Tag Archives: pneumothorax

General

Don’t Get Lateral View Chest Xrays to Diagnose Pneumothorax

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Pneumothorax is typically diagnosed radiographically. Significant pneumothoraces show up on chest xray, and even small ones can be demonstrated with CT.

Typically, a known pneumothorax is followed with serial chest xrays. If patient condition permits, these should be performed using the classic technique (upright, PA, tube 72" away). Unfortunately, physicians are used to ordering the chest xray as a bundle of both the PA and lateral views. 

The lateral chest xray adds absolutely no useful information. The shoulder structures are in the way, and they obstruct a clear view of the lung apices, which is where the money is for detecting a simple pneumothorax. The xray below is of a patient with a small apical pneumothorax. There is no evidence of it on this lateral view.

Bottom line: only order PA views (or AP views in patients who can’t stand up) to follow simple pneumothoraces. Don’t fall into the trap of automatically ordering the lateral view as well!

Lateral chest xray

General

Pneumothorax: How Big Is Too Big?

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One of the big unanswered questions in the management of pneumothorax is, how big is too big? At what size is a chest tube of some type mandatory? 

The problem is that we just don’t have any good data. Seems like a simple problem, right? Unfortunately, it’s not. A pneumothorax is a three dimensional collection that surrounds the lung in very random ways. All we had to detect and “measure” them for decades was the lowly chest x-ray. Unfortunately, this is a 2D shadow picture that does not allow us to accurately estimate the size.

A few old papers exist that tried to quantify pneumothorax, but they are of no use now that we have chest CT. Unfortunately this new technology has drawbacks, as well. First, it’s just a stack of 2D images that our minds assemble into a 3D mental model, so it’s still difficult to quantify the air. And second, you shouldn’t be getting a chest CT just to diagnose pneumothorax. In blunt trauma, it’s really just for checking the thoracic aorta for injury.

So we’re left with the original question, and there are three answers. If there is any physiologic compromise (hypoxia, tachypnea, anxiety), then the chest should be drained. If the pneumothorax is enlarging over serial chest x-rays, then it should be drained before it causes physiologic change. And finally, if there is concern that it is so large that it will take too long to absorb, especially in older patients with comorbidities, a chest drain should be inserted. This is a somewhat soft indication, however.

Bottom line: The three reasons above are the usual answers to the question, “how big is too big?” For me, once the pneumothorax pushes the lung 1-2 cm away from the chest wall from apex to base, it’s time for a tube.

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General

Flying After Pneumothorax

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Patients who have sustained a traumatic pneumothorax occasionally ask how soon they can fly in an airplane after they are discharged. What’s the right answer?

The basic problem has to do with Boyle’s Law (remember that from high school?). The volume of a gas varies inversely with the barometric pressure. So the lower the pressure, the larger a volume of gas becomes. Most of us hang out pretty close to sea level, so this is not an issue.

However, flying in a commercial airliner is different. Even though the aircraft may cruise at 30,000+ feet, the inside of the cabin remains considerably lower though not at sea level. Typically, the cabin altitude goes up to about 8,000 to 9,000 feet.Using Boyle’s law, any volume of gas (say, a pneumothorax in your chest), will increase by about a third on a commercial flight. 

The physiologic effect of this increase depends upon the patient. If they are young and fit, they may never know anything is happening. But if they are elderly and/or have a limited pulmonary reserve, it may compromise enough lung function to make them symptomatic.

Commercial guidelines for travel after pneumothorax range from 2-6 weeks. The Aerospace Medical Association published guidelines that state that 2-3 weeks is acceptable. The Orlando Regional Medical Center reviewed the literature and devised a practice guideline that has a single Level 2 recommendation that commercial air travel is safe 2 weeks after resolution of the pneumothorax, and that a chest xray should be obtained immediately prior to travel to confirm resolution.

Bottom line: Patients can safely travel on commercial aircraft 2 weeks after resolution of pneumothorax. Ideally, a chest xray should be obtained shortly before travel to confirm that it is gone. Helicopter travel is okay at any time, since they typically fly at 1,500 feet or less.

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References:

  • Practice Guideline, Orlando Regional Medical Center. Air travel following traumatic pneumothorax. October 2009.
  • Medical Guidelines for Airline Travel, 2nd edition. Aerospace Medical Association. Aviation, Space, and Environmental Medicine 74(5) Section II Supplement, May 2003.
General

Pigtail Cathers Instead Of Chest Tubes?

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I reviewed this abstract a few months ago, and now I’ve had the opportunity to hear it and see the data. Here’s an update on whether this is worthwhile..

This was a relatively small, prospective study, and only 40 of 74 eligible patients were actually enrolled over 20 months at a Level I trauma center in the US. Pain was measured using a standard Visual Analog Scale, as was complication and failure rate, tube duration and hospital stay.

The following interesting findings were noted:

  • Chest wall pain was similar. This is expected because the underlying cause of the pneumothorax, most likely rib fractures, is unchanged.
  • Tube site pain was significantly less with the pigtail
  • The failure rate was the same (5-10%)
  • Complication rate was also the same (10%)
  • Time that the tube was in, and hospital stay was the same

There were a few questions regarding blinding of the pain scale raters, but other than the small sample size, the study was nicely done.

Bottom line: There may be some benefit in terms of tube site pain when using a smaller catheter instead of a chest tube. But remember, this is a very small study, so be prepared for different results if you try it for your own trauma program. If you do choose to use a smaller tube or catheter, remember to do so only in patients with a pure pneumothorax. Clotted blood from a hemothorax will not be completely evacuated.

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Reference: A prospective randomized study of 14-French pigtail catheters vs 28F chest tubes in patients with traumatic pneumothorax: impact on tube-site pain and failure rate. EAST Annual Surgical Assembly, Oral paper 12, Jan 17, 2013.

General

Pigtail Catheters Instead Of Chest Tubes?

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Traditionally, hemothorax and pneumothorax in trauma has been treated with chest tubes. I’ve previously written about some of the debate regarding using smaller tubes or catheters. A paper that will be presented at the EAST meeting in January looked at pain and failure rates using 14Fr pigtail catheters vs 28Fr chest tubes.

This was a relatively small, prospective study, and only 40 of 74 eligible patients were actually enrolled over 20 months at a Level I trauma center in the US. Pain was measured using a standard Visual Analog Scale, as was complication and failure rate, tube duration and hospital stay.

The following interesting findings were noted:

  • Chest wall pain was similar. This is expected because the underlying cause of the pneumothorax, most likely rib fractures, is unchanged.
  • Tube site pain was significantly less with the pigtail
  • The failure rate was the same (5-10%)
  • Complication rate was also the same (10%)
  • Time that the tube was in, and hospital stay was the same

Bottom line: There may be some benefit in terms of tube site pain when using a smaller catheter instead of a chest tube. But remember, this is a very small study, so be prepared for different results if you try it for your own trauma program. If you do choose to use a smaller tube or catheter, remember to do so only in patients with a pure pneumothorax. Clotted blood from a hemothorax will not be completely evacuated.

Related posts:

Reference: A prospective randomized study of 14-French pigtail catheters vs 28F chest tubes in patients with traumatic pneumothorax: impact on tube-site pain and failure rate. EAST Annual Surgical Assembly, Oral paper 12, 2013.