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Reperfusion Injury Questions

Hello all - first and foremost thank you to anyone who is able to take time to respond. I'm looking for some guidance and trying to understand if tis is a common death in dogs or was there any way to potentially avoid it.

I recently posted on r/petloss with more of the story of how I got this dog, but long story short I got him about a year ago from a shelter and he was already fixed and UTD on shots. We took him into our regular vet on March 9th for a checkup and the only thing she noted was that he was a little bit skinny (made sense at the time - he wasnt eating in the shelter). We took him for an appoint on October 10th and got a clean bill of health. On November 4th, Balto started showing some signs of distress after eating his breakfast. He had laid back down in his crate but then started crying and dragging his back legs. We rushed him to an emergency vet where he was ultimately diagnosed with a diaphragm hernia - the scheduled surgery for November 6th.

I spoke with the surgeon when I dropped him off who coincidentally also had a diaphragm hernia at birth, and also did her residency under the Dr who performed a hip replacement on our other dog. I felt really good about it and we spoke mostly about what the recovery would look like. Less than 4 hours later Balto was dead. The surgeon called when he was out of surgery and said that his liver was twisted / firm and dark purple. His entire intestines' was in his chest cavity along with his spleen. They removed the spleen when moving everything back to the abdomen because it didn't fit. She said he was starting to come out of anesthesia but his legs were cold and tongue was blue-ish and he didn't have the correct pulse.

She called again 10 minutes later and said he was in cardiac arrest and they were performing CPR but he was not going to make it.

After this, the vet mentioned his true cause of death was reperfusion injury. She sent me the following text to help explain it:

"Reperfusion injury refers to a cascade of events occurring at the cellular level in response to the sudden reintroduction of highly oxygenated blood into an anaerobic (no oxygen) environment. As the oxygen returns, there is generation of a large number of free oxygen radicals and other highly reactive compounds. These compounds have a short half-life and are unstable. They are generated and interact immediately with cells. This interaction can severely damage cellular integrity and generate more free radical molecules.
This situation is important in chronic diaphragmatic hernia management because reexpansion of chronically atelectic lungs and restoring blood flow to chronically compromised portions of liver or gastrointestinal tract results in generation of free radicals. Conditions such as reexpansion pulmonary edema and liver shock, reported as complications of chronic diaphragmatic hernia repair, may be fatal."

I found the textbook that she quoted, and the wording is slightly different. The textbook says the following - bolding and emphasis mine.

  1. Discuss reperfusion injuries. Reperfusion injury refers to a cascade of events occurring at the cellular level in response to the sudden reintroduction of highly oxygenated blood into an anaerobic environment. As the oxygen returns, there is generation of a large number of free oxygen radicals and other highly reactive compounds. These compounds have a short half-life and are unstable. They are generated and interact immediately with cells. This interaction can severely damage cellular integrity and generate more free radical molecules. Only by reacting with a free radical scavenger is the cycle interrupted.

This situation is important in chronic diaphragmatic hernia management because reexpansion of chronically atelectic lungs and restoring blood flow to chronically compromised portions of liver or gastrointestinal tract results in generation of free radicals. Conditions such as reexpansion pulmonary edema and liver shock, reported as complications of chronic diaphragmatic hernia repair, may be blunted by careful consideration of the potential for reperfusion injury. No single method is effective in preventing or managing reperfusion events in patients. Medications, such as steroids or free radical scavengers, and management practices, such as lobectomy for severely compromised liver lobes and slow gradual reinflation of compromised lung tissue over several days, may decrease the severity of reperfusion injury.

I guess my question is - was there something missed? What question do I need to ask the surgeon to help understand that they did everything they could to prevent this from happening? Is reperfusion injury a common death reason for correcting a diaphragm hernia in dogs?

Thanks for any help / advice that anyone can offer.

8 comments

  • First I'm very sorry about your dog.

    I don't know as much of the veterinary world. And there's a ton of information your vet and surgeon has on your specific case that no one online will have, so no one here is going to give you very specific answers to your case. So take everything that follows with a grain of salt, and talk more with your surgeon, not internet strangers. And it sounds like your dog was in a very dangerous situation, keep in mind a bad outcome doesn't necessarily mean anyone did anything wrong, you and your surgeon included. I can tell you some general things about how repurfusion can be dangerous in humans though.

    I was confused why both your explanations are hung up on free radicals. Not that there aren't, I'm guessing there'd be more than usual. It's just a bizarre explanation of repurfusion injury. There's many dangers, but basically if you have dead or poorly perfused tissue (sounds like there was a lot of this from your description), and there's a turniket or a hernia acting as a turniket in this case squeezing the blood supply so nothing is getting in or out, or very little is getting in or out, all of the harmful dead stuff from the process of that tissue dying is somewhat stuck there. But once this narrowing is resolved (taking off a turniket or getting the tissue out of the henria in this case) now there's blood flow and all the material form this dying or dead tissue has a clear route back to the rest of the body. It also sound like in this case there was a really horrific large hernia with probably multiple sections of multiple organs that had already infarcted (died from lack of oxygen/blood flow) based on what you wrote. Sometimes in humans you can resect small portions of dead intestine and reconnect remaining pieces, but you can't just take out their whole liver, they need that.

    But free radicals is a weird red herring thing to talk about. Potassium is the main killer for repurfusion injury. There's very little potassium outside cells (like in your blood and fluids), but tons inside cells. Well we have a whole mass of tissue from multiple organs that just died and that's all getting released at once. The heart does not like this, and can go into arrhythmias and stop beating. Potassium is actually the final drug used in a lethal injection in capital punishment for instance. There's tons of other harmful things going on too. But if large sections of multiple orgams had already died or been severely injured by the hernia, there may not have been any possible way to save them. And if you leave them that way the harmful stuff will find it's way out eventually anyways, and the dead gi organs will cause massive septic shock as all the bacteria spill out from the inner gut through all the dead tissue into the rest of the body. Long story short, ischemia or infarction of bowels and other gi organs from a hernia or any other cause is an extremely dangerous situation requiring emergency surgery and can be fatal in humans, and even with that it may be impossible to save them. I'm guessing it's similar for dogs.

    Again take everything I said with a grain of salt, your surgeon has the best information on what actually happened. I just wouldn't get too hung up on "free radicals." Ischemic or infarcted orgams is an extremely dangerous situation for tons of reasons.

8 comments