Anesthetic Safety Standards

The staff of Aloha Animal Hospital understands that many owners #1 reason for not scheduling needed dental or surgical care is concerns about their pet’s safety while under anesthesia. While anesthesia can pose a risk, most of that risk can be eliminated by good pre-anesthetic care, use of proper anesthetics, and thorough monitoring throughout the procedure. This page describes the details of Aloha Animal Hospital’s Anesthetic Safety Standards and how each step we take makes anesthesia as safe as possible for your pet.

Pre-Anesthetic Care
There are several steps that we take to reduce anesthetic risks before even performing an anesthetic procedure.

The Physical Examination

There is no substitute for performing a thorough physical examination prior to anesthesia. Important aspects of a pre-anesthetic physical are:

• Vital signs
• Gum color & pulses
• Cardiovascular system
• Respiratory system

Pre-Anesthetic Blood Testing

Pre-anesthetic blood testing is important because a physical examination alone cannot tell us everything about the health and function of your pet’s internal organs. Blood tests performed prior to anesthesia help your veterinarian evaluate:

• Bone marrow
• Immune system
• Platelets for clotting
• Kidney function
• Liver function
• Blood sugar levels
• Proteins

While this step may be optional at other hospitals, we understand the important role that blood testing plays in anesthetic safety. For this reason, recent blood testing is always required at Aloha Animal Hospital prior to any procedure. If any abnormalities are found that could increase your pet’s risk, your veterinarian will discuss the risks and may suggest postponing the procedure to perform further diagnostics or treatments before proceeding with anesthesia.

Pre-Anesthetic Electrocardiogram

An electrocardiogram or ECG evaluates the electrical current of the heart and can show arrhythmias, heart enlargement and abnormal heart beats. When might a pre-anesthetic ECG be indicated?

• Patients with known or suspected heart disease
• Senior pets
• Breeds that are prone to heart related problems

Intravenous Catheters

An IV catheter is placed as the last pre-anesthetic step. The IV catheter serves several purposes.

• Avoids multiple pokes for IV medications
• IV medications do not accidentally go outside the vein
• IV fluids are administered for maintenance of blood pressure
• Allows for immediate access in the event of an unforeseen complication,
  like a slowed heart rate

Although complications are exceedingly rare, having an IV catheter already in place for emergency treatment may well save your pet’s life in such an instance.

Proper Anesthetics
The use of modern, safe anesthetics is the second way in which we reduce risk to your pet during anesthesia. Use of a combination of medications keeps your pet pain free, reduces the amount of any one medication needed, which reduces side effects on heart rate and respirations and shortens your pet’s recovery time.

Pain Medication

Pain medications are important in almost every procedure, even a routine dental cleaning. There are several levels of pain medication that can be given depending on the severity of pain anticipated with the procedure. Types of pain medications used are:

• Non-steroidal anti inflammatory drug or NSAID.  Tylenol and ibuprofen are NSAIDs used for people but are not safe for pets. The NSAIDs used for our pet patients, like Rimadyl and Metacam, are much safer and more effective.  
• Opiods, like hydromorphone provide stronger pain control for cases such as a surgical tooth extraction or an abdominal surgery.
• Regional blocks are performed at the surgery site using marcaine and lidocaine to give local pain control as well.
• A combination of an NSAID, an opiod, and a regional offer better control of pain.
• Pain medications also help to reduce the amount of anesthetic needed during a procedure which reduces your pet’s risk of complications.

Studies show that pain medications work best when given before the procedure is started. If given during the procedure or during recovery, the pain receptors have already been stimulated and do not respond as well to the medication as they do when treated before stimulation.

Sedatives

Sedatives are given to the patient just before the anesthetic induction phase. The two sedatives most commonly used at Aloha Animal Hospital are diazepam (valium) and dexdomitor. The benefits of sedatives are:

• Sedatives help to calm any anxiety. Decreasing anxiety before an anesthetic procedure helps to ensure your pet’s safety
• Smaller amounts of anesthetic agents are needed to achieve general anesthesia and less anesthetics means less risk.
• Diazepam is a very safe medication for pets with heart disease and seizure histories.
• Dexdomitor is reliable and predictable product that not only provides sedation and pain control but is also reversible as well.

Anesthetic Induction Agents

Anesthetic induction drugs are the medications that when given make your pet lose consciousness or initiate general anesthesia. Our preferred induction agent is propofol.  Why is Propofol a preferred method of anesthetic induction?

• Propofol is short acting. This means it takes affect very quickly but also wears off very quickly, spending only about 15 minutes in the body. 
• By being quickly cleared from the body, it reduces that amount of drugs in the body at one time and improves recovery time after the procedure.
• It is also the medication that most human anesthesiologists prefer to induce anesthesia in their own patients. 

Inhalant Anesthetic

Inhalant anesthetics are how general anesthesia is maintained. Inhalant anesthetics are delivered through an endotracheal tube mixed with oxygen. Sevoflurane is type of inhalant anesthetic used at Aloha Animal Hospital:

• Sevoflurane is the newest inhalant anesthetic in veterinary medicine, although it has been used in humans for quite some time.
• The body responds quickly to changes in levels of sevoflurane. This makes maintaining the appropriate “plane of anesthesia” easier to do and with faster response. 
• Sevoflurane is cleared quickly from the body when administration has been stopped making the pet recover faster, feel less groggy and go home sooner.

Anesthetic Monitoring
The last but one of the most important aspects of anesthetic safety is good anesthetic monitoring. At Aloha Animal Hospital we have trained technicians monitoring your pet’s vital signs and plane of anesthesia throughout the procedure. These vitals are recorded and are stored in your pet’s record after the procedure. Below we will talk about the importance of each item and how it affects our decisions during anesthesia.

Heart rate and rhythm

It is normal for your pet’s heart rate to be slower under anesthesia but a normal rhythm should always be maintained.

• All pets under anesthesia are connected to a continuous ECG
• All pets also have pulses measured by a pulse oximetry machine during anesthesia.
• The anesthetic technician will also take periodic HR manually to verify that both ECG and pulse oximetry equipment is reading accurately

Respiratory rate, oxygen and carbon dioxide

A regular respiratory rate is important but even more important than the number of breaths taken is the quality of gas exchange. As your pet breathes it should be oxygenating the blood and releasing carbon dioxide from the body during exhalation. There are several monitors used to analyze this.

• Pulse oximetry- discussed earlier as monitoring the heart rate, it also measures the amount of oxygen in the blood. Good oxygenation is important during anesthesia.
• End tidal CO2 monitor- this counts a patient’s respirations per minute but more importantly it shows the amount of carbon dioxide in each breath in and out. Carbon dioxide levels will change more quickly than oxygen levels and therefore can predict a problem before oxygen levels are affected. This allows us to make changes or treat respiratory problems before low oxygen levels (hypoxia) occur. Treating before hypoxia develops can prevent detrimental affects to brain, heart and internal organs.

Temperature

Body temperature is very important during anesthesia. Body temperature will begin to drop during anesthesia. As body temperature decreases it causes blood pressure to fall, slows metabolism of anesthesia and prolongs recovery. We use several methods to help maintain body temperature during anesthesia.

• Warm water recirculating blankets use water continuously heated to a constant temperature and pumped through a pad that the patient lays on. This pad helps maintain a normal body temperature without the possibility of burning the patient like a heating pad might do.
• Socks- Since paw pads are a big source of heat loss during anesthesia, we place socks on the feet of our patients when they are anesthetized. This decreases heat loss during the procedure.
• Blankets and space blankets- foil blankets like those used for camping help reflect body heat back to the patient. Fleece blankets are also used over the patient for added insulation.
• Close monitoring-body temperature is closely followed during anesthesia so that additional measures can be taken if body temperature begins to drop too rapidly.

Blood Pressure

Good blood pressure helps maintain normal blood flow to vital organs during anesthesia. If blood flow is poor for prolonged periods of time, damage to brain, heart or abdominal organs can occur.

• Blood pressure is monitored by a cuff on the leg, the same as you or I would have our pressure measured.
• IV fluids are very important in helping to maintain blood pressure during anesthesia. Increasing the flow of IV fluids can quickly correct a low pressure.
• Maintaining good body temperature during anesthesia also helps to keep blood pressures in an acceptable range.

Depth of Anesthesia and The Importance of Well Trained Staff

One of the most difficult concepts to explain is depth of anesthesia. This is the level at which the patient is not conscious of what is going on around them but it not so deep asleep that vital signs begin to deteriorate. The appropriate depth of anesthesia may require very different levels of anesthetic gas to achieve from patient to patient or even within the same patient at different times during a procedure. For example, at the very beginning of a dental procedure more anesthetic may be needed to achieve the appropriate plane of anesthesia but once the patient has been under anesthesia for 15 minutes, less anesthetic may be needed to remain at the right plane. If for instance an extraction is needed, although the patient is not feeling any pain at the start of the extraction, it is creating more stimulation to nerve endings and therefore may require more anesthesia during the extraction to maintain the same level of anesthesia. Once the extraction is completed, less anesthetic may be needed again. As you can see the depth of anesthesia needs constant monitoring. This is why having a trained staff member assigned to your pet during anesthesia is one of the most important safety steps we can take.

Post-Anesthetic Monitoring

Monitoring doesn’t stop when the procedure is complete. Post anesthetic monitoring is important also. Here are some aspects of the recovery that must be watched:

• Your pet will not be able to swallow immediately after the procedure. For this reason, the endotracheal tube must stay in place until your pet’s ability to swallow returns to protect your pet’s air way from possible aspiration. 
• Body temperature can continue to decrease as anesthetics wear off.  Continued warming techniques and temperature monitoring are important post-anesthesia.
• Some pets will try to stand quickly after anesthesia but may not be coordinated enough to do so. Having a staff member standing by will stop a pet from becoming too active too quickly.
• Although all pets receive pain management before a procedure begins, some pets can be more sensitive to pain than others.  Assessment of pain levels during the recovery period allows us to administer more pain medication if needed and provide for your pet’s comfort.

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