Surgery Tech. Week Three

Front 1

What is the Role of the Veterinary Technician in patient monitoring?

Back 1

Checking and recording findings every 5-10 minutes on an anesthesia form.

Must alert the veterinarian to changes or abnormalities during surgery

Do NOT be afraid to speak up ==> its your job!

Front 2

What are the goals of monitoring?

Back 2

To be able to determine the depth (stage & plane) of anesthesia.

To be able to keep the depth (stage & plane) of anesthesia at a level that prevents a patient from moving or feeling pain during the procedure.

To prevent the depth (stage & plane) of anesthesia from becoming too deep which may endanger the patient’s life or well-being.

Front 3

What is the #1 cause of anesthetic problems?

Back 3

the failure to monitor properly

Front 4

What are the patient parameters?

Back 4

-Heart Rate (HR) and Rhythm
-Respirations Rate and Rhythm
-Pulse and Blood Pressure
-Capillary Refill Time (CRT)
-MM color
-Eye Position
-Muscle Tone
-Reflexes
-Temperature
-Response to Surgery

Front 5

How do you ascertain the patient's Heart Rate, Quality & Rhythm?

Back 5

HR - Auscultation with stethoscope, esophageal stethoscope, pulse oximeter, surgical monitor.
Quality - strength currently vs. presurgical
Rhythm – Auscultation or ECG
Pulse deficit – HB but not a palpable pulse with each beat.
**Can palpate heart through a cat’s chest wall

Front 6

How do you ascertain the patient's Respirations?

Back 6

Rate – Auscultation, watch chest, surgical monitor
Depth (Shallow vs Deep) – Inspiratory phase is longer
Surgical anesthesia – 8 to 20 breaths/minute
Rhythm- Dissociative anesthetics can cause irregular breathing patterns.
Watch for gasping or agonal breathing.

Front 7

How do you ascertain the patient's blood pressure and pulse?

Back 7

Pulse strength-femoral, lingual, carotid, dorsal metatarsal & digital. Indirectly measures blood pressure.
Blood pressure – Oscillometric, Doppler
Normal: Systolic: 100 – 150 mmHg
Diastolic: 60 – 80 mmHG
Mean Arterial Pressure (MAP): 60 - 100 mmHg

Front 8

Monitoring CRT?

Back 8

Should be < 2 seconds
If delayed  poor tissue perfusion.
Low arterial BP or peripheral vasoconstriction

Front 9

Mucous Membrane Color (MM)

Back 9

Indicator of tissue perfusion
Pink (good) – Blood in capillaries
Pale - Poor tissue perfusion (shock, blood loss) or anemia
Dark red – septic, hyperthermia
Blue or purple (cyanotic) - Lack of oxygen

Front 10

Eye Position and Pupil Size

Back 10

Ventrally rotated – medium or surgical anesthesia
Centrally rotated – light or deep levels of anesthesia
Pupils constrict more slowly as depth increases
Pupil dilation occurs as anesthesia becomes deeper

Front 11

Muscle Tone

Back 11

Muscles relax as animal goes deeper under anesthesia
Some drugs will cause muscle rigidity (dissociative)

Front 12

How do you test for jaw tone reflex?

Back 12

Test by prying apart upper and lower teeth with two fingers. Don’t attempt to intubate if jaw tone is strong/present. Don’t get bitten!!!

Front 13

How do you test for Swallow reflex?

Back 13

Watch or palpate larynx. The first to go, last to return.

Front 14

How do you test for Pedal reflex?

Back 14

Used frequently. Fully extend the leg, pinch webbing between toes, feel for “pullback”. Check both front & rear legs.

Front 15

How do you test for the Palpebral reflex?

Back 15

gently touch medial canthus-be careful when using instruments for this.

Front 16

How do you test for anal reflex?

Back 16

Pinch and observe sphincter - not used as much

Front 17

How do you test for corneal reflex?

Back 17

Remains even under deep anesthesia. Used in patients near death. Vagal stimulation.

Front 18

What is fairly common for the pedal and palpebral reflexes?

Back 18

It is fairly common for animals to have a pedal reflex but no palpebral reflex.
The patient will be in Stage 3, plane 1 or lighter if pedal reflex is present.
Don’t rely solely on the palpebral reflex.

Front 19

For cats, what is one of the best indicators of the depth of anesthesia? What should you do with this info?

Back 19

-the strength of the heartbeat
-Palpate the strength of the heartbeat prior to anesthetizing a cat.
-If you are having trouble feeling the heartbeat during anesthesia, the cat is too deep!

Front 20

What are the Anesthetic Monitoring Devices?

Back 20

Stethoscope
Pulse Oximeter
ECG
Blood Pressure Monitor
-Oscillometer
-Doppler
Capnograph
-Graph of the amount of CO2 expired
-End Tidal CO2 – high levels may indicate hypoventilation
Thermometer
Multi-Parameter Monitors

Front 21

What is the pulse oximeter?

Back 21

Evaluates the level of oxygen saturation in the blood to assess tissue perfusion.
Measures how much hemoglobin is saturated with oxygen
Also monitors pulse rate.
Sensors or probes emit wavelengths of light that travels through tissue and the photodetector senses the light.
Oxygenated hemoglobin absorbs more infrared light and allow more red light to pass through
Deoxygenated hemoglobin absorbs more right light and allows more infrared light to pass through.

Front 22

What causes abnormal pulse oximeter readings?

Back 22

-Patient movement (shivering, tremors, seizure)
-Poor perfusion (hypothermia, shock/hypovolemia, vasoconstriction)
-Anemia
-Skin pigmentation
-Reduced localized perfusion (due to gradual tissue compression from probe)
-Very thin tissue (i.e. cat’s tongues and ear pinnae can be too thin for probes to measure accurately – a damp swab can be placed under the probe to increase width and compensate for thin tissue)
-Interference (visible light, electromagnetic energy, surgical diathermy)
-Abnormal hemoglobin

Front 23

What is the Capnometer?

Back 23

measures the levels of exhaled CO2

Front 24

What is a Capnography?

Back 24

graph of the expired CO2

Front 25

What is End-tidal CO2 (EtCO2)?

Back 25

comes from the last portion of a breath and is representative of the CO2 in alveoli

Front 26

What does Low EtCO2 mean?

Back 26

(hypocapnia, hypocapnea, hypocarbia)
Overzealous artificial respiration
Increased respiratory Rate
Too light of a plane of anesthesia
Pain
Hypoxia

Front 27

What does High EtCO2 mean?

Back 27

(hypercapnia, hypercapnea, hypercarbia)
Hypoventilation
Hypothermia
Exhaustion of soda lime
Stuck valve
Kinked ET tube

Front 28

What does a Multi-parameter Anesthesia Monitor monitor?

Back 28

Heart rate
Respiratory rate
ECG
Pulse Ox
NIBP (noninvasive blood pressure monitoring)
ETCO2 (capnography) – Measures exhaled CO2 levels

Front 29

When should temp be measured?

Back 29

Should measure before, during and after anesthetic period.
Should measure every 15 minutes but may not be practical.

Front 30

What is hypothermia?

Back 30

(<97°F)
Anesthetic drugs relax muscles  diminished shivering, decreased metabolism, decreased heat production.
Surgical site is shaved and prepped
Room temperature fluids
Cold gases are inhaled
Body cavity is open – organs exposed to ambient temp

Front 31

Normals for dogs and cats

Back 31

DOGS CATS
 Respiration 8-10 brpm 8-10 brpm
 Heart Rate 60-120 bpm 120-180 bpm
 Blood Pressure mmHg
Systolic 100-150 100-150
Diastolic 60-80 60-80
Mean (MAP) 60-100 60-100
 Pulse Oximetry 95-100% 95-100%
 EtCO2 35-45 mmHg 35-45 mmHG
 Temperture 970-100 0 F 970-100 0 F

Front 32

How many stages of anesthesia are there?

Back 32

Four

Front 33

How many planes are there? What stage do they occur in?

Back 33

Stage 3: Four Planes within it: 1, 2, 3 and 4

Front 34

What stage and plane do we want to be in?

Back 34

We want to be in Stage 3 and in plane 1, 2, or 3 depending on the procedure

Front 35

When does a crisis occur?

Back 35

Once the patient reaches Stage 3, plane 4 it’s a crisis
Stage 4 worse!

Front 36

How do we avoid a crisis?

Back 36

Monitor properly

Front 37

What is Stage 1?

Back 37

Stage 1
Induction/Voluntary Excitement
Animal is conscious, this stage is most variable

Urination or defecation may occur

Respiratory rate and heart rate may increase

Pain sensation present, so painful procedures should be avoided (animals may bite or scratch)

Front 38

What is Stage 2?

Back 38

Stage 2-Involuntary Excitement

Dogs may whimper or howl, cats may cry
Consciousness is lost, but swallow reflex remains
Reflexes are exaggerated, so avoid any unnecessary stimulation.
Pain sensation present
Salivation or vomiting may occur
May hold their breath
Try to have animals pass rapidly through this stage.
Patients with cat box inductions or “masking down” without premedication exhibit prolonged Stage 2 behavior

Front 39

What is Stage 3?

Back 39

Stage three: surgical anesthesia





There are four planes within Stage 3
These are where most patients are during surgery.
Muscle relaxation begins at this stage

Front 40

What is plane 1?

Back 40

Plane 1 - light anesthesia
Cessation of all limb movements
Nystagmus occurs-rapid eye movement.
Eyeball is central or maybe rotated downward.
 Sufficient for minor surgery
Breathing: is chiefly thoracic

Front 41

What is plane 2?

Back 41

medium anesthesia. This is optimal for most surgeries.
Respirations are slow and regular
Nystagmus stops
Eyeball rotates downward (in dogs and cats)
Muscle relaxation becomes more pronounced
Breathing is equally thoracic and abdominal

Front 42

What is plane 3?

Back 42

deep anesthesia! Be careful!
Respirations are slow and regular
Abdominal muscles relaxed
Eyeballs return to central as the tone of eye muscles are lost.
Third eyelid relaxed
Breathing is chiefly abdominal
Be careful here-the animal is getting close to emergency level if much deeper.

Front 43

What is plane 4?

Back 43

anesthetic emergency- Near death
Avoid this stage at all times!
Rapid, weak pulse, pale mucus membranes
Animal is in shock
Low TISSUE PERFUSION of blood
Lower-than-normal blood pressure
Pupils may begin to dilate-consider atropine
Breathing is shallow and only abdominal
Anal reflex remains

Front 44

What is stage 4?

Back 44

Stage 4-Overdosage

This is an EMERGENCY
Breathing stops, MM become cyanotic due to lack of oxygen
Pupils suddenly dilate
Brain death occurs rapidly unless immediate resuscitative steps are taken.
This occurs due to the FAILURE TO MONITOR the patient !!!!

Front 45

How do patients respond in Stage 1 and 2?

Back 45

Stage 1 & Stage 2 – Patients will struggle

Front 46

How do patients respond in Stage III/Plane 1?

Back 46

Stage III/Plane 1 – May respond with movement

Front 47

How do patients respond in Stage III/Plane II?

Back 47

Stage III/Plane II – HR and RR may increase

Front 48

How do patients respond in Stage III/Plane III?

Back 48

Stage III/Plane III – No response

Front 49

How do patients respond in Stage III/Plane IV?

Back 49

Stage III/Plane IV – No response

Front 50

How do patients respond in Stage IV?

Back 50

Stage IV – No Response

Front 51

Define anesthesia

Back 51

Defined as “a loss of sensation”

Front 52

What is general anesthesia?

Back 52

a reversible state of unconsciousness, immobility, muscle relaxation and the loss of sensation throughout the entire body produced by administration of one or more anesthetic agents.

Front 53

In order to anesthetize the animal, what must be anesthetized?

Back 53

The brain

Front 54

What is regional anesthesia?

Back 54

loss of sensation in a limited area of the body by administration of a local anesthetic agent in close proximity to sensory nerves.

Front 55

What is local anesthesia?

Back 55

loss of sensation in a small area of the body by the administration of a local anesthetic agent.

Front 56

What is topical anesthesia?

Back 56

loss of sensation of a localized area by administration of a local anesthetic applied directly to the body surface or wound.

Front 57

What is sedation?

Back 57

drug-induced CNS depression and drowsiness

Front 58

What is tranquilization?

Back 58

drug-induced state of calm, a reduced sense of anxiety and increased sense of tranquility

Front 59

What are the two types of anesthetics?

Back 59

-Injectable anesthetics
-Inhalation anesthetics

Front 60

What are injectable anesthetics?

Back 60

Can include sedatives, tranquilizers, analgesics and anesthetics

Front 61

What are inhalation anesthetics?

Back 61

Halogenated anesthetic agents
Most commonly used general anesthetic agents in veterinary medicine
Halothane, Methoxyflurane, isoflurance, sevoflurane.
Liquids at room temperature.
Stored inside the vaporizer and evaporate in oxygen (becomes a gas) and is delivered to the patient via an anesthetic machine.
Can be transported, absorbed and excreted from body with little change.

Front 62

What are premedications?

Back 62

administration of medications and anesthetic agents to calm and prepare the patient for anesthetic induction.

Front 63

What are different types of premedications?

Back 63

Anticholinergics
Analgesics
Sedatives
Tranquilizers
Dissociatives

Front 64

What is Anesthetic induction?

Back 64

process by which an animal loses consciousness and enters surgical anesthesia. The goal is to take the patient from consciousness to stage III anesthesia smoothly and rapidly, so an ET tube can be placed.

Front 65

What are the Reasons for Anesthesia?

Back 65

Surgery
Restraint
-Split/cast, wound care, grooming, capture, transport
To allow a thorough examination
-EENT, radiology, endoscopy, musculoskeletal
Seizure control
-“status epilepticus”
Pain Control
Capture & control of wild animals

Front 66

What is the role of the CVT?

Back 66

-Operation & maintenance of the anesthetic equipment
-Administration of anesthetic agents
-Endotracheal Intubation
-Anesthetic Control
-Patient Monitoring
-Most anesthetic agents have a narrow therapeutic index.
Must pay attention to dosage calculations
Must pay attention to route of administration
Can be lethal if not carefully assessed and managed.

Front 67

Effects of Anesthesia (what systems do we concentrate on for anesthetics?)

Back 67

CNS
Cardiovascular
Pulmonary (lungs)

Front 68

What is the number one rule of thumb?

Back 68

most anesthetic drugs depress physiological systems

Front 69

What is my job?

Back 69

Your job is to manage the stages and plane of the patient to prevent death due to OVER-suppression

Front 70

What are the CNS effects?

Back 70

-Most drugs exert their effects by interfering with synaptic transmission--connection between nerve endings
-Anesthetics affect the higher brain centers first then the spinal cord and the lower brain centers
-Pain still transmitted, but not sensed or perceived due to suppression. Will feel pain upon recovery.
-Depresses the temperature-regulating center leading to hypothermia.

Front 71

What are the Cardiovascular effects--all effects that depress the system?

Back 71

-Decreased cardiac output (usually)
-Vasodilation
-Decreased blood pressure
-Decreased tissue perfusion  may lead to decreased renal blood flow (watch in renal patients)kidney damage
-Heart rate-drug dependent (atropine may mask this effect)

Front 72

What are the Respiratory System Effects--depresses respiratory system?

Back 72

-Slower RR (respiratory rate) usually occurs
-Drugs directly suppress the CNS respiratory center
-Relaxation of intercostal muscles and diaphragm  reduced tidal volume (volume of air inspired and expired with each breath)
-Atelectasis-collapsed alveoli (caused by lack of deep breaths)
-With adequate O2 levels and the anesthetic depression from the induction drug, apnea is common after induction
-CO2 retention  respiratory acidosis

Front 73

What is diffusion?

Back 73

Molecules move from an area of high concentration to an area of low concentration. No energy is required.
Smell of perfume or a meal in a room

Front 74

What is Anesthetic Gas Diffusion?

Back 74

-Molecules move from the side of high pressure to the low pressure side of the membrane
-Example of membrane ==> lung alveoli
-The greater the difference ==> the faster the molecules move
-Each gas moves according to its own pressure gradient, regardless of other gases in the mixture.
-Example of a gas mixture: oxygen, nitrogen, CO2

Front 75

What is the Gas Anesthetic Pathway?

Back 75

Anesthetic gases enter the lungs ==> alveoli ==> pass through the alveolar membrane ==>
pulmonary circulation ==>
left side of the heart ==> vessel rich group (VRG) (brains and major organs)

Front 76

What is the induction phase?

Back 76

vaporizer was just turned on

Front 77

Where is the highest anesthetic concentration in the induction phase?

Back 77

Highest anesthetic concentration is in “y”-piece and hoses.

Front 78

Where is the lowest anesthetic concentration in the induction phase?

Back 78

Lowest concentration of anesthetic gas is in the brain
(Highest) vaporizer hoses ==> Inspired air ==> Alveolar air ==> blood ==> brain (Lowest)
-Values decrease from left to right during induction

Front 79

What is the recovery phase?

Back 79

vaporizer was just turned off

Front 80

Where is the highest concentration in the recovery phase?

Back 80

Lowest anesthetic concentration is in “y”-piece and hoses.

Front 81

Where is the lowest concentration in the recovery phase?

Back 81

-Highest concentration of anesthetic gas is in the brain
(Lowest) Vaporizer==> hoses ==> Inspired air ==> alveolar air ==> blood ==> Brain (highest)
-Values decrease from right to left during recovery

Front 82

What is the vessel rich group?

Back 82

Brain and major organs
Lots of vessels ==> therefore the highest blood flow rate (10% of body wt but 75% of blood flow)

Front 83

What is the muscle group?

Back 83

-Muscle and Skin
-Largest volume of any tissue group (50% body wt-20% of blood flow)

Front 84

What is the fat group?

Back 84

-Fat
-Low blood flow (20% of body wt-5% of blood flow)
-Amount varies between breeds and individuals (pug vs whippet)

Front 85

What is the vessel poor group?

Back 85

-tendons, bone, ligaments,
-Low blood flow (20% of body wt-1% of blood flow)

Front 86

What is tidal volume?

Back 86

the volume of air inspired and exhaled in a normal breath

Front 87

What are tidal volume calculations for dogs?

Back 87

Calculations (in dog)
Tidal volume = body weight (lbs) x 5 ml O2/lb

Front 88

What are tidal volume calculations in cats?

Back 88

Tidal volume =body weight (lbs) x 2.5 ml O2/lb

Note: cat is half the volume of the dog

Front 89

What is the Inspiratory Reserve Volume?

Back 89

The extra volume of air that can be inspired over and beyond the normal tidal volume.

Front 90

What is the Expiratory Reserve Volume?

Back 90

The amount of air that can be expired by forceful expiration after the end of a normal tidal expiration

Front 91

What is the Residual Volume?

Back 91

The volume of air remaining in the lungs after the most forceful expiration.

Front 92

What is the Total Lung Capacity?

Back 92

The maximum volume to which the lungs can be expanded with the greatest inspiratory effort (sum of all above + tidal volume)

Front 93

What is the Vital Capacity?

Back 93

The volume of air that can be expelled from the lungs from a position of full inspiration to complete expiration (sum of inspiratory reserve volume, expiratory reserve volume and tidal volume)

Front 94

What is dead space?

Back 94

Dead space is where no gas diffusion occurs.

Front 95

What is anatomical dead space?

Back 95

conducting passageways (trachea, bronchi).

Front 96

What is alveolar dead space?

Back 96

the gas that is trapped in atalectic (collapsed) alveoli

Front 97

What is physiological dead space?

Back 97

the combination of anatomical and alveolar dead spaces

Front 98

What is mechanical dead space?

Back 98

endotracheal tube, “y”-piece