Pneumothorax And Oxygen: The Final Post!
Okay, this is the last time I’m going to write about this. Hopefully I can provide the final nail in the coffin for this idea. Previously, the oldest paper I could find that was cited as a reason to use high inspired oxygen to treat pneumothorax was from 1983. I found what I think is the earliest (and the last that I will discuss) from 1971!
Twelve patients were retrospectively reviewed who recovered without intervention from a spontaneous pneumothorax. Another 10 were monitored prospectively with the same condition, but were given “high concentration oxygen” (??) by mask from 9 to 38 hours at a time. During intervening periods, the patients breathed room air. Daily chest xrays were obtained, and here is the cool part:
The inner edge of the chest wall and the outer edge of the lung were traced on transparent paper. This was then superimposed on graduated graph paper and the area corresponding to the pneumothorax cavity was measured. The rate of absorption was expressed in cm2/24 hrs.
Need I say more? The authors did show graphically that the apparent rate of absorption tripled in the treated patients, from about 5cm2/day to about 15cm2/day, and was higher in patients with a larger pneumothorax. The problem here is the same as before: chest xray does not allow volumetric estimates, so any results relying on them are suspect. At least it’s not a rabbit study.
Bottom line: There’s just no convincing data to support this practice, so let’s stop using it. Simple physics suggests that this should work, but the effect is just not clinically significant enough to offset the possibility of mishaps from an inpatient admission for oxygen therapy (see yesterday’s post). As I mentioned yesterday, look at the clinical status of your patient. If they have any detectable blood in their chest, they’ll probably need drainage. If not, and if they feel normal, discharge and follow up with a repeat xray in a week. The pneumo will probably be gone. If they do have some compromise, then insert the smallest tube you can. If done properly and a one-way valve can be used, the patient may still be managed as an outpatient.
Reference: Oxygen therapy for spontaneous pneumothorax. Br Med J 4:86-88, 9 Oct 1971.