicians at Henry Ford Hospital in Detroit have just published a case report on the use of this route for contrast administration. They treated a pedestrian struck by a car with a lack of IV access sites by IO insertion in the proximal humerus, which took about 30 seconds. They then intubated using rapid sequence induction, with drugs injected through the IO device. They performed full CT scanning using contrast injected through the site using a power injector. Images were excellent, and ultimately the patient received an internal jugular catheter using ultrasound. The IO line was then discontinued.
This paper suggests that the IO line can be used as access for injection of CT contrast if no IV sites are available. Although it is a single human case, a fair amount of studies have been done on animals (goats?). The animal studies show that power injection works adequately with excellent flow rates.
The authors prefer using an IO placement site in the proximal humerus. This does seem to cause a bit more pain, and takes a little practice. A small xylocaine flush can be administered to reduce injection discomfort in awake patients. Additionally, the arm cannot be raised over the head for the torso portion of the scan.
Bottom line: CT contrast can be injected into an intraosseous line (IO) with excellent imaging results. Insert the IO in a site that you are comfortable with. I do not recommend power injection at this time. Although the marrow cavity can support it, the connecting tubing may not. Have your radiologist hand-inject and time the scan accordingly.
Note: long term effects of iodinated contrast in the bone marrow are not known. For this reason, and because of smaller marrow cavities, this technique is not suitable for pediatric patients.