1 Guidelines for Anesthetic Management in Clinical Practice

Clinical Standards in Veterinary Anesthesia

Clinical Standards in Veterinary Anesthesia

Can we improve veterinary anesthesia?

Can we improve veterinary anesthesia?

• Safe anesthetics and analgesics are available

• Needed anesthetic and monitoring equipment are available

• Needed expertise and instructions are available

What Really Works in Anesthesia / Pain Management?

What really works well – practical, reasonable, & profitable

What I can implement for my practice

What brings success for my hospital – patients, clients, staff

AAHA Anesthesia Guidelines for Dogs and Cats –Goal of the Guidelines:

“Improving patient care across all veterinary practices”

Ralph Harvey, DVM, MS, Diplomate ACVAUniversity of Tennessee CVM

Anesthesia is a real concern for all informed parties.

Veterinarians and their staff desire to make anesthesia successful in all regards, not just immediate survival and recovery.

Our clients do worry about anesthesia. They want to know that “Everything is OK”. Their anxiety is real and it is fully justified!

“Problem-Based” Anesthesia“Problem-Based” Anesthesia

• “Problem-based” anesthetic management serves as

the framework for our individualized patient care.

• Choices of anesthetic medications, monitoring, and supportive care are all based on recognition of the individual patients needs.

• Get everything ready before inducing anesthesia.

“Anesthetic Concerns”“Anesthetic Concerns”

• Appropriate patient evaluation provides for the

recognition of anesthetic risks and/or anesthetic

concerns for that specific patient and procedure.

• Focused monitoring and patient evaluation lead to

individualized patient care.

• Keep it safe for personnel

• Control waste gases

Implementing the anesthesia standard from start to finishImplementing the anesthesia standard from start to finish

PRIOR to Anesthesia…PRIOR to Anesthesia…

• Patient evaluation

• Individualized plan development

• Owner instructions for night before/day of anesthetic event

• Informed consent

• Equipment inspection

• ASA 1 Normal healthy patients– No discernable significant disease; elective ovariohysterectomy or castration

• ASA 2 Patients with mild systemic disease– Skin tumor, simple fracture, uncomplicated hernia, cryptorchidectomy, localized infection, compensated disease

• ASA 3 Patients with severe systemic disease– Fever, dehydration, anemia, cachexia, or moderate hypovolemia; co-morbidity influencing anesthesia

• ASA 4 Patients with severe systemic disease that is a constant threat to life– Uremia, toxemia, severe dehydration and hypovolemia, anemia, cardiac decompensation, emaciation, or high

fever

• ASA 5 Moribund patients not expected to survive with or without operation– Extreme shock and dehydration, terminal malignancy or infection, or severe trauma

How Risky? - ASA Physical Status 1-5Modified from: American Society of Anesthesiologists

ASA Physical Status Category - With examples of each category:

Equipment Checklists – Pilots use them, so should we!Equipment Checklists – Pilots use them, so should we!

Anesthetic Equipment & SuppliesAnesthetic Equipment & Supplies

A. Electrocardiogram

B. Pulse Oximeters

C. Blood pressure

D. Blood gases

Anesthetic Equipment & SuppliesAnesthetic Equipment & SuppliesAnesthetic agents & appropriate antagonist agents

Anesthetic Equipment & SuppliesAnesthetic Equipment & Supplies

Inhalant Anesthetics

InjectableAnesthetics

Inhalant Anesthetics

GeneralGeneral Equipment troubleshooting, awareness of health

hazards and a means of assisting ventilation

Designated recovery area

Patient MonitoringPatient Monitoring

A practice team member is dedicated solely to monitoring the condition of each anesthetized patient

Patient MonitoringPatient Monitoring

The following equipment is utilized during anesthetic procedures:

a) Pulse oximeter / Doppler

b) Blood pressure monitor

c) Continuous electrocardiograph (ECG) monitor

d) Respiratory monitor or capnograph

Anesthesia MonitoringAnesthesia Monitoring

Vigilant monitoring, properly-functioning equipment, and well-trained and attentive staff are essential for interpreting monitoring data, identifying and responding to changes in patient physiologic status.

Why monitor?Why monitor?

• Is the patient adequately anesthetized and immobilized?

• Is the patient’s pain adequately managed?

• Is the autonomic response adequately subdued?

Why monitor?Why monitor?• What are the current

physiologic consequences of anesthesia?

• Are observed abnormalities serious enough to warrant treatment?

These guidelines were approved by the Diplomates of the ACVAA in December of 1994, and first published in the Journal of American Veterinary Medical Association on April 1, 1995. (JAVMA, Vol. 206, No. 7, 936-937.

Recommendations for Monitoring Anesthetized Veterinary Patients:

ACVAA Monitoring Guidelines Update, 2009 Document

OSHA Safety and Health Topics:Waste Anesthetic Gases

OSHA Safety and Health Topics:Waste Anesthetic Gases

• Some potential effects… Employers and employees should be aware of the potential effects of waste anesthetic gases and be advised to take appropriate precautions.

“…In the United States, OSHA requires individual veterinary hospitals and practices to maintain a system to prevent waste gases from building up in the area of use …

http://www.osha.gov/SLTC/wasteanestheticgases/index.html

ACVA Commentary and recommendations on waste anesthetic gases in the workplacehttp://www.acva.org/professional/Position/waste.htm

Risk factors and occupational hazards:Risk factors and occupational hazards:

• …the level of WAG depends on the presence of gas scavenging systems, good anesthetic practices, and periodic examination and maintenance of anesthetic machines” Johnson: http://www.cfpc.ca/cfp/2000/Dec/03_01.html

•

• Effective waste anesthetic gas management includes:Engineering Controls, Work Practices, Air Monitoring Hazard Communication and Training

http://www.cfpc.ca/cfp/2000/Dec/03_01.htm

Waste Anesthetic Gas

Evacuation Systems:

Pop-off Valve 19mm tubing

Scavenger interface

Scavenger SystemsScavenger Systems

• Must be accompanied by good technique to reduce exposures!

• Scavenging removes waste gases from pop-off valve only, not leaks or technical errors

• Removes waste anesthetic gases from work area

• Interface and relief valves positive and negative relief

• Reservoir (often a reservoir bag)

Activated charcoal canisters:Activated charcoal canisters:

This canister will last “approximately” 12-15 hours of average surgery time.

However, the true test is to weigh the unit.

The canister can retain 50 grams more than when you started using it.

No warning when full!

http://www.surgivet.com/catalog/catalog31.html

Getting started with the first case of the day

Getting started with the first case of the day

Preanesthetic EvaluationPreanesthetic EvaluationPatient history

Physical exam

Diagnostic test(s)

Anesthesia Plan DevelopmentAnesthesia Plan Development

Knowledge of specific and underlying disease Functional status of cardiopulmonary system Response to preoperative stabilizing measures Knowledge of drugs and effects

Anesthesia Plan DevelopmentAnesthesia Plan DevelopmentAddress all phases of anesthesia

– Drugs• Sedation/tranquilization• Induction• Pain management• Cardiovascular support

– Supportive care• Fluid resuscitation• Thermal support• Positioning

– Monitoring

Patient PreparationPatient Preparation

• IV catheter placement• Hemodynamic stabilization• Pre-induction monitoring• Premedication/sedation• Preoxygenation with open mask

Preanesthetic ProceduresPreanesthetic Procedures

• ASA I: normal patient

• ASA II: with mild systemic disease

• ASA III: with systemicdisease & limited activity

• ASA IV: incapacitating systemic disease

Use an individualized patient care plan


• Insert and secure IV catheter

• Prepare perioperative fluids and start infusion

• Set up monitors for easy connection to patient

Multimodal AnesthesiaMultimodal Anesthesia

• Select and administer as indicated:

Tranquilizers or sedatives

Opioids or other analgesics

*Administer intravenous and inhalant anesthetics as selected

GeneralGeneral Anesthetics are administered by or under the supervision

of a veterinarian on the premises

Ensure Airway PatencyEnsure Airway Patency

• Suitable size,cuffed endotracheal tube

• Start Oxygen flow from anesthetic unit

• Connect to endotracheal tube

• Adjust oxygen flow

• Add inhalant anesthetic as indicated


Many variables have the potential to influence the response to anesthesia in an individual patient

Perioperative AnesthesiaPerioperative Anesthesia

• Maintain appropriate levels of anesthesia

• Regularly monitor and record:Anesthetic depthPulmonary parametersCardiovascular parameters

•

Anesthetic EmergenciesAnesthetic Emergencies

In the event of respiratory or cardiac arrest, the practice team follows a standard procedure for resuscitationdirected in each case by a veterinarianbased upon the unique patient needs.


Dosages & indications

of emergency

medications are readily

available in chart form


Emergency drugs and equipment are:

Readily available

Kept in a designated place

Portable

Clearly labeled

Appropriately stocked at all times

Anesthetic Management Critical CareAnesthetic Management Critical Care

• Especially challenging in High Risk patients

Helpful Adjunctive ProceduresHelpful Adjunctive Procedures

• Local anesthetic nerve block

• Epidural analgesia

• Analgesic drug infusion (CRI)

Anesthetic Maintenance by Either:Anesthetic Maintenance by Either:

• An oxygen-enriched mixture with the selected inhalant anesthetic

• Continuous infusion or intermittent doses of injectable anesthetic

• Combination of injectable or inhalant anesthetics

Circulatory Function ConcernsCirculatory Function Concerns

• Hypertension– Increase anesthetic concentration or add additional analgesics

• Hypotension– Reduce anesthetic concentration

– Increase IV fluid rate of administration

– Administer vasopressors and/or inotropes

• Arrhythmias– Diagnose and treat as indicated

– Reduce incidence during isoflurane or sevoflurane

– Lidocaine without epinephrine or other antiarrhythmics as necessary

Pulmonary Function ConcernsPulmonary Function Concerns

• Oxygen flow rate depends on the breathing system used.

• Minimal flow rate =10 ml /kg/minute An additional 500 ml/minute is frequently required

• Oxygen saturation (SpO2) >90%• End tidal CO2 < 50 mmHg• Manual or mechanical IPPV if needed

Recovery: Special Considerations

Recovery: Special Considerations

• Continue supplemental oxygen until SpO2 levels are acceptable on room air

• Extubate when patient can adequately protect airway

• Provide adequate thermal support• Reassess patients pain level and adjust

medications as indicated• Reapply eye ointment until adequate blink reflex

Provide A Dedicated Recovery Area And Equipment

Provide A Dedicated Recovery Area And Equipment

Patient should be monitored by trained staff Patient support until they return to base line values

Improvements in veterinary anesthesia helps assure better results for the surgical patient

Improvements in veterinary anesthesia helps assure better results for the surgical patient

Provided by Charles E. Short, DVM, PhD, ACVAA, ECVAAEmeritus Professor of Anesthesiology & Pain Management,

Cornell University

In Consultation with:

Prepared using the accreditation standards of the American Animal Hospital Association, Copyright © 2012

Ralph C. Harvey, DVM, MS, Diplomate ACVAA Associate Professor Anesthesiology, University of Tennessee

1 Guidelines for Anesthetic Management in Clinical Practice

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