Monitoring the anesthetized patient (E1) Flashcards
What is the best equipment for monitoring the patient?
YOU YOU BIG JABRONEE
What do we monitor when anesthetizing a patient?
anesthetic depth body temperature circulation ventilation oxygenation (circulation and ventilation combo)
What are the three most important aspects to monitor?
Oxygenation
Circulation
Ventilation
What do we look at to monitor anesthetic depth?
Eye position Reflexes Muscle relaxation Movement EtCO2
What is the eye position for a properly anesthetized dog, cat, or calf?
Rolls ventrally; unmoved means they are too heavy/light
What is the eye position for a properly anesthetized horse?
WHO KNOW! Unreliable.
Nystagmus/tearing = too light
What are some reflexes we test?
Palpebral
corneal
Withdraw
T/F The corneal reflex should be absent in a properly sedated patient
NO! This means they’re dead
How do you test the palpebral reflex for dogs/cats? Horses? What do you see for each?
Dogs: tap medial canthus; absent
Horse: brush cilia, slow closure of eye present
What drug can cause the jaw to tighten when administered?
Ketamine
What is MAC and why is it important?
Minimum alveolar concentration; the concentraiton of inhalant in the lungs needed to prevent movement in 50% of patients
A low MAC means what?
The drug is very potent
What is key about MAC x 1.5?
95% of patients are anesthetized at this level
What is the MAC of Isoflurane for dogs/cats/horses
Dogs: 1.28%
Cats: 1.63%
Horses: 1.3%
What is the MAC of sevoflurane for dogs/cats
Dogs: 2.3%
Cats: 2.6%
What can we measure that represents the level of anesthetic in the brain of patients?
End tidal concentration
normal respiration is controlled by what?
Arterial levels of CO2
EtCO2 is usually how much lower than PaCO2?
3-5 mmHg
EtCO2 should be kept below what when anesthetized?
60 mmHg; 40 mmHg in normal patients
Delivery of O2 to tissues can be calculated how?
CO x Oxygen content of blood (CaO2)
T/F Capillary refill time is key tool to assess anesthetic depth
FALSE; would never run this test in an anesthetized patient
T/F Pulse pressure is a good indicator for Mean arterial pressure
FALSE
Pulse pressure is SAP-DAP
this difference can be affected by drugs ie Ketamine- causes weak pulse but the Mean Pressure is still high
What is the gold standard of blood pressure monitoring?
Arterial catheter
What are the two ways we can indirectly measure blood pressure?
Doppler
Oscillometric
Carbon dioxide is directly linked to a patient’s:
metabolism, perfusion, and ventilation
Minute ventilation can be calculated by what? Is it a good indicator of ventilation?
Tidal volume X frequency
NO
What is the most useful tool to detect apnea and hypoventilation
End tidal CO2
The measure of pCO2 is called what?
Capnography
What are the two different ways to measure pCO2? (location of the sensor)
Mainstream: measurement device is between ET tube and breathing circuit
Sidestream: sampling device is between ET tube and breathing circuit
What is the key consideration when using the sidestream sampler?
Low flow rates; could pull all the O2 out of the system
What are some causes of high EtCO2?
Hypoventilation, fever, increased CO, exhausted soda lime
What are some causes of low EtCO2?
hypothermia, DEcreased CO, hyperventilation, patient disconnect
What is a decrease in PaCO2 classified as? Increase?
Respiratory alkalosis
Respiratory acidosis
Pulse oximetry is a good way to measure what?
Pulsatile arterial blood in tissue bed
Where would the ideal SpO2 be for an anesthetized patient? What is a danger level?
Ideal is 93-95%
Less than 90% is at risk for hypoxemia
How can PaO2 be estimated?
SpO2 - 30;
T/F PaO2 is most helpful when the patient is breathing room air or transitioning
TRUE
we dont use this measurement for patients under general anesthesia
T/F Dark pigmented skin can affect a pulse oximeter reading
TRUE
Cats can experience hyperthermia when given what class of drugs?
Opioids
Intermittent positive pressure ventilation should be used when:
Intra-thoracic surgery
Head trauma/brain tumor
All horses
T/F You always wean horses from IPVV?
FALSE; never wean them unless brain surgery/ head trauma you would decrease the inhalant
What are the two ways to wean a patient from IPVV?
Lower respiratory rate to increase PaCO2
Discontinue inhalant to decrease CO2 set point in brain
What strategy for weaning would you use for a patient presenting with a head trauma or tumor?
ONLY Decrease the inhalant
NEVER lower the resp rate
T/F
Anesthetics are dose dependent cardio vascular and respiratory depressants, and as such need to be titrated to the lowest effective concentration
TRUE
A horse wakes up in the middle of Sx right after you just checked for a palpebral reflex (which was absent) what most likely happened, and what should you have noticed prior to the animal waking up?
Horse is on its back isnt it? Swelling of the head during surgery will depress the reflex
you should have noticed nystagmus or tearing which are both indication of a light plane of anesthesia in horses
You should begin anesthesia with a _____ flow rate and then switch to ____
High flow rate
lower/maintenance rate, remember we titrate back
____ is the KEY to patient survival
DO2- delivery of Oxygen to tissues
What is the threshold for Pulse rate of Dogs/Cats?
> 60 in dogs
> 80 in cats
below is considered bradycardia
Accuracy of oscillometric machines is dependent on ____; if it is too small the machine will ____ BP; if too big the machine will ___ BP
Cuff size
too small -> overestimate
too big -> under estimate
T/F
A arterial catheter is placed in all surgeries involving cattle or horses
TRUE
T/F
The sole benefit of using a pulse oximeter is that it calculates the SpO2 of the blood in the peripheral tissues, which is directly correlated with lung function
FALSE
Pulse ox tells you jack shit about lung function, it one of the limiting things about it.
