Category Archives: General

GI Contrast In CT Scanning for Blunt Trauma

Torso CT scanning has become a mainstay in the evaluation of major blunt trauma. The question of using GI contrast in these CTs arises from time to time. There is an ongoing battle between the ED physician/trauma surgeon, who want quick clinical and relevant results, and the radiologist, who wants nice pictures and a comprehensive list of diagnoses.

IV contrast is so helpful and immediately available that it is virtually a no-brainer to use. The only exception is in patients who have a known allergy to it. GI contrast is more complicated. Ideally, it should be given in divided doses over about an hour, and there just isn’t time for it in trauma patients.

We designed a prospective, randomized study more than 10 years ago that looked at groups of patients who either did or did not receive oral contrast. We studied 394 patients and looked a the need for laparotomy based on study results, delayed diagnoses, and nausea/vomiting.

Thirteen percent of the patients in each group vomited. There were two aspirations, both in the non-contrast group. There were 50 abnormal scans in the contrast group and 55 in the no-contrast group. Nineteen contrast and 14 no-contrast patients were taken to OR.

Most interesting, there were 6 bowel injuries in the contrast group and one was not seen by CT. There were 3 bowel injuries in the no-contrast group and all were seen on CT. We found that there were always other signs of injury, such as mesenteric stranding or bubbles. 

Bottom line: Oral contrast is not necessary in acute blunt trauma patients undergoing CT of the abdomen. 

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How To: Retrograde Urethrogram

One of the hallmarks of urethral injury is blood and the meatus in males. The standard answer to the question “how do you evaluate for it?” is “retrograde urethrogram.” Unfortunately, too few people know how to perform this test, and not all radiologists are familiar. Many times it falls to the urologist, who may not be immediately available.

The technique is simple. The following items are needed:

  • A urine specimen cup
  • A tube of KY jelly (not the little unit dose packs)
  • A bottle of renografin or ultravist contrast
  • A 50-60 cc Toomey syringe (slip-tip)
  • A fluoroscopy suite

Pour 25cc of contrast and 25cc of KY jelly in the specimen cup, cap it and shake well. Draw the contrast jelly up into the syringe. Under fluoro, insert the tip of the syringe into the penis and pull the penis toward yourself, pinching the meatus around the tip of the syringe. Slowly inject all the contrast, watching the contrast column on the fluoro screen. Once there is easy flow into the bladder, you can stop the study. If you see extravasation into the soft tissues, stop the study and call Urology.

The advantages to using this technique are:

  • The contrast/jelly mix creates a contrast gel that is less likely to leak from the meatus when injected
  • The jelly makes it easy to insert the catheter if no urethral injury is detected

Normal urethrogram:

Normal urethrogram

Abnormal urethrogram:

Abnormal urethrogram

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Trauma 20 Years Ago: Intraosseous Access

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.

EZ IO device

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How To Predict the Need for Chest Tube in Occult Pneumothorax

Occult pneumothorax occurs somewhere between 2% and 12% in all blunt trauma patients. Many of these pneumothoraces never progress and thus never need treatment. Is there a way that we can identify ones that are likely to get worse?

A retrospective study of 283 blunt trauma patients with occult pneumothorax was presented at the EAST Annual Scientific Assembly last January. A total of 98 of these patients underwent chest tube insertion within 7 days, and 185 patients were successfully observed.

The authors noted an inverse relationship between age and successful conservative management. Patients with more serious injuries failed expectant management more frequently. Finally, patients with more rib fractures also tended to fail.

The authors estimated the risk of failure of expectant management based on these critieria and found:

  • Age > 35 – 36%
  • ISS > 24 – 20%
  • Rib fractures >= 4 – 53%

The risk with having none of these was 10%, and the risk with all was 75%! 

The time interval for placement was also interesting. 80% of the failures requiring a chest tube occurred within 24 hours, with most occurring in the first 2 hours. The authors also found that 40% of patients who were placed on a ventilator failed.

Obviously, this is a small retrospective study and the exact criteria for placing a chest tube were not specified. Nevertheless, it provides a simple tool that allows us to keep an eye on a subset of patients who are likely to fail observation of occult pneumothorax.

Reference: Factors Predicting Failed Observation of Occult Pneumothoraces in Blunt Trauma. Selander, Med Univ of South Carolina. EAST 2010 Annual Scientific Assembly.

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