AAST 2011: Acute Kidney Injury From IV Contrast

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.

AAST 2011: The Initial Hematocrit Matters

Traditional teaching is that we bleed whole blood, and it takes time to pull volume out of the interstitial space to replace it. Therefore, the initial hematocrit should be normal when a fresh, bleeding trauma patient rolls through the doors.

An observation I have made over the years is that this is not necessarily so. A few patients have low initial hemoglobin or hematocrit readings, and they tend to be bleeding briskly from somewhere. A paper to be presented at next week’s AAST meeting in Chicago shows just that.

The authors retrospectively reviewed 198 trauma patients requiring emergency surgery at a Level I trauma center. Patients with lower initial hematocrits tended to have lower systolic blood pressure, lower GCS, lose more blood, and require infusion of more blood products during surgery. They also had a higher ISS and mortality. The biggest jump in these indicators occurred when the Hct dropped below 37.

Bottom line: A low hematocrit on the first blood drawn during trauma resuscitation is more helpful that previously thought. Be sure to check those lab values early, and if the hematocrit value is in the mid-30s or lower, start looking for significant sources of bleeding.

Reference: The initial hematocrit matters in trauma: a paradigm shift? AAST 2011 Annual Meeting, Paper 38.

AAST 2011: Benefit of Transport to a Trauma Center

Most trauma systems set certain prehospital criteria that, when met, direct that patient to a trauma center. It is now well-established that care of these patients results in improved survival if they are managed at those centers. Unfortunately, undertriage is still a problem, meaning that those patients may not always be taken to a hospital most appropriate to care for their injuries. What is the penalty that your patient pays if this happens?

The University of Toronto performed a nice, prospective study across a large region with both urban and rural areas. Database information was analyzed for all victims of motor vehicle crashes who had a severe injury (ISS>15) or who died. Over 6,000 crash victims’ data were analyzed. 

Just under half of the victims (45%) were triaged to a trauma center. Of those who were taken to other hospitals, slightly more than half (58%) were transferred to one within 24 hours, but nearly 5% died in the non-trauma center ED. The overall mortality for severely injured patients who were taken to a nontrauma center was 8.7%. This was a 30% increase in adjusted mortality compared to those taken to a trauma center directly.

Bottom line: Follow the rules! EMS authorities and trauma systems should make it a priority to adopt the CDC protocol (see below) or create trauma guidelines based on them that ensure patients with significant injuries are taken directly to a trauma center. Going to the nearest hospital (if it is not a trauma center) or bending to the patient’s preference is not in their best interest (and may kill them)!

Click here to download the Centers For Disease Control and Prevention (CDC) National Trauma Triage Protocol. This should be used as a standard!

Reference: The mortality benefit of direct trauma center transport in a regional trauma system: a population-based analysis. AAST 2011 Annual Meeting, Paper 50.

AAST 2011: Acute Kidney Injury And Multiple Organ Failure

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.

AAST 2011: Autopsy Reports and Performance Improvement

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.

AAST 2011: Predicting Post-Traumatic Stress Disorder (PTSD) After Trauma

Today is the last day of the annual AAST meeting, so I’ll wind up with one last abstract presented at this meeting.

PTSD can cause significant morbidity after trauma. Most centers manage this problem reactively, when the patient exhibits obvious symptoms in the hospital or after discharge. Wouldn’t it make more sense to screen for it routinely? Is there a way to figure out which patients are at higher risk?

The University of Pittsburgh prospectively screened 1,386 injured patients presenting to their followup clinic using the PTSD Checklist - Civilian (PCL-C) instrument. A score of>=35 has a sensitivity of 85% and was considered a positive result.

The authors found that more than 25% of their outpatient clinic patients met the threshold. The most common mechanism was assault, both blunt and penetrating. Younger age (<55), female gender and motor vehicle crash were also found to be predictors.

Bottom line: Consider routine PTSD screening in patients with the listed risk factors, just like we perform routine TBI screening in patients with head injuries. The PCL-C is self-administered and takes only about 5 minutes to complete. The most reliable way is to send it home with your patient, with instructions to complete it before they see you or their primary physician in the outpatient clinic.


Reference: Predictors of post-traumatic stress disorder (PTSD) following civilian trauma: highest incidence and severity of symptoms after assault. AAST 2011 Annual Meeting, Paper 33.