Infection (e.g., gas gangrene) can cause gas to be trapped in the subcutaneous tissues. Subcutaneous emphysema can be caused by medical procedures and medical conditions that cause the pressure in the alveoli of the lung to be higher than that in the tissues outside of them.
So here's a quick look at PFE's most important numbers right now (for April 14, 2017). PFE shares slipped 0.12% or $0.04 from the previous trading session. That took the Pfizer stock price to $33.88.
For instance, if you have purchased a put on Pfizer with a strike price of $25, and the stock dropped to $20, you could go out into the open market, buy the stock for $20 and turn around and sell it for $25, making a $5 profit. The tricky part about options is that they expire.