Monthly Archives: August 2011

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AAST 2011: Patients Evaluated But Not Transported By EMS

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Injured patients transported to the ED are just the tip of the iceberg. There are some patients who are evaluated by EMS, either at the scene or in their home, but never transported. These patients do not appear in any trauma registry and little information is known about how they do after their evaluation.

Stanford University reviewed county data and found 5,865 patients out of 69,000 who were evaluated by EMS but not transported (3 counties, 3 years of data). Over a quarter (29%) presented to an ED later and 92 were admitted (2% of the total). By linking available vital statistics data, at least 7 were found to have died.

Bottom line: Patients who are evaluated by EMS but ultimately not transported to a hospital may have unsuspected problems. The mortality is very low (0.14%) but these may represent preventable deaths. It is not practical to force everyone to go to the ED. However, it should be cost-effective to at least make a followup call the next day on these select patients to see if they should be urged to get further evaluation in the ED.

Reference: The forgotten trauma patient: outcomes for injured patients evaluated by EMS but not transported. AAST 2011 Annual Meeting, Oral Paper 46.

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AAST 2011: CT Evaluation of Penetrating Neck Trauma

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In the old days, stab injuries to Zone 2 in the neck meant a trip to the operating room. Then it became acceptable to evaluate stable patients with this injury via endoscopy, angiography and a swallow study. Most chief residents didn’t have the patience for this and opted for OR anyway. CT now promises to simplify the evaluation process, rolling these studies into one fast and simple one.

USC+LAC and the University of Maryland directed a prospective multicenter study that looked at the sensitivity and specificity of using CT angiography of the neck to evaluate penetrating injuries.All patients underwent a structured physical examination of the neck. If hard signs of injury to the vascular tree or aerodigestive tract were present, they were immediately taken to OR (6%). Nearly all of these patients had an injury that required repair. If they had no signs, they were merely observed (51%). None had a missed injury.

The remaining 159 patients had a positive exam (minor oozing, small stable hematoma) underwent CT angio of the neck (54% stabs, 42% gunshots, 4% other). The majority were in Zone 2 (41%), but 24% were in Zone 3, 21% in Zone 1, and 14% crossed multiple zones. Overall sensitivity was 100% and specificity was 97%. CT angio was nondiagnostic in 3 patients due to missile fragment artifact.

Bottom line: CT angio of the neck is a fast and accurate exam that can be used in stable patients with an abnormal physical exam but no hard signs of injury. This fits my bias, and we have already been using the scanner this way for stabs. I would now recommend cautiously extending its use for select gunshots as well.

Hard signs of neck injury:

  • Unstable vital signs
  • Large, expanding, or pulsatile hematoma
  • Active bleeding
  • Air bubbling
  • Voice or airway disturbance
  • Hematemesis / hemoptysis
  • Thrill / bruit
  • Neurologic deficit

Reference: Evaluation of multidetector computed tomography for penetrating neck injury: a prospective multicenter study. AAST 2011 Annual Meeting, Oral Paper 61.

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AAST 2011: Autopsy Reports and Performance Improvement

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Autopsy reports have traditionally been used as part of the trauma performance improvement (PI) process. They are typically a tool to help determine preventability of death in cases where the etiology is not clear. Deaths that occur immediately prior to arrival or in the ED are typically those in which most questions arise.

The American College of Surgeons Trauma Verification Program includes a question on what percentage of deaths at a trauma center undergo autopsy. Low numbers are usually discussed further, and strategies for improving them are considered. But are autopsies really that helpful?

A total of 434 trauma fatalities in one state over a one year period were reviewed by a multidisciplinary committee and preventability of death was determined. Changes in preventability and diagnosis were noted after autopsy results were available. The autopsy rate was 83% for prehospital deaths and 37% for in-hospital deaths. Only 69% were complete autopsies; the remainder were limited internal or external only exams.

Addition of autopsy information changed the preventability determination in 2 prehospital deaths and on in-hospital death (1%). In contrast to this number, it changed the cause of death in about 40% of cases, mostly in the prehospital deaths.

Bottom line: From a purely performance improvement standpoint, autopsy does not appear to add much to determining preventability of death. It may modify the cause of death, which could be of interest to law enforcement personnel. I would still recommend obtaining the reports for their educational value, especially for those of you who are part of training programs.

Reference: Dead men tell no tales: analysis of the utility of autopsy reports in trauma system performance improvement activities. AAST 2011 Annual Meeting, Paper 63.

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AAST 2011: Acute Kidney Injury From IV Contrast

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Yesterday, I wrote about using acute kidney injury (AKI) as a predictor for multiple organ failure. But what about kidney failure that we may inadvertently create through the use of IV contrast during CT scan evaluation? Contrast is generally safe for use in the general trauma population, but is known to cause renal problems in high risk groups like the elderly and critically ill.

Investigators at UCSD retrospectively reviewed ICU patients who had no history of pre-existing renal disease. A total of 570 eligible patients were identified, and 170 (30%) developed AKI. Being old (age>=75) or severely injured (ISS>=25) was a predictor of AKI, but IV contrast was not. Even during subgroup analysis, the addition of contrast to the elderly or severely injured patient population did not predict AKI.

Bottom line: This limited study shows that IV contrast exposure may be considered safe, even in the elderly and severely injured. However, I still recommend that all risks and benefits be thoroughly weighed in every patient, and that scans that have little diagnostic and therapeutic benefit be avoided.

Reference: Is contrast exposure safe among the highest risk trauma patients? AAST 2011 Annual Meeting, Paper 69.

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AAST 2011: Acute Kidney Injury And Multiple Organ Failure

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Organ failure after major trauma is relatively common. Acute renal failure can occur for a variety of reasons, and tends to occur early. This abstract from Denver Health looked at acute kidney injury as a predictor for the development of multiple organ failure.

The authors retrospectively reviewed 12 years of their registry data for patients at high risk for developing organ failure. They found that multiple organ failure (MOF) developed in 21% and that 8% died. They also noted that if acute kidney injury (AKI, serum creatinine > 1.8mg/dL) occurred by day 2, it predicted the failure of additional organs. Specifically, 80% of these patients developed MOF, with a 34% mortality. Renal failure was a better predictor of multiple organ failure than heart, liver or pulmonary failure seen on day 2.

Bottom line: Early kidney failure, as shown by creatinine elevation, is a reliable predictor of multiple organ failure in severely injured patients. Prevention of acute kidney injury makes sense and may help, but further investigation is needed to demonstrate the mechanism.

Reference: Acute kidney injury and post-trauma multiple organ failure: the canary in the coal mine. AAST 2011 Annual Meeting, Paper 20.