Designing an anesthesia plan (Proceedings)

PLAN 1. an outline; draft; map. 2. to devise a scheme for doing, making or arranging. 3. refers to a detailed method, formulated beforehand, for doing or making something.

The development of an anesthesia plan is the first step towards well-managed anesthesia care for your patient. The foundation for a good anesthesia plan is set in knowledge and understanding of the procedure to be performed, the needs of your patient and the resources available to you. Your ability to assess the patient and understand what you will have to work with is an essential element for planning. Equally important is your knowledge of the resources available to the patient, as well as those resources available to you, the anesthetist. Anesthesia is not without complications, therefore anticipation of problems arising from anesthesia and/or the operative procedure is crucial to the plan.

An anesthesia plan has several components. For this presentation we will focus on:

• Pre-anesthetic patient assessment,

• Anticipated anesthesia and procedural problems, along with contingency planning

• Anesthesia drug and support therapy

• Physiological monitoring

• Post anesthesia recovery

• Collaboration with the health care team

For some, anesthesia planning frequently revolves around what anesthetic drug(s) is best used for a specific procedure. Anesthesiologists are often questioned: "What's the best drug to anesthetize a cruciate repair?" or "What do you use on a GDV?" These questions could have several different answers depending on one's resources and experience. In order to give an answer that would benefit both the anesthetist and the patient, we need more information. Rather than basing our options primarily on a procedure, we can base them on the patient's needs and what we have to work with. In order to understand the patient's needs we must first, evaluate the patient. Therefore, the development of an anesthesia plan starts with a pre-anesthetic patient assessment.

Pre-anesthetic patient assessment

A pre-anesthetic patient assessment will allow the anesthetist to determine the patient's physical status and reveal what you the anesthetist have to work with. Physical status has a very strong influence on the outcome of anesthesia. Patients with a poor physical status have an increased risk of complications during anesthesia. The results from this patient evaluation will provide information that will allow the anesthetist to make prudent decisions in regard to the anesthesia care. If you do not actively look for problems, you will not find them. The goal of this evaluation is to understand the patient's ability to tolerate the administration of various anesthesia drugs and then recover from their effects without detriment.

This evaluation typically will start with a patient history, some questions to consider when evaluating a patient are:

• Why are you anesthetizing this patient? What is the presenting complaint? What is its medical history? Does the patient have any co-existing diseases? Is the patient taking any medications at this time? What is the current body weight and has the patient lost or gained weight recently? Changes in activity level, food and water intake, and/or behavior should also be noted.

• The previous history should also be included. What previous medical problem has the patient experienced and what previous medications have been administered to the patient?

• Has the patient been anesthetized before? If so what drugs were used? Were there any complications? If so, what were they and how were they remedied? Was the patient injured by the previous anesthesia episode?

All anesthesia drugs have some detrimental affect on the various organ systems in the body. One goal for the anesthetist is to help the patient maintain physiological homeostasis, a normal stable environment, during the anesthesia period. A systemic evaluation is commonly used to help the anesthetist predict how the patient will respond to the effects of various drugs. The physiological systems of primary interest are the cardiopulmonary, neurological, hepatic, renal and endocrine systems. Therefore, the anesthetist must be confident in the performance of these systems and their ability to function properly under stress.

A logical starting point for this systemic evaluation is a thorough physical examination of the patient. Perform a complete physical examination. It is important for you to perform your own exam, even if someone else has examined the patient previously. If you are the individual to anesthetize the patient, then you need to have first-hand knowledge of its physical condition. The opportunity for a repeat physical exam is not a waste of time. Second looks often turn up problems that were missed on initial exams. The exam should include; patient observation, an oral exam, auscultation of the thorax, assessment of mucous membrane color, capillary refill time, pulse quality, heart rate and rhythm, respiratory rate and character, palpation of the abdomen (unless contraindicated), temperature and assessment of body composition, etc... Radiographs and laboratory evaluations will help answer questions regarding the patient's ability to tolerate both anesthesia and operative procedure induced stress, as well as its ability to metabolize anesthetic drugs. This information also provides the pre-anesthesia baseline for patient status.

Anticipated anesthesia and procedural problems

The anesthetist must have an understanding of the requirements imposed by the operative procedure to be performed. Veterinary patients require anesthesia for many therapeutic and diagnostic procedures. These procedures all have different requirements and the potential to generate complications for the patient. Hypotension, hypoxia, hypothermia, hemorrhage and pain are just a few complications that may arise during anesthesia. The potential for complications arising from both anesthesia and the operative procedure is referred to as "Operative Risk". The anesthetist must have a good understanding of the operative risk and anticipate a response to support the patient and maintain physiological homeostasis. Once the pre-anesthesia patient assessment is complete, and you understand the operative risks for the patient, you can develop effective contingency plans to deal with the operative complications you anticipate.

Setting specific goals for the individual patient allows the anesthetist to develop a focus and improve the quality of anesthesia support for the patient. These goals should take into account the requirements of the procedure, the physical status and needs of the patient as well as the resources available to you. Perhaps the best question to ask is "What do I want to achieve when I anesthetize this patient?" The easy answer to that question would be an uneventful anesthesia and recovery period that did not harm the patient. While this is an easy answer, it often proves a very difficult task, depending on; the patient's physical status, the demands of the procedure and your available resources.

Anesthesia drug and support therapy

In order to produce anesthesia and provide patient support, the anesthetist must rely on the effects of various drugs. There is no perfect anesthesia drug. All anesthesia drugs can produce undesirable effects in our patients. As far as goals for the anesthesia drug plan is concerned, let's go back to the question "What do I want to achieve?"

Analgesia, immobilization, amnesia, muscle relaxation and physiological homeostasis are the desired end-points for an anesthesia drug plan. Often the choice of drugs may be limited and your selection may not include the "optimal" drug of choice for a particular patient or situation. Your knowledge and experience with the drugs available to you is a cornerstone in the anesthesia drug plan. What are the advantages to these drugs? What are the disadvantages of these drugs? What are the needs of the patient and which drugs will best support this patient? Thinking your way through these questions as you develop an effective anesthesia drug plan will require knowledge, understanding and experience with the drugs available at your facility. One advantage to a well-designed anesthesia drug plan comes from the forethought used to generate the plan and anticipate complications. Planning will produce a drug protocol that will safely meet the requirements of the individual patient and provide the best support for the patient. The safest drug protocols are the drugs you are most familiar with. Justification for the use of a new drug in your protocol is if the new drug provides something to meet the patient needs that none of your routine drugs can provide. New drugs should be used in low doses on more healthy patients until you are familiar with what results to expect from the drug's use.

Physiological monitoring

How will you know if your patient is adequately supported during anesthesia? The purpose of patient monitoring is to provide information that can be used by the anesthetist and allow for prudent decisions that will maximize patient support and safety. Patient monitoring should be designed to allow the anesthetist to recognize problems at the earliest stages and respond before these early complications can evolve into an anesthesia crisis. It is somewhat controversial among anesthetists and anesthesiologists what parameters are the most important. When designing a monitoring plan, a systemic approach to monitoring works well. Correlate the information gathered during the pre-anesthesia patient assessment and take into account any problems that might arise from the patient's co-existing diseases. Keep in mind the anticipated problems list you developed earlier in this plan. How will I know if the patient is experiencing a complication? If you don't look for it you probably won't know. What do I need to monitor? Which parameters will alert me to danger for the patient? A systemic approach to monitoring will allow the anesthetist to evaluate the cardiovascular, respiratory and central nervous systems. Decreased cardiopulmonary function produced by anesthesia drugs can have significant effects on oxygen delivery to the tissues of heart, brain, liver, kidneys and other areas of the body. Most common anesthetic complications are related to the cardiovascular and respiratory system, therefore a major focus of physiological monitoring is the cardiopulmonary system. Anesthetists spend much of their time in direct contact with the patient. We use our senses to evaluate the patient and analyze the data we perceive through sight, sound and feel. We can augment that information with the addition of electrical and mechanical equipment to give the anesthetist additional information. When we use additional devices to assist our monitoring we must also ensure the information provided is accurate. In order to do this, we must confirm that the equipment is dependable and in good working order. The anesthetist must also have a clear understanding of both the equipment and the significance of the information provided by the equipment. The additional information provided by the monitors is intended to make the anesthetist's job easier and provide a more complete picture of the patient's physiological status. If the data provided by the monitoring equipment is unreliable then it only serves to misinform, distract and confuse the anesthetist. When evaluating the patient, it is important to look at the whole and not just one or two parameters. This means the anesthetist must not only focus on the monitors attached to the patient, but we must also focus on the patient itself and evaluate all the data we have available.

Post anesthesia recovery

Once the patient has been anesthetized, instrumented and the operative procedure has been performed, the anesthetist will need to recover the patient from anesthesia. The patient will eventually have to return to the pre-anesthesia status and support itself. The planning and the forethought used to develop the earlier portions of this anesthesia plan need to be remembered when planning for recovery. What are the patient's needs? As you remove your support from the patient, will the patient be pain-free? Will the patient be able to achieve or maintain physiological homeostasis? How will I know if there is a problem?

Most common anesthesia related complications experienced during recovery are related to pain, hypothermia, respiratory, and circulatory complications. Pain management is a primary focus for the post anesthesia patient. Post operative analgesics and/or tranquilizers can also help smooth the transition from anesthetized to awake and comfortable. Rapid recoveries are often the goal of anesthetists, but often, smooth gradual recoveries are more desirable for overall patient comfort. Patients require frequent assessment during the postoperative period. Most patients anesthetized become hypothermic despite the efforts of the anesthetist to maintain normal body temperature. Patients tend to hypoventilate, vasoconstrict and shiver when experiencing hypothermia and have a higher incidence of post procedural wound infection. In addition they take longer to metabolize drugs and recover from anesthesia. Evaluation of respiratory and cardiovascular function is as important during recovery as it was during the operative period. Patients can become hypoxic; patients are typically breathing lower concentrations of oxygen (21%-room-air), hypoventilation in addition to shivering can lead to hypoxia. Airways may become obstructed pre or post endotracheal extubation. Certain breeds are more prone to respiratory complications ie: brachycephalic syndrome. The circulatory system also requires monitoring post procedural. Patients may be hypovolemic post surgery and as we attempt to re-warm the patients they can vasodilate and increase the vascular space leading to hypotension/hypovolemia, which can result in poor tissue perfusion with lower concentrations of oxygen. Post surgical intervention bleeding is also a possibility to produce hypotension/hypovolemia without the knowledge of the hospital care staff. The recovery room is an environment where problems often arise, especially if a proactive monitoring approach is not taken. Develop a planned response for each problem you anticipate.

Collaboration and plan authorization

The anesthesia plan is an excellent tool to help the anesthetists improve the quality of care they provided. The plan is a blueprint of anesthesia care. Using this plan to design the patient's anesthesia care allows the anesthetist to logically think through the care required by the patient during anesthesia. The ability to think through problems in advance can help avoid an anesthesia crisis or expedite your response to complications.

In this presentation, a lot of time and energy is devoted to planning anesthesia care for the individual patient. It is essential the anesthetist understand the patient's requirements. Anticipated complications and planned responses must be thought through. The objective has been to develop a plan that takes into account both the needs of an individual patient along with the operative risk associated to both anesthesia and the operative procedure. Resources available to the patient (skills and knowledge of both the surgeon and anesthetist, as well as equipment and drugs available) should be assessed. Anesthesia drug and physiological monitoring plans are developed that will allow you to provide analgesia, support physiological homeostasis and alert you to problems early in their development.

After you have developed an individualized anesthesia plan, you need to discuss the plan with the collaborating veterinarian and discuss your concerns, your strategy to deal with the anticipated problems, explain your logic behind the choice of drugs, monitoring equipment and techniques used in the plan. Technicians are required to work under the supervision of a veterinarian. The veterinarian must be involved in the decision making process and be aware of your plan. "Two heads are better then one" - The discussion of your plan with other health care team members can serve to increase your knowledge and understanding of both your patient and the resources available to you.