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        New Message Board Archives >> Medications, Treatments, Therapies 2005 >> Oxygen--report from Dr. Rozen
        
(Message started by: Bob_Johnson on Jan 26^th, 2005, 10:42am)

Title: Oxygen--report from Dr. Rozen
Post by Bob_Johnson on Jan 26^th, 2005, 10:42am

Headache. 2005 Jan;45(1):98.

CLUSTER.

[No authors listed]

Rozen TD. High oxygen-flow rates for cluster headache. Neurology. 2004;63:593 The two most effective cluster abortive agents are injectable sumatriptan and inhaled oxygen. Because most cluster headache sufferers are cigarette smokers and at high risk of coronary artery disease, many develop contraindications to triptans. Oxygen, the safest of all cluster therapies, is not effective for every patient. In Kudrow's landmark study, 75% of patients responded to 100% oxygen at 7 L/min, although only 57% of older chronic cluster headache patients had relief. A recent study documented a gender difference in response to oxygen because only 59% of female cluster patients responded to oxygen, whereas 87% of men did. In most textbooks and articles on cluster headache treatment, patients are instructed to use 100% oxygen via a nonrebreather face mask at 7 to 10 L/min. The rationale behind this prescribed oxygen-flow rate is unknown but has become doctrine since the Kudrow study. Prescribing higher flow rates of oxygen up to 12 L/min has recently been suggested, but there is no documentation that this may improve efficacy. Higher oxygen-flow rates (up to 15 L/min) are not known to benefit cluster headache patients refractory to standard oxygen therapy. Three cluster headache patients who demonstrated no response to standard oxygen therapy were exposed to higher flow rates of oxygen (14 to 15 L/min) to assess response. Comments: Once again, Dr. Todd Rozen's observations will change my clinical practice!-Stewart J. Tepper, MD I have questions: Were these empirical observations or do Drs. Kudrow and Rozen know how rate of flow affects oxygen delivery? Is oxygen uptake higher with higher flows? After all, 100% oxygen is 100% oxygen unless under hyperbaric pressure! Perhaps higher flow rates dry the nasopharyx to a greater extent. If patients perceive a higher flow rate, might this be an enhanced placebo effect? It seems like an interesting study to be conducted, and it would be useful to test if using nasal cannulae is just as good. Pulse oximetry and arterialized capillary blood gases could be used to monitor oxygen saturation and CO(2) retention/carboxyhaemoglobin levels in smokers.-David S. Millson, MD.

PMID: 15663630 [PubMed - as supplied by publisher]

Title: Re: Oxygen--report from Dr. Rozen
Post by floridian on Jan 26^th, 2005, 12:07pm

I think that Dr. Tepper needs to be taken behind the wood shed and given a good education! Higher flow rate of oxygen leads to an enhanced placebo response?? I don't think there is a placebo effect for cluster headaches - either the excruciating pain ends for physiological reasons or it doesn't, and it has little to do with faith in the therapy or patient attitude! 100% oxygen is 100% oxygen, but if a person is breathing more of it per minute, they are supersaturating the blood with O2 - something that doesn't happen with the little nose clip that dribbles some oxygen into the air a person breathes. There is no need to experiment with nasal cannulae, as we know that they usually don't work, while high volume oxygen from a non-rebreathing mask usually does.

While it is good to see doctors discussing and thinking, that seems to be happening outside the real world of patient experience.

Title: Re: Oxygen--report from Dr. Rozen
Post by Gator on Jan 26^th, 2005, 9:39pm

I agree with you Floridian. These people need to talk, but they have a lot to learn about the realm of cluster headaches. The whole concept of an oxygen saturation of 100% being sufficient doesn't apply to the therapy the way we use it. According to a pulse oximeter, I can be 100% "saturated" without supplemental oxygen at all. With a person in the throes of an attack gasping for breath and sucking in whole lung fulls of oxygen, it takes a higher flow rate to keep up.

7lpm is not enough to use an NRM with. The oxygen threapy specialist at the medical supply place I get my oxygen would not even give me an NRM unless the flow rate was 10lpm or above. Even at 15lpm, I have be able to think clearly enough to control my breathing or the delivery system falls behind and I end up having to take the mask off to get a breath.

Title: Re: Oxygen--report from Dr. Rozen
Post by Chillrmn1 on Jan 27^th, 2005, 6:28am

I also agree. My neuro first prescribed 8 L/M. This amount could not keep up with my respirations utilizing a non-rebreather mask. Could not abort at this low level. Went back to Neuro and complained about the low rate and repeated what this site stated concerning 12 - 15 L/M being required. Said he never heard of such a high rate but he wrote prescription as I requested. The 15 L/M rate was enough for my respirations and ........... O2 turned out to be a great abortive for me when used early upon onset. I switch between 10 and 15 L/M while breathing to try to conserve my O2.

Title: Re: Oxygen--report from Dr. Rozen
Post by Bob P on Jan 27^th, 2005, 7:40am

I can see what Tepper is saying. Your blood can only transport so much O2. Your lungs can only transfer so much O2. If 8 lpm gives 100% O2 saturation in the blood, any more O2 is simply exhaled.

I'm 6'4", 240 lbs. and use 7-8 lpm. It works just fine in 5-10 minutes.

Title: Re: Oxygen--report from Dr. Rozen
Post by floridian on Jan 27^th, 2005, 8:48am

Some people can abort by vigorous exercise at the first sign of a cluster. Great if it works, but it doesn't work for everyone.

When the hemeglobin gets to 100% saturation, that is a limit for oxygen under ordinary circumstances. But breathing pure oxygen can further increase oxygen delivery to cells - the amount of oxygen dissolved in the blood plasma (ie, water) can still go up. Hyperbaric can increase it even more. To trigger vasoconstriction and abort a cluster headache, some people need LOTS more oxygen.

Title: Re: Oxygen--report from Dr. Rozen
Post by Bob P on Jan 27^th, 2005, 9:50am

Being an engineering type, I guess I look at the mechanics of it. Seems to me 100% saturation is the max you can have. I've never heard of something being 110% saturated. To me saturated means it is holding all it is capable of holding.

I still suggest that people start at a higher level, maybe 12 lpm, and lower the flow rate each attack until it appears to be taking longer or not working as well. Then jack it back up a liter or two. That should put them at their optimum flow rate without waste.

Title: Re: Oxygen--report from Dr. Rozen
Post by floridian on Jan 27^th, 2005, 11:25am

on 01/27/05 at 09:50:12, Bob P wrote:

There are two carriers of oxygen in the blood - hemoglobin and water. The hemoglobin is more efficient in many ways, but it is surrounded by water and dependent on the water. In the short run, the capacity of the hemoglobin system is limited by the number of red blood cells in the body. You are correct that the hemoglobin system doesn't go above 100%. Hemoglobin is like a bucket - it can only hold so much.

The blood's water is not usually saturated with oxygen, even when the hemoglobin is. Even in the lungs, the amount of oxygen in the blood's water is limited because air contains inert gasses like nitrogen. The fact that the water is not holding 100% of the physical limit is not a problem in a healthy person - there is still enough oxygen to nourish the tissues.

The water can hold more oxygen if the partial pressure of oxygen in the lungs is increased. This can be done by increasing the % of oxygen in the breath stream. A nasal cannula might increase the oxygen in the breath from 20% to 30% or 50%, but a person is still breathing in lots of nitrogen. Even when the amount of O2 in the breath reaches 100%, a further increase is possible by increasing the pressure of the breath stream (hyperbaric oxygen). It is essentially "pushing" more oxygen into the blood plasma.

I agree with you that there is no sense in using more oxygen than necessary to abort. But this level varies from person to person - for some it is enough to exercise vigorously and increase the air flow to the lungs. For some people, a low flow of pure oxygen is enough. But many people with clusters require more, or require it quickly ... and it is easier to abort in the early stages.

Title: Re: Oxygen--report from Dr. Rozen
Post by Ueli on Jan 27^th, 2005, 1:29pm

Usually, the talk about saturation is for ordinary folks at normal conditions. If the saturation level is far below 100% the patient suffers from a malfunction of the lungs and needs additional oxygen, about 2 liters / minute, through those nose thingies, for several hours a day. That is about the only use most oxygen peoples and many doctors have heard about. (Recently, the oxygen lady measured my saturation just for fun, with some wired up thimble. 97% is not bad for a heavy smoker ;).)

A clusterhead wants to get more than the normal amount of oxygen in the blood. How is this achieved?

Haemoglobin has 4 sites to bind oxygen. But it takes a high concentration oxygen to saturate all 4 sites, as can be seen here:
http://www.cryst.bbk.ac.uk/PPS2/course/section12/hbcv2.gif
(stolen from http://www.cryst.bbk.ac.uk/PPS2/course/section12/haemogl1.html)

Therefore, by filling our lungs with 100% oxygen, we utilize the full oxygen capacity of haemoglobin. The oxygen dissolved in the blood serum is not very important, less than 1% of the total.

So the important point is to fill the lungs with pure oxygen. This is obviously not possible with a leaky mask, that mixes the oxygen with room air. What I do is this: 1) install a flap on the 2nd exhaust too (salvaged from a discarded mask) and 2) adjust the strap tight enough for the mask fitting all around the rim. In this way I get along with about 8 liters / minute. Huffing and puffing like an asthmatic steam engine doesn't bring anything but increased oxygen wastage. Keep breathing at a normal rate, if the mask fits the oxygen level in the lungs will always be 100% :).

PFNADs, Ueli [smiley=smokin.gif]

Title: Re: Oxygen--report from Dr. Rozen
Post by floridian on Jan 27^th, 2005, 1:49pm

Here's a bit more (if our brains are not saturated already).

The amount of oxygen needed to saturate the hemoglobin varies - in the graph below, people with acidic blood need more oxygen to get close to the ideal 100%

http://members.aol.com/Bio50/LecNotes/LNPics/ln20b.gif
(from http://members.aol.com/Bio50/LecNotes/lecnot20.html).

For reference, ordinary air has an oxygen pressure of around 150 mm but in the lung alveoli it is usually much lower - 100 to 105 mm pO2 (at sea level, with average atmospheric pressure).

I'm not saying that clusterheads have acidic blood, but we do have an analogous problem when in cycle - if something starts to lower blood oxygen, it doesn't bounce back when that stress (apnea or whatever) is removed.

So we are more like the red or blue curve than the normal. And the only way to get our hemoglobin O2 levels up is by pumping up the oxygen, saturating the water phase to oxygenate the heme carrier. Pure oxygen has a pO2 of 760, which should be enough unless our chemistry is fubar. The rate that we breathe the pure Oxygen would affect how fast we come back up near 100% - full or rapid breaths possibly being better than shallow or relaxed breaths. Breathing faster also removes CO2 quicker, which could have an effect (probably raising pH and making it easier for the heme to stay oxygenated).

Quote:

Headache. 1990 Jul;30(8):474-80.

Association of sustained oxyhemoglobin desaturation and onset of cluster headache attacks.

Kudrow L, Kudrow DB. Medical Clinic for Headache, Encino, California 91436.

Ten episodic cluster headache patients in their active cluster period, ten patients in remission and five control subjects were monitored for minute to minute changes in oxygen saturation (SaO2) and pulse rate before and after nitroglycerin (NTG) administration. A transient but significant decrease in SaO2 and increase in pulse rate of 25 minutes duration occurred following NTG in all groups. These changes may reflect physiologic hemodynamic effects of NTG as a smooth muscle relaxant. Subsequently, SaO2 levels and pulse rate recovered to baseline values in remission and control groups. In contrast, SaO2 values in the active cluster group decreased further and after an extended period culminated in cluster headache attacks in 10/10 patients. Three major changes, therefore, distinguished active cluster patients from remission and control groups. First, the magnitude of oxygen desaturation increased after the physiological effects of NTG ceased. Second, oxygen desaturation was sustained for an additional 9 to 30 minutes duration. Third, the hypoxemic state culminated in attacks in all cases. Our findings suggest that the active cluster period may be characterized by an impaired mechanism to autoregulate, and thus compensate, for hypoxemia. It is further proposed that persistence of hypoxemia and the cluster attack onset may share a common mechanism, coupling the two events. We suggest that abnormal central and/or peripheral chemoreceptor activity may be responsible for these events.

Title: Re: Oxygen--report from Dr. Rozen
Post by Bob_Johnson on Jan 27^th, 2005, 2:46pm

Why, it's like looking at "Dueling Banjos" !

Title: Re: Oxygen--report from Dr. Rozen
Post by floridian on Jan 27^th, 2005, 3:06pm

Thank you, thank you very much.

http://www.masterengraver.com/astronaut-banjo.jpg

Ueli, take a bow!

Title: Re: Oxygen--report from Dr. Rozen
Post by BikerBob on Jan 28^th, 2005, 4:16pm

What works best for me...

Less than 10 lpm is nowhere near as effective as 11-12 lpm.
More than 12 lpm seems to be wasting O2.

Using a non-rebreather mask, I start at 12 lpm standing
and shaking my legs (sometimes voluntarily and
sometimes involuntarily) imagining blood flowing to my
feet for a few minutes. Then I turn it down to 11 lpm, sit,
try to relax, take long slow inhales through my nose and
exhales through my mouth. Depending on the hit; this
works in 5, 10, 15 minutes or not at all. I can tell in 3- 5
minutes if it's not going to work in 15 and only then use a
triptan.

I've been getting hit at about 7pm, 9pm, 11pm, 1am, and
if I don't take a triptan at 1am, again at 3am and 5am.

The O2 has worked for all but the 1am hits.

I've used up two H tanks in the last 25 days.
That's equivalent to 20 E tanks? O2 is cheap.

Bob

Title: Re: Oxygen--report from Dr. Rozen
Post by scott22 on Jan 28^th, 2005, 7:27pm

The big problem is that some people need higher rates to keep up with their breating, bottom line. I know my setup tops out at 10 lpm and that's barely enough to keep from having to rip the mask off to get air when i'm having a bad attack and breathing rapidly.

If 7 or 8 lpm keeps up with your breathing, than yeah that's all you need.