Healing Under Pressure (HBOT treatments)

[Guest guest]

This article is primarily about HBOT on horses.

However, HBOT has helped women recover from implant

related diseases. Both Patty and I have used HBOT.--

When I was doing HBOT, they were making progress with

a child who was a victim of a near-drowning incident.

If you have the resouces to get these treatments, I

would suggest checking HBOT out.

Rogene

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Healing Under Pressure

by:

February 2004 Article # 4922

http://www.thehorse.com/viewarticle.aspx?ID=4922

Oxygen is one of the most crucial components of the

energy production process that fuels body tissues. It

sustains life and enables injured tissues to heal. In

recent years, a very effective procedure for helping

heal many ailments has developed from the idea that

for optimum healing, more oxygen than is normally

contained in and surrounding our bodies can be

beneficial. As usual, when human medicine makes a

breakthrough, it isn't long until someone figures out

how to help horses with that same type of therapy.

Enter hyperbaric oxygen therapy (HBOT) for horses.

How It Works

Hyperbaric oxygen therapy involves subjecting the

patient to high levels of oxygen under pressure in a

special chamber. At normal atmospheric pressure, there

is a limit to the amount of oxygen carried by red

blood cells and only a tiny amount of oxygen is

dissolved in the plasma. HBOT is discussed in terms of

atmospheres absolute (ATA). Atmospheric pressure at

sea level is equal to 1 ATA. Higher pressure than this

on the body would be similar to what a person would

experience under water; each 33 feet (10 meters) of

sea water provides an equivalent increase of 1 ATA of

pressure. Thus when you are 33 feet under water, you

are experiencing 2 ATA (one from normal atmospheric

pressure and one from the addition of 33 feet of sea

water). This gives an idea of the pressure you would

feel in an oxygen chamber. Treatments in a chamber are

given at 1.5 to three times the pressure of one

atmosphere.

Increasing the amount of air breathed cannot

significantly improve oxygen delivery to the body by

way of hemoglobin, even if you breathe pure oxygen.

But with increased pressure, the oxygen level in blood

plasma increases, with higher delivery to all body

tissues. Under these conditions, oxygen is physically

dissolved in the plasma, even in the veins (which

ordinarily carry only blood that is depleted of

oxygen). The dissolved oxygen is more readily utilized

by the body than the oxygen carried by red blood

cells.

In humans, pressure chambers are used to speed healing

of soft tissue injuries, aid recovery of stroke

victims, and in treating many problems--including

carbon monoxide poisoning, coma, burns, circulatory

problems, Lyme disease, lung abscesses, difficult

wounds, bone infections, hard-to-treat infections

(especially those caused by anaerobic bacteria),

traumatic brain injuries, spider bites resulting in

necrotic (dead) tissue, and diabetes (preventing

non-healing infections and amputations). Many studies

show HBOT's efficacy in treating wounds and ischemic

tissue (that is deprived of blood), reducing edema,

and stimulating the immune system.

The patient is put in a chamber and the air pressure

is slowly increased. When it reaches the prescribed

pressure, pure oxygen is put in to replace the air.

Normal partial pressure of oxygen in the arterial

system is about 100 mm of mercury (mmHg). The oxygen

level in the air inhaled at a pressure of three

atmospheres (in a pressure chamber) would be near

2,280 mmHg. The actual amount in the arterial blood

would be somewhat less than that, but this is a much

higher amount than is normally dissolved in the blood,

says Fairfield Bain, DVM, Dipl. ACVIM, ACVP, ACVECC,

of Hagyard-son-McGee Veterinary Associates in

Lexington, Ky. The oxygen is forced into the blood and

body fluids, making its way to any damaged areas of

the body that can't be reached by normal blood

circulation or areas where vessels have been hindered

by injury or infection.

HBOT for Horses

A few years ago, the first pressure chamber for horses

was created by Equinox Technologies Limited in

Vancouver, British Columbia, and the first available

unit was purchased by Doug Herthel, DVM, for his Alamo

Pintado Equine Medical Center in Los Olivos, Calif. It

was a mobile unit built like a large trailer that held

two horses at a time.

Equinox had taken their first experimental chamber to

two racetracks n Canada, where it was tested on racing

injuries in Thoroughbreds and Standardbreds. Herthel

had been trying to develop a similar chamber for about

six years. " We actually started building one in 1994,

but the mechanics of it became too difficult. We were

working with a Navy contractor, making one from

concrete, but testing showed it wouldn't hold up to

pressure. After Equinox came up with theirs, we were

ecstatic, " says Herthel.

He now treats horses from all over the country with a

newer version of the chamber. It is in use every day,

treating two to four horses daily.

Since then, more units have been put into clinics,

distributed by a company called Equine Oxygen Therapy.

There are HBOT chambers at WinStar Farm and

Hagyard-son-McGee Equine Hospital in Lexington,

Ky.; KESMARC (an equine rehabilitation center) in

Versailles, Ky.; Fossil Creek Veterinary Clinic in

Loveland, Colo. (under the direction of Kara Keesling,

DVM); and the University of Tennessee in Knoxville.

Bill Casner, chairman and co-owner of WinStar Farm;

Hub , owner of KESMARC; and Bain are partners

in Equine Oxygen Therapy. Bain serves as vice

president and medical adviser for the group.

This partnership has designed several models for

horses. " The function of our chambers has not changed,

but we keep improving them for ease of use, operator

safety, and comfort and safety of the horse, " says

. " The most recent model--which was just

installed at Hagyard-son-McGee--is the biggest

one in existence at present. It is more than nine feet

in diameter, opens at the back and front, and is

stationary. The one we are designing now is a round

stall, 10 feet in diameter and 9 1/2 feet tall. It's

recessed into a concrete pad, so the horse doesn't

have to walk up a ramp. He goes through a 42-inch

door, you turn him loose, and he can walk around

without being restrained in any way. A horse with

laminitis can even lie down to be more comfortable. "

The first model was less than eight feet in diameter,

and there wasn't much head room for a horse. It was

designed to be taken around the country. Horses

accustomed to a trailer were comfortable in it, and

foals were small enough to turn around in it, but

young, inexperienced horses often became frantic. The

larger chambers available now seem to work better.

A horse being treated is put into the chamber for

30-90 minutes once a day, for however many treatments

are needed for that particular condition.

" It's usually a 90-minute treatment, once the chamber

is up to pressure, " says Herthel. " Some conditions

require only one or two treatments; others need 10 to

20 treatments. In severe cases of laminitis, we may

treat a horse twice a day. "

Not only does the treatment increase oxygen levels,

but the pressure helps reduce swelling anywhere in the

body. Herthel uses it for severe limb edema,

lymphangitis, etc. " Any instance where there is

swelling--in the brain, the foot, or intestines--the

oxygen therapy is helpful, " he says. " The pressure per

square inch in the chamber is incredible. It's like

being 60 feet under water. "

Herthel says that care must be taken using HBOT. Short

daily treatments are better than prolonged sessions,

since exposure to high-pressure oxygen for long

periods could lead to oxygen toxicity.

" You also take precautions to have the humidity in the

chamber just right, and ground the horse, " says

Herthel. " If there's any static electricity in there,

you could have a major fire. " For good airway health,

air breathed in should not be too dry. In order to

ground the horse, depending on the chamber, either a

rubber strap can be attached to the horse's body or

the horse can stand on a rubber mat.

Commonly Treated Conditions

HBOT is one of the most powerful tools available as an

adjunctive form of therapy, and in some cases it works

well as the primary therapy in horses, says Casner.

Colic and laminitis are the number one and two

killers, respectively, of horses, and oxygen therapy

(in conjunction with other therapies) can be very

useful in treating both.

Colic--HBOT helps restore blood flow to tissues after

colic surgery. Herthel says it also reduces

obstructive swelling in the intestinal tissue and

improves oxygenation of the resection (after abdominal

surgery to correct colon torsion, small intestine

strangulation, etc.). Herthel has found that many

colic cases respond much better to surgery when

treated with HBOT before and after surgery.

says HBOT is used in human medicine to relieve

or prevent gaseous buildup after abdominal surgeries.

" This also works well in horses, and we are hoping

there will be a study on gas colics, " he says.

Laminitis and navicular syndrome--HBOT can arrest

laminitis in the early stages, Casner says. " If you

can treat the horse before the structures in the foot

collapse (before there's crushing of the blood

vessels), it is very effective, " explains Casner. " In

older stallions, the two things that most commonly

kill them are colic and laminitis. "

Effects of oxygen therapy on problems like navicular

syndrome and laminitis are now being studied.

Researchers at the University of Tennessee are

starting controlled studies on laminitis to get the

data needed to document the effects of HBOT.

" They will be working with different stages of

laminitis, with a control group to make comparisons,

to see how well this really works, " says .

" At Hagyard-son-McGee Equine Hospital, they've

treated acute onset cases of laminitis that resolved

very quickly and successfully, " says . " There's

a better success rate if you can start treatment right

away, rather than waiting a week--after the damage is

done. We are hoping that after the controlled studies

are published, the veterinary community will embrace

this, and people will start HBOT earlier in the course

of the disease. "

Infections--HBOT increases blood flow to the infection

site, which increases the amount of antibiotic

delivery. The extra oxygen also increases the

effectiveness of the antibiotic, magnifying the way it

works against bacteria. Herthel says that high-dose

oxygen " tends to potentiate the effect of some

antibiotics, such as sulfamethoxazole (SMZ). You are

also getting 15 times the amount of oxygen to a tissue

that was lacking oxygen due to infection or poor

circulation. " Oxygen also stimulates faster cell

turnover, and thus faster healing.

Casner says, " Oxygen acts to kill bacteria. Most

bacteria causing serious infection are

anaerobic--working best in an environment without

oxygen. At pressure, with oxygen at a higher level, it

is also detrimental to aerobic bacteria. "

Extra oxygen also helps white blood cells function

better to kill the organisms.

Bain adds, " Certain antibiotics such as gentocin and

amikacin don't work well in low-oxygen environments.

Oxygen therapy enhances their function and gives a

whole combination of benefits. HBOT is an adjunctive

therapy; we are still using antibiotics and

anti-inflammatory drugs and other treatments. It's a

component process in which everything is working

together. "

Abscesses--Internal abscesses (such as in the lungs or

the abdomen) are sometimes not diagnosed early.

says, " By the time they are diagnosed, there

is a thick-walled capsule of connective tissue around

them that keeps antibiotics from reaching the site.

This results in prolonged antibiotic treatment (often

with no resolution of the abscess) at high cost to the

owner, and potentially fatal consequences for the

horse. HBOT helps the antibiotic get to the site and

enhances its ability to fight the infection. "

Bone injuries--Casner says studies have been done in

which fractures were created in rabbits, with HBOT

used to treat one group and a control group without

treatment. The rabbits were euthanized to determine

the amount of healing. In the rabbits treated with

HBOT, the bones healed not only faster, but stronger.

Septicemia and joint ill in foals--At

Hagyard-son-McGee, Bain and Slovis, DVM,

Dipl. ACVIM, evaluated HBOT for treating foals with

septic joints. In 2002, all the foals which came into

the clinic with septic joints went through a standard

protocol using systemic antibiotics, lavage to flush

the joints with antibiotics, etc. After 30 to 90 days'

treatment, they took the foals which were hopeless

(which would ordinarily be euthanized) and moved them

into a test group. They continued to use their

standard treatments, but combined them with HBOT. They

had a 60% recovery rate in foals which were going to

be put down!

Infection eats the bone away, but with oxygen

treatment the joints healed and the integrity of the

bone was regenerated. Bain says, " The changes we see

on X rays in these foals indicates dead bone. Even

though we have the foals on antibiotics, there is poor

blood supply to dead bone; the antibiotics don't get

there and are not very active if they do. Even if the

foal survives, the body has to clean up all that dead

tissue. HBOT stimulates and enhances the clean-up

process and healing process to speed resorption of

dead bone. It can also help salvage some tissues that

would otherwise go on to die. "

Soft tissue injuries--Many injuries result in

inflammation and swelling. Studies have shown that

soft tissue injuries treated with HBOT recover in half

the time. New blood vessels form more quickly,

improving blood supply to injured areas, and there is

swift reduction in edema (swelling). Since oxygen is

normally carried by red blood cells, any tissues with

a compromised blood supply suffer from poor healing.

But with HBOT, oxygen is forced into all body fluids

and delivered to areas with restricted circulation.

Injured tendons and ligaments respond well to

treatment; HBOT can be useful in dealing with bowed

tendons, surgical repair of tendon or ligament

injuries, etc. Surgical traumas (incisions) also heal

faster with HBOT, as do large surface wounds and

pressure sores. It decreases tissue swelling and helps

salvage damaged tissues in traumatic injury. In

chronic wounds, it assists growth of new skin and

stimulates collagen production.

Bain says, " In a severe wound with lots of tissue

damage, there is usually a certain amount of sloughing

away. Using HBOT early in treatment may salvage some

of the tissues that have lost their blood supply; we

can sometimes save bits around the margin and reduce

the amount of tissue lost. "

Reproductive problems--Herthel wrote an article three

years ago describing how he'd treated some older

stallions for laminitis and noticed an increase in

fertility. After reading that, Casner decided to treat

WinStar's stallion Kris S. in the chamber, and there

was a ery dramatic change. The stallion's covers in

the breeding shed had declined, but after HBOT

treatments his libido increased (along with his sperm

count), and the morphology (cell structure) of his

semen was much improved.

Casner says HBOT has also worked well for mares they

hadn't been able to get in foal. " We treated four out

of five mares one year that had been bred on multiple

covers, " he says. " We finally put them in the chamber,

and they got in foal the next time they cycled. We

don't entirely understand why it worked, but suspect

there may have been a bacteria involved that we were

able to eliminate with the oxygen treatment. We

probably also enhanced the integrity of the uterine

lining. "

has also treated mares which were unable to

conceive. " One mare went to the breeding shed 16 times

in two years without becoming pregnant. After three

treatments in the chamber, she was bred, and had a

live, healthy foal this spring, " he says.

Bleeders--Casner uses HBOT on horses which have bled

(suffered from exercise-induced pulmonary hemorrhage,

or EIPH). " Many of them have chronic infections in the

back of their lungs, " he says. " We bring them to the

farm, put them in the chamber, and give them five or

six treatments in combination with antibiotics. We've

had very good esults in clearing up the infection and

healing the lung tissue. "

Dummy foals and other neurological problems-- " We use

it on dummy foals because it reduces edema, " says

Casner. " The oxygen in a pressure chamber has the

ability to penetrate the cerebrospinal fluid. " Head

and spinal trauma often create neurological damage,

thought to result from swelling of these tissues

within a confined space, loss of blood and oxygen

supply, and the sequential effects of these factors on

nervous tissue. HBOT reduces the swelling and

increases the blood supply.

" We've also used HBOT experimentally on EPM, " says

Casner. " There are many things it holds promise for;

it will be another strong tool in the veterinarian's

arsenal. "

Spreading the Word

" HBOT is an amazing tool, and the veterinary community

is starting to embrace it, but there are some who are

so traditional in their forms of treatment that they

continue to be very narrow in their vision--though

there are volumes of clinical research in the human

field to support this therapy, " says Casner.

" Dr. Bain says hyperbarics is the most significant

veterinary tool since the ultrasound machine, " Casner

adds. " He recently worked with a racehorse with a lung

abscess that was treated with conventional methods for

30 days and continuing to worsen. The trainer then

requested that hyperbarics be combined with

traditional treatment. Dr. Bain was then able to heal

the horse in a very short time. "

But veterinarians who have chambers are cautious about

using this routinely even though they want to. " I use

the term 'cautious' only in the spirit of selecting

appropriate patients for HBOT treatments and not just

treating any willy-nilly problem, " says Bain. " The

theoretical applications are considered for each

patient's clinical problem before considering HBOT as

a treatment modality. "

" Oxygen therapy is nothing short of miraculous in

treating many problems--especially infections--but the

question a lot of people have is that if it's so good,

why aren't more veterinarians doing it? Many vets have

never heard of it; this treatment was not taught in

vet school, and until recently there were no equine

chambers, " explains Casner. " Most veterinarians have

no experience with it. But this will eventually

change. "

Herthel says HBOT is such a powerful tool, " that the

way we use it, oxygen is a drug. " He feels that

eventually more veterinarians and equine clinics will

use this, and that there should be a chamber in every

major horse center.

" It can save a horse in many situations where there is

no hope otherwise, " says Herthel. " We have horses

doing fine today that had acute laminitis and would

not have made it without the oxygen therapy. We've

treated many horses with bone infections that would

have died. Some of the colics with intestinal

obstruction, and some horrific infected wounds, can

turn around quickly with oxygen treatment. "

This useful tool can make the difference between life

or death for many horses, he says. However, HBOT can

get expensive with one treatment session running

$400-$500. The type of injury or illness being treated

will determine how many sessions are needed.

Bain says that since HBOT is such a new therapeutic

modality to the horse, there isn't much research out

there yet. " We've had a few small clinical case

studies that Dr. Herthel has done or that we've done

here at our hospital, " says Bain. " But there have been

no basic research projects yet at academic

institutions involving the horse specifically. Many

medical schools have hyperbaric facilities, however.

Duke University is a leader in this field, along with

the University of Kansas Medical Center and

Washington University. They have what they call a

'magic list' of things that Medicare will pay for

(including wounds, diabetic wounds, chronic bone

infections, burn injuries, etc.), and this is

basically how HBOT is applied to human medicine.

" Usually medicine looks at what animal research has

done and applies it to humans, " says Bain. " We are

looking at what they are doing with people and

applying it to horses--and hoping this will find its

place in veterinary medicine. "