Category Archives: General

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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Extended FAST Exam in Trauma Patients

By now, every emergency medicine physician and surgeon knows what FAST is. This valuable technique allows us to quickly (get it?) determine whether a patient has blood in the abdomen or around the heart which might require operative management. Extended FAST (E-FAST) is an extension of the original technique that allows us to detect the presence of pneumothorax or hemothorax more quickly and accurately than with the conventional chest x-ray.

Both hemothorax and pneumothorax can be missed by x-ray. It takes at least 200cc of free fluid in the chest to show on the chest x-ray, assuming an ideal body habitus. As little as 20cc can be detected using the E-FAST. Studies have also shown that 30-50% of pneumothoraces are missed by x-ray. This diagnostic inaccuracy is due to the fact that hemothoraces settle out posteriorly and pneumothoraces anteriorly. Since the vast majority of chest x-rays in major trauma patients are taken with the patient supine to protect their spine, the bulk of the blood or air have layered out and cannot be seen well. A chest x-ray is still needed, however, to determine injury to the mediastinum and lung parenchyma.

E-FAST exam can be performed by using the standard curvilinear probe. It is usually placed longitudinally on the anterior chest to detect pneumothorax, using the space between two ribs as the “window” to the pleura. The depth setting should be adjusted so that only about 4cm is visible on the display. The junction of the visceral and parietal pleura should be visualized at the backside of the ribs. With a very steady hand, the junction between the two sets of pleura should be scrutinized closely.

If the two sets of pleura slide freely over each other, pneumothorax is unlikely. If not, it may be present. Pneumothorax is not a uniform phenomenon, except when it is of large size. It may be necessary to move the probe to a few other rib spaces to ensure that a smaller pneumothorax is not present.

FALSE POSITIVE ALERT! If the patient is not ventilating well, or if they have a right mainstem intubation, the affected lung(s) may not show the sliding sign, leading the examiner to think they have a problem when they may not.

To detect a hemothorax, the probe is directed upward somewhat when doing the right and left upper abdominal views. A dark triangle located above the diaphragm indicates fluid in the chest (blood). The dark crescent on the left in the image below is a large hemothorax.

E-FAST hemothorax

The bottom line: Extended FAST can be helpful in detecting a significant hemothorax or pneumothorax and can expedite the definitive management of those conditions. If you are already familiar with FAST, a little extra ultrasound training may be very helpful.

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