Actually it's been my experience and I think it is documented in the literature as well, that the subclavian is the most dependable line in the severely hypovolemic patient.
The clavicle helps hold the vein open and you don't need to find a pulse to place it, the clavicle and it's landmarks are palpable whether the heart is beating or not.
First of all, I would be interested in seeing that literature. I believe you that it exists, and I'm not being a smartass. I really want to hear someone justify subclavian lines in these emergency situations.
When a patient is severely hypovolemic, as you've described, the subclavian vein is likely to be somewhat collapsed. Regardless of the fact that your landmarks are constant, your target becomes very small and your chance of a pneumothorax increases significantly.
Secondly, it only takes common sense to see why an IJ or subclavian would not be the best option in codes or trauma situations:
It is a patient safety and healthcare worker safety issue.
Trauma:
The patient is in a c-collar, which negates IJ. Also, there are multiple people trying to assess the patient, intubate, place chest tubes, etc. Imagine using sterile technique and placing a subclavian during this. What if you drop the patient's only good lung?
It is much easier to place a temporary groin line (assuming that you can't get 2 large-bore peripherals), stabilize the patient, and then place a more sterile, long-term line once the patient is in the ICU. You can place the groin line in about 1-2 minutes, using the best sterile technique you can, and then d/c it before it can get infected.
Code:
The patient is very likely to be receiving chest compressions. How safe is it for the worker doing compressions for you to be sticking a large needle in the patient's chest? How safe is it for the patient? With his/her chest moving up and down with each compression, the chances of a pneumo would skyrocket.
Maybe I'm wrong, but to me it's just common sense.
Do any of the more experienced residents or attendings have more information regarding this?