Candid,
Hang in there... What you appear to be experiencing is a "High Cycle" where the hits come fast, furious, hang on like a klingon, and resist preventative and abortive medications including oxygen therapy.
There are solutions for this condition and it is
NOT the result of too much oxygen, but it can be an indication of a low arterial pH and that oxygen therapy is not being used effectively..
We've anecdotal proof that high cycles like this correspond to a low arterial pH... If this is the case, your arterial blood is likely too acidic. The normal blood pH should be 7.4 (7.35 to 7.45). If your arterial pH is in the low end of this range or below, your vascular system reacts to this condition by dilating. Arteries react like this in response to a higher than normal CO2 level so dilation takes place to increase blood flow from the body to the lungs to release the excess CO2.
This condition also appears to make the cluster headache triggering mechanism more effective and that results in an increase in the frequency, intensity, and duration of cluster headache attacks. A low arterial pH also tends to make oxygen therapy less effective. In other words, it takes longer than normal to abort the cluster headache pain with oxygen therapy even if used correctly.
The simple solution I use when a high cycle starts is to take 4 to 6 calcium citrate tablets with vitamin D, magnesium and zinc a day. A mineral supplement blend like this acts as a chemical buffer to bring a low pH condition back up to neutral.
During my high cycles, I average 3 to 4 attacks a day and during low cycles, I average is 3 to 4 attacks a week. If I dose on the mineral supplements, the frequency of my cluster headaches drops to one attack in ten days... I use the Kirkland brand Calcium Citrate tablets from Costco. Citracal® Plus Bone Density Builder has a similar formula but at slightly lower concentration per tablet.
I also drink 2 to 3 glasses of lemonade a day during high cycles. One 8 ounce glass with lunch and two with dinner. Strange as it may sound, the citric acid in lemonade actually elevates the arterial pH and this helps to further lower the frequency, intensity, and duration of my attacks.
Arteries sense a high pH condition as being caused by not enough CO2 so they constrict to slow the flow of blood from the body to the lungs to allow CO2 levels to build.
Check the pH balance chart at the following link:
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Cutting down on red meat and maxing out on green veggies can also help elevate arterial pH.
As you indicated you've an oxygen regulator capable of 25 liters/minute, the first thing you need to do is keep it at that setting and breathe as deeply as possible. 25 liters/minute is superior to 15 liters/minute and it's the minimum flow rate that supports hyperventilation...
Higher oxygen flow rates work even better and faster as they support a greater level of hyperventilation...
What kind of non-rebreathing mask are you using? If you've got one of the disposable masks with the 1-liter reservoir bag, order an O2PTIMASK™ kit from DJ here on CH.com.
The breathing technique used during oxygen therapy is very important. I stand while doing the following to give my diaphragm full range of motion in order to ventilate the lungs to the maximum extent possible to cast off CO2.
Exhale as completely as possible... and when it feels like your lungs are empty... their not, so do an abdominal crunch like in doing sit ups along with a coughing maneuver only hold the squeeze you feel in your chest muscles until you hear a wheezing sound for at least a second... then inhale as deeply as possible and repeat.
If you're doing this breathing technique correctly, you should start feeling the symptoms of paresthesia, a slight tingling of the fingertips and the back of your neck along with a slight feeling of dizziness in less than a minute. Paresthesia is the best indication you've hyperventilated long enough and cast off enough CO2 to push your system into respiratory alkalosis (an elevated arterial pH).
The arteries in and around your trigeminal nerve will react to an elevated pH by constricting (as they would from an imitrex injection) and this will help abort the attack.
Take care,
V/R, Batch