Surgery and anesthesia always pose a risk for the patient. It is therefore recommended that the patient is not only evaluated for their present complaint and disease, but also undergo a pre-operative assessment to account for the suitability of anesthesia and surgery.
The assessment will help detect possible underlying problems, such as compromised kidneys, diabetes, liver problems, or anemia, and will allow for adjustments in the procedure that will protect the patient’s health and comfort. Furthermore, a thorough assessment will help with the prognostication and highlight aspects of a patient’s health that might need attention and post-operative management.
The pre-operative assessment is usually divided in to three parts:
The first part consists of history taking (anamnesis) and a physical examination, including a visual inspection, palpation, and auscultation. Based on this, a general physical status of the animal can be assigned, and the follow-up blood testing planned and scoped. However, as a baseline testing can reflect early signs of disease that are not yet noticeable in the physical examination, a routine blood testing is recommended regardless of the physical examination.
The blood testing generally comprises a complete blood count (CBC) and a biochemistry profile.
The CBC reports the number and size of the erythrocytes (RBC), which are the oxygen-carrying cells; and the platelets (PLT), which help the blood coagulate; as well as the number of leukocytes (WBC), which are the immune-related cells. By measuring the abundance and size of these cells, the clinician can get valuable information about the possible oxygenation of the animal (anemia), ongoing systemic infections, and clotting-related deficiencies that might result in adjustment of the procedure or postponement of the surgery.
To complement the CBC, a biochemistry profile is taken. The main purpose of this test is to show that the major organs, liver and kidney, are working properly so that these can efficiently metabolize the sedatives and anesthetics distributed to the animal. Depending on the physical exam and the CBC, the testing can be expanded to include tests for pancreas function, thyroid function, electrolytes, and so forth.
If the physical examination and the blood testing show any severe abnormalities, extended specific testing for these abnormalities are recommended. Such testing can include urinalysis, x-ray, coagulation studies, and electrocardiogram.
In conclusion, to minimize the risk of complications, both during and after surgery, a pre-operative assessment should be performed. Hematology and clinical chemistry can provide great input that complements the physical exam in this assessment.