Kentucky's ongoing attempt to end racing in state proceeds..

[Riot]

Originally Posted by Rupert Pupkin

Every vet and trainer I know say exactly the opposite. They will all tell you that if a horse who doesn't normally bleed, all of a sudden bleeds (a decent amount like a 3), there is almost certainly something going on. As Chuck said, it could be an infection. It could be an injury that has yet to be diagnosed. It could be a lot of things. It would be a huge mistake to just assume that the horse bled for no reason and that a bigger dose of lasix is the answer.

Whoa - that's not how it's looked at

What I am saying is that no, "other things" are not considered causal for Exercise Induced Pulmonary Hemorrhage.

There can be bleeding in the lungs due to other things that are NOT EIPH. Not all bleeding is EIPH. But 93% of race horses have evidence of microscopic bleeding due to EIPH in their lungs after races.

Including some lung infections (which can be secondary to chronic subtle bleeding in origin, as blood is the perfect bacterial growth medium)

[Rupert Pupkin]

Originally Posted by Riot

Whoa - that's not how it's looked at

What I am saying is that no, "other things" are not considered causal for Exercise Induced Pulmonary Hemorrhage.

There can be bleeding in the lungs due to other things that are NOT EIPH. Not all bleeding is EIPH. But 93% of race horses have evidence of microscopic bleeding due to EIPH in their lungs after races.

Including some lung infections (which can be secondary to chronic subtle bleeding in origin, as blood is the perfect bacterial growth medium)

I wasn't talking about microscopic bleeding. It may very well be true that 93% of racehorses have evidence of microscopic bleeding. Microscopic bleeding is not a big deal. We don't need lasix for microscopic bleeding. Microscopic bleeding isn't going to affect a horse's performance in the least bit. Could it turn into a problem eventually? Yes, of course it conceivably could turn into a problem if it gets worse. But there is also a good chance that the microscopic bleeding won't get any worse and it will never turn into a real problem and it will never affect the horse's performance.

I know you will probably argue that we should use lasix prophylactically to make sure that the microscopic bleeding doesn't get worse. That is a fair argument. Some people will agree with that argument and others won't.

[Riot]

Originally Posted by Rupert Pupkin

I wasn't talking about microscopic bleeding. It may very well be true that 93% of racehorses have evidence of microscopic bleeding. Microscopic bleeding is not a big deal. We don't need lasix for microscopic bleeding. Microscopic bleeding isn't going to affect a horse's performance in the least bit.

Whoa, wrong, no, yes, it does. Microscopic bleeding is indeed the big deal. It causes small airway and alveoli scarring, impedes their breathing, sets them up for lung infections, pneumonia, fear of running. This is precisely why we use lasix in most horses! Not just to keep from looking at massive, uncontrolled bleeding which is only visible in the larger airways.

There are about 18 branching divisions looking down into the lungs, and the bronchoscope only goes down a few. If there is so much bleeding down in the lungs that it's bubbling up to be visible, that's not good!

Yes, it's true the horses are not approved for lasix use on the track until they have a visible episode of bleeding (bleeding so significant it's literally coming up out of their lungs into their bronchi), but we know that 93% have bleeding that isn't severe enough to see grossly on a scope. Yes, we want to protect their lungs, too! If your distal airways at the tiny microscopic aveolar sacs are filled with blood cells, you can't get oxygen exchange and you start to suffocate. A horse can and will pull up with this, and the horse can get scoped, and you might not see bleeding grossly in the larger airways. But if you do bronchoalveolar lavage (not done stallside at the track commonly to diagnose EIPH) yes, you find the cause.

This is why the AVMA and AAEP support lasix use in race horses.

Remember that 30 years ago, we didn't even have common stallside bronchoscopy right after races to diagnose bleeding. We only diagnosed it if blood came out the nostrils. Now, we know better, as more horses that don't bleed visibly out their nostrils still have blood in the larger airways. And we know that horses that still don't have blood in the larger airways still show evidence of EIPH by blood down in the smaller airways and alveoli (air sacs that exchange oxygen with the tiny blood capillaries). 93% of them do.

The end point is: we use lasix in the United States and South America, and it's a good thing for race horse lungs. We could eliminate our lasix use on race day, but it would still be used in the morning to prevent injury to horse lungs when they work at speed (just like other countries do now). Why? Because it protects horse lungs. Even if a race isn't on the line.

[RolloTomasi]

Originally Posted by Riot

Microscopic bleeding is indeed the big deal. It causes small airway and alveoli scarring, impedes their breathing, sets them up for lung infections, pneumonia, fear of running. This is precisely why we use lasix in most horses! Not just to keep from looking at massive, uncontrolled bleeding which is only visible in the larger airways.

Are you suggesting that furosemide stops microscopic bleeding?

[Riot]

Originally Posted by RolloTomasi

Are you suggesting that furosemide stops microscopic bleeding?

Yes. Research shows a decrease in red blood cells and hemosiderophages via transtracheal washes post lasix vs. without lasix.

Diagnosing EIPH gives vastly different incident percentages depending upon the method: visual assessment by laypeople vs visual assessment by vet vs. bronchoscopy vs. transtracheal wash (TTW) or bronchoalveolar levage (BAL).

The gold standard is something we don't do on the track, BAL or TTW.

We do use bronchoscopy, but it misses evidence of lower airway bleeding, only detecting visible blood that has been moved up into the upper airways.

[RolloTomasi]

Originally Posted by Riot

Yes. Research shows a decrease in red blood cells and hemosiderophages via transtracheal washes post lasix vs. without lasix.

Is decreasing the severity of bleeding the same as stopping bleeding?

[Riot]

Originally Posted by RolloTomasi

Is decreasing the severity of bleeding the same as stopping bleeding?

Not necessarily - sometimes lasix makes it less, sometimes it makes it stop completely, sometimes it doesn't do anything. Overall yes, lasix vastly reduces the incidence of detection of bleeding due to EIPH in horses, including stopping it in some horses.

Here's a cross section of lung (viewing it from the horses left side, the front of the horse is on the left) showing where bleeding occurs, the top (dorsal) back (caudal) part of the lung. We only detect blood when it comes out of the lungs up into the trachea. The trachea isn't shown here, it would be to the left of the lungs:





Here's a horse bleeding so bad blood is bubbling out of the lungs, up the trachea, and out the nose. Only 1 out of 20 will bleed so badly this is seen:



Here's a horse with a little blood in the trachea via bronchoscopy: