May 6, 2025 • 18 mins
Curious about the scientific evidence behind treating joint infections in foals? This eye-opening conversation with Dr. David Wallace explores groundbreaking research validating common clinical practices while revealing surprising limitations.
Septic joints in foals present a clinical challenge requiring both local and systemic antimicrobial therapy. Until now, veterinarians have largely extrapolated treatment protocols from adult horses without solid evidence supporting these approaches in neonatal patients. Dr. Wallace's research addresses this critical knowledge gap, examining whether concurrent intravenous regional limb perfusion (IRLP) and systemic amikacin administration achieves therapeutic concentrations in both compartments.
The results offer reassurance that splitting the amikacin dose—one-third for regional perfusion and two-thirds systemically—effectively treats both joint infections and underlying systemic disease. Most joints achieved therapeutic concentrations, though significant challenges emerged with hind limb perfusions. The metatarsophalangeal joint consistently failed to reach target levels, revealing important technical limitations around tourniquet placement and vascular integrity that clinicians should consider when treating these patients.
This conversation highlights numerous opportunities for future research, from evaluating alternative tourniquet designs to determining appropriate dose adjustments for multiple affected limbs. Dr. Wallace emphasizes that individual patient response remains paramount, reminding us that "foals are not small horses" and require specialized approaches. Whether you're a practicing veterinarian, student, or equine enthusiast, this episode provides valuable insights into evidence-based care for our youngest equine patients. Subscribe now to stay updated on the latest advances in veterinary medicine!
JAVMA article: https://doi.org/10.2460/javma.24.10.0678
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Wellness Pet Foods (00:01):
Mealtime is more than a bowl of food.
It's the foundation for a longand healthy life.
At Wellness, dry recipes arecrafted with the highest quality
natural ingredients for a tastethat pets love and
scientifically proven throughAFCO feeding trials to ensure
that every complete and balancedmeal supports the five signs of
wellbeing.
With Wellness Pet Foods, petparents can share a life of
(00:25):
well-being together with theirpet.
Sarah Wright (00:31):
This is Veterinary Vertex, a podcast of the AVMA
Journals.
In this episode we chat abouthow concurrent intravenous
regional limb perfusion andsystemic amikacin achieves
variable synovial fluid amikacinconcentrations and healthy
neonatal foals with our guest,David Wallace.
Lisa Fortier (00:50):
Welcome listeners.
I'm Editor-in-Chief LisaFortier, and I'm joined by
Associate Editor Sarah Wrightand David hey.
David, thanks so much fortaking the time to be with us
here today.
I know you're very busywrapping up your residency.
David Wallace (01:02):
Thank you, guys for having me.
It's an honor to be here.
Sarah Wright (01:04):
All right, let's trot on over.
So, David, your JAVMA articlediscusses how concurrent
intravenous regional limbperfusion and systemic amikacin
achieves variable synovial fluidamikacin concentrations in
healthy neonatal foals.
Please share with our listenersthe background on this article.
David Wallace (01:22):
Yeah.
So we know a lot about regionalimperfusion use in adults, and
I think what a lot of people aredoing is kind of extrapolating
what we do know from adults andusing it in foals.
So kind of what we set out todo was to try and look at the
most common techniques that areused and try and figure out,
like, is it truly reaching theconcentrations we want?
(01:44):
And so we looked at a couple ofolder articles that are looking
at, you know, appropriate dosesfor falls at that age, what
MICs we're trying to accomplish,both synovially and
systemically, to make sure we'retreating systemic infections
that pretty commonly lead tosynovial sepsis, and then just
try and make sure that we'rehitting those markers as often
(02:06):
as possible.
Sarah Wright (02:07):
I come from the zoo world where we're always
trying to figure out like doesthis drug actually work in the
species?
Is it reaching therapeuticlevels?
So I have a very healthyappreciation for studies like
this.
So definitely worthwhile.
And what are some of theimportant take-home messages
from this article?
David Wallace (02:22):
Yeah.
So I think the most importantthing that we found is that it
does work.
I know what a lot of peoplethat I talked to beforehand.
They were concerned that bysplitting the dose, like we did
in this paper, is going to takeaway from the systemic
concentration that you're goingto achieve and you would be
short-changing the treatment of,let's say, on fallopalbitis or
pneumonia or something like that.
And so what we found is that bysplitting the dose a third in
(02:44):
the regional perfusion andtwo-thirds systemically we are
reaching appropriate systemicconcentrations for continued use
.
We are getting close to thetrough concentrations to allow
for 24-hour dosing.
We're a little bit above whatwe'd like to accomplish.
So that might need to be lookedat to see if, like if you're
going to be dosing this multipledays in a row is there going to
(03:04):
be buildup of theaminoglycoside.
But then, on top of that, we'realso reaching appropriate
synovial concentrations in mostof the joints that we tested.
There's a couple caveats, Ithink, to that statement, but it
is shown to be effective at thedoses that we've used with the
splitting that we did in thistreatment.
Lisa Fortier (03:23):
David, I really applaud you guys for putting
some evidence behind somethingthat we've been doing, as you
said, empirically for a longtime.
What sparked your researchinterest in this topic?
Did you have a foal that had aresistant infection or did you
end up with some nephrotoxicity?
What really sparked like, oh,we need to look into this and
make sure it's legit?
David Wallace (03:44):
Yeah.
So I think kind of, in talkingas a resident, I needed a
research project and so tryingto come up with what we wanted
me to do.
Coming into the residency I dida ton of internships and so
I've seen a ton of differentways to do regional perfusions
and falls.
Everyone has their own cocktail, everyone has their own
technique that they want.
Um, and our internal medicineclinician at OSU actually had a
(04:08):
question about this because theywere wondering if you have a
horse that has multiple legsthat have synovial sepsis and
you're trying a dose splittinglike what's appropriate, and we
were like, well, before we tryand dive into that, we need to
make sure that it works, justdoing one leg.
Umoonover is my mentor and hedoes done a ton of work in the
realm of adult IV, regional andperfusions, and so this kind of
(04:30):
seemed like a natural next stepto go to foals and I just
realized this is a huge hole inthe literature and we need to
start down the path of trying tofigure out what's appropriate
for foals when we're trying touse these techniques.
Lisa Fortier (04:42):
Yeah, very important.
Mike's a great mentor.
I'm glad you found him.
David Wallace (04:46):
Yeah, I like working with him.
Lisa Fortier (04:49):
Always when Sarah asked you a little bit earlier
what were some of the mostimportant findings.
But every time we do a studylike this, we find things that
surprise us, that lead to morestudies.
So when you and Mike were doingthis one, what did you find
were some of the most surprisingfindings?
David Wallace (05:04):
So I think the most surprising finding that we
found was that the hind limbthat we were treating for
regional perfusions had a coupleof problems that kind of
muddied the waters of some ofour findings.
And so specifically the hindlimb, fetlock or the metatarsal
phalangeal joint, almost all ofthe falls, you know, there were
maybe one or two that actuallyreached appropriate
(05:24):
concentrations, but for the vastmajority of them they were well
below even the low end of thetarget that we were trying to
achieve.
And you know, looking furtherinto that, we have questions
about why that might havehappened of the amikacin while
the perfusion was going, and wedid find a pretty significant
(05:45):
amount of venous escape orbypass of the tourniquet.
And so the question is, youknow, is the tourniquet
ill-fitting because the gas canshape, is a little bit irregular
.
So you know, if we were to redothis study or if someone was to
do another study, it might beworth looking at, you know,
extra padding or looking at thedifference between a wide rubber
tourniquet or pneumatictourniquet that we used.
(06:07):
Also, six out of the eight legsthat we perfused had rupture of
the saphenous vein at some pointduring perfusion and so we got
really high doses orconcentrations in the
tarsacurral joint, but very lowconcentrations in the
metatarsophalangeal.
And so the question there is isit just because it was so
(06:31):
extravasated that it justdiffusely or passively diffused
into the joint that was near andkind of took away from what
could go more distally?
Or is it that we need a highervolume in the hind limb because
it's got a highercross-sectional area?
So we've got a few kind of, youknow, inconsistent things that
we could try and tighten up, Ithink, in the study design to
try and prove that thistechnique does work there.
But I think that's probably thefirst thing that we need to
investigate.
Lisa Fortier (06:52):
Yeah, tourniquets around the hawk are hard for
adults in surgery, right Ifyou're doing a hind limb
tenoscopy or anything?
So hopefully you and Mike arein the woodshed figuring out
some better way to get a hindlimb tourniquet on a horse in
the hawk region.
Sarah Wright (07:07):
So, david, you kind of alluded to this already
about some future areas ofresearch, but what are the next
steps for research in this topic?
David Wallace (07:13):
Yeah, I think this is probably the most
exciting part, because we haveessentially just opened the door
a little bit and I think a lotof people can take this a ton of
different ways.
I think the first thing that weneed to look at is probably
that hind limb and see, like youknow, is the tourniquet need to
(07:33):
be extra padded?
Do we need to look at um like ameta-analysis came out for
adults looking at the differencebetween wide rubber tourniquets
and pneumatics that might needto be investigated in the falls
to see if one is moreappropriate than the other?
Um, looking at, uh, differentdrugs instead of just
aminoglycosides, um that can beused for perfusions Probably the
most important next step.
For you know we've done this inhealthy neonatal foals.
(07:53):
Now we need to start doing itin actually clinically affected
foals, because we know thatfoals that are clinically
affected are going to havedifferent metabolism rates of
aminoglycosides.
It's also going to change asthey age up, so we may need to
look at dose changes as they gofrom neonatal to kind of
pre-weaning, to weaning, toyearling ages.
(08:15):
I think that's something thatneeds to be looked at.
And then one of the big ones isif we have more than one leg
that's affected.
How are we going to furthersplit that dose?
Because we're going to keeptaking it away from systemic.
At least this way it hastreated the systemic infection,
or at least it suggests that itwill.
But if we take more away fromthe systemic dose, is that going
(08:35):
to actually further drop thatdown, and so I think we need to
look at that as well.
So I think that's reallyexciting that you know we've got
kind of the baseline studydesign and now we everyone can
just run with it and, you know,try and fill in all these holes
have you and mike started any ofthose studies yet?
not yet.
We have some ideas and we havea new resident coming in
starting in july and he'salready starting to kind of pull
(08:58):
together something and try andget her on to doing that one.
So we do have someone trying todo that.
Um, I want to go into academia,so I think that this is nice,
that I can kind of latch ontothis and maybe make this the
rest of my career if I have todo research in academia, just
keep hammering out these finerpoints.
Sarah Wright (09:17):
Lots of great ideas.
We hope to see many moremanuscripts from you then in
Javma.
And do you see a role for AI inthis area of research?
And do you see a role for AI inthis area of research?
David Wallace (09:27):
Yeah, this is the harder one that I was trying to
come up with because, you know,growing up I read a lot of
Isaac Asimov and AI scares me.
(09:48):
But I do think that there is aplace for it, especially in the
data coalition, because one ofthe hardest things that I had to
do, you know, in betweenperforming all the profusions
and then writing the manuscript,was the data, you know, just
sifting through it, and it's alot of numbers to try and get
through.
So I had a hard time trying tosift through and find, you know,
if there were lab errors thatyou know one number didn't fall
in line like it would make senseto, and then we would send
backup samples to retest those.
So I do think that, like somesort of AI would help kind of
collate that data, find thoseoutliers that might need to be
(10:13):
retested to make sure that itactually, you know, is that
number or was that a lab errorthat needs to, you know, be
reassessed, and then you know,aid in just kind of getting some
of the statistical analysisstarted and then still have a
statistician kind of you know,double check.
All those things.
I do think it can help a lotwith, you know either data
coalition specifically, studydesign, I think in certain areas
as well.
But I do think that that willkind of start to have a bigger
(10:34):
role as it gets a little bitmore improved.
Sarah Wright (10:37):
Yeah, it'll be super interesting.
I think that's definitely oneof the more common answers that
we receive, so if any of ourlisteners have any ideas,
definitely let us or authorsknow.
And for those of you justjoining us, we're discussing how
concurrent intravenous regionallimb perfusion and systemic
amikacin achieve variablesynovial fluid amikacin
concentrations with our guestDavid.
Lisa Fortier (10:58):
Hey, David, you talked about doing a few
internships and that kind ofsparked the idea for this
manuscript.
But how did your training orother work prepare you to not
just design the study but getthe study done, cross the finish
line, get the manuscriptwritten and submitted?
David Wallace (11:17):
Yeah.
So I think I was very fortunatein having a lot of internships
and very high volume practicesso we saw a whole bunch of foals
with septic joints when I wasin Kentucky.
So I've done you know, almostprobably hundreds of you know
full IV regional imperfusions,which helped me in the study
design because we initially hadtried to do this under sedation
(11:39):
and I remember back thateveryone I've done in a clinical
example was under generalanesthesia.
So after getting kicked in thestomach a few times by the half
sleep full, it was like, okay,maybe we just anesthetize them
because that's clinically whatwe're going to do anyway.
But I got a lot of skills inyou know doing the regional
perfusions.
I got to work with a ton ofdifferent veterinarians who all
(11:59):
have different ways of you knowviewing what the appropriate
dose splitting is.
I talked to a few who sparkedthe concern that well, if we're
taking away from systemic dosing, are we shortchanging them?
And or if we're giving a fulldose systemically and a partial
dose regionally, are weoverdosing them and potentially
setting them up fornephrotoxicity?
And so just getting theopportunity to work with so many
(12:22):
like really well-knownveterinarians, getting all the
different pieces of you knowempirically what they think
works and just going.
Well, I guess maybe I shouldjust go and figure out what
actually works and then to workwith Mike Schoonover, who has
done a ton of work in the realmof regional imperfusions already
and he already had, you know,some connections with different
(12:43):
labs to do the assays, just kindof help, you know, fill in
those gaps and made it very easyto just kind of run with it
once we got the project started.
Lisa Fortier (12:53):
Have you had the opportunity to share this data
in this manuscript with thoseother doctors that you worked
with in your internship andgotten their support or swayed
them perhaps?
David Wallace (13:03):
Not yet.
I was waiting for it to getaccepted so I could prove like,
hey, it's actually going to getpublished.
And then I was going to send itto him or at least call him and
just be like hey, I got thispaper published, just want to
know what your thoughts are onit.
And if you think that we missedsomething or need to go another
direction and prove somethingelse, like, let me know because
I want to do more on it.
So we've got more holes to filland I would welcome all Sure,
(13:31):
sounds like you're the nextleader, though.
Sarah Wright (13:35):
Yeah, I love that you're open to feedback too.
That's awesome.
Now this next set of questionsis going to be very important
for our listeners, and the firstone is going to be about the
veterinarian's perspective.
What is one piece ofinformation the veterinarian
should know about amikacinconcentrations and healthy
neonatal foals?
David Wallace (13:51):
I think the first thing to know is that at least
this technique we know works.
That doesn't mean that othertechniques probably won't, and
probably should look into that.
(14:12):
But we did find, you know,check that we could make sure
that the tourniquets were inplace no joint achieved in the
even near the appropriatetherapeutic dose that we wanted,
and that's, I think, just anindividual response.
And so I think it's veryimportant that, even though
you're using this, thesetechniques that have been, you
know, shown to suggest that theywork, response to therapy is
(14:33):
going to be very important.
And so if you are doing thesame thing over and over and not
achieving any sort ofprogression in the case, it
might be because that horse isnot going to respond
appropriately and we need to goto a different technique,
whether it's directintra-articular injections or
use a different antimicrobial.
So I think that's important toknow that.
You know this isn't the end-all, be-all treatment.
Sarah Wright (14:58):
But on the other side of the relationship, what's
one thing clients should knowabout this topic?
David Wallace (15:03):
I would probably say about the same thing,
because, you know, anytime aveterinarian tries a therapy and
it doesn't work, you know it'svery frustrating for the client.
I think it is important forthem to realize that there is an
individual variability to theresponse of any therapy that
we're going to do and to just,you know, be patient.
You know we're going to keepchecking all of our vitals, keep
checking cytologies and thingslike that, to ensure that we're
(15:26):
making headway, and know that ifwe aren't, we're going to pivot
and try something else.
And so I think it's justimportant for them to just kind
of, you know, have a littlegrace and be patient with us as
we try to sift through some ofthese.
You know, nuances with,especially with foals they're,
you know everyone thinks thatthey're small horses and they're
not.
They're their own thing.
Lisa Fortier (15:44):
They definitely are.
And if you only got kicked inthe stomach when they're under
sedation, try to do this, you'redoing pretty well and it is
pretty silly, you know, when youthink it takes somebody on the
head, somebody in the forearm,somebody in the hind limbs and
the tail and then you to do theregional.
David Wallace (15:59):
So it's just like a waste of these falls and
getting them anesthetized sothat once they were still, the
manpower didn't need to be quiteas high, so I've really enjoyed
(16:22):
working with everybody on thisproject.
Lisa Fortier (16:24):
Yeah Well, David, I really enjoyed speaking with
you and Mike at the conferenceand over your poster, and so
glad I convinced you eventuallyto submit this to JAVMA, and
I've learned more from you todaytoo.
So, thank you for agreeing tobe on our Veterinary Vertex
podcast.
David Wallace (16:40):
Thank you guys for having me.
It's been great and it's agreat honor.
It's the first time I've everbeen recorded for something, so
it was great.
Lisa Fortier (16:47):
Very good.
As we wind down, we like to aska little bit more of a personal
question.
David Wallace (17:03):
And most of the time this dates people, but
we'll and we're always surprisedtoo.
Uh, what is the first concertyou attended?
So I went and saw acdc whenthey did the black ice tour.
Uh, that had to have been 2008,2009.
Um, I grew up listening toclassic rock, so I love acdc,
and it is only the first concertthat I went to, because I tried
to go to Led Zeppelin's reunionconcert back around the same
time and I didn't get pulled forthe drawing.
So that would have been it andthat would have.
That is my absolute favorite,so I wish that was my first one.
Lisa Fortier (17:24):
You know, ACDC is on tour again this year.
David Wallace (17:26):
And I am tempted to.
If I weren't still a resident,I would have be tempted to go
watch, but I'm afraid I'mprobably going to be on call
that weekend.
Lisa Fortier (17:35):
Yeah, they're selling out all over.
I still need to look up and gettickets somewhere.
Sarah Wright (17:39):
It's so hard to get concert tickets nowadays
it's crazy.
So best of luck to anyone whotries.
Well, thank you so much, David.
Again, just echoing Lisa, wereally appreciate you being here
today and for sharing yourresearch with us too.
David Wallace (17:53):
Thank you guys for having me.
Sarah Wright (17:59):
And to our listeners.
You can read David's article onJAVMA.
I'm Sarah Wright with LisaFortier.
Be on the lookout for nextweek's episode and don't forget
to leave us a rating and reviewon Apple Podcasts or whatever
platform you listen to.
Mealtime is more than a bowl of food.
It's the foundation for a longand healthy life.
At Wellness, dry recipes arecrafted with the highest quality
natural ingredients for a tastethat pets love and
scientifically proven throughAFCO feeding trials to ensure
that every complete and balancedmeal supports the five signs of
wellbeing.
With Wellness Pet Foods, petparents can share a life of
(00:25):
well-being together with theirpet.
Sarah Wright (00:31):
This is Veterinary Vertex, a podcast of the AVMA
Journals.
In this episode we chat abouthow concurrent intravenous
regional limb perfusion andsystemic amikacin achieves
variable synovial fluid amikacinconcentrations and healthy
neonatal foals with our guest,David Wallace.
Lisa Fortier (00:50):
Welcome listeners.
I'm Editor-in-Chief LisaFortier, and I'm joined by
Associate Editor Sarah Wrightand David hey.
David, thanks so much fortaking the time to be with us
here today.
I know you're very busywrapping up your residency.
David Wallace (01:02):
Thank you, guys for having me.
It's an honor to be here.
Sarah Wright (01:04):
All right, let's trot on over.
So, David, your JAVMA articlediscusses how concurrent
intravenous regional limbperfusion and systemic amikacin
achieves variable synovial fluidamikacin concentrations in
healthy neonatal foals.
Please share with our listenersthe background on this article.
David Wallace (01:22):
Yeah.
So we know a lot about regionalimperfusion use in adults, and
I think what a lot of people aredoing is kind of extrapolating
what we do know from adults andusing it in foals.
So kind of what we set out todo was to try and look at the
most common techniques that areused and try and figure out,
like, is it truly reaching theconcentrations we want?
(01:44):
And so we looked at a couple ofolder articles that are looking
at, you know, appropriate dosesfor falls at that age, what
MICs we're trying to accomplish,both synovially and
systemically, to make sure we'retreating systemic infections
that pretty commonly lead tosynovial sepsis, and then just
try and make sure that we'rehitting those markers as often
(02:06):
as possible.
Sarah Wright (02:07):
I come from the zoo world where we're always
trying to figure out like doesthis drug actually work in the
species?
Is it reaching therapeuticlevels?
So I have a very healthyappreciation for studies like
this.
So definitely worthwhile.
And what are some of theimportant take-home messages
from this article?
David Wallace (02:22):
Yeah.
So I think the most importantthing that we found is that it
does work.
I know what a lot of peoplethat I talked to beforehand.
They were concerned that bysplitting the dose, like we did
in this paper, is going to takeaway from the systemic
concentration that you're goingto achieve and you would be
short-changing the treatment of,let's say, on fallopalbitis or
pneumonia or something like that.
And so what we found is that bysplitting the dose a third in
(02:44):
the regional perfusion andtwo-thirds systemically we are
reaching appropriate systemicconcentrations for continued use
.
We are getting close to thetrough concentrations to allow
for 24-hour dosing.
We're a little bit above whatwe'd like to accomplish.
So that might need to be lookedat to see if, like if you're
going to be dosing this multipledays in a row is there going to
(03:04):
be buildup of theaminoglycoside.
But then, on top of that, we'realso reaching appropriate
synovial concentrations in mostof the joints that we tested.
There's a couple caveats, Ithink, to that statement, but it
is shown to be effective at thedoses that we've used with the
splitting that we did in thistreatment.
Lisa Fortier (03:23):
David, I really applaud you guys for putting
some evidence behind somethingthat we've been doing, as you
said, empirically for a longtime.
What sparked your researchinterest in this topic?
Did you have a foal that had aresistant infection or did you
end up with some nephrotoxicity?
What really sparked like, oh,we need to look into this and
make sure it's legit?
David Wallace (03:44):
Yeah.
So I think kind of, in talkingas a resident, I needed a
research project and so tryingto come up with what we wanted
me to do.
Coming into the residency I dida ton of internships and so
I've seen a ton of differentways to do regional perfusions
and falls.
Everyone has their own cocktail, everyone has their own
technique that they want.
Um, and our internal medicineclinician at OSU actually had a
(04:08):
question about this because theywere wondering if you have a
horse that has multiple legsthat have synovial sepsis and
you're trying a dose splittinglike what's appropriate, and we
were like, well, before we tryand dive into that, we need to
make sure that it works, justdoing one leg.
Umoonover is my mentor and hedoes done a ton of work in the
realm of adult IV, regional andperfusions, and so this kind of
(04:30):
seemed like a natural next stepto go to foals and I just
realized this is a huge hole inthe literature and we need to
start down the path of trying tofigure out what's appropriate
for foals when we're trying touse these techniques.
Lisa Fortier (04:42):
Yeah, very important.
Mike's a great mentor.
I'm glad you found him.
David Wallace (04:46):
Yeah, I like working with him.
Lisa Fortier (04:49):
Always when Sarah asked you a little bit earlier
what were some of the mostimportant findings.
But every time we do a studylike this, we find things that
surprise us, that lead to morestudies.
So when you and Mike were doingthis one, what did you find
were some of the most surprisingfindings?
David Wallace (05:04):
So I think the most surprising finding that we
found was that the hind limbthat we were treating for
regional perfusions had a coupleof problems that kind of
muddied the waters of some ofour findings.
And so specifically the hindlimb, fetlock or the metatarsal
phalangeal joint, almost all ofthe falls, you know, there were
maybe one or two that actuallyreached appropriate
(05:24):
concentrations, but for the vastmajority of them they were well
below even the low end of thetarget that we were trying to
achieve.
And you know, looking furtherinto that, we have questions
about why that might havehappened of the amikacin while
the perfusion was going, and wedid find a pretty significant
(05:45):
amount of venous escape orbypass of the tourniquet.
And so the question is, youknow, is the tourniquet
ill-fitting because the gas canshape, is a little bit irregular
.
So you know, if we were to redothis study or if someone was to
do another study, it might beworth looking at, you know,
extra padding or looking at thedifference between a wide rubber
tourniquet or pneumatictourniquet that we used.
(06:07):
Also, six out of the eight legsthat we perfused had rupture of
the saphenous vein at some pointduring perfusion and so we got
really high doses orconcentrations in the
tarsacurral joint, but very lowconcentrations in the
metatarsophalangeal.
And so the question there is isit just because it was so
(06:31):
extravasated that it justdiffusely or passively diffused
into the joint that was near andkind of took away from what
could go more distally?
Or is it that we need a highervolume in the hind limb because
it's got a highercross-sectional area?
So we've got a few kind of, youknow, inconsistent things that
we could try and tighten up, Ithink, in the study design to
try and prove that thistechnique does work there.
But I think that's probably thefirst thing that we need to
investigate.
Lisa Fortier (06:52):
Yeah, tourniquets around the hawk are hard for
adults in surgery, right Ifyou're doing a hind limb
tenoscopy or anything?
So hopefully you and Mike arein the woodshed figuring out
some better way to get a hindlimb tourniquet on a horse in
the hawk region.
Sarah Wright (07:07):
So, david, you kind of alluded to this already
about some future areas ofresearch, but what are the next
steps for research in this topic?
David Wallace (07:13):
Yeah, I think this is probably the most
exciting part, because we haveessentially just opened the door
a little bit and I think a lotof people can take this a ton of
different ways.
I think the first thing that weneed to look at is probably
that hind limb and see, like youknow, is the tourniquet need to
(07:33):
be extra padded?
Do we need to look at um like ameta-analysis came out for
adults looking at the differencebetween wide rubber tourniquets
and pneumatics that might needto be investigated in the falls
to see if one is moreappropriate than the other?
Um, looking at, uh, differentdrugs instead of just
aminoglycosides, um that can beused for perfusions Probably the
most important next step.
For you know we've done this inhealthy neonatal foals.
(07:53):
Now we need to start doing itin actually clinically affected
foals, because we know thatfoals that are clinically
affected are going to havedifferent metabolism rates of
aminoglycosides.
It's also going to change asthey age up, so we may need to
look at dose changes as they gofrom neonatal to kind of
pre-weaning, to weaning, toyearling ages.
(08:15):
I think that's something thatneeds to be looked at.
And then one of the big ones isif we have more than one leg
that's affected.
How are we going to furthersplit that dose?
Because we're going to keeptaking it away from systemic.
At least this way it hastreated the systemic infection,
or at least it suggests that itwill.
But if we take more away fromthe systemic dose, is that going
(08:35):
to actually further drop thatdown, and so I think we need to
look at that as well.
So I think that's reallyexciting that you know we've got
kind of the baseline studydesign and now we everyone can
just run with it and, you know,try and fill in all these holes
have you and mike started any ofthose studies yet?
not yet.
We have some ideas and we havea new resident coming in
starting in july and he'salready starting to kind of pull
(08:58):
together something and try andget her on to doing that one.
So we do have someone trying todo that.
Um, I want to go into academia,so I think that this is nice,
that I can kind of latch ontothis and maybe make this the
rest of my career if I have todo research in academia, just
keep hammering out these finerpoints.
Sarah Wright (09:17):
Lots of great ideas.
We hope to see many moremanuscripts from you then in
Javma.
And do you see a role for AI inthis area of research?
And do you see a role for AI inthis area of research?
David Wallace (09:27):
Yeah, this is the harder one that I was trying to
come up with because, you know,growing up I read a lot of
Isaac Asimov and AI scares me.
(09:48):
But I do think that there is aplace for it, especially in the
data coalition, because one ofthe hardest things that I had to
do, you know, in betweenperforming all the profusions
and then writing the manuscript,was the data, you know, just
sifting through it, and it's alot of numbers to try and get
through.
So I had a hard time trying tosift through and find, you know,
if there were lab errors thatyou know one number didn't fall
in line like it would make senseto, and then we would send
backup samples to retest those.
So I do think that, like somesort of AI would help kind of
collate that data, find thoseoutliers that might need to be
(10:13):
retested to make sure that itactually, you know, is that
number or was that a lab errorthat needs to, you know, be
reassessed, and then you know,aid in just kind of getting some
of the statistical analysisstarted and then still have a
statistician kind of you know,double check.
All those things.
I do think it can help a lotwith, you know either data
coalition specifically, studydesign, I think in certain areas
as well.
But I do think that that willkind of start to have a bigger
(10:34):
role as it gets a little bitmore improved.
Sarah Wright (10:37):
Yeah, it'll be super interesting.
I think that's definitely oneof the more common answers that
we receive, so if any of ourlisteners have any ideas,
definitely let us or authorsknow.
And for those of you justjoining us, we're discussing how
concurrent intravenous regionallimb perfusion and systemic
amikacin achieve variablesynovial fluid amikacin
concentrations with our guestDavid.
Lisa Fortier (10:58):
Hey, David, you talked about doing a few
internships and that kind ofsparked the idea for this
manuscript.
But how did your training orother work prepare you to not
just design the study but getthe study done, cross the finish
line, get the manuscriptwritten and submitted?
David Wallace (11:17):
Yeah.
So I think I was very fortunatein having a lot of internships
and very high volume practicesso we saw a whole bunch of foals
with septic joints when I wasin Kentucky.
So I've done you know, almostprobably hundreds of you know
full IV regional imperfusions,which helped me in the study
design because we initially hadtried to do this under sedation
(11:39):
and I remember back thateveryone I've done in a clinical
example was under generalanesthesia.
So after getting kicked in thestomach a few times by the half
sleep full, it was like, okay,maybe we just anesthetize them
because that's clinically whatwe're going to do anyway.
But I got a lot of skills inyou know doing the regional
perfusions.
I got to work with a ton ofdifferent veterinarians who all
(11:59):
have different ways of you knowviewing what the appropriate
dose splitting is.
I talked to a few who sparkedthe concern that well, if we're
taking away from systemic dosing, are we shortchanging them?
And or if we're giving a fulldose systemically and a partial
dose regionally, are weoverdosing them and potentially
setting them up fornephrotoxicity?
And so just getting theopportunity to work with so many
(12:22):
like really well-knownveterinarians, getting all the
different pieces of you knowempirically what they think
works and just going.
Well, I guess maybe I shouldjust go and figure out what
actually works and then to workwith Mike Schoonover, who has
done a ton of work in the realmof regional imperfusions already
and he already had, you know,some connections with different
(12:43):
labs to do the assays, just kindof help, you know, fill in
those gaps and made it very easyto just kind of run with it
once we got the project started.
Lisa Fortier (12:53):
Have you had the opportunity to share this data
in this manuscript with thoseother doctors that you worked
with in your internship andgotten their support or swayed
them perhaps?
David Wallace (13:03):
Not yet.
I was waiting for it to getaccepted so I could prove like,
hey, it's actually going to getpublished.
And then I was going to send itto him or at least call him and
just be like hey, I got thispaper published, just want to
know what your thoughts are onit.
And if you think that we missedsomething or need to go another
direction and prove somethingelse, like, let me know because
I want to do more on it.
So we've got more holes to filland I would welcome all Sure,
(13:31):
sounds like you're the nextleader, though.
Sarah Wright (13:35):
Yeah, I love that you're open to feedback too.
That's awesome.
Now this next set of questionsis going to be very important
for our listeners, and the firstone is going to be about the
veterinarian's perspective.
What is one piece ofinformation the veterinarian
should know about amikacinconcentrations and healthy
neonatal foals?
David Wallace (13:51):
I think the first thing to know is that at least
this technique we know works.
That doesn't mean that othertechniques probably won't, and
probably should look into that.
(14:12):
But we did find, you know,check that we could make sure
that the tourniquets were inplace no joint achieved in the
even near the appropriatetherapeutic dose that we wanted,
and that's, I think, just anindividual response.
And so I think it's veryimportant that, even though
you're using this, thesetechniques that have been, you
know, shown to suggest that theywork, response to therapy is
(14:33):
going to be very important.
And so if you are doing thesame thing over and over and not
achieving any sort ofprogression in the case, it
might be because that horse isnot going to respond
appropriately and we need to goto a different technique,
whether it's directintra-articular injections or
use a different antimicrobial.
So I think that's important toknow that.
You know this isn't the end-all, be-all treatment.
Sarah Wright (14:58):
But on the other side of the relationship, what's
one thing clients should knowabout this topic?
David Wallace (15:03):
I would probably say about the same thing,
because, you know, anytime aveterinarian tries a therapy and
it doesn't work, you know it'svery frustrating for the client.
I think it is important forthem to realize that there is an
individual variability to theresponse of any therapy that
we're going to do and to just,you know, be patient.
You know we're going to keepchecking all of our vitals, keep
checking cytologies and thingslike that, to ensure that we're
(15:26):
making headway, and know that ifwe aren't, we're going to pivot
and try something else.
And so I think it's justimportant for them to just kind
of, you know, have a littlegrace and be patient with us as
we try to sift through some ofthese.
You know, nuances with,especially with foals they're,
you know everyone thinks thatthey're small horses and they're
not.
They're their own thing.
Lisa Fortier (15:44):
They definitely are.
And if you only got kicked inthe stomach when they're under
sedation, try to do this, you'redoing pretty well and it is
pretty silly, you know, when youthink it takes somebody on the
head, somebody in the forearm,somebody in the hind limbs and
the tail and then you to do theregional.
David Wallace (15:59):
So it's just like a waste of these falls and
getting them anesthetized sothat once they were still, the
manpower didn't need to be quiteas high, so I've really enjoyed
(16:22):
working with everybody on thisproject.
Lisa Fortier (16:24):
Yeah Well, David, I really enjoyed speaking with
you and Mike at the conferenceand over your poster, and so
glad I convinced you eventuallyto submit this to JAVMA, and
I've learned more from you todaytoo.
So, thank you for agreeing tobe on our Veterinary Vertex
podcast.
David Wallace (16:40):
Thank you guys for having me.
It's been great and it's agreat honor.
It's the first time I've everbeen recorded for something, so
it was great.
Lisa Fortier (16:47):
Very good.
As we wind down, we like to aska little bit more of a personal
question.
David Wallace (17:03):
And most of the time this dates people, but
we'll and we're always surprisedtoo.
Uh, what is the first concertyou attended?
So I went and saw acdc whenthey did the black ice tour.
Uh, that had to have been 2008,2009.
Um, I grew up listening toclassic rock, so I love acdc,
and it is only the first concertthat I went to, because I tried
to go to Led Zeppelin's reunionconcert back around the same
time and I didn't get pulled forthe drawing.
So that would have been it andthat would have.
That is my absolute favorite,so I wish that was my first one.
Lisa Fortier (17:24):
You know, ACDC is on tour again this year.
David Wallace (17:26):
And I am tempted to.
If I weren't still a resident,I would have be tempted to go
watch, but I'm afraid I'mprobably going to be on call
that weekend.
Lisa Fortier (17:35):
Yeah, they're selling out all over.
I still need to look up and gettickets somewhere.
Sarah Wright (17:39):
It's so hard to get concert tickets nowadays
it's crazy.
So best of luck to anyone whotries.
Well, thank you so much, David.
Again, just echoing Lisa, wereally appreciate you being here
today and for sharing yourresearch with us too.
David Wallace (17:53):
Thank you guys for having me.
Sarah Wright (17:59):
And to our listeners.
You can read David's article onJAVMA.
I'm Sarah Wright with LisaFortier.
Be on the lookout for nextweek's episode and don't forget
to leave us a rating and reviewon Apple Podcasts or whatever
platform you listen to.
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