Anesthetic Techniques in Veterinary Practice Animal Medicine 1 chapter 9

### Anesthetic Techniques

• Commonly used in small animal practices.
• Strategies for minimizing adverse effects include selecting a balanced anesthetic protocol, correcting physiological abnormalities before anesthesia, and using the minimum dose required.

Induction Methods

• Intravenous - Short-acting agents are injected intravenously.
• Mask or Chamber - Anesthetic inhalation is achieved through a mask or chamber.
• Intramuscular - Anesthetic agents are administered intramuscularly.

Intramuscular Induction

• Anesthetic agents are administered via intramuscular (IM) injection.
• Anesthetic depth gradually increases, peaks, and then gradually decreases.
• After injection, the anesthetist has little control over the rate of anesthetic onset, and the depth and duration of anesthesia.

General Considerations

• When selecting an anesthetic protocol, the veterinarian takes into account the patient's physical status, minimum patient database, and the procedure.
• Protocols may be modified for ill, pediatric, or otherwise compromised animals.
• It is crucial to carefully calculate, check, and recheck drug doses, oxygen flow rates, and fluid administration rates.
• Double-checking all injectable drug doses before administration is essential.
• Labelling all syringes with the patient name, drug name, and drug concentration is mandatory.
• All IV agents should be administered "to effect" unless otherwise instructed.

Patient Preparation

• Patient preparation is crucial to ensure a safe and successful anesthetic event.
• Never take shortcuts or skip steps.
• Incomplete patient preparation can result in life-threatening consequences.

Minimizing Adverse Effects

• Treat any physiological abnormalities before anesthesia.
• The anesthetic protocol should be based on the patient’s minimum database.
• Use a balanced protocol consisting of multiple agents.
• Administer no more than the minimum dose needed to achieve the desired level of anesthesia.

Anesthesia Techniques in Small Animal Practices

• General anesthesia is commonly used in small animal practices
• Anesthetic protocols are tailored to the specific patient's needs and the procedure being performed.
• Veterinarians select the appropriate anesthetic agents and dosages to minimize adverse effects and ensure patient safety.

Minimizing Adverse Effects of Anesthesia

• Pre-anesthetic Assessment: Correcting or treating any underlying physiological abnormalities before administering anesthesia significantly reduces the risk of complications.
• Balanced Anesthesia: Using a combination of anesthetic agents helps maintain a balanced state of anesthesia and minimize side effects.
• Dosage Accuracy: Double-checking drug dosages, including oxygen flow rates and fluid administration rates, is crucial for patient safety.
• Minimum Dosing: Administering the lowest effective dose of anesthetic agents is a key principle for minimizing complications.
• Individualization: Every patient's response to anesthesia may differ; therefore, administering intravenous drugs "to effect" allows for individual adjustments based on the patient's response.

Intramuscular Anesthetic Induction

• Anesthetic agents are injected directly into the muscle.
• The onset of anesthesia takes longer than intravenous injection but provides prolonged effects.
• The induction process typically follows a pattern of increasing depth until the peak effect is reached, followed by a gradual decline.
• While practical for some situations, it offers less control over anesthetic depth compared to other methods.
• Intramuscular injections require careful consideration as the anesthetic depth is less predictable than with intravenous methods.

Lesson 9.1 Learning Objectives

• Describe anesthetic techniques commonly used in small animal practices.
• List strategies used to minimize adverse effects when selecting an anesthetic protocol.
• Describe how different methods of anesthetic induction and maintenance influence the dynamics of an anesthetic event.
• Prepare a small animal patient, anesthetic equipment, and anesthetic agents and adjuncts for general anesthesia.
• Describe induction of general anesthesia by intravenous injection of a short-acting agent, by mask or chamber induction, or by intramuscular injection.
• Explain cautions and risks associated with each method of anesthetic induction, and strategies to maximize patient safety.

Patient Preparation

• Thorough patient preparation is critical to avoid life-threatening consequences
• Do not skip any steps
• Incomplete preparation can lead to serious complications

Selecting an Anesthetic Protocol

• A comprehensive list of anesthetics and adjuncts is created for each patient
• This list outlines calculated dosages, routes of administration, and the order of administration
• The veterinarian-in-charge selects the protocol
• Carefully calculate, check, and recheck drug doses, oxygen flow rates, and fluid administration rates
• The protocol is tailored based on the patient’s minimum database, physical status, and the procedure
• Modifications are required for ill, pediatric, or compromised animals

Minimizing Adverse Effects of Anesthesia

• Address and treat any physiologic abnormalities before administering anesthesia
• Base the protocol on the results of the patient’s minimum database
• Utilize a balanced protocol that incorporates multiple agents
• Double-check all injectable drug doses before administering
• Label all syringes with the patient name, drug name, and drug concentration
• Administer only the minimum dose needed to achieve the desired level of anesthesia
• Administer all intravenous agents "to effect" unless otherwise specified

General Anesthesia: Intramuscular Induction

• Anesthetic agents are administered via intramuscular (IM) injection
• Anesthetic depth gradually increases, reaches a peak, and then gradually decreases
• The anesthetist has limited control over the progression of anesthesia after injection.