All posts by TheTraumaPro

Observation of Occult Pneumothorax

An occult pneumothorax is one that is seen only on CT scan, but not on conventional chest x-ray. They are noted in somewhere between 2% and 10% of major blunt trauma patients. Although management is usually conservative, this has not been well studied.

A paper was presented at the AAST earlier this year based on a prospective, multicenter trial. The authors attempted to determine what factors were predictive of failure of observation. They were able to quantify the size of the pneumothorax by measuring a line from the largest collection to the chest wall.

Sixteen centers participated and enrolled 569 patients, who had 588 occult pneumothoraces. Of those, 21% had immediate chest tube drainage (no reasons were given). The remaining 448 patients were observed, and 27 of those patients failed. Failure was determined if they had progression of the pneumothorax, developed respiratory distress, or developed a hemothorax. 

Risk factors were found to be: positive pressure ventilation (14% of observed group failed), size > 7mm, respiratory distress. 

The authors recommend that patients with respiratory distress and those placed on positive pressure ventilation have a drainage system inserted. Those with pneumothoraces greater than 7mm bear close watching.

Our practice is to monitor any patient with an occult pneumothorax with a followup chest x-ray (one view only) performed after six hours. If the pneumo is still not visible, no further observation is done. If it becomes visible, serial 6 hour x-rays are obtained until it is stable or requires a chest tube.

Reference: Management of blunt traumatic occult pneumothorax: is observation harmful? Results of a prospective multicenter study. Forrest O Moore, et al. Paper #5 presented at 69th Annual AAST Meeting, September 22, 2010.

A Shortage of On-call Surgical Specialists to EDs?

The results of a survey published this month details problems caused by the lack of surgical specialists on call to emergency departments. It was conducted by the Robert Wood Johnson Clinical Scholars program and Yale University. They sent the survey to ED directors at 715 randomly selected hospitals around the country. The response rate was very good, with 62% returning their surveys.

An overwhelming majority (74%) of EDs indicated that they experience inadequate call coverage by surgical specialists. Notable comparisons included:

  • Teaching hospital (68% had problems) vs non-teaching hospital (78%)
  • Level I trauma center (60% had problems) vs Level II trauma center (59%) vs Level III trauma center (77%)

Almost two thirds of respondents said they had lost 24/7 coverage of at least one surgical specialty within the last 4 years. Hospitals in metropolitan areas were more likely to experience this problem, as were hospitals in the Northeast and South, compared to the West and the Midwest.

As you can imagine, coverage issues can cause larger problems. Nearly a quarter of hospitals either lost or downgraded their trauma center level due to lack of surgical specialist coverage. And 27% reported patients leaving before they could be seen by the specialist.

The percentage of hospitals with no coverage or problem coverage by surgical specialty was as follows:

  • General surgery – 36%
  • Trauma surgery – 64%
  • Neurosurgery – 75%
  • Plastics – 81%
  • Hand – 80%
  • Ortho – 50%

It is becoming apparent that there are limits to the amount of on-call specialty coverage that money can buy. Careful coordination and regionalization may offer aid to some centers, but we need to look critically at strategies in use that work and find ways to disseminate them to maintain the best emergency care possible.

Reference: The Shortage of On-call Surgical Specialist Coverage: A National Survey of Emergency Department Directors. Academic Emerg Med 17(12):1374-82, Dec 2010.

Orthopedic Hardware And TSA Metal Detectors

Many trauma patients require implantable hardware for treatment of their orthopedic injuries. One of the concerns they frequently raise is whether this will cause a problem at TSA airport screening checkpoints (Transportation Safety Administration)

The answer is probably “yes.” About half of implants will trigger the metal detectors, and these days that usually means a pat down search. And letters from the doctor don’t help. It turns out that overall, 38% are detected when the scanner is set to low sensitivity and 52% at high sensitivity. 

Here is a more detailed breakdown:

  • Lower extremity hardware is detected 10 times more often than upper extremity or spine implants
  • 90% of total knee and total hip replacements are detected
  • Upper extremity implants such as shoulder, wrist and radial head replacements are rarely detected
  • Plates, screws, IM nails, and wires usually escape detection
  • Cobalt-chromium and titanium implants trigger alarms more often than stainless steel

 If your patient knows that their implant triggers the detectors, they have two options: request a patdown search, or volunteer to go through the full body millimeter wave scanner. This device looks at everything from the skin outwards, and will not “see” the implant and is probably the preferred choice. If they choose to go through the metal detector and trigger it, they are required to have a patdown. Choosing to go through the body scanner after setting off the detector is no longer an allowed option. 

Source: Detection of orthopaedic implants in vivo by enhanced-sensitivity, walk-through metal detectors. J Bone Joint Surg Am. 2007 Apr;89(4):742-6.