Handbook of Veterinary Anesthesia

William W. Muir, John A. E. Hubbell

• Publisher: Mosby
• Year: 2012
• eBook ISBN: 9780323290555
• Edition: 5
• Topic: Medicine
• Subtopic: Veterinary Medicine

- UPDATED anesthetic drug information and NEW pain management techniques provide the latest on indications, toxicities, and recommended dosages.- EXPANDED step-by-step overviews of anesthetic and analgesic techniques make it easier to review and perform procedures.- UPDATED coverage of euthanasia, including the most current AVMA guidelines, provides today's accepted protocols for the provision of euthanasia.- UPDATED complementary and alternative strategies provide non-pharmacologic interventions for pain management.- UPDATED research findings and clinical applications address special anesthetic considerations necessary in cats.

1

Introduction to Anesthesia

“There are no safe anesthetic agents; there are no safe anesthetic procedures; there are only safe anesthetists.”

ROBERT SMITH

Overview

The applied practice of veterinary anesthesia is based on a general understanding of the following: (1) the terms used to describe the drugs, techniques, and consequences of anesthesia (2) the pharmacology, pharmacokinetics, pharmacodynamics, and toxicology of the drugs used to produce and antagonize anesthesia, (3) the current methods for delivering and assessing the anesthetic drugs’ effects, and (4) and appropriate therapy for anesthetic-related complications or emergencies. This chapter defines commonly used terms, outlines general uses for anesthetic drugs, their combinations, and conventional methods used to produce immobilization and anesthesia in animals.

General Considerations

I Anesthesia’s purpose is to produce a convenient, safe, effective, and economical means of facilitating medical and surgical procedures while minimizing stress, pain, discomfort, and adverse side effects to the subject and attending personnel.

II Criteria for selection of drugs and techniques

A Species, breed, age, weight, and body type

B Behavior

C Physical status and coexisting disease processes

D Nature, location, and severity of pain

E Current and past medications

F Knowledge and experience of personnel (Fig. 1-1)

FIG. 1-1 A dedicated, knowledgeable, and vigilant anesthetist is key to successful anesthesia.

G Familiarity with available equipment and techniques

H Duration and type of procedure to be performed

III Responses vary because drug doses and techniques are initially developed for the “average, normal, healthy” animal; thus, it is essential that drugs, drug dosages, and anesthetic techniques are selected based on the subject’s physical status (developed by the American Society of Anesthesiologists: ASA)

A Physical Status 1— A normal healthy patient

B Physical Status 2—A patient with mild systemic disease

C Physical Status 3—A patient with severe systemic disease

D Physical Status 4—A patient with severe systemic disease that is a constant threat to life

E Physical Status 5—A moribund patient who is not expected to survive without the operation

IV Definitions

A Medical terms used in the practice of anesthesia: Most definitions of anesthesia incorporate a loss of feeling (analgesia) and/or awareness (unconsciousness). Muscle relaxation and a reduction in the stress response are added benefits.

Acupuncture: The stimulation of specific trigger points based on traditional Chinese medicine

Additive: An effect in which two substances or actions used in combination produce a total effect the same as the sum of the individual effects.

Agonist: A drug that produces an effect by interacting with a specific receptor site (e.g., opioid agonist morphine)

Akinesia: Loss of motor response (movement) usually caused by blockade of motor nerves

Allodynia: Pain evoked by a stimulus that does not normally cause pain

Analeptic: a central nervous system (CNS) stimulant or respiratory stimulant

Analgesia: Loss of sensitivity to pain; relief of pain without loss of consciousness

Anesthesia: Total loss of sensation in a body part or in the whole body, generally induced by a drug or drugs that depress the activity of nervous tissue either locally, regionally, or generally (centrally). The act of producing anesthesia is generally divided into phases that include the preanesthetic, anesthetic, and postanesthetic periods (see box)

The Five Phases of Anesthesia

I Preanesthetic or preinduction period

II Induction

III Maintenance

IV Recovery

V Postanesthetic period

Balanced anesthesia: Surgical anesthesia produced by a combination of two or more drugs or anesthetic techniques, each contributing its own pharmacologic effects; includes tranquilizers, opioids, nitrous oxide, muscle relaxants, and inhalants

Dissociative anesthesia: A CNS state ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Preface
• Chapter 1: Introduction to Anesthesia
• Chapter 2: Animal Evaluation and Preparation
• Chapter 3: Preanesthetic and Perioperative Medications
• Chapter 4: Local Anesthetic Drugs and Techniques
• Chapter 5: Local Anesthesia in Ruminants and Pigs
• Chapter 6: Local Anesthesia in Horses
• Chapter 7: Local Anesthesia in Dogs and Cats
• Chapter 8: Injectable Anesthetic Drugs
• Chapter 9: Inhalant Anesthesia and Inhalant Anesthetics
• Chapter 10: Neuromuscular Blocking Drugs
• Chapter 11: Equipment for Tracheal Intubation and Securing the Airway
• Chapter 12: Anesthetic Machines and Breathing Systems
• Chapter 13: Ventilation and Mechanical Assist Devices
• Chapter 14: Monitoring During Anesthesia
• Chapter 15: Acid-Base Balance and Blood Gases
• Chapter 16: Perioperative Fluid Administration
• Chapter 17: Temperature Regulation During Anesthesia: Anesthetic-Associated Hypothermia and Hyperthermia
• Chapter 18: Pain and Pain Therapy
• Chapter 19: Integrative Medicine: Acupuncture Analgesia
• Chapter 20: Anesthetic Procedures and Techniques in Dogs
• Chapter 21: Anesthetic Procedures and Techniques in Cats
• Chapter 22: Anesthetic Procedures and Techniques in Horses
• Chapter 23: Anesthetic Procedures and Techniques in Ruminants
• Chapter 24: Anesthetic Procedures and Techniques in Pigs
• Chapter 25: Anesthetic Procedures and Techniques in Camelids
• Chapter 26: Anesthetic Procedures in Exotic Animals
• Chapter 27: Anesthesia for Cesarean Section
• Chapter 28: Respiratory Emergencies
• Chapter 29: Cardiovascular Emergencies
• Chapter 30: Euthanasia
• Physical Principles of Anesthesia
• Drug Schedules
• Guiding Principles for Research Involving Animals and Human Beings
• Index