Lecture 3 Monitoring the Anesthetized Patient 1 Flashcards
Why do we monitor?
to WARN anesthetist of changes in depth or status of patient to facilitate an early response
When does monitoring begin?
- Begins preop => recovery
- peri-op mortality within 1st 3 hours
Individualized Anesthesia Plan Provides basis for
- Drug selection
- Monitoring & support
- Anticipated complications & plan of action to address them
Why is the The Anesthesia Record important?
- Legal record of events
- Prompts to observe, evaluate & record patient status
- *Irreversible CNS & cellular changes occur within 3-5 min of cessation of blood flow*
- Trends can be recognized
What are the safest anesthetic agents?
“There are no safe anesthetic agents, there are no safe anesthetic procedures. There are only safe anesthetists”
What is the Best/Most expensive Monitoring Equipment
- Is an attentive anesthetist: YOU!!! (or vet tech that is educated)
- LOOK at/touch your patient
- Use your senses
What do we monitor?
- Anesthetic Depth
- Body Temperature
- Circulation
- Ventilation
- Oxygenation
Why do we monitor anesthetic depth
- Too light – arousal, awareness, movement, pain
- Too deep – anesthetics are DOSE DEPENDENT cardiovascular and respiratory depressants
proper oxygenation will require what 2 systems to be working
circulatory + respiratory function
How can you use eye position to check anesthetic depth for dogs, cats and cattle
- Eye Position:
- Rolls ventrally @ surgical plane
- Centered @ light/deep planes
- Differentiate with palpebral
- Dogs, cats & cattle
How can you use eye position to check anesthetic depth for horses
- Horses – medial position
- May be unreliable
- Different positions in each eye
- Nystagmus/tearing => TOO LIGHT!!!
How can you use eye position to check anesthetic depth for Sheep, goats, camelids
globe does NOT rotate
How do you test the palpebral reflex for anesthetic depth for:
- Small animals
- Horses (add about horses being on back blood to head)
- Ruminants/ swine
- Small Animals
- tap medial canthus
- absent @ surgical plane
- Horses
- gently brush cilia, slow closure of eyelids
- Present @ surgical plane
- Ruminants/swine
- Absent @ surgical plane
- How can you use the corneal reflex for anesthetic depth
- Withdrawl relfex
- Corneal
- ALWAYS present
- Never use in patient believed to be alive!!
- Withdrawal
- Toe pinch withdrawal will be present if too light
How can you use Jaw Tone for anesthetic depth
- Varies with depth
- Subjective
- Not reliable with dissociative anesthetics
- Ketamine will cause muscle regidity
- What is Minimum Alveolar Concentration (MAC)
- What is it used for?
- is the concentration of inhalant in the lungs needed to prevent movement (motor response) in 50% of animals in response to a noxious or surgical (pain) stimulus.
- MAC is used to compare the strengths, or potency of inhalant anesthetic
- What is the MAC for isoflurane in dogs, cats and horses
- for sevoflurane for dogs and cats
- ISOFlurane:
- Dog 1.28%,
- Horse 1.3%
- Cat 1.63%,
- MAC for SEVOflurane:
- Dog 2.3%,
- Cat 2.6%
- 95% patients adequately anesthetized at what MAC number
- Why dont you keep all patients at the same MAC?
- 1.5 MAC
- Not as same MAC because:
- Pre-med/intra-op analgesia ↓ MAC
- MAC reflects population not individual
- Need to titrate to patient
- Typically at what % will we start the iso setting on and what flow (high or low)?
- For how long in a circle system?
- Why?
- start patients on 2% iso with high flow
- first 15 min
- to get the iso concentration higher in the circuit
Will all the % of iso be absorbed?
- a certain amount will be soluble in the blood and tissue
- that is why the expired % iso and inspired % is different
How can we use End tidal inhalant Concentration (Et-inhalant) for anesthetic depth
- Is the concentration of inhalant gas expired at the End of expiration
- Et-iso concentration gas reflects brain concentration
- End-tidal inhalant % more precise than vaporizer setting
What is the primary driver for respiration
CO2