Memorial-610 Hospital for Animals

910 Antoine Drive
Houston, TX 77024


Anesthesia: Management of Pain

Surgical procedures are not possible without some form of anesthesia. Not only does anesthesia provide relief from pain, but it also eliminates stress, movement and provides muscle relaxation. Whether a procedure requires a local anesthetic to suture a small cut, or total surgical anesthesia to repair a fractured leg, the anesthesia must performed carefully and specifically for the patients needs. No one anesthetic agent is ideal for all patients. Inhalant anesthetics, provide the safest anesthesia for the patient. Pre-anesthetic agents are used to decrease potential side effects and provide an easy, smooth induction during anesthesia. The use of these pre-anesthetic agents also greatly reduces the total amount of anesthetic agent required for the surgical procedure. The patient is monitored constantly while under anesthesia and adjustments are made as needed to keep the patient stable. After surgery is complete, post-operative pain is reduced through additional forms of drug therapy. Pain management is an important area of consideration for all patients. Appropriate steps are taken to control pain whenever possible. This obviously allows for better patient comfort and improved healing.

Physical examination: All animals undergoing anesthesia at Memorial-610 receive a same day exam with special attention to organs and systems affected by anesthesia. This is true even if your pet was seen here the day before since we know that some problems can develop literally overnight. Other problems such as heart arrhythmias can come and go, escaping detection at one physical, but revealing themselves at the next.

Pre-anesthetic Blood Tests: All pets are required to get blood tests before anesthesia. Blood tests help detect anesthetic (and surgery) risks that might be undetectable on the physical exam. Blood can be drawn up to two to four weeks before an anesthetic procedure, or an in-house laboratory is available so tests can be performed the same day as surgery. These tests include:

Kidney and liver function - these organs must metabolize and eliminate many anesthetics
Tests for dehydration – dehydration reduces blood volume and increases risk of blood pressure problems and shock
Electrolytes - if these are abnormal, heart arrhythmias and cardiac arrest can result
Red blood cells - if these are low, oxygen delivery to vital organs can be compromised
White bloods cells - these are important for fighting infection
Platelets - these are needed for clotting (stopping bleeding)

Other diagnostic tests: If abnormalities are found on the physical exam or pre-anesthetic blood tests, additional tests may be required to determine the nature and severity of the problem. These may include urine analysis, electrocardiogram, radiographs (x-rays), ultrasound or additional blood tests.

Intravenous catheter and fluids: These are used for all procedures. An IV catheter is a small tube that is placed in the vein before anesthesia. Anesthetic emergencies are rare, but when they occur, blood pressure is usually low which makes it difficult to find veins to deliver emergency drugs quickly. A catheter in the vein provides a way to deliver emergency drugs quickly when needed. In addition, patients recover better and have fewer problems when they receive intravenous fluids during anesthetic procedures.

Anesthetic drug protocols: Because anesthesia can decrease heart rate, we routinely pre-medicate patients with an injection that counteracts this effect. Other drugs are used to reduce the amount of anesthetic drugs needed, and to aid in pain control immediately after surgery. Most anesthesia protocols use an injectable drug to induce anesthesia. In very short procedures, this may be all that is needed. In all but the shortest procedures the patient is maintained on isoflourane gas anesthesia, administered through a tube placed in the windpipe. This is widely considered the safest gas anesthetic in the veterinary profession.

Monitoring: Monitoring of heart rate, respiratory rate, electrocardiogram, body temperature, blood pressure, oxygen saturation of the blood, expired carbon dioxide levels, and reflexes are all performed during anesthetic procedures at Memorial-610. Changes in any of these parameters can be early warning signs of difficulties with anesthesia, and close monitoring by people and machines allows us to make adjustments in the anesthesia protocol to avoid more serious problems.

Thermal support: Anesthesia can also compromise any pet's ability to maintain normal body temperature. Temperature monitoring and hot water bottles, water blankets, and warmed blankets and towels are used as needed.

Individualized anesthetic protocols: Every patient's drug doses are adjusted for body weight, age or any other factor that affects anesthetic drug doses. The types of drugs used are modified as well in some cases. In addition, if problems are noted in the pre-anesthetic evaluation, steps are taken to reduce anesthetic risk associated with those problems.