Transcript MonitoringWithInstrumentationDrDevStudentCopy

MONITORING ANIMALS WITH THE USE OF
INSTRUMENTATION
These machines can be very useful, especially
in the situations where the technician can’t
always be with the patient through the
entire procedure; however you should never
completely rely on your machines
The following can be monitored via
machines: Blood pressure, Central Venous
Pressure, Blood Gases, Pulse Oximetry,
Capnography, and Electrocardiography
◦ Measures the electrical activity of the heart – NOT
the mechanical activity.
 REMEMBER THAT THE EKG CAN CONTINUE EVEN IF YOUR
PATIENT’S HEART IS NOT CONTRACTING. This is called
________________________________________
◦ The complexes should be of normal configuration,
consistent size, rate, and rhythm
◦ If the complexes look abnormal:
 Alert the Dr.
 Check the patient!
 Check the lead placement
A cardiac arrhythmia is any pattern of
electrical activity that differs from the
healthy, awake animal
MOST COMMON EKG ABNORMALITIES SEEN WHICH
MUST BE ADDRESSED are:

1) ________________________________
◦ Diagnosed when a patient’s HR under anesthesia is:
>200 bpm in cat
>180 bpm in small dog
> 160 bpm in large dog
◦ Causes:
 Can be _________________ (atropine, ketamine),
or response to surgical stimulation
 If animal is “huffing” during surgery
 if reflex activity is present or moving occurs, patient may
be too “light”
 Can also occur in situations of
________________, ______________________, or
high ______________ levels
 Pre-existing conditions of the heart, thyroid,
anemia, shock (compensatory/early)
◦ Treatment:
 Emergency treatment can include applying
pressure to the eyeballs

2) _______________________________
◦ Diagnosed when patient’s HR under anesthesia is:
< 60 bpm in large dog
<70 bpm in small dog
< 100 bpm in a cat
◦ Causes:
 Can be drug related (xylazine, dexmedetomidine, opioids)
 Increased anesthetic depth, hypoxia (late stages),
hypothermia
◦ Treatment:
 Can give reversal agents or atropine
 Assess other parameters before deciding management

3) ________________________
◦ Electrical impulse through the heart is not being
transmitted efficiently.
 _______________________: There is a P wave for every
QRS complex, but the P-QRS interval is prolonged
 _______________________: Some P waves are not
followed by QRS complexes
 _______________________: The atria and ventricles are
contracting independently. No normal relationship
between P waves and QRS complexes
 2nd and 3rd degree blocks can be seen after
alpha-2-agonist administration & high vagal
tone

4) _________________________________
◦ Impulse arising from the ventricular muscle causing
an uncoordinated heart contraction
◦ QRS complexes are wide and bizarre
◦ Causes:
 hypoxia, heart disease or trauma, electrolyte
abnormalities, etc
 Epinephrine release can stimulate the formation of
VPCs
 Don’t forcibly restrain an animal during the induction of
anesthesia!

5) ______________________: > 3 VPCs in a
row, more than 15 in one minute, or VPCs +
falling blood pressure
 EMERGENCY!!
 Can be treated with __________________given IV

6) ________________________
◦ Contraction of small muscle bundles within the atria
or ventricles
 Atrial fibrillation
 No p-waves, high HR, normal QRS complexes
 Ventricular fibrillation
 Absence of QRS complexes
 CARDIAC ARREST IS IMMINENT
ECG: Atrial Fibrillation
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Refers to arterial blood pressure
_______________________Pressure – produced by
the contraction of the ventricles as it propels
blood through the aorta, pulmonary artery,
and other major arteries
______________________ Pressure – the pressure
that remains when the heart is resting between
contractions.
_______________________(MAP) - average
pressure through the cardiac cycle and best
indicator of organ perfusion under anesthesia
= diastolic pressure + (systolic-diastolic pressures)
3
BLOOD PRESSURE

Pulse pressure – pressure detected by
manual palpation
◦ the difference between systolic and diastolic
pressure


Blood pressure can vary with age, breed,
species, and instrumentation
It is important to monitor TRENDS in
blood pressure in addition to actual
values
BLOOD PRESSURE

Normal systolic BP in awake dogs and
cats:120
◦ Normal range: 90-150 mm Hg
◦ Should ideally remain at or above _______mm Hg in anesthetized
patients

Normal diastolic BP in awake dogs and cats:
80
◦ Normal range: 50-90 mm Hg

Normal MAP: 90-100 mm Hg
◦ Should be maintained above ________mm Hg in anesthetized
patients
◦ This is the best indicator of blood perfusion to the internal organs

INDIRECT BP MONITORING
◦ Method most commonly used in private practice
◦ Noninvasive, less technically difficult than direct
monitoring

2 types of INDIRECT BP monitors:
 ______________________
 Measures systolic, diastolic, MAP
 _____________________
 Measures systolic only
INDIRECT BP MONITOR: OSCILLOMETRIC
determines, systolic, diastolic, and MAP by
detecting the oscillations within the cuff caused
by the pulsation of the artery beneath the cuff
 Less labor intensive than Doppler monitors
but tend to be less consistent in their
ability to register blood pressures for
smaller patients
 The machine can be set to automatically
take a BP measurement every 2 to 3
minutes
-1 minute cycles tend to create an ischemic
challenge to the extremity

Cuff width should be _______________of limb
circumference for dogs and cats
 Excessively ___________cuffs will lead to an underestimation of blood pressure
 Excessively ___________ cuffs will lead to an overestimation of blood pressure

Location of cuff is important
 Most consistent cuff location for small patients is the
________________, other: tail base, distal tibia
 Don’t hesitate to try all locations as needed
 Good locations for larger animals include metacarpus,
metatarsus, and distal tibia just above tarsus
-
More consistently effective when monitoring small patients
-Measures systolic pressure only
-Hair is clipped at the probe site
-The depression in the probe must be filled with ultrasound gel
-place the probe over the metacarpal or metatarsal artery
-Once you hear the swishing sound of the heart beat, tape the probe
in place
-Both excessive and inadequate pressure can create difficulties
measuring accurately
◦ Cuff width is as important with doppler BP
measurement as with oscillometric BP
measurement
 Cuff width should be 30-50% of limb circumference for
dogs
 Excessively wide cuffs will lead to an underestimation of
blood pressure
 Excessively narrow cuffs will lead to an overestimation of
blood pressure
◦5 readings are taken, the highest and lowest are
thrown out. The average of the other 3 are used to
determine the SAP.
http://www.youtube.com/wa
tch?v=Li4oGhfKmDQ
http://www.vasg.or
g/doppler_use.htm

Used less than indirect methods in private
practice
◦ Indwelling catheter is placed in ___________ or
______________________artery
◦ Catheter is connected to a manometer or pressure
transducer via a fluid-filled tubing and the
pressure is displayed
http://www.vasg.org/direct_arterial_pressures.htm
◦ Check the patient!
◦ _______________________ the inhalant anesthetic setting
◦ ____________________the IV fluid flow rate
◦ ____________________ to ensure proper placement/size
◦ Finally…. Hetastarch, Dopamine, Dobutamine ….to be used
in emergencies!


Measurement of the blood pressure in a
central vein: ______________________
Assesses how well the blood is returning to
the heart and the ability of the heart to
receive and pump blood
◦ Helpful in monitoring animals with right sided
heart failure and preventing over-hydration in
animals receiving IV fluids
www.dcavm.org/08techmar.html
http://books.google.com/books?id=LtGS0t1MI
skC&pg=PA410&lpg=PA410&dq=manometer
+veterinary+medicine&source=web&ots=BIO
CQL_14Z&sig=MZnEtUSN6vpdi4TTnNjYkAduv
a4&hl=en&sa=X&oi=book_result&resnum=9
&ct=result#PPA410,M1
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Refers to measurement of ____________ by
measuring dissolved oxygen and carbon
dioxide gas in arterial blood.
Indicate how well the patient is obtaining
oxygen and delivering it to the tissues
and how well the lungs are expelling
carbon dioxide
◦ All of these depend on the respiratory function
of the patient.
OXYGEN EXISTS IN 2 FORMS IN THE BLOOD:
 1) Free molecule dissolved in plasma (PO2 or PaO2)
 Measured by a blood gas analyzer
 Values below 60 mm Hg indicate hypoxia!!
 2) Chemically combined with hemoglobin in RBCs
(SO2 or SpO2)
 Measured by a _____________________

Not commonly used in private practice
 Blood sample should be taken from an artery
 Sample is placed on ice and should be run
within 2 hours of collection
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
Inexpensive, noninvasive, portable, easy to
use
Clip is placed on a thin strip of tissue that is
nonpigmented and hairless
◦ Most commonly the _____________, but can also
use the pinna, rectal mucosa, toe webbing, lip,
vulvar fold, Achilles tendon, under base of tail

Values should read _________% or greater
under anesthesia
◦ Values between _______________% indicate
hypoxemia
◦ Values less than 90% indicate a need for therapy
 Treatment: assisted ventilation, supplement oxygen
◦ Values less than ______% for greater than 30 sec. is
a medical emergency

PaCO2 : The portion of carbon dioxide that is
dissolved in plasma (Carbon dioxide partial
pressure in the arteries)
◦ Measured using a blood gas analyzer
◦ An awake patient’s levels are usually less than 45
mm Hg. It is common to see levels of
____________mm Hg in an anesthetized patient
because the animal doesn’t breathe deeply enough
to eliminate the usual amount of CO2
◦ If greater than 60 mm Hg, hypoventilation is present.
Assess other parameters to determine oxygenation
and assist ventilation if necessary

Carbon dioxide build-up can result in
respiratory __________________
◦ Commonly seen levels are 7.2-7.3 as compared to
normal values of 7.35-7.45
◦ Blood pH is measured via blood gas analyzers


A ___________________ is placed on the
endotracheal tube: it monitors the
amount of CO2 that is expired
Noninvasive
◦ Info is displayed as a graph

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Measures ______________________
As inspiration occurs, CO2 should be around __________
Hypercapnea: ET CO2 greater than ________mm Hg
◦ Causes: CO2 canister needs changing, hypoventilation
(should correct when patient is bagged)
Hypocapnea = ET CO2 less than 35 mm Hg
◦ Tachypnea, dead space, too much assisted ventilation,
improper endotracheal tube placement/connection
◦ The main reason for a low SpO2 in an anesthetized
patient is decreased ventilation
 1) The animal is not breathing well and you need to
assist it
 Respiratory rate should be 8 – 20 breaths /min for
the average patient (avg = 10-12 bpm). Small
patient may need more breaths.
 Try just occasional breaths at first
 2) The patient has _________________________– the oxygen
isn’t getting to the areas in the lungs where the blood is
 Check that the machine is hooked up properly
 Check that the oxygen is turned on/in tank
 Check that the endotracheal tube is placed correctly and
the cuff is properly inflated. If the tube is in too far, the
gas/O2 will only go to one side of the lungs.
 3) The patient’s pulse is weak
 Check that the patient isn’t too deep
 Check the blood pressure and act accordingly (see
section on blood pressure)
 4) The sensor is slipping off the patient
 5) The sensor has been at one location for a long
time and is too dry or is pinching off blood supply to
the area. The following locations may be used for the
pulse ox. probe: tongue, lips, ear, toe webbing,
prepuce, and vulva.