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  Discussion on Midazolam and Morphine
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Member:
Obtunded

Posted on Saturday, Jan 15, 2005 - 3:20 am:

I experienced a very horrible scenario tonight. As a paramedic i was responded to an incident that was reported as a car vs. horse & rider. On arrival, it was car vs. horse only. A horse had gotten out of a paddock and was struck by a car on a rural road at night.

The poor horse had both hind legs fractured and had fallen 10 feet into a shallow freezing (literally) water and snow filled ditch. The creature was clearly suffering.

Although I could see that euthanasia was the only humane option, there was no means to do so, and I believe the owner needed to hear it from a vet.

In my collection of goodies, I have morphine and midazolam that we use for various things, but together they are an effective sedative/analgesic.

It was my intent to try and make the horse more comfortable, but I was duty bound to leave and respond to a call for a human. I bawled my eyes out and ended up booking off later and going home.

God forbid, but if I am ever faced with such a scenario again, would morphine and or midazolam provide effective sedation and/or analgesia?

Can you suggest dosing? (Midaz is .05 - .3 mg/kg is an indction dose in humans)



Member:
36541

Posted on Monday, Jan 17, 2005 - 7:32 am:

Wow Ian, that is my nightmare vision as I travel to and from my own ER practice. I hope the memory will be more bearable if the question can be answered. I have driven many miles with my horses, and have often wondered what I could do if I needed to give one of my own animals a humane end, if they clearly could not be saved. Veterinary assistance and meds aren't usually available quickly in an interstate crash situation. I know it is morbid, but maybe a significant percentage of us would feel better if we had some kind of plan...
Member:
Eoeo

Posted on Monday, Jan 17, 2005 - 9:43 am:

In our part of the counctry, if you have an accident and your horse is injured critically, you have to deal with it yourself. The State Patrol will not put an animal out of it's misery andwill not allow you to use their weapon. For that reason, I carry a 38 calibre hand gun when I haul the horses. I never thought I could shoot an animal however, I have had to shoot a puppy that had been run over by the school bus and was screaming so badly I couldn't let him suffer. If a horse was in that condition I believe I could do it. There is a certain spot on their head that is the best to do this. Their skulls are very thick but there is one area that supposedly isn't and that is the spot to do it. I just pray that I never have to make that decision. I would rather have a vet euthanize them. EO
Member:
36541

Posted on Monday, Jan 17, 2005 - 10:10 am:

I was reluctant to bring it up before, but does anyone know where that spot is? I don't want to dwell on it, but I have always felt I should know and I don't. I carry a gun , with permit when I travel, primarily with Ian's real-life vision in mind. The only thing worse than being in that hopefully rare situation would be making it worse because of ignorance.
Member:
Erika

Posted on Monday, Jan 17, 2005 - 10:30 am:

Hey all,
If you think you can kill a horse with a bullet, be very, very certain. My friend had a horror story about that. Don't read any further if you're squeamish!
My friend had horses pastured next door to her, whereas the owners lived somewhere else. One day they discovered one of the horses with a complete break of it's leg standing in the field.
After a pow wow with the neighbors, they decided to put the horse out of its misery. With a shot to the head, the horse DrOpped like a rock. They all went home.
Next day, my friend DrOve by and saw the SAME HORSE standing in the field--broken leg, blood all over his head and nostrils!
Moral of the story--unless you know horse-head anatomy very well, please call a vet. You can usually find a 24 hour emergency service, and it's much kinder than a shot to the sinuses!
Good luck to all, and here's hoping that none of us are faced with anything like this ever again.
Erika
Moderator:
DrO

Posted on Monday, Jan 17, 2005 - 5:36 pm:

Hello All,
Let's see, where to begin on this morbid but very important topic.

Ian, I am glad you waited: morphine and all other narcotics often have an exciting effect on the brain of horses causing trembling, makes them want to run, even when lying down. When used in the horses, narcotics should be combined with sedatives, however the benzodiazapams (Midaz) also can produce a short paradoxical excitability in a horse so may not be the best choice. The receptor activity for these reactions could be different and the combination block the excitement receptor of the other producing the desired effect but I am loathe to come up with a dose with this mixture since I can find no work about the horse with it.

Now to euthanasia of the horse with a pistol. First I believe when done properly it is a humane method, the horse appears to just DrOp without so much as a flicker of the ear. Second is that events happen all the time where a horse is suffering, unfixable, and professional help is hours away or just not available. During times like this I believe this is justifiable but only if you have experience with the proper use of a pistol.

To someone with such experience I should not have to say, but will anyway, spectators should not be around the horse when you shoot, at the very least have them behind you so if you do something really wrong, you are the only one shot.

Anything bigger than a .38 could make a real mess but a .22 short may not be powerful enough (I have been afraid to try). I use .22 Stingers (similar to a long but more power). When I have had to put down the poor beasts who are the suffers' of back yard attempt invariably the shot was made too low. The way to find the correct spot is by drawing a straight line from the ear to the opposite eye on both sides of the horse. Where they intersect is the point where the bullet should enter and the bullet should enter perpendicular to the skull. I hope my next question is a lot lighter subject than this.
DrO
Member:
Paul303

Posted on Tuesday, Jan 18, 2005 - 2:22 am:

What a gut wrenching topic - yet so important. Thank you Dr.O, for addressing it in such a level straightforward manner. This topic has danced darkly in the back of my head over the years after some of the fiascos I've had the bad luck to be present at.
Member:
36541

Posted on Tuesday, Jan 18, 2005 - 5:45 am:

Thank you Dr O, for answering the question. Like many ER healthcare providers, I am more than a little superstitious. Now that know exactly what I would do in the situation, it feels like a talisman against the event happening. I'm sure it sounds crazy to some of you, but others will know just what I mean.
Member:
Obtunded

Posted on Tuesday, Jan 25, 2005 - 1:25 am:

Hi Dr. O,

Thanks for your comments... Interesting, because I've heard advice similar to yours from our own vet in the past. I had since read a couple of studies that discuss the use of Morphine, and the conclusion were that Morphine is an inexpensive and effective analgesia for horses (post operatively). From the literature I've read I also understand Midaz is frequently used - in conjnction with other induction agents that probably counter or offset the paradoxical effects you mention. The equine dose is .125 - .5mg/kg.

...up here in Canada, we can't legally carry handguns and rifles aren't transported without legitimate purposes. It makes for a safer community but it makes on-the-spot euthanasia more difficult... ;-)

Thanks again for your comments!

Ian
Moderator:
DrO

Posted on Tuesday, Jan 25, 2005 - 8:00 am:

While Midaz has been used in about a dozen published research studies over the past 7 years and appears to be potentially useful as a induction agent, particularly in combination with ketamine, it has not gained widespread use in the field that I am aware of, at least here in the USA. This is probably because the induction using it is a bit uneven and there are cheaper products approved for use in the horse.

Though there are many studies on morphine they are not as encouraging as you suggest, this seems to summarize the findings best:
Vet Clin North Am Equine Pract. 2002 Apr;18(1):47-60.
Use of opioids for pain and anesthetic management in horses.
Bennett RC, Steffey EP.
Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK.

So far, study results do not provide convincing, objective evidence to support the opinion that systemically administered opioids consistently and effectively relieve pain in horses. Given this lack of evidence, and considering that opioids stimulate locomotor and other forms of unwanted excitant behavior, reduce propulsive gastrointestinal motility, decrease alveolar ventilation (especially in association with general anesthesia), and require regulatory and practical considerations for abuse potential in both humans and horses, we conclude that routine, indiscriminate administration of opioids for pain relief in horses is not justified. Identification and focused, objective study of selective beneficial opioid actions to provide guidance for appropriate clinical use is long overdue.

I have not seen anything published since 2002 to change my mind on this.
DrO
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