Expectations of Anesthesia Knowledge and Performance

Carprofen

NSAID

Good- long acting, central and peripheral, inflammatory post-op pain, no reaction with anesthetics;

Bad- inadequate for surgical pain

Ugly- interferes with homeostasis (clotting, hypotensive renal perf, GI like melena, ulcers),

Acepromazine

Drug Info: phenothiazine/sedative/dopramine antagonist/alpha 1 adrenergic antagonist

Good:

reliable tranq, anesthetic sparing, inexpensive, long-acting, reduced afterload, not controlled

Bad: no analgesia, no reversal, vasodilation (decrease BP) at high dose, long-acting, splenic enlargement/RBC sequestration

Ugly: hypovolemia, shock, anemia, limited cardiac output due to afterload reduction

Hydromorphone

Opioid; synergism for sedation; analgesia; full mu agonist

Good: titratable analgesia, intermediate duration of action, sedation

Bad: vomiting, decreased resp, decreased HR, controlled

Ugly: deep corneal ulcer or esophageal FB due to vomiting

Morphine

Analgesia; full mu opioid; NOT VERY LIPOPHILIC and not readily absorbed systemically -> makes for best choice as epidural

Good: titratable analgesia, inexpensive, long-acting, sedation

Bad: vomiting, decreased respiration, decreased HR, histamine release, controlled

Ugly: vomiting detrimental; methadone an alternative

Propofol

GABA agonist; IV only

Good: rapid induction; short-acting

Bad: transient apnea, transient BP decrease, short shelf life, no analgesia

Ugly: repeated exposure in cats

Isoflurane

Inhalant anesthetic

Good: more potent (less to achieve same effect), cheaper

Bad: drop BP, hypoventilation, malignant hyperthermia

How do you calculate drug volumes for anesthesia?

Multiply mg dose x weight in kg

Divide value by drug concentration on bottle

How do you calculate the rate of IV fluid administration?

(weight in kg) x (5 ml/kg*hr) x (15 drops/ml if >10 kg weight with normal set OR 60 drops/ml is

Calculate the IV fluid rate in an 8 kg dog.

(8 kg) x (5 ml/kg*hr) x (60 drops/ml) x (1 hr/60 min) x (1 min/60 sec) = 0.67 drops/sec with microdrip set

Calculate the IV fluid rate in a 14 kg dog.

(14 kg) x (5 ml/kg*hr) x (15 drops/ml) x (1 hr/60 min) x (1 min/60 sec) = 0.29 drops/sec with normal set

What do you need to set up the induction station?

1. ET tubes

2. Inflation syringe

3. IV Cath supplies

4. Gauze tie

5. Dry gauze

6. Laryngoscope

What catheter supplies are needed? (4)

1. Catheter

2. Tape strips

3. T-port

4. Saline

What size catheter is appropriate for a cat, beagle, and coonhound?

Cat: 22g

Beagle: 20g

Coonhound: 18g

You should flush the ------, not the catheter.

T-port (needleless)

Know how to place an IVC and do IM and SQ injections.

K

What size laryngoscope is needed for a cat, Beagle, and Coonhound?

Cat: 0-1 Miller

Beagle: 2 Miller

Coonhound: 3 Miller

What is the induction agent?

Propofol

How do you assess induction dose if premeds cause slight, moderate, or profound anesthesia?

Slight: 1/3- all induction dose

Moderate: 1/2-2/3 induction dose

Profound: 1/3-1/2 induction dose

What should be started that must be temporarily stopped to bolus induction agent?

IV fluids

What is the role of the assistant while intubating?

1. Grasp outside maxilla

2. Allow jaw to drop open

3. Use gauze to exteriorize tongue

What THREE things should clue you to give additional induction agent?

1. Jaw tone

2. Movement

3. Coughing/swallowing

Describe how to intubate.

1. Laryngoscope in left hand

2. Place tip at base of tongue under epiglottis

3. Push down to expose glottis

4. ET tube in right hand, place between arytenoids

5. Advance to premeasured length

6. Hook up breathing circuit

How can you verify ET tube placement? (4)

1. Visualization between cords

2. Auscultate breath sounds

3. Chest expansion when given breath

4. Tube condensation

What are the roles of each person during epidural placement?

Surgeon keeps sternal

Assistant monitors

Anesthetist places

What must be done prior to placing epidural?

Place an esophageal stethoscope and monitor vitals and depth every 5 minutes

Position patient and clip/prep insertion site

What needle size is used for an epidural?

Same as IV catheter per type of animal

Name the FOUR major steps in placing an epidural.

1. Palpate L7-S1

2. Place finger on L7

3. Insert spinal needle below finger

4. Pop through ligament

What TWO signs tell you your epidural is in the correct location?

1. Hanging drop

2. Loss of resistance

What FIVE things do you do immediately after epidural?

1. Disconnect from breathing circuit

2. Position in dorsal

3. Reconnect to breathing circuit

4. Place doppler

5. Surgeon prep (shave/vacuum/initial prep)

What is the extubation criteria? (3)

1. Cough

2. Swallow

3. Lifting of head

True or False: The patient needs to only show one of the extubation criteria to be appropriately extubated.

True!

How do you set up and perform a functions check on an anesthesia machine?

Connect oxygen supply -> attach breathing circuit and reservoir bag -> close pop-off valve -> occlude patient end -> pressure to 20 cmH2O for 30 seconds to check for leak -> open pop-off valve -> THEN stop occluding with your thumb

Describe the advantages and disadvantages of either type of breathing circuit.

Circle Advantage: low FGF (4-30), preservation of heat and moisture, less environmental pollution, easier to ventilate

Circle Disadvantage: higher resistance, technologically complex, constrained to distance, equilibrate circuit to new concentration

NRB Advantage: low resistance, simple, no distance limitation, immediate control of inspired concentration

NRB Disadvantage: high FGF (150-300), loss of heat and moisture, environmental pollution, harder to control ventilation

When should you use a rebreathing circuit over a circle breathing circuit?

What is MAC and how does it apply to the individual patient?

Standard index of potency

Low MAC = more potent

High MAC = less potent (need more to get effect)

To calculate MAC, divide iso number by MAC 1.3

Iso: 1.3-1.6

Increased with hyperthermia and CNS stimulants

Decreased with pregnancy, hypothermia, extremes of age, other anesthetic agents (pre-med/injectables)

Multimodal management can help keep anesthetized even if MAC low because lower MAC = less inhalant needed and avoid inhalant side effects (cardiovascular depression, resp depression, better BP)

What should be your initial inhalant setting based on premed effect?

Slight/none: 2%

Moderate: 1.5%

Profound: 1.25%

What are the effects of improper inhalant concentrations?

Too light: everything increases

Too deep: everything decreases

How do you set an initial fresh gas flow rate?

Initial should be 2L/min; after 4 time constant on circle (prep and surgery): use 10-20 ml/kg/min

How can you apply the concept of time constant to determine rates of change in a circle breathing system?

The time constant helps predict how quickly a circle system changes its gas composition after changing FGF. It is calculated as time constant = circuit volume/FGF rate. After 1 time constant about 63% of old gas has been replaced. 4 time constants will be 98% and basically equilibrated.

Increasing FGF decreases the time constant and allows faster changes in anesthetic concentration, which decreasing flow increases the time required for equilbration.

FGF is the OXYGEN only.

How do you set an appropriate maintenance fresh gas flow rate?

10-20 ml/kg/min

What are the normal values for physiologic parameters? FINISH

HR/Pulse: 60-120 bpm

RR: 8-20 breaths/min

BP: SAP >90, MAP >60

ETCO2: 35-45 mmHg

Temp: 100-102.5 F

PCV: 35-55%

TP: 5.5-7.5

Glu: 70-120 mg/dL

What are the effect of abnormal physiologic parameters?

Heart rate: decreased (decreased perfusion, hypothermia); increased (hypovolemia, hypoxemia, hypercapnia)

BP: decreased (decreased perfusion, vasodilation); increased (pain, hypercapnia)

Low SPO2: hypoxemia

High ETCO2: hypoventilation/hypercapnia -> respiratory acidosis

Low ETCO2: hyperventilation; low cardiac output

RR: decreased (hypoventilation, hypercapnia)

Temp: decreased (decreased metabolism, delayed drug metabolism, arrhythmias); increased (increased metabolic demand; malignant hyperthermia)

How do you assess parameters of anesthetic depth?

Light: central eye position, strong palpebral, rigid jaw tone

Medium (ideal): ventromedial eye position, slight palpebral, slacking jaw tone

Deep: central eye position, no palpebral, loose jaw tone

What do you do if the patient is too deep?

- allow 15 minutes for equilibration

- decrease by 0.25%

-allow 15 minutes

- reassess

- repeat as needed until in adequate surgical plane

- do not go below 0.75%

What do you do if the patient is too light?

- turn vaporizer to maximum until back to ideal surgical plane

- increase oxygen flow rate to max until back

- increase 0.25% from previous

What do you do if there is surgical stimulation but no depth change?

What do you do if they get lighter due to it?

Give hydro

Adjust depth and give hydro

Describe anesthetic depth using planes and stages.

Stage I: voluntary movement and loss of consciousness

Stage II: stage of involuntary excitement

Stage III, Phase I: light (movement, strong to moderate jaw tone, central eye position, has palpebral, increased to normal HR, rr, response to surgical stimulation)

Stage III, Phase II: medium (the goal; ventromedial eye, no movement, moderate to absent jaw tone, normal HR, RR, response to stimulation)

Stage III, Phase III: deep

Stage IV: extreme (no corneal reflex, eyeballs central, respiratory arrest followed by CV collapse, decreased HR, RR, surgical stimulation)

How do you use a Doppler?

1. Find cuff 30-40% limb circumference

2. Place probe just distal to cuff and tape it there with jelly

3. Adjust until you hear a clear, strong pulse sound

4. Inflate until Doppler sound disappears then inflate 20-30 more

5. Deflate slowly, about 2-5 mmHg a second

6. The pressure at which you first hear the pulse return is your systolic arterial pressure (SAP). Should be above 90.

7. Take 3 readings and use the average.

What are the treatments for hypotension?

1. Assess depth, decrease inhalant

2. LRS bolus 10 mg/kg X2

3. Vetstarch bolus 5 mls/kg X2

4. Consult instructor if unreseolved

What are the signs of surgical stimulation?

Increased HR, Increased BP, Increased RR, Increased resp effort, somatic movement, swallowing, tense/rigid, eye movement, Increased ETCO2, dilated pupils, sweating, tearing

How do you assess a patient for pain in the post-op period?

Glasgow pain scale