Hi asthma2012, and thanks for your post. While we cannot provide medical advice or diagnostics over the internet (for your own safety), your concern certainly warrants a reply.
Since the prescription you mentioned calls for 2 puffs every 4-6 hours, that is the way you should take the inhaler. If you're taking 2 puffs, and you still hear the 'squeak' 10-15 minutes later, it does not necessarily mean the albuterol has not been effective. You may want to consider if you feel compromised and/or short of breath when you hear the 'squeak'. Does it limit your physical activity at all?
If you are compliant with the medication regimen (2 puffs every 4-6 hours), and the breath sound ('squeak'), persists, this may be something you want to take up with your prescribing physician, especially if you feel physically compromised.
What do you think?
Leon (site moderator asthma.net)