Anesthetic Problems - Lecture 2

• Anesthetic procedures have the potential to cause death
• Veterinary technicians play a vital role in preventing & identifying anesthetic problems
• Knowing your skill set, supplies, equipment, drugs, and the patient's status is essential
• When unsure, always ask for help or seek a second opinion
• Practice scenarios with the staff to prepare for emergencies
• Veterinary technicians are highly active in resuscitation efforts
• Maintain sufficient supplies to handle unexpected issues and consumable item needs

"Swiss Cheese Model" of Major Accidents & Errors

• Patient harm can occur when there are flaws in the system and human glitches

Responding to an Emergency:

• Triage needs
• Be aware of the room and what supplies are at hand before facing an emergency
• Always think before acting
• Have a crash cart supplied and ready daily, and after each use
• Maintain an up-to-date drug list and supplies
• Utilize closed-loop communication
• Avoid harm and panic, maintain clarity, and take deep breaths
• Involve others to leverage more brains, thus creating a better strategy
• Conduct post-emergency follow-up discussions

Causes of Anesthetic Problems:

• Human error
• Equipment failure
• Adverse effects
• Increased patient risk

Human Error:

• Inadequate training in equipment or agent usage can be problematic
• Failure to get a detailed history of the patient
• Errors in drug calculations and administration must be avoided
• Errors caused by fatigue, haste, or inattention can be detrimental
• Supplies and equipment require adequate care and maintenance
• Equipment-related errors can compound issues

Adverse Effects of Drugs:

• Reduce adverse effects at all costs
• Choosing a protocol suitable for the patient's condition or needs is crucial
• Being familiar with disadvantages/adverse effects & contraindications of drugs
• Balanced anesthesia, multidrug protocols, can be safer and MAC sparing compared to single-drug protocols
• Administer the minimal required drug amount
• Always titrate to effect
• Frequent adjustments and depth assessments are important

Equipment: ADS Issues:

• Potential equipment failure or inaccuracy
• Carbon dioxide absorbent exhaustion, related to a rebreathing system
• Oxygen supply failure can have significant impact
• Blockage of the endotracheal tube (ET)
• Disconnected or kinked connections may cause problems
• Blocked parts like flutter valves are problematic

APL / Pop-Off Valve Problems:

• The pop-off valve is left in a closed state
• No tread feature during IPPV
• Technician is distracted and leaves it closed
• It breaks in a closed state

Semiclosed Pop-Off Valves:

• Components within APL can become faulty
• Leak tests open APL, which should decompress otherwise there may be an issue, do not use
• Sticky spring feature

Notice Excessive Pressure:

• Remove the bag from the machine

Vaporizer problems: are not an issue

• Result in overdose
• The wrong anesthetic agent is used, avoidable with key filters
• The vaporizer tips, or moves, can cause agent to splash around
• The vaporizer dials get stuck or jammed
• Oxygen is flowing at a speed or rate less that 0.5L/min which most vaporizers require
• If non serviced or outside of the delivery specification(0.2% +/-)

Common Emergencies During Anesthesia:

• Animals that will not stay anesthetized
• Animals that are too deeply anesthetized
• Pale mucous membranes
• Prolonged capillary refill time
• Hypotension
• Dyspnea and/or cyanosis
• Tachypnea
• Apnea
• Abnormal heart rate & rhythm
• Respiratory arrest
• Cardiac arrest
• Vomiting/Regurgitation
• Higher Risk Patients
• Recovery

Animal Will Not Become Anesthetized (Or Stay Anesthetized):

• An inadequate vaporizer setting must be monitored
• Leakage around the endotracheal tube (ET)
• Respiratory issues
• Apnea or improper tidal volume are concerning
• Tachypnea, rapid, shallow breathing from poor inhalation of iso
• Blocked, wrongly placed or not connected endotracheal tubes
• Blocked ETT increase in breathing system pressure, can feel like resistance
• Confirm endotracheal tube is not blocked
• Try to give IPPV
• Check for trachea, check ETCO2
• Visually inspect for low compliance in IPPV?
• A small endotracheal tube will cause issues

Responding to Inadequate Anesthetic Depth:

• Prepare to administer injectable anesthetic drugs to put patients asleep
• Propofol or MAC sparing agent
• Check ADS for loose or misassembled parts, and leaks
• Air could be leaking around the endotracheal tube cuff
• Check that there's adequate oxygen
• Administer IPPV if breathing is normal

Responding to Inadequate Anesthetic Depth:

• Check if the vaporizer setting is appropriate and adjust
• Ensure the vaporizer has sufficient liquid anesthetic
• Re-check the patient's monitoring parameters
• Consult the team for troubleshooting
• If no causes are identified, switch to another machine

Too Deeply Anesthetized:

Signs: are

• Less than 6 rpm, or very shallow or exaggerated respirations
• Respiratory depression, hypoventilation
• Flaccid muscle
• Absent Reflexes
• Dilated pupils; absent pupillary light reflex, centrally positioned eyes
• Hypotension
• Bradycardia
• Pale or cyanotic mucous membranes
• Capillary refill time greater than 2 seconds
• Cardiac Arrhythmias
• Cold body temperature is often less than 35° C

Responding to Excessive Anesthetic Depth:

• Immediately decrease the vaporizer setting
• Inform the vet
• If patient is not stable or experiences CV/Resp arrest, turn off the vaporizer
• Ventilate the animal with IPPV using pure oxygen.
• Clear the inhalant by disconnecting the inhalant and flushing

Anesthesia Considerations:

• Discontinue inhalant and detach ADS from ETT, and only administer O2
• Reverse all agents
• Maintain a capnography of 15-18 ETCO2
• Add more air to the cuff if chest pressure is elevated

Responding to Excessive Anesthetic Depth:

• Reversal drugs such as, Atipamezole, or naloxone
• Fluids such as, external heat
• Safest to assume that the animal's anesthetic depth is too deep, that is, no reflexes or tones, hypotensive or breathing to low
• Decrease the vaporizer setting while observing the animal carefully

Pale Mucous Membranes:

• Blood Loss can lead to Pale Mucus Membranes
• Anesthetic agent that can either vasodialate, or vasoconstrict
• Hypothermia
• Pain
• Stress

Treating Pale Mucous Membranes:

• Ensure that they are receiving the least amount of inhalant to achieve desired depth
• Check other vital signs including respiration, pulse, heart rate, fill time for capillaries
• Assist the patient with IPPV, and 100%
• Hypoventilation
• Low O2 in rooms
• If so, use common recovery, and extube
• Check oxygen levels
• Ruleout any issues like blood loss
• Call the veterinarian

Prolonged Capillary Refill Time (>2 seconds):

Hypoperfusion can be caused blood pressure unable to adequately and superficially

• Result of conditions already prior
• Result as Secondary to bloodloss
• Deep Anesthesia

Treating Prolonged Capillary Refill Time:

• Check animals pulse
• Observe animal for any signs to shock

Hypotension: low blood pressure

If @ or under the below values your patient is hypotensive & hypoperfused

• ≤80 mmHg SAP – 50 mmHg DAP
• ≤ 60 mmHG MAP
• Minimal vasodilations drugs
• Dose dependent from drugs to vasodialate & the body's hypothermia
• To give control pain.
• Fluids can give colloids, can’t maintain blood

Hypotension & Treatment:

• Reduce Inhalant

• if patient is not light, reduce vasodilation & improve BP continuously to a stable point

• 2nd Fluid's.

• If patient needs administer with Vet at 10 ML’s 3rd drugs if patients requires

• If patient requires CV drugs with vet, E-G, or Vasocontsrition