Patient Monitoring Flashcards
Why do we monitor patients under anesthesia
dramatically reduces morbidity and mortality; improves the quality of anesthesia and analgesia
when do we monitor patients
immediately following sedation, during anesthesia, post-anesthesia until normal physiological variables and stable
what period is associated with the highest morbidity and mortality? what can you do to avoid it?
- Recovery period is associated with the highest morbidity and mortality therefore don’t stop monitoring after you extubate your patient!
what do we typically measure during anesthesia
depth and physiological variables
in general, what is the relationship between depth and physiological variables
as you depress the CNS (get deeper), physiological variables lower
linear relationship
how often do we monitor and record variables related to depth and physiology
every 5 minutes
how should we go about determining/assessing patient depth and physiological variables and why?
- Multiple variables are considered
when assessing a patient’s depth
of anesthesia and physiologic
status - A patient’s status can change
quickly therefore we monitor
continuously and record data
every 5 minutes to monitor
trends
what are ways to monitor patient depth using:
- physical exam
- monitors
physical exam:
- physiologic variables
- eye position and movement
- eyelid movement
- reflexes
- tear production
- jaw tone
monitors:
- EEG
in general, as patients become deeper what happens to eye position
moves ventromedially
what does eyelid movement tell us about patient depth and what is the exception
- During inhalant anesthesia = patient too light
- During injectable anesthesia with ketamine (equine in particular) = patient may be adequately anesthetized
if an animal has nystagmus what does that tell us
they are too light
how can we determine depth with palpebral in companion animals
-Assess Medial and Lateral Palpebral
-Lateral palpebral reflex is lost at a lighter plane of anesthesia
what is specific to horses regarding palpebral reflex
as one reflex (fan eyelids)
what is tearing a sign of in horses
-tearing is a sign of a light plane of
anesthesia irrespective of anesthetic protocol (injectable or inhalant)
jaw tone is a very helpful indicator of depth in what species? what does it tell us?
cats
lack of muscle relaxation = too light plane of anesthesia
how do signs related to depth of anesthesia in dogs and cats differ between inhalant and injectable anesthesia
jaw tone: tight in a medium light plane of anesthesia with injectable
eye position: stays central regardless of depth with injectable
palpebral reflex: present in a medium light plane and slow in a medium deep plane with injectable
CVS and respiratory variables and depth of anesthesia
HR; increases = light
BP; increases = light
RR; increases = light
resp effort/pattern; increases = light
what are the components of the physical exam (manual) to monitor physiological variables in an anesthetized patient
observe:
- mm rolour
- RR
palpate:
- pulse (or auscult)
- CRT
- temperature of extremities
what types of monitors can we use to monitor pulse rate
pulse oximeter
pulse minder
doppler BP monitors
oscillometric BP monitors
what types of monitors can we use to monitor BP
doppler BP monitor
oscillometric BP monitor
invasive (direct)
why is EKG not a heart PERFORMANCE indicator
it is just measuring electrical activity
purpose, advantages and disadvantages of a pulse minder
- Detects perfusion and displays pulse rate
- Advantages: easy and fast,
- Disadvantage: limited to just pulse rate vs new equipment (ex. Pulse oximeter)
why can EKG be misleading
-may not have good contact of the leads
-it reads deflection from baseline so may get two deflections on a single beat or other artifacts making the rate inaccurate
advantages of EKG (2)
HR and rhythm displayed
components of a doppler (4)
- Piezoelectric crystal
- Box that converts ultrasound
waves to audible signal - Cuff to place proximal to probe
- Sphingomanometer
cuff size in small animals should be ?
35-40% of the circumference of the placement site for a Doppler and 30-40% of the circumference of the placement site for an oscillometric monitor
T/F Doppler gives accurate BP regardless of extremes (hypo or hypertension) in all species
F; it does give reliable pressure readings but only useful in dogs and cat
pressure determined using a doppler represents _______ pressure in the dog and __________ pressure in the cat
systolic…. mean
advantages of a doppler (4)
- Non-invasive
- Audible pulse signal
- Less interference of arrhythmias on blood pressure measurement
- Reliable with extremes in blood pressure
disadvantages of a doppler (3)
- It requires manual placement of the probe
- Electrical interference = noisy!
- Useful in small animal patients only
what information will an oscillometric bp monitor display
systolic
diastolic
mean
pulse rate
if you had a hypo/hypertensive patient or a patient with an arrhythmia is it better to use a doppler or oscillometric monitor
doppler baby
what can we use to measure:
- oxygenation (O2)
- ventilation (CO2)
Oxygenation:
- pulse oximeter
- arterial blood gas
Ventilation:
- arterial blood gas
- capnograph (ETCO2)
advangtes and disadvantages of direct blood pressure measurement
Advantages:
* Accurate
* Continuous data
* Useful in a range of species
Disadvantages:
* Requires arterial catheter-potential for complications
* Skill required to place
* Require monitor capable of displaying direct arterial pressure
how does a pulse oximeter work and what info does it give us
uses red and infrared light to measure hemoglobin oxygen saturation
SpO2; heart rate/pulse rate
what do we want to see on a SpO2 reading
> 90% (normally 90-100 in arteries)
advantages vs disadvantages of pulse oximeter
Advantages:
* easy and fast to use,
* non-invasive
Disadvantages:
* it requires light transmission
through tissue therefore pigmentation alters its ability to
transmit light
* vasoconstriction can interfere
with its ability to read
* less accurate in large animals
due to thickness of suitable
tissue (ie. Tongue)
* Only telling you hemoglobin
saturation not oxygen content
what is a major disadvantage of pulse oximeters
only telling you hemoglobin saturation not oxygen content so it assumes normal hemoglobin levels…
T/F vasoconstriction and skin pigmentation can interfere with pulse oximeter readings
T
what can blood gas analyzers be used to measure
- Can measure pH, PaCO2, PaO2, electrolytes, Hb,
- Can measure glucose, lactate etc….
advantages and disadvantages of blood gas analyzers
Advantages:
* Accurate
Disadvantages:
* Cost
* Maintenance requirements
why do we measure END tidal CO2
at the end of an exhale there is less expired CO2 mixing with inspired O2, making the reading a more accurate indicator of arterial CO2 concentration…
how is capnography and pulse oximetry similar
both use infrared
advantages and disadvantages of capnography
Advantages
-Non-invasive
-Continuous information on adequacy of ventilation (ie. Elimination of CO2)
Disadvantages
* Adds to dead space-important in small patients
* Moisture can clog sampling line
temperature changes during anesthesia meaning
-Changes in body temperature are common
-Can change normal physiologic function (contribute to bradycardia, hypotension)
-Can alter pharmacodynamics and pharmacokinetics of drugs
temperature changes during anesthetic recovery meaning
Shivering dramatically increases oxygen consumption
It is UNPLEASANT and UNCOMFORTABLE
