Jared,

Good on you for getting the Rx for oxygen therapy flow rate raised to 15 liters/minute.  Next time tell your doc it's working well but could be working even better with a flow rate of 25 liters/minute to make the aborts come even faster.

The tingling or prickling sensation of the finger tips, lips, back of the neck and possibly a slight dizziness you're feeling are a good sign you are hyperventilating with oxygen therapy correctly and the flow rate is high enough to support a low level of hyperventilation. 

These symptoms are indicative of respiratory alkalosis (also good) and they're called paresthesia.

If you feel the symptoms of paresthesia, (again it's a good sign) you are pumping CO2 out of your lungs faster than your body is generating it through normal metabolism and this will result in fast aborts with greater efficacy.

Respiratory alkalosis means the pH of your arterial blood is being elevated by voluntarily hyperventilating with 100% oxygen and this elevated arterial pH stimulates the vasoconstriction in and around the trigeminal nerve that's needed to abort the cluster headache. 

A flow rate of 15 liters/minute is ok for cluster headaches at the lower pain levels.  However, once they climb above 6 to 7 on the 10-Point headache pain scale, a flow rate of 25 liters/minute or higher will be needed to get the same fast and reliable aborts. 

I use an oxygen flow rate of 40 liters/minute after jump starting my system into respiratory alkalosis with a flow rate of 60 liters/minute for one minute or until I start sensing the same symptoms of paresthesia.  At that point I throttle back to 40 liters/minute and hold that flow rate until the abort.

If you stop and think about it, when you take imitrex, part of it's therapeutic effect is to stimulate vasoconstriction.

Don't be surprised if you start having re-attacks.  They are common for the first few weeks after you start using this method of oxygen therapy and they'll eventually go away all by themselves.

We've defined a re-attack as another cluster headache that happens 15 to 40 minutes after a successful abort with oxygen therapy.  If the next attack comes an hour or two later... it's just a regularly scheduled cluster headache as oxygen therapy is only an abortive...  not a preventative.

I made a post yesterday in the thread titled "Quick question about Optimask" with an attachment that explains a bit more about the O2PTIMASK™ and also about re-attacks.

Fortunately a re-attack is just another cluster headache and it will abort just as fast as the last one if you start on oxygen early.  Staying on oxygen after the abort to bring the total time on oxygen up to 15 minutes, but at a lower flow rate can help prevent re-attacks.

Again, good on you... Keep it up.

V/R, Batch