[tempestn]

Yes, it's unfortunate that it is really difficult to formally study something like this. You can't very well induce choking to test the options.

My completely uninformed guess is that the 'further lodge the blockage' thing might be a result of the marketing campaign ("death blows", etc.) rather than an established fact. In that case, although it would take a few extra seconds, I can see it making sense to try back blows before the HM. For one thing, you may actually dislodge the blockage more quickly. (Especially, one would think, in cases that make the HM difficult, such as with pregnant women, or even if it's just physically difficult to get into the correct position due to surroundings.) And while of course I agree with you that a few broken ribs is an easy trade for continued breathing, I expect in rare cases those abdominal injuries could have serious (or even fatal) consequences. Ah, yes; a quick search came up with this[1].

[1]: http://www.ncbi.nlm.nih.gov/pubmed/8576987

[ars]

> You can't very well induce choking to test the options.

Why not?

Put some soft rubber on a string and place it in the airway then try to dislodge it. If you have any problems pull it out with the string.

It wouldn't hurt the person - you can hold your breath for a minute with no problem.

If it's uncomfortable you can spray some local anesthetic in the throat first.

[cornellwright]

Maybe you could try this, but I don't think this is something that any reputable institution's IRB would approve.

I would actually recommend trying what you suggest on cadavers. You'd have to inflate the lungs first though.