Trauma Mortality vs Cancer Mortality from CT Scans for Trauma
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.
- Comparison of trauma mortality and estimated cancer mortality from computed tomography during initial evaluation of intermediate-risk trauma patients. J Trauma 70(6):1362-1365, 2011.
- Health risks from low levels of ionizing Radiation: BEIR VII, Phase 2. Washington DC: The National Academies Press, 2006.
Lack of EMS Documentation is Associated With Increased Mortality
EMS policy and the trauma center verification process requires that all trauma patients delivered to a trauma center must have a copy of the EMS run sheet. Two parameters that are commonly used to monitor performance improvement (PI) in EMS are:
- accurate record of scene physiology (SBP, HR, RR, GCS)
- request by on-scene BLS for ALS assistance
A study looked at the impact of those criteria on patient survival. A total of 4744 patients from the National Trauma Data Bank were analyzed.
Physiologic data: About 28% had at least one missing physiologic data point, with respiratory rate being most commonly missed. They found that the mortality in the group with missing data was over twice as high (10.3%) as it was in the group with complete date (4.5%).
BLS call for ALS assistance: This assist was called for in 17% of cases. These cases were less likely to involve penetrating injuries and more likely to involve car or motorcycle crashes. Injury Severity Score was the same. Eventual patient mortality was the same for BLS calling ALS and ALS response alone.
So why does failure to record physiologic data translate into higher mortality? The initial response may be that the patient was sicker, and so they needed more intense care during transport with less time to record vitals. However, the researchers controlled for this and found it was not a factor. Other issues that may be a factor are EMS training and proficiency, leadership at the scene and enroute, and available staff and resources, among other things.
The researchers speculate that documentation might be a good global measure of appropriate or inappropriate prehospital care that rolls all of these possible factors into one easily identifiable audit filter. They recommend that this be used to focus performance improvement efforts and hopefully improve survival.
I recommend that the results of this study be taken to heart and used to help persuade EMS programs to get religious about recording complete vital signs and leaving the run sheet at the trauma center every time a patient is delivered. Documentation should be evaluated regularly, and all cases with any missing vital signs should be reviewed closely. Trauma Center PI programs should work with EMS to analyze this data and look for the patterns that increase mortality.
Reference: Lack of Emergency Medical Services documentation is associated with poor patient outcomes: a validation of audit filters for prehospital trauma care. Journal of the American College of Surgeons, 210(2):220-227, 2010.
Trauma Mortality: The New Nomenclature - Part 2
Yesterday I tried to clarify the most commonly assigned type of trauma mortality, anticipated mortality without opportunity for improvement (AMW/OOI). Today, I’ll cover another, and I’ll finish the series on Monday.
Old nomenclature: potentially preventable death
New nomenclature: anticipated mortality with opportunity for improvement (AMWOI)
Again, these sound somewhat similar but they are quite different. Potentially preventable death used to be applied to patients who had obvious care issues that had some potential to change outcome. But it also contained a number of patients discussed yesterday who had support withdrawn due to age or degree of injury. There was some nagging doubt that, it something else had been done, maybe they would have recovered. So several of the “potentially preventable” deaths in the old category have been moved to the “without opportunity for improvement” category.
Unfortunately, a larger group of patients from the nonpreventable death category have moved into the “with opportunity for improvement” category. This is actually a good thing, though. The AMWOI category looks at whether there were any care issues, regardless of whether support was eventually withdrawn.
Whereas the vast majority of deaths at any center should fall into the AMW/OOI category, a modest number will be classified as AMWOI. The actual number depends on how broadly or narrowly an opportunity for improvement is defined. If you consider a few areas of missing documentation on the trauma flow sheet an opportunity for improvement, then you’ll have a lot of deaths classified this way. Concentrate on issues that might have actually had an impact on the outcome. The key is to develop a set of criteria that is realistic and that work for you. If the number of AMWOI deaths seems high, go back and look at those criteria and adjust them. You can still work out a system for improving trauma flow documentation without it changing every death in a trauma activation to one with an opportunity for improvement.
Monday, I’ll finish up with a few words on unanticipated mortality.
Trauma Mortality: The New Nomenclature
The American College of Surgeons adopted a new naming convention for trauma deaths last year. Of course, anytime you change something up, there will be some confusion. I’m going to compare old and new and give some of my thoughts on the nuances of the changes.
Old nomenclature: Nonpreventable death
New nomenclature: Anticipated mortality without opportunity for improvement (AMW/OOI)
They seem similar, right? But the new name takes into account a growing phenomenon: elderly patients (or younger ones for that matter) who sustain injuries that might be survivable, but are devastating enough to cause the family to withdraw support. Technically, the deaths could be preventable to some degree, but the family did not wish to attempt it. The new system recognizes that it is an expected outcome due to patient or family choice.
There are several key points to handling AMW/OOI. First, if your center is providing great care, the majority of your deaths should be classified this way. Every one of them needs some degree of review, whether from just the trauma medical director and/or program manager or via the full trauma PI committee. However, your full PI committee needs to at least see a summary of the death if it’s not discussed in full.
How to decide on abbreviated review and report vs discussion by full committee? It depends on your trauma volume, and program preference. Higher volume centers do not usually have the luxury of discussing every case due to time constraints.
Tomorrow I’ll discuss the next type of trauma mortality, aniticipated mortality with opportunity for improvement, and I’ll finish the series on Monday.