Anesthetic monitoring Flashcards
Why do we monitor?
to keep the patient safe and to regulate anesthetic depth
What is key in monitoring?
Prevention
When does monitoring end and begin?
When animal is dropped off and after recovery period
What are the stages of anesthesia
- Pre medication
2.Induction
3.Maintenance: 1-4 planes
4.Recovery
What to monitor during pre medication
HR, RR, perfusion, Pulses, Drooling/vomiting, level of sedation, reactions to medications
What to monitor during induction
HR/RR, perfusion, pulses, CNS reflexes-depth
What to monitor during maintenance
HR/RR, perfusion, pulses, CO2/O2 concentrations, bloop pressure, CNS reflex’s -depth, temperature
In the recovery stage, vitals should be monitored until awake/ambulatory every
5-10 minutes
_ is one of the most important stages of anesthesia morbidity is higher in this stage than any others
Recovery
What does the eye position do during anesthesia
pupils being in central position then move rostroventral in an adequate plane then move BACK central as the patient moves into a deeper plane
Eye position reflex check is ineffective is using which class of drugs
Dissociatives (ketamine- eyes are fixed centrally)
ACVA monitoring recommendation for class P1 and P2
Q5 monitoring
ACVA monitoring recommendation for class P3-P5 and horses on inhalant anesthesia and/or anesthetized over 45 min.
continuous monitoring
From stage I through stage IV of anesthesia there is a progressive decrease in
pain perception, motor coordination, consciousness, reflex responses, muscle tone and cardiopulmonary function
What stage of anesthesia is described?
-Period of voluntary movement
-P begins to lose consciousness
-Characterized by: fear, excitement, disorientation, struggling, urination, defecation, increased HR and RR
-Stage ends with loss of ability to stand and recumbency
Stage I
What stage of anesthesia is described?
-Period of involuntary movement; the “excitement stage”
-Characterized by: breathing irregular, vocalization, struggling, paddling, increased HR and RR, pupils dilated, muscle tone marked, reflexes present
-Actions are not under conscious control
-Stage ends with muscle relaxation, decreased respiratory rate, and decreased reflex activity
Stage II
What should be done during induction to prevent injury to animal, the restrainer, or the anesthetist
patient passed through excitement stage as quickly as possible
What stage of anesthesia is described
-Period of sx anesthesia
-Divided into 4 planes
Stage III
Stage III plane 1is not adequate for
surgery
Stage III plane 2 is a suitable depth for
most surgical procedures
In stage III plane 2, surgical stimulation may produce
-mild increase in HR, BP, or RR
-P remains unconscious and immobile
-PLR is sluggish; pupil size is moderate
Stage III plane 3 is
deep anesthesia- excessive for most procedures
Stage III plane 4 is _ _ _
early anesthesia overdose
What plane of stage III is described
-regular resp. pattern, no involuntary movements
-eyeballs start to rotate ventrally, pupils partially constricted, decreased PLR
-ET tube may be passed and connected
-Other reflexes are still present but decreased response
Plane 1
What plane of stage III is described
-suitable depth for most sx procedures
-characterized by: regular and shallow resp. w/ decreased rate, BP and HR middle decreased, relaxed muscle tone, pedal and swallowing reflexes are absent, ventromedial eye rotation
-Mild increase in HR, BP, or RR
-P remains unconscious and immoble
-PLR is sluggish, pupil size is moderate
Plane 2
What plane of stage III is described
-deep anesthesia- excessive for most procedures
-characterized by: low HR and RR, decreased tidal volume, reduced pulse strength, increased CRT, poor to absent PLR, reflexes totally absent , muscle tone is very relaxed
plane 3
What plane of stage III is described
-abdominal breathing
-fully dilated pupils; dry eyes
-all reflexes absent
-marked depression of the CVS, pale MM, increased CRT
-flaccid muscle tone
plane 4
Stage IV is a period of
anesthetic overdose
Stage IV is characterized by
-cessation of respiration
-circulatory collapse
-death
(resuscitate immediately to save the patient)
Objectives of surgical anesthesia
-P doesn’t move, isn’t aware, doesn’t feel pain, no memory of procedure
Vital signs of circulation
HR and rhythm, pulse strength, CRT, MM, bp
Vital signs of oxygenation
MM, CRT, Hg saturation, inspired oxygen, arterial blood oxygen
Vital signs of ventilation
RR and depth, breath sounds, end-expired CO2 levels, arterial CO2, blood pH
What causes bradycardia in anesthesia
-alpha2 agonists and opioids
-excessive anesthesia depth
-adverse effects of drugs
What causes tachycardia in anesthesia
-anticholinergics and cyclohexamines
-inadequate anesthetic depth
-pain
-hypotension
-blood loss and shock
-hypoxemia and hypercapnea
Causes of arrhythmias
Drugs, medical states or diseases
How to detect 1st or 2nd degree heart block
use ECG to detect
What cardiac arrhythmia is described?
-HR coordinated with respirations
-Decreases during expiration
-Increases during inspiration
-Normal in dogs, horses, and cattle
-NOT normal in cats
Sinus arrhythmia (SA)
What cardiac arrhythmia is described?
-Abnormally slow heart rate
-Common during anesthesia: excessive anesthetic depth and drug reactions
-Correct with reversal agents or anticholingerics
Sinus bradycardia
What cardiac arrhythmia is described?
-Abnormally fast HR
-Inadequate anesthetic depth, drug reactions, surgical stimulation
-Tx according to cause
Sinus tachycardia
What cardiac arrhythmia is described?
-Delay or interruption of electrical impulse conduction through the AV node
AV heart block
What does a first degree AV heart block look like
prolonged P-R interval
What does a second degree AV heart block look like
occasional missing QRS complexes
What does a third degree AV heart block look like
-atrial and ventricular contractions occur independently
-randomly irregular P-R intervals
_ and _ degree AV blocks can be seen in normal resting horses
first and second
When are first and second degree blocks commonly seen
after admin. of alpha2agonists or with high vagal tone, hyperkalemia, or cardiac disease
What does third degree block indicate? - is not commonly seen in anesthetized patients
a cardiac disease
What is a supraventricular premature complex (SPC)?
one or more normal QRS complexes closely following the previous QRS complex
What is supra ventricular tachycardia
a series of 3 more more SPCs in a row
What is ventricular premature complexes (VPC)
one or more wide , bizarre QRS complexes closely following the previous QRS complex
What is ventricular tachycardia
a series of 3 or more VPCs in a row
What is fibrillation
chaotic, uncoordinated small muscle bundle contractions within the atria and ventricles
What fibrillation is described?
-fine undulating baseline
-absence of P-waves
-tachycardia
-normal QRS complexes at irregular intervals
Atrial fibrillation
What fibrillation is described?
-Undulating baseline
-Absence of QRS complexes
ventricular fibrillation
What is PEA
cessation of heart contractions and/or palpable pulse in the presence of normal or nearly normal ECG
BP evaluates _ _ during anesthesia
tissue perfusion
Factors involved in blood pressure
heart rate stroke volume, vascular resistance, arterial compliance (elasticity), blood volume
Systolic pressure is produce by
contraction of the left ventricle
Diastolic pressure is
the pressure that remains in the arteries when the heart is in the resting phase between contractions
What is the best indicator of blood perfusion to internal organs
Mean arterial pressure (MAP)- average pressure through the cardiac cycle
What does a MAP of <60mmHg in small animals and ruminants indicate?
decreased organ perfusion
What does a MAP <70mmHg in horses indicate?
decreased organ perfusion
How to maintain and correct hypotension
IVF at a rate sufficient to maintain BP, administer dopamine and dobutamine as needed
