Tag Archives: pneumothorax

High Inspired O2 Is Not An Effective Pneumothorax Treatment

The use of high concentrations of inspired oxygen seems to be a time-honored technique for trying to avoid chest tube insertion for pneumothorax. But does it stand up to scrutiny, or is this just an urban legend?

This recommendation is based upon a single case report involving 8 patients in 1983! Six patients with a pneumothorax of less than 30% showed a decrease in size of 4.2% per day on average. The two patients with pneumothoraces larger than 30% did not respond. A response was only seen with oxygen administered by a partial nonrebreather mask, not by nasal cannula.

What’s the problem? First, this is a very small case report. There were no controls, so it is entirely possible that the resolution rate without treatment was the same as that seen in this report. Furthermore, this study was performed prior to the availability of chest CT. Therefore, the true size of the pneumothoraces is only a guess since volumetric calculations could not be performed. It is not possible to distinguish a 4% change in the size of a pneumothorax by regular chest xray (click here for more details).

The bottom line: If the patient needs supplemental oxygen for management of other pulmonary conditions, then administer it. It is not indicated as an independent treatment for pneumothorax, and its use for this condition should be abandoned!

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Reference: Noninvasive treatment of pneumothorax with oxygen inhalation. Chadha TS. Respiration 44(2):147-52, 1983

Factors Predicting Failure of Observation of Occult Pneumothorax

An occult pneumothorax is defined as one that is seen on CT scan, but not on plain chest x-ray. It is a common finding in blunt trauma that is evaluated using CT 2-12% of scans), but there is no consensus on management. It is recognized that some of these progress and require insertion of a chest tube, while many can be observed safely. The authors try to define what factors predict the need for chest tube management.

The authors reviewed their experience over a 3 year period, and identified 642 patients (10% of their registry entries) with a pneumothorax. 283 were occult, and 98 ultimately received a chest tube.

They found that age>35, ISS>24, more than 4 rib fractures, and need for positive pressure ventilation increased the risk for chest tube insertion. These seem to make sense, but there was one significant limitation in this study: there were no standard indications for a chest tube insertion among the surgeons involved with these patients. There was significant variability, so the actual need for tube insertion was probably less than reported.

An audience member related one anecdotal factor for chest tube as well: a heavy smoking history. This makes intuitive sense, but not everything that makes sense is borne out by research.

At Regions, we define an occult pneumothorax the same way these authors did. We routinely get a delayed chest xray 6 hours later. If there is still no visible pneumothorax, we stop looking. If it is visible, we will obtain periodic (q12-24 hrs) xrays until it stabilizes or grows to a size that demands tube or pigtail insertion.

Given the data conveyed in this paper, we will consider watching a bit longer than 6 hours in patients at higher risk.

Reference: Factors Predicting Failed Observation of Occult Pneumothorax in Blunt Trauma. Selander, Minshall, couillard, Leon. Medical University of South Carolina.

Presented at the 23rd Annual Scientific Assembly of the Eastern Association for the Surgery of Trauma