This 11 minute video podcast covers the history of snowmobiles, some injury pattern and risk factor information, and closes with some safety tips to pass on to your patients.
Trauma 20 Years Ago: CT Imaging of the Aorta
CT scan is now the standard screening test for injury to the thoracic aorta. But 20 years ago, we were still gnashing our teeth about how to detect this injury.
An interesting paper was published in the Journal of Trauma 20 years ago this month on this topic. Over a 2 year period, the Medical College of Wisconsin at Milwaukee looked at all patients who underwent imaging for aortic injury. At the time the gold standard was aortogram. They looked at patients who underwent this study and CT, which was not very common at the time.
They had 50 patients who underwent aortography alone and 17 who underwent both tests. Of the 17, 5 had the injury, but only three were seen on CT. There were also two false positives. Sensitivity was 83%, specificity was 23%, with 53% accuracy. The authors concluded that any patients with strong clinical suspicion of aortic injury should proceed directly to aortogram.
Why the difference today? Scan technology and resolution has increased immensely. Also, the timing of IV contrast administration has been refined so that even subtle intimal injuries can be detected. CT scan is now so good that we have progressed from the CV surgeon requiring an aortogram before they would even consider going to the OR, to the vascular surgeon / interventional radiologist proceeding directly to the interventional suite for endograft insertion.
Today, we take for granted that fixing fractures early is a good thing. However, this topic was still under debate 20 years ago. Trauma care has always been prioritized, with life-threatening injuries taking precedence. It was very common for major trauma patients to undergo operation for their torso injuries, and then be deemed “too unstable” to undergo repair of their extremities.
Weigelt et al reported decreased pulmonary complications with early fixation in 1989. A study published in July 1990 looked at 121 early vs 218 late femur fixations with respect to more concrete outcomes. The patients were similar with respect to hypotension, transfusions and associated injuries.
They found that delayed fixation increased pulmonary shunt, especially in patients with more severe injuries, and increased the incidence of pneumonia in older patients. It also resulted in more ICU days and a significantly longer hospital stay in the more severely injured group.
This paper was a valuable addition that began to shape our appreciation for the importance of early fixation of most fractures. Major trauma makes patients sick, but they are in the best condition they will be in for weeks at the time they arrive at the hospital. This makes it the ideal time to take care of injuries that may otherwise contribute to morbidity and mortality.
Reference: Fabian et al. Improved outcome with femur fractures: early vs delayed fixation. J Trauma 30(7):792, 1990.
The pre-hospital concept of “scoop and run” was first popularized in the mid-1980’s. It came about because there was recognition that significant delays were occurring on scene. A big time sink was obtaining IV access. The failure rate for IV starts in the field was 10-40% and typical start times were in excess of 10 minutes!
As a result of “scoop and run”, the emphasis shifted to airway protection, c-spine stabilization and control of external hemorrhage. A quicker alternative to IV access was sought, and the idea of intraosseous access was revived.
IO access was first described in 1941, and was used in children due to the higher degree of difficulty in obtaining IV access in kids. It did not require visualization of the site and could be inserted in moving ambulances, including helicopters.
The authors of this paper looked at IO infusion using a sternal insertion site. This site was chosen due to the belief that only areas with red marrow were suitable. They found that delivery of fluids and drugs was virtually identical to IV. The authors did cite contraindications to using this device, including previous sternotomy, sternal fracture, osteoporosis, and congenital anomalies like pectus.
Ultimately, this paper revived interest in IO access for adults, which has now evolved to easy-to-insert tibial devices that are inserted with a power drill.
Reference: Evaluation of an Intraosseous Infusion Device for the Resuscitation of Hypovolemic Shock. Holcroft, Blaisdell et al. J Trauma 30(6): 652. 1990.
This month is the 20th anniversary of the MESS score, a system that helps predict salvageability of mangled extremities (Mangled Extremity Scoring System). Obviously, the acronym was chosen to help describe the clinical problem.
The system was originated at the Harborview Medical Center in Seattle. The development was not very scientific; the authors put their heads together and made a list of the four things that they observed predicted limb salvage:
The system was used retrospectively in a group of 25 patients(!) and the authors found a nice breakpoint at 7. Any mangled extremities with a MESS of 7 or more required amputation. They then applied this to 26 patients prospectively(!) and got the same result.
As you can see, the numbers were small, and there was no followup information. Nevertheless, MESS still stands today, and the critical MESS score has not changed much. It has been validated by a number of other studies during the past 20 years. It is conceivable that the critical score will slowly creep upward with advancements in flap coverage and surgical technique, but it hasn’t done so yet.
Reference: Objective Criteria Accurately Predict Amputation Following Lower Extremity Trauma. Johansen, et al. J Trauma 30(5): 568, 1990.
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