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Monday, February 28, 2011

Playing It Safe

One of the most important pieces of equipment during anesthesia monitoring is the electrocardiogram (ECG or sometimes EKG).  With this tool we can not only keep track of the actual rate of the heart but also note electrical abnormalities in the heart, problems with rhythm, and issues with abnormal contraction patterns.  Not using an ECG during general anesthesia is taking a big and unnecessary risk. 

Today we had an issue with our ECG machine.  Remember that this is my first full week in the new location and I'm adjusting to the new staff and patterns.  Though I've worked with all of them before I don't know all of the ins-and-outs of the team yet.  We had induced our first procedure, a routine neuter, and had him under anesthesia.  As my assistant was connecting the monitoring equipment (ECG, blood pressure, and pulse oximeter) she noticed that the ECG wasn't reading at all.  It was strange because the graph wasn't coming up on the screen at all, yet the computer acknowledged that it had found and recognized the machine.  She tried to get it to work and went through various screens, turning it on and off, and finally rebooting the whole computer.  Nothing worked and the ECG still wouldn't read. 

Since the dog was already anesthetized and a neuter usually takes me less than seven minutes, I forged ahead and finished as quickly as I could.  We still had all of our other monitoring equipment so I wasn't without physiologic data.  The dog did fine and recovered normally.  But we still had three more anesthetic procedures, all dentals.  And we still couldn't figure out what was wrong with the ECG!  My assistant contacted tech support and they didn't know what was going on either.  They started to research it and said they'd call us back.

While waiting I made the decision not to proceed with the dental cleanings.  Those all would have taken longer than an neuter and I didn't want to take any risks of missing a serious cardiac abnormality.  So I called the owners, explained the situation, apologized for the inconvenience, and had them reschedule the cleanings.  I hated to do that as it potentially caused a problem for the client, as well as lost the revenue from the procedures.  However, my primary concern should always be to the health and safety of the pet, so I did what I thought was the right thing.  Thankfully the clients were very understanding of what happened.

In situations like this a vet should always remember that their first priority is the pet, not the client or even the business.  We shouldn't take risks that don't need to be taken, especially with anesthesia.  I've heard anesthesia described as the closest to the conditions of death we willingly take a patient.  So when we take this step we need to do it as safely as possible.  And if all of the equipment that keeps it safe isn't working as it should, we should think of the patient and consider canceling an elective procedure.

Later that afternoon we learned that a few days prior a different assistant had accidentally messed with some of the settings.  After looking into it further we discovered a setting that needed to be activated to allow the ECG pattern to display.  Somehow we had overlooked this when troubleshooting earlier, and if we had only noticed it we could have followed our original schedule.  I'm also very surprised that the tech support couldn't describe how to check that.  So our machine actually WAS working properly, but needed a single setting to be readjusted. I don't regret our decision to reschedule things, and I'm glad that everything will be in good working order for tomorrow.

9 comments:

  1. This comment has been removed by the author.

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  2. Interesting perspective. If I had to lose a piece of monitoring equipment in surgery, it would be the EKG first. After all, a good technician's hands are all the EKG we really need.

    I would much rather have ETCO2, SPO2, and BP monitoring then ECG - esp since I have had several cases with normal ECGs that were actually in full cardiac arrest.

    The most recent happened with an older (6 y/o) Doberman c-section with likely underlying cardiomyopathy.

    We had a Doppler on her lingual artery to measure her HR and hear it, and my technician was monitoring her femoral pulses frequently. Suddenly, the Doppler went silent - about the same time my technician said "her pulses are gone!" and I noticed that her uterine pulses had stopped.

    The ECG meanwhile, was still ticking along with a normal HR of 90. The rhythm looked odd, but it was regular still. It NEVER changed.

    We've also had our EKG read heart rates when not hooked up to anything.

    I trust it least of all our equipment.

    (P.S. - we got the Dobie back. She arrested 5 times during the c-section but made it through just fine, amazingly! A good story about why breeding an older dog with genetic propensities toward heart disease coupled with no preventative care is NOT a good idea!!)

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  3. I almost never see an EKG abnormality either but frequenly see low blood pressure and hypoventilation. Seems like some EKG monitors are very fickle about giving good readings. If anyone can recommend a good one we are shopping for a new anesthesia monitor.

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  4. With my limited experience, I feel like I wouldn't value the ECG monitor as highly. After all, the ECG can read out completely normally while the patient is in cardiac arrest! I think you made the right decision to cancel the dentistries, albiet a difficult one.

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  5. I'm pre-vet (starting this fall). I've only shadowed at a handful of clinics, but none of them use ECG routinely for general anesthesia (regardless of the procedure). They've all had it available; but have only used it when there's a pre-existing condition.

    The way you described it suggests it should be used more than I've seen.

    Did I just happen to hit the few clinics that don't use it, or is there something else going on here that, in my lack of knowledge, I'm just not understanding?

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  6. Anon-I believe some form of monitoring should be used for essentially all procedures. What form you use depends on what the clinic has available-some of the equipent if very expensive, the procedure and the pet. Very complete monitoring systems (similar to human anesthesia) are rapdidly becoming the stardard of care for pets as they are more and more regarded as family members. That's my opinion anyway!

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  7. Personally, I feel that an ECG is extremely important. If someone is getting normal readings when a pet is in cardiac arrest, I'd argue that their specific machine wasn't functioning properly and should be serviced. I've never had an ECG read other than I expected it to unless there was some physical or mechanical problem with the equipment. A properly functioning ECG should give you the proper readings.

    If ECGs are of so little use, then why do they use them so much in vet schools and referral practices? Why do cardiologists rely so heavily on them? Why will you never see a human anesthesia without one?

    Okay, non-vets forgive me with the next bit, as I'm going to slip into medical talk... I've seen plenty of cases VPCs and heart blocks on ECGs during routine procedures in otherwise healthy pets. Without the ECG to detect these we might have missed an arrhythmia that could have led to a serious condition in the patient. I don't think the average tech or vet could tell the difference between a sinus arrhythmia going into bradycardia versus a heart block. An ECG will tell you this right away.

    Is it foolproof? No. And it shouldn't be your only monitoring. But I won't do a general anesthesia without one.

    Okay, new blog idea. Feel free to jump in and disagree with me on today's entry. ;)

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  8. It's common for the ECG to read a heart rate in a patient without a pulse due to electromechanical dissociation. It's not a faulty machine, but continued electrical activity in the heart.

    I'm not saying they are not important, I am saying they are the LEAST important of all the monitoring equipment. I think far more patients die from hypoxia or hypotension, or suffer long-term sequelae.

    Further, I would argue that the ECGs on anesthesia monitoring machines are a far cry different from those used by cardiologists. Ours can print out a strip of the rhythm, but it doesn't have tick marks or measurements, so you can qualify height of QRS complexes or p-waves. The ones associated with general anesthesia machines give you an idea about heart rate and rhythm, but they are nothing compared to those used by cardio specialists.

    My technicians can tell when a patient's pulse has become irregular on palpation of the femoral artery. They can also tell me when they are becoming weaker or stronger. I trust them more than that machine.

    I'm not saying chuck it out, I'm just saying it doesn't offer much information (in my opinion) that a skilled technician cannot appreciate from careful examination of the patient.

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  9. I guess our ECG is more advanced, as we do have all of the graphs and ticks that can quantify measurements. I can also use all 6 leads, though honestly I only feel comfortable analyzing the common lead 2 view. I am able to take analyze height and width of waves, and have done so many times.

    Now I completely agree that a machine doesn't replace a skilled tech, and you should never rely on equipment over people. However, I do think that the machines can quantify things that a person cannot.

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