I'm sorry I am coming into this so late. Any discussion with FF523 is interesting. It always makes me search the literature to make sure I am not the crazy one. As for the original scenario, I find it hard to believe that this was a true call. Bilat, nontraumatic tensions pneumos just don't happen. What stars and planets aligned to cause the exact same pathology to occur on two seperate organs at the same exact moment? I'm not saying that it doesn't happen, because there are cases in the literature, but these are usually sick people or pneumos that have been induced via some form of trauma. A quick pubmed search will turn up a few case reports. It also appears that needle decompression is not overly successful. It usually requires chest tube insertion.
As for your run of the mill unilateral tension pneumo, the teaching is that if you xray it you might as well give the pt their malpractice check before they leave the ER. TENSION pneumo is a clinical diagnosis (especially by the time they get to the ER). If you are not able to distinguish a tension pneumo from a pulmonary contusion you need to go back to whatever school you graduated from for some remediation. Spontaneous pneumos, however, are diagnosed with xrays. There is no emergent rush to fix them, which is why we don't needle them. Get your chest xray, set up your chest tube under nice, sterile condtions, appropriately anesthestize your patient and make them feel better.
As for the discussion of cyanosis and pulse ox, you need to have 5 mg of deoxygenated hemoblobin in order to become cyanotic. This means that the pulse ox at which you see cyanosis depends on their hemoglobin level. Anemic patients will require a much lower pusle ox before they become cyanotic. Let's us 15 as our normal hemoglobin level. This means that your pulse ox would need to be about 67% before you see cyanosis. Take an anemic person with a hemoglobin of 7. They would need to get there deoxygenated hemoglobin down to 2, which means they would need a pulse ox of about 30% before you would see cyanosis. Let's look at some one who is a heavy smoker or lives at a high altitude and has a higher hemoglobin level of say 25. They would be cyanotic with a pulse ox of about 75%. It is possible to be cyanotic with a pulse ox over 90% depending on your hemoglobin level as well as the cause of the cyanosis.
Back to the OP, I guess when all else has failed, drop two needles in the chest. They will just end up with two chest tubes. Hope I have made the situation as clear as mud.