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MTF Carter

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Posts: 27
 #1 
Potentially useful data for the motocross world and the problem known as "arm pump"

we looked at NIRS during a series of static handgrip exercises at 40kg in one healthy male subject. A TR Band inflator was used to create a radial artery occlusion. we placed a Moxy on the (L) abductor pollicis brevis and another monitor on the (L) abductor digit minimi. 

*The radial artery was occluded with 12cc of air at min 5:00
*At min 45, the subject preformed a handgrip at 40kg for 5mins.
*SmO2 recovers slightly above baseline in the thumb as collateral vessels off of the ulnar artery serve to perfuse the (L) abductor pollicis brevis.  
*there is a noticeably different SmO2 recovery on the opposite side of the hand(abductor digit minimi) that is fed by the ulnar artery.
*the hang grip is repeated at 55:00min.
*the increase in heart rate is respectable for the isolated exercise.
*a third hand grip trial was pro formed at 1:18:00 for 4mins.
*at the end of handgrip the TR Band was released and the radial pulse was restored before recovery.
*hyperemia in both abductor pollicis brevis and abductor digit minimi. This is more pronounced in the abductor digit minimi. 
*a handgrip was preformed at 1:33:00 with no TR Band. SmO2 did not fall as far during the trial.
*subject walked to the cardiac research center from 1:41:00 and was seated in the lab at 1:43:00.
*brachial pressure was measured using a Philips VS3. (128/85 MAP=100 HR=80)
*3 brachial artery cuff occlusions (200mmHg) were done at 1:46:30, 2:00:00, and 2:10:00.
*at 2:20:00, a 40kg Handgrip was done with the opposite (right) hand to increase HR, SmO2, and tHb.
*at 2:22:00 the subject did a 40kg handgrip with the (Left) hand.
*Left brachial artery cuff occlusion at 200mmHg at end handgrip 2:24:00
*2:24:00 subject released grip.
*Cuff we deflated at 2:30:00

Subject who is a motocross rider described the pain during occlusion similar to the arm pump felt on a motocross bike.

Hope that is some helpful blood flow muscle oxygenation data for a motocross trainer.

Because I work in the hospital now and no longer as a trainer I don't get time to do these kind of studied but hopefully somebody can expand on this. I think loading the muscle up with as much O2 before the race is a great idea but it only goes so far. the next trick is to figure out how to keep the riders from gripping the bars so tight that the create an occlusion. 

Ride on!

sorry for the poor quality image my computer didn't feel like loading the PDF I had made of this. 
 
Screen Shot 2015-11-13 at 4.21.42 PM.png
The Blue arrows indicate the time the radial artery was occluded using the TR Band Inflator Tr-band.jpg 

DanieleM

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Posts: 264
 #2 
Hi MTB Carter,

looking at test procedure it seems like there is an arterial occlusion from min 5 to min 1:22.
If so I would expect a drop of SmO2 in the abductor pollicis brevis which I don't see.

Would be also good if you could split the activity in few parts.

Thanks
MTF Carter

Development Team Member
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Posts: 27
 #3 
DanieleM,

Thanks for the feedback! You are absolutely correct. The SmO2 should drop and that is exactly what we wanted to see. However this is a very healthy elite level athlete so collateral circulation is very good in the hand. I believe the reason you don't see a drop in SmO2 is because the abductor policies brevis is also being fed by collaterals off of the ulnar artery. The TR band allows for venous flow during radial artery occlusion.

What is interesting here is that when the radial artery is fully open in the BLUE segment.. the SmO2 doesn't drop the same amount even though the grip is the same (40kg). so the question becomes is the muscle in a state of hyper-extraction due to the lack of flow?  When the flow is fully restored it would 
appear that the muscle is extracting less. On of the things we are looking at is in a patient population when the leg is re-vascularized does more flow lead to less extraction during exercise? Can these patients now exercise with the increase in flow?  

On the motocross track the arm pump riders get with an occlusion is often the end of their race. After they get this arm pump they have to pull of and recover. Some of the work I did with Clint and Jurge in the past seemed to suggest that if we increased MVC in riders they decreased the amount of arm pump they got. this was also flow related as the pain was likely a result of an arterial and venous occlusion. the last drop in SmO2 replicates this with the mid grip cuff occlusion.

That was probably a lot more information then you were expecting haha! yes, occlusion = SmO2 drop... unless you haven't also occluded collateral flow... this is basically what is the main factor in vascular disease. the body attempts to bridge the gaps. unfortunately much like a blocked highway... you can put in a detour but it is not quite as good as the real thing.

Screen Shot 2015-11-18 at 11.09.47 AM.png    

DanieleM

Development Team Member
Registered:
Posts: 264
 #4 
Hi again,

What is interesting here is that when the radial artery is fully open in the BLUE segment.. the SmO2 doesn't drop the same amount even though the grip is the same (40kg). so the question becomes is the muscle in a state of hyper-extraction due to the lack of flow?  When the flow is fully restored it would appear that the muscle is extracting less. On of the things we are looking at is in a patient population when the leg is re-vascularized does more flow lead to less extraction during exercise? Can these patients now exercise with the increase in flow? 
Yes, that makes absolutely sense: you want to produce the same energy, as you are doing here, if you have more flow you don't need to desaturate much.
But, I would still think that at rest in theory, with radial occlusion, we should see some desaturation either in pollicis (less flow from radial) or in minimi (ulnary).
Just a speculation: the ulnary at rest can increase the blood flow to serve both pollicis and minimi.

Then the 3 brachial artery occlusion, I can see they last approximately 4 or 5 minutes, and of course they desaturates almost completely both pollicis and minimi.
Perhaps first occlusion lasted a bit more (saturation approaches 0)
It's interesting the hyperemia observed here.
Venous occlusion before arterial one?
Would be good to have a zoom on these areas.

Very nice job [wink]  
juergfeldmann

Development Team Member
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Posts: 1,501
 #5 
Yes
 Would be good to have a zoom on these areas.
looking  at  a  closer situation to see the   possible three  stages  of  change in tHb  compression,  outflow restriction and  occlsuioo9n    as arterial occlusion  and than   possible out flow reactions or  if  the pressure  stays  and additional tHb increase  when we let go  art occlusion but maintain  venous occlusion.  Carter  super great   feedback on here
Thanks so much
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