Test 2: 17 monitoring Flashcards
5 basic goals of anesthesia
Unconsciousness
Amnesia
Immobility
Analgesia
Blunted autonomic responses
* Cardiovascular
* Respiratory
* Endocrine
* Immune
stage 1 of anesthetic depth
awake to unconcious
Stage of voluntary movement
stage 2 of anesthetic depth
excitatory
stage of delirium or involuntary movement
stage 3 plane 1 of anesthetic depth
light anesthesia
stage 3 plane 2 anesthetic depth
moderate anesthesia
stage 3 plane 3 anesthetic depth
moderate-deep anesthesia
stage 3 plane 4 anesthetic depth
deep anesthesia
stage 4 anesthetic depth
stage of extreme CNS depression
results in death if not controlled
stage 1 is characterized by
voluntary movement:
* Initial administration to loss of consciousness
* Some analgesia (deeper phases)
* Breath-holding in excited, stressed animals
* Tachycardia
* Pupillary dilation
* Salivation
* Urination
* Defecation
*Ataxia
* Recumbency
stage 2 Anesthetic depth characteristics
delirium or involuntary movement (excitatory)
* Loss of consciousness to onset of regular breathing pattern
* Loss of voluntary control
* CNS depression -> reflexes more primitive and exaggerated
* External stimuli -> reflex struggling, breath holding, tachypnea, hyperventilation
* Tachycardia, tachyarrhythmias
* Pupil dilation
* Palpebral and eyelash reflexes prominent
* Nystagmus (horses)
* Vocalization
* Salivation (ruminants, cats)
* Vomiting (dogs, cats, goats)
* Laryngospasm (pigs, cats)
stage 3 anesthetic depth characteristics
surgical anesthesia
- Unconsciousness
- Progressive depression of reflexes
- Muscle relaxation
- Ventilation slow and regular
- Vomiting and swallowing reflexes lost
Classification
- Planes 1-4
- Light, medium, deep
stage 4 anesthetic depth characteristics
extreme CNS depression → death
* Respirations cease
* Heartbeat slows then stops
* Blood pressure at shock level
* Capillary refill markedly delayed
* Pupils widely dilated
* Death unless immediate resuscitation
eyeball position and rotation during anesthesia for ruminants
eyeball position and rotation during anesthesia for cats and dogs
eyeball position and rotation during anesthesia for horses
what are some things that might prevent change in eyeball position and rotation during anesthesia
- Ketamine → Eye does not typically rotate
- Neuromuscular blockade
nystagmus during anesthetic depth for horses
changes in nystagmus during anesthesia for ruminants and swine
what are some things that effect nystagmus during anesthesia
- Small animals – nystagmus not normally present under surgical anesthesia
- Ketamine
- Neuromuscular blockade
how does palpebral reflex change during anesthesia
how does jaw tone change during anesthesia
how does sphincter tone change during anesthesia
Gag and swallow reflexes indicate — level of anesthesia in nearly all species
light
— reflex lost at deeper planes
Cough
Response depends on — and —
stimulus intensity and anesthetic depth
when using ketamine, some laryngeal reflexes may persist but —
are not coordinated
need to intubate
Focal facial or neck muscle twitching, myoclonus can be seen with what drugs?
propofol
etomidate
Loss of consciousness occurs before or after loss of spontaneous movement and physiologic response
before
pt can start to move when still unconscious
— movement reliable sign of light level of anesthesia
Spontaneous
Any single measure defines —. Assess all available parameters to form —
only itself
composite estimate of system
what happens to CV system during anesthesia
- Decreased contractility
- Decreased systemic vascular resistance
- Reduced blood pressure
Autonomic response to noxious stimulus
* Increased arterial blood pressure
* Increased heart rate
CV system may not be reliable way to assess anesthetic depth based on opposite effects of pain and anesthesia
what are some confounding factors to CV system during anesthesia
some drugs effect CV system
physiologic status: hypovolemia, temp, hypoventilation
Disease states: hemorrhage, anemia, cardiovascular disease
Co-morbidities
species
two important questions about respiratory system during anesthesia
how is animal ventilating?
how is animal oxygenating?
Autonomic response of respiratory system to noxious stimulus
- Increased respiratory rate
- Change in respiratory pattern (irratic, panting)
- Patient-ventilator dyssynchrony (fight ventilation)
how to measure inhalant gas delivery
End-tidal concentration of volatile anesthetic agent
Minimum Alveolar Concentration (MAC) will be proportional to the amount of drugs getting to the brain
- Inter- and intra-individual variability
what is target controlled infusions
way to monitor injectable anesthetics
based off pharmodynamic and pharmokinetic parameters to form model that you can use to adjust rate of infusion
limitations:
* need a bunch of blood samples→ not practical in small animals
* drug interactions
* patient variability- some pts need more drugs then others
how does EEG monitoring work
computer processes brain activity to give number that correlates to how deep a pt is
EEG changes
* Low amplitude, high-frequency wave pattern during awake state
* High amplitude, low-frequency pattern during anesthesia
-> burst suppression -> electrical silence (deep levels of anesthesia)
what are some EEG devices
Bispectral Index TM (BISTM)
Cerebral state index (CSI)
NarcotrendTM monitor
EEG do not reflect — properties of drugs
analgesic
response to noxious stimulus at light plane will result in
- Movement!
- Rapid increase in heart rate and blood pressure
- Increase in respiratory rate or erratic respiratory pattern → Patient-ventilator dyssynchrony
- Pupil dilation
- Increased jaw tone, anal tone
Horses:
* Lacrimation
* CAUTION: May see movement before ANY autonomic changes (BE VIGILANT!)*
Response to noxious stimulus at a deep plane
- No movement
- Minimal-to-absent changes in heart rate
- Minimal-to-absent changes in respiratory rate
- Pupil dilation
- Very relaxed jaw tone, anal tone
Monitoring — can be used in conjunction with physical patient assessment.
anesthetic drug delivery
— is emerging but cannot supplant physical patient assessment and monitoring.
Electroencephalography technology (EEG)
Assess all available information and clinical picture to judge —
anesthetic depth.
