THE ANESTHETIC PLAN
Today it is not sufficient to define "good" anesthesia simply as that which does not result in patient morbidity and mortality. Providing appropriate patient comfort, sedation, and analgesia and minimizing the stress response associated with surgery and anesthesia define modern anesthesia. The emphasis should be on developing a comprehensive anesthetic plan for each individual based on that patient's physical status and signalment, the reason for anesthesia and analgesia, and the animal's temperament. Physical status is determined from a comprehensive preanesthetic physical examination and review of pertinent laboratory data.
No one anesthetic plan is suitable for all dogs and cats. A good plan includes appropriate drug selection, the need for the amount and type of perioperative fluids, an approach to patient monitoring, and support of patient homeostasis. Currently, a multidrug approach is preferred for general anesthesia. The key components of general anesthesia—unconsciousness, analgesia, muscle relaxation, and amnesia—are best met by choosing drugs from several pharmacologic categories: sedatives and tranquilizers, hypnotics, opioids, inhalants, and local anesthetics can be used in combination. Analgesic adjuncts including local anesthetic nerve blocks, epidural analgesia, and analgesic infusions should be considered where appropriate.
THE MONITORING PLAN
The most important aspect of safe anesthesia is patient monitoring. The American College of Veterinary Anesthesiologists (ACVA) developed a set of monitoring guidelines that emphasize its importance, which can be found at acva.org. A comprehensive monitoring plan includes determining at regular intervals adequate circulation, ventilation, oxygenation, and body temperature. A trained observant and focused individual who understands the clinical pharmacology and the patient adaptation to anesthetic drugs should be present with the patient. This person must be able to determine normal vs. abnormal response to surgery and anesthesia.
Untoward reaction to anesthetic drugs, blood loss, cardiac rhythm disturbances, inappropriate anesthetic depth, and inadequate analgesia need to be recognized early because recognition and rapid intervention are the keys to preventing irreversible changes. Regular palpation of a peripheral pulse, observation of mucous membrane color, and observation of patient ventilation are the minimum monitoring requirements.
Consideration should be given to obtaining and learning how to use modern anesthetic monitoring devices. These devices greatly enhance the ability to discern the unexpected. Modern anesthetic monitors can be configured for capnometry, electrocardiography, blood pressure, pulse oximetry, and body temperature to optimize the monitoring of cardiovascular and respiratory function. Monitoring should continue well into the recovery period at regular intervals until the patient is awake, warm, and comfortable.
CONTINUING YOUR EDUCATION
The measures outlined in the AAHA Anesthesia Guidelines for Dogs and Cats are a good step toward safe anesthetic procedures in all pets. For further guidance, numerous continuing education opportunities in anesthesia are available at local, regional, and national meetings. Anytime a question arises regarding any aspect of anesthesia, you should contact an ACVA diplomate. Contact the anesthesiologist at your alma mater, or refer to acva.org for a list of ACVA consultants.
Dr. Richard Bednarski, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, was the chair of the anesthesia guidelines task force.