Person receiving CPR

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We’ve all seen the TV trope of cardiac arrest and CPR: the patient collapses, perhaps clutches their chest. Heroic bystanders, or hospital personnel, rush to their side, start chest compressions and rescue breathing and start yelling things like “I need 45 femtograms of herporthonephrine STAT!” and “Don’t you die on me!” Half a TV minute later, the patient takes a huge, gasping breath and sits up, looking slightly bewildered but none the worse for wear. The chorus of violins rises and all is well.  Roll credits.

TV lied to you.

This quotation¹ about a Journal of the American Medical Association CPR study² in humans highlights the hard-nosed reality (emphasis mine):

One analysis of 24 studies of in-hospital cardiac arrests revealed that the chance of survival for patients was about 15%. And a study that looked at patients from 2000 to 2009 found that more than 25% of those who survive an in-hospital cardiac arrest will live with brain damage.

And this study looks at patients already in hospital. While you can argue that perhaps these patients were sicker to begin with (because they were already in hospital) they also had access to oxygen, fluids, personnel and all manner of things that should make CPR easier to perform.

So, the odds of going home neurologically intact after CPR in the hospital are somewhere around 10%.

Wanna know what the success rate that stupid, lying TV routinely shows for CPR?

A whopping 70%³.

This is like if TV told me there were only four Teletubbies®, when in reality there are 30 of those creepy guys out there⁴. Ditto the Wiggles®.

In all fairness, when looking at the statistics surrounding CPR and survival, a confusion of numbers, variables, and end points come into play:

• Was bystander CPR performed?
• What caused the arrest?
• Did the patient have a survivable disease before CPR?
• Did they get a heartbeat back, only to die later?

You can quote numbers all day long and find different outcomes and endpoints, but for me the true metric is did the patient go home and were they anywhere close to normal?

That’s the 10% number above.

Now, while this is much higher than the odds that you will go to the ER for a pogo-stick-related injury (1 in 115,300 or 0.00017673282%), it’s still pretty slim. It’s about as common as people who know that Mitt Romney’s given name is actually Willard (7%).

If we look at the numbers in pets, things are even grimmer. A UC Davis College of Veterinary Medicine study from 2012⁵ showed only a 5% rate of discharge from the hospital after CPR (6% for dogs and 3% for cats). (For the sake of discussion, I am going to omit cardiac arrests under anesthesia here – that’s far more survivable.)

Why is it so bad in pets? I think it’s due to the fact that pets, unlike people who may have a survivable event like a heart attack, usually are very ill already and cardiac arrest is the terminal event in their illness. They just can’t keep going on…and die. (It is very, very rare for dogs and cats to have an actual heart attack, which is a common cause of survivable cardiac arrest in people.)

That’s pretty much it in a nugget:

• People → heart attack  → CPR  → 10-20% survival
• Pets → super, super sick from kidney failure, cancer, sepsis, etc.  → CPR  → less than 5% survival

This all brings me to the main question: Is CPR worth it in pets?

One could say – why not? What do you have to lose? That is a valid point. Once heartbeat and breathing cease (the definition of cardiac arrest), patients are unconscious and not experiencing pain. So, all the chest-thumping, injections and artificial breathing don’t cause pain (that we know of, anyway).

Also, it can give owners the impression that we did all we could for their pet. CPR is the ultimate all-hands-on-deck medical treatment and doing it might give people the confidence that all that could be done by the medical team was done. Even if it is for show, it has merit in giving pet owners some peace of mind.

When I do CPR, I try and do it letter-perfect and not miss anything. It’s chaotic enough, what with all the scrambling for medication and monitors (not to mention all those crazy Teletubbies® running about), that things can invariably get missed, but we try and train and do it the right way.

But the false impression that TV gives laypeople about the success rate that their pet will come back and be able to go home has crept into the clinic. I have had many pet owners think something must have been wrong with our efforts in CPR because they almost always go home on TV.  So even if we did everything properly, the impression is there that we didn’t do it right.

The financial cost has to be a consideration, as well. CPR for pets can cost anywhere from $200 to $600, or more, depending on circumstances. For some folks, this effort for something that has such a dismal chance may not be realistic.

The other reason CPR is something to consider not doing is that it might give false hope. Just the fact that we can do CPR gives some people the impression that successful CPR means there’s a good chance of recovery and going home. The sad reality is that after CPR, we can rarely get a patient to stay better off than how they were just prior to CPR.

Imagine a 19-year-old cat with severe kidney failure. If this cat has a cardiac arrest and CPR is successful, we still have a 19-year-old cat in kidney failure. It may be better to accept the reality that life is finite and that death is the natural end of all life. But I know that’s a hard and unpleasant lesson for many.

For critical patients that I admit to the hospital, I try and have a realistic discussion of a pet’s chances if CPR becomes necessary – and I try to have this talk as early in the hospital admission process as I can. I usually have to get over pre-conceived notions of success, most of them gleaned from TV. When I start to quote the success numbers for CPR, though, many folks will see the light and say “Do what you can do to prevent it, Doc, but if it happens, just let her go.” I almost always agree with this sentiment, although young patients with treatable conditions and anesthesia are the big exceptions.

I hope the actual numbers on survival after CPR in pets will help clear up some of the confusion. And hopefully, TV writers will read this and start incorporating a heftier dose of reality in their medical dramas. When they’re not writing for Teletubbies, that is.

References

1. The heart-stopping reality of cardiac arrest   
2. In-Hospital Cardiac Arrest   
3. It isn’t like this on TV: Revisiting CPR survival rates depicted on popular TV shows     
4. Kidding. Really, there’s only four Teletubbies, no matter what Dr. Johnson heard on the street.
5. RL McIntyre et al. “Assessment of Cardiopulmonary Resuscitation in 121 dogs and 30 Cats at a University Teaching Hospital (2009–2012).” JVECC 2014, Vol. 24, N. 6, p 693–704