gsxraddict,

Two comments...  The best information on maximum exposure to 100% oxygen says we can breath it without any breaks breathing air for 10 to 12 hours.  After that, the symptoms of pulmonary oxygen toxicity start.  They're much like pneumonia due to the edema or swelling and fluid build up in the lungs.  As such, these symptoms make it very painful to continue breathing 100% oxygen. 

Fortunately, this condition clears in a matter of minutes without any lasting effects if the user stops breathing 100% oxygen and resumes breathing room air at the first sign of breathing difficulty.

I can speak from experience as a Navy pilot with over 3000 hours flying fighters on and off aircraft carriers breathing 100% oxygen from takeoff to landing on every flight. Most lasted over two hours and several missions lasted over 7 hours.   I might also add I was breathing the 100% oxygen at flow rates well over 25 liters/minute and at times over 45 liters/minute for extended periods.

The second point is an oxygen flow rate of 8 liters/minute may work if you are very fast starting the therapy and catch the CH as it's just starting while the pain level is very low. 

Unfortunately, once the pain level climbs over Kip-4 or Kip-5, you're going to be in for some heavy sledding and a along for the ride with very long abort times... if an abort is even possible.

We've plenty of data and lots of experience that tells us a flow rate of 15 liters/minute is the absolute minimum and even then, that flow rate is only good up to a Kip-6 to Kip-7.  Even then there will still be a lengthy abort time.

If you really want fast aborts of your CH attacks, a flow rate of 25 liters/minute is needed. If you want the fastest aborts possible, you'll need much higher flow rates. 

It takes an oxygen flow rate minimum of 25 liters/minute to start hyperventilating.  Higher flow rates make it even easier to hyperventilate and that pushes your system into respiratory alkalosis with an elevated arterial pH.  Both of these conditions are safe and very effective in stimulating vasoconstriction, one of the major components of the CH abort mechanism.  Moreover, flow rates this high will result in average abort times of 7 minutes without the side effects associated with triptans.

Shoot me a PM and I be happy to send more information on this method of oxygen therapy.

Take care,

V/R, Batch