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Friday, October 21, 2016

Are Multiple Anesthetic Procedures Safe?

Any time anesthesia is performed on a patient there are certain effects on the body.  Brain activity changes, heart and respiratory rates slow, body temperature drops, blood pressure decreases, heart contraction can change, and many other physiological alterations.  All of this sounds scary, and to some degree it is.  Anesthetizing a patient to a degree where we can perform surgery without them knowing and reacting actually can bring them closer to death than just about anything else we do.  No matter what precautions we take, there is no way to make anesthesia 100% risk-free.

But even with all of that being true, it doesn't mean that we can't have a very safe anesthetic procedure and even do multiple ones in a year.  In fact, that's a common question I will get and the reason for today's post.  We may do a dental cleaning then a few months later notice a lump that we want to remove.  Some clients are worried that performing anesthesia again in the same year will be a big risk and cause complications.  I can assure everyone that this is not the case when done properly.

There are many ways to anesthetize a patient, and the exact drugs, dosages, and procedures will vary from one vet to another.  The anesthetic protocols we use at my clinic aren't "magic" and in fact they were designed in consultation with board-certified anesthesia specialists.  Anyone can use these drugs and procedures.  But the vet down the road from me may give different pre-medications, may induce the pet differently, and may maintain them on a different type of inhaled gas.  Or, they may use the same gas but the rest are different.  There are numerous combinations of protocols available in anesthesia text books and at conferences.  In vet school we are taught several of these techniques so that we learn a variety of methods.  The main take-away on this point is just because one vet performs anesthesia a certain way doesn't mean that every vet will do the same thing.  If you have any concerns ask your vet specific questions about which drugs are used and why.  To give an example, even though this will mean little to most pet owners, we typcially pre-medicate with acepromazine and butorphanol, both at low doses, induce with propofol, and maintain with sevoflurane.  The drugs and dosages may change depending on the pet's health status or the type of surgery being performed. 

Regardless of the protocols used, there is one main thing to remember.  The drugs used have limited duration of effects on the body.  Sevoflurane gas changes it's concentration in the blood stream within a few minutes.  Propofol starts to wear off within a few minutes.  Other drugs may take longer, but they are still completely eliminated from the body within 12-24 hours.  This means that by the day after the surgery the medications used are out of the system and the body is returning to normal.  As long as there were no unexpected complications there are no lasting effects on the body's organs.

Because of how the body processes these drugs and removes them there is no long-term accumulation in the blood stream.  Therefore doing another surgery in a week or two is no more dangerous than doing it in a year or two.  By the time of the second anesthetic event the body has cleared all of the medications and effects of the first surgery to the point of it essentially reacting as if no previous procedure had ever been performed.

Doing multiple surgeries within the same year or even same month is no more risky than doing them years apart.

With that being said, there are certainly good reasons to wait longer.  Though the anesthesia itself may be safe, damaged tissues need time to heal and this can take anywhere from weeks to months.  A surgeon may elect to wait many months to do a second surgery simply so that anything changed, repaired, or removed during the first surgery has a good chance to heal before tissues in that area are stressed again.

When in doubt, ask your vet lots of questions about why they may want to do multiple procedures close together.  But also realize that such things aren't inherently dangerous simply because there is a short amount of time between them.