What Percent Pneumothorax Is It?

What percent pneumothorax?

Frequently, radiologists and trauma professionals are coerced into describing the size of a pneumothorax seen on chest xray in percentage terms. They may something like “the patient has a 30% pneumothorax.”

The truth is that one cannot estimate a 3D volume based on a 2D study like a conventional chest xray. Everyone has seen the patient who has no or a minimal pneumothorax on a supine chest xray, only to discover one of significant size with CT scan.

Very few centers have the software that can determine the percentage of chest volume taken up with air. There are only two percentages that can be determined by viewing a regular chest xray: 0% and 100%. Obviously, 0% means no visible pneumothorax, and 100% means complete collapse. Even 100% doesn’t really look like 100% because the completely collapsed lung takes up some space. See the xray at the top for a 100% pneumothorax.

If you line up 10 trauma professionals and show them a chest xray with a pneumothorax, you will get 10 different estimates of their size. And there aren’t any guidelines as to what size demands chest tube insertion and what size can be watched.

The solution is to be as quantitative as possible. Describe the pneumothorax in terms of the maximum distance the edge of the lung is from the inside of the chest wall, and which intercostal space the pneumothorax extends to. So instead of saying “the patient has a 25% pneumo,” say “the pneumothorax is 1 cm wide and extends from the apex to the fifth intercostal space on an upright film.”

How To Rapidly Reverse Coumadin in Head-Injured Patients

A growing number of adults, usually elderly, are taking Coumadin (warfarin) to manage chronic medical conditions or deep venous thrombosis. While warfarin is a very useful drug for these problems, it is notoriously difficult to maintain tight control of INR. If an individual on warfarin is involved in a fall or vehicular crash, bleeding complications can become life-threatening. A recent Journal of Trauma article shows that mortality more than doubles in elderly patient who are admitted awake after just falling from standing.

The key is to rapidly reverse an elevated INR. Vitamin K can be used to increase biological activity of several clotting factors, but this occurs over several hours. Plasma is also used, but there are several considerations. Many hospitals have only frozen plasma, and there may be a delay of 30 to 45 minutes to thaw it. Multiple units may need to be transfused in order to normalize higher INRs, which may cause volume overload in elderly patients with cardiovascular disease.

More recently, activated Factor VII (NovoSeven) has been used to aid rapid reversal of the INR. NovoSeven is FDA approved for only the following uses:

  • Bleeding or surgery in hemophiliacs
  • Bleeding or surgery in congenital Factor VII deficiency

Use of NovoSeven for rapid reversal of warfarin is an off-label use, and physicians must weigh the risks and benefits prior to use. It is also very costly, about $7000 per vial. To download a printable copy of our protocol, click here.


PROTOCOL – PATIENTS ON WARFARIN WITH HEAD INJURY AND ABNORMAL CT SCAN

Check INR. Goal INR is 1.2-1.4

If > 1.4

  • Give Vitamin K 10 mg IV
  • Transfuse thawed plasma 15ml/kg (4-6 units)
  • Consider NovoSeven Weight <= 100kg – give 2mg IV

Repeat INR at 2hrs, 4hrs, 12hrs and 24 hrs after NovoSeven administration.

If INR increases to > 1.4, repeat plasma transfusion as needed.


Related post:

Reference: J Trauma. 2009 Jun;66(6):1518-22; discussion 1523-4.

NOTE: This guideline is based on protocols in use at the Regions Hospital Level I Adult and Pediatric Trauma Centers. As with any potent drugs or procedures, undesired side-effects may occur. The individual physician prescribing these medications or procedures is solely responsible for the safety of his or her individual patient.

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