There is a famous quote by Dr. Robert Smith, MD regarding anesthetic safety, "There are no safe anesthetic drugs, there are no safe anesthetic procedures. There are only safe anesthetists." Being a good anesthetist and providing the safest anesthetic care comes before, during and after an anesthetic procedure. One very important component of safe anesthesia is the pre-anesthetic preparation and work-up. What this means will vary and is depending on species, breed, age, the intended procedure(s), and any concurrent medical issues.
In every case, the patient should have a full physical exam and full medical history taken. Both are very important in making an individualized anesthetic protocol. A full physical exam will ensure that the patient is healthy enough for anesthesia and that no additional abnormalites are found, that may need addressing during the anesthetic period. It is also important when gathering or giving the medical history, that any past medical abnormalities or anesthetic complications are discussed, even if seemingly unremarkable.
Once those are complete, the clinician can make a diagnostic plan. In some cases, this may mean blood work will need to be obtained and submitted. Blood work gives us some insight as to how the pet's internal organs are functioning, which generally cannot be evaluated with our naked eyes. This may be as simple as determining a patients red blood cell count and glucose level (generally in the very young) or may mean a full panel to assess the function of the liver, kidneys, thyroid glands, pancreas, adrenal glands and more. Recommendation for pre-anesthetic blood work in veterinary species is more common than in humans, as human physicians often rely on us to provide them a verbal medical history, which may give clues to potential underlying medical concerns, while our patients cannot provide us those same details.
Additional diagnostics that may be recommended are imaging such as radiographs (x-rays), ultrasound, cat scan and/or MRI, depending on the presenting complaint and the age of the patient. In otherwise seemingly healthy patients, radiographs of the chest are often recommend to ensure there is no evidence of pulmonary disease or cancer which is more common in elderly patients. If the patient has concurrent medical issues or abnormalities found on the bloodwork or physical exam, these other imaging modalities may be needed to gather a full picture of the pet's health.
An ECG and/or echocardiogram may also be recommended. The ECG will give the clinician a quick snap shot as to whether the pet has a normal heart rhythm or not. Some hospitals will recommend this in any patient, as it can catch an underlying rhythm disturbance that neither the pet parent or the veterinarian knew was present. It may also be recommended it the patient has known or suspected cardiac disease or an abnormal rhythm heard on physical exam. Abnormal heart rhythms can present significant anesthetic risks if undiagnosed and/or untreated, so this can be a very important tool. The echocardiogram is a visual imaging tool to evaluate the size of the heart chambers, determine how well the heart is contracting, determine if there are valvular changes, anatomical abnormalities and/or clots present. This can give important information about the patient's anesthetic risk that radiographs cannot, and drastically change what drugs are chosen and how a patient is managed under anesthesia if hypotension occurs.
Once the work-up is complete and a full health picture is known, the clinician may recommend pre-anesthetic treatments. Not every patient will need pre-anesthetic therapies but in some cases medications to prevent nausea, provide anxiolysis or other medically necessary therapies will be recommended. Clinicians will also most likely recommend a period of fasting (just like in people) prior to the procedure. This, especially in conjunction with anti-nausea medications, can not only minimize the risks of vomiting and aspiration but the addition of anti-nausea medication has also been shown to promote patients returning to feeding quicker. This allows for quicker hospital discharge, quicker healing and in general allows the patient to feel more normal faster.
The pre-anesthetic period is an important component of good anesthetic care. This is a collaboration between the veterinary team and the pet parent. In a world where veterinary insurance is not commonly used, the cost of work-up may result in stress and feelings of uncertainty as to what tests are actually necessary. Good communication and collaboration will allow clients to have enough information to understand what tests are truly necessary for safest anesthesia and why, what tests may be helpful but also may not change the course of anesthetic planning and safety, and what risks there may be if tests are not approved. Clients can then make an educated, then documented, decision regarding their pet's anesthetic work up and/or management prior to anesthesia. In the end, all of our goals are to provide the safest and most comfortable anesthetic experience we can to our furry loved ones!
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