Surgery Midterm Flashcards
Instrument metal that is harder and stronger, used for thumb forceps, hemostats, retractors, and needle holders.
Martensitic Steel
Instrument metal that is softer, high tensile strength resistant to corrosion, surgical implants, bowls, pans and trays are usually made out of this.
Austenitic Steel
Occasionally used as inserts in tips of instruments especially needle holders, often identified by golden handles.
Tungsten Carbide
Cleans by a process called cavitation, utilizes high frequency vibrations to remove dirt.
Ultrasonic Cleaning
What are three ways to lubricate medical instruments?
Instrument detergents that contain lubricants, lubricant sprays, instrument milk
Common methods of instrument sterilization
Steam autoclave
Ethylene oxide gas
Cold sterilization
Gas cylinders contain _____ or _____ ____ for deilvery to the patient
Oxygen or nitrous oxide
Oxygen is delivered at ____% versus room air which is __-___%
100%, 20-21%
Oxygen cylinders are colorer _____
Green
Volume in any E cylinder can be calculated by multiplying the pressure in pounds per square inch by __
0.3
Full Oxygen tank
2200 PSI / 660 Liters
1/2 full oxygen tank
1100 PSI / 330 Liters
Nitrous Oxide containers are ____
Blue
What is different on nitrous oxide and oxygen to avoid confusion?
Pin number on the yoke
Gas enters at the ___, exits at the ___, displacing the rubber or plastic gauge
bottom, top
What is the minimum oxygen flow rate to a patient?
1/2 Liter (500 mL)
Wick in a glass jar absorbs anesthetic to increase surface area, as oxygen flows past wick it collects the anesthesia to carry to the patient
Non-Precision Vaporizor
Designed for use with one anesthetic only, deliver exact concentration of gas as dialed
Precision Vaporizor
Allows oxygen to bypass vaporizer and enter the breathing circuit, containing no anesthetic gas. Best to depress when patient is not directly attached to the system
Oxygen flush valve
Dilutes the concentration of inhalation agent delivered
Oxygen flush valve
A low pressure hose that carries gas and/or gas mixed with anesthetic to the breathing circuit, preventing return of this gas to other components
Fresh Gas inlet
Minimum volume bag to select for a patient
60 ml/kg
Periodic bagging helps prevent ____
Atelectasis
Flushes the alveoli and airways with fresh gas, necessary when animal is not breathing on its own
Bagging
What occurs when a bag is overinflated?
Back pressure into the lungs and can cause alveoli to break
Maximum amount to bag
15-20 cm H2O (mm HG)
If the scavenger is too strong, what may occur to the bag?
Under inflation
On exhalation, the gas passes through the exhalation hose and either to the ___ ____ ___ or into the ____ _____
Pop off valve, CO2 Canister
Prevents buildup of excessive pressure in the system
Pop Off Valve
What two instances should the pop off valve be closed for?
Bagging a patient, conducting a leak test
Gases that do not exit via the pop off valve go where?
CO2 Canister
___ ___ in canisters cleanses CO2 from the circuit
Soda lime
When should CO2 canisters be changed?
Every 6-8 hours of use
Usually situated on top of the CO2 absorber, measures pressure within the circuit
Pressure manometer
Pressure should not exceed ___ cm H2O or mmHg
20 cm
Rebreathing circuits are available in what sizes?
3: pediatric, large animal, adult
2 types of rebreathing systems
Closed, semi-closed
What breathing circuit is used for animals <5-7 kg?
Non-rebreathing
This breathing circuit has no inhalation flutter valve, allowing gas to flow directly through the fresh gas inlet to the inlet hose for delivery to the patient.
Non-rebreathing system
What breathing circuit reduces resistance associated with breathing
Non-rebreathing
Mask induction level
300 ml/kg/min
Intubation after induction with injectable drugs (level)
200 ml/kg/min
Non-rebreathing flow rates
High, 200 ml/kg/min
Rebreathing flow rates (closed and semiclosed)
Closed: 15 ml/kg/min
Semi-closed: 25-50 ml/kg/min
Flow rates at the end of anesthesia are _____ immediately to the flow rates used during induction
increased
What does inceasing flow rates fo recovery do?
Saturates anesthetic circuit with oxygen
Dilutes the expired concentration of gases, replacing them with pure oxygen
More rapid recovery results
What are some long term effects of anesthetic gas exposure?
Reproductive disorders, liver and kidney damage, nervous system dysfunction
What anesthetics are considered greater hazards?
Methoxyflurane, halothane
Do waste anesthetic gases have cancer causing effects?
No
Whenever possible avoid being closer than ___ feet from the nose of an animal recovering from anesthesia
3 minutes
Hoses, reservoir bags, masks, ET tubes, and other rubber components can be washed with?
Soap and water (minimal soap, usually chorohexadine)
What is available if human exposure to injectable agents?
Narcotic reversing agents
Delivers anesthetic gases directly from the anesthetic machine to the lungs
Endotracheal tubes
ET tubes with beveled end and side holes, possible cuff
Murphy tube
ET tube with no side hole or cuff, abrupt decrease in diameter of tube, used in birds and reptiles
Cole tubes
Clear and stiff material used for ET tubes
Polyvinyl chloride
Flexible, less traumatic, absorbant ET tube material, may kink or collapse
Red rubber
Pliable, strong, less irritating ET tube material, resists collapse
Silicone
ET tubes are measured by ____ diamter
Internal diameter
ET tubes range in size from __ - __ mm
1-30mm
Clear, aquarium like boxes used to induce general anesthesia
Anesthetic chambers
Used in feral, vicious, or intractable animals to reduce stress
anesthetic chamber
Anesthetic chambers are either ____ or ____
Acrylic or Perspex
Disadvantage of anesthetic chambers
Can not monitor patient closely
Carrier gas for anesthetic machines is either _____ or ____ ____
Oxygen or nitrous oxide
Small cylinders attached directly to anesthetic machine
E tanks (small)
Large cylinder attached remotely to anesthetic machine
H Tanks (large)
Reduces outgoing pressure to a usable level
Pressure reducing valve
In Canada, oxygen cylinders are white, in the US they are _____
Green
Nitrous cylinders are what color?
Blue
Carbon dioxide cylinders are what color?
Gray
What color are medical air cylinders?
US- yellow
Canada/Europe- white and black
Pressure reducing valves (pressure regulator) reduce gas pressure to a constant __-__ psi
40-50 psi
Indicated pressure in the gas line between the pressure reducing valve and flowmeter
Line Pressure Gauge
Line pressure gauge should read __-__ psi after the oxygen tank is opened
40-50 psi
Sizes of laryngoscopes for small animals
0-5
Size of laryngoscopes for large animals
18 inch blade
Indicated gas flow in liters per minute
Flowmeter
Where carrier gas enters a vaporizer from the flowmeter
Vaporizer inlet port
Bypasses vaporizer and flowmeter, delivers short, large burst of pure oxygen directly into rebreathing circuit, used to refill rebreathing bag to deilver pure oxygen to a patient
Oxygen Flush Valve
Used to deliver low vapor pressure anesthetics, rarely used
Non-precision Vaporizer
Used to deliver high vapor pressure anesthetics
Precision Vaporizers
Precision vaporizers, high resistance gas flow
VOC (Vaporizer Out of Circuit)
Low resistance gas glow, Non precision vaporizer
VIC (Vaporizer in circuit)
In these vaporizers, oxygen from the flowmeter enters the vaporizer prior to entering the breathing circuit
VOC
In these vaporizers, oxygen enters the breathing circuit from the flowmeter, exhaled gases pass through the vaporizer
VIC
Due to manual ventilation or activation of oxygen flush valve
Back pressure
Color code for Isoflurane
Purple
Color code for Sevoflurane
yellow
Color code for Halothane
red
Color code for Desflurane
blue
Induction rate for Isoflurane
3-5%
Maintenance rate for Isoflurane
1.5-2.5%
Induction rate for Sevoflurane
4-6%
Maintenance rate for Sevoflurane
2-4.5%
Induction rate for Desflurane
10-15%
Maintenance rate for Desflurane
8-12%
What is the primary absorbant ingredient in CO2 canisters?
Calcium Hydroxide
CO2 becomes more ____ with use
acidic
Negative pressure is indicated by what?
A collapsed reservoir bag
What three sizes do breathing tubes come in?
50 mm, 22mm, 15 mm
Non-rebreathing system used in very small patients (<2.5 kg)
Semi-open system
What is not found on a semi-open non-rebreathing system?
No CO2 canister, pressure manometer or unidirectional valves
Machine choice is based on animal body weight. What is considered small and large?
Small <150 kg
Large >150 kg
What is maintenance fluid rate?
30 ml/lb/day (60 ml/kg/day)
What is fluid rate during anesthesia?
5 ml/lb/day (11 ml/kg/day)
What are fluid rates for shock? (cats and dogs)
Dogs: 40 ml/lb/day (88 ml/kg/day)
Cats: 25 ml/lb/day (55 ml/kg/day)
Balanced electrolytes, saline and Dextrose are what type of fluid?
Crystalloid solutions
Blood/plasma, Synthetics and Blood substitues are what type of fluid?
Colloid Solution
Controlled drugs that have extreme potential for abuse, no approved use
C1
Controlled drugs that have high abuse potential (give examples)
CII - Opium, pentobarbital, morphine
Controlled drugs that have some abuse potential
CIII
Controlled drugs that have low abuse potential (give examples)
CIV - phenobarb, diazepam
Controlled drugs with the lowest abuse potential
CV
Sympathetic drugs used to decrease salivation and inhibit bradycardia
Anticholenergics
Similar to Atropine but has a longer duration (can last 2-3 hours)
Glycopyrrolate (Robinul)
Quicker onset than Glycopyrrolate, can also be treatment for organophosphate toxicity, and is a pretreatment/treatment for bradycardia, AV block
Atropine Sulfate
Examples of anticholinergics
Atropine and Glycopyrrolate
Example of a Phenothiazine
Acepromazine maleate
Neurologic agent, “modifying psychotic behavior”, provides no analgesia. Reduces seizure threshold, mental calming sedation, and increased threshold to external stimuli.
Acepromazine
______ Acts on the brainstem to cause a loss of vasomotor regulation leading to lower blood pressure
Phenothiazine
What side effects are associated with Ace?
“Ace face”, ataxia, hypotension, hypothermia, decreased platelet function
What species should avoid use of Ace?
Horses (causes penile prolapse), geriatric animals, animals in shock, boxers, sighthounds
Mixture 50/50 with ketamine in same syringe as an induction agent
Diazepam
Less irritating than Diazepam
Midazolam
Induction agent when combined with tiletamine
Zolazepam
Special considerations for Benzodiazepines
Light sensitive
Xylazine (Rompun), Medetomidine (DexDomitor), and Detomidine are examples of what?
Alpha 2 Agonsists
What is the site of action for alpha 2 agonists?
Sympathetic nervous system receptors in the brain
What is a benefit of alpha 2 agonists?
They have reversal agents
What is released as a neurotransmitter of the sympathetic nervous system (stimulation of fight or flight)?
Norepinephrine
Stimulation of the ___ _ recepter causes a STOP in the release of norepinephrine
Alpha 2
Side effects of alpha 2 agonists
Profound bradycardia, supresses salivation and swallowing reflex
Antagonist to xylazine and detomidine, primarily used for dogs
Yohimbine
Antagonist to Medetomidine
Atipamezole (Antisedan)
Oxymorphone, hydromorphone, fentanyl, torb, bupenorphine, morphine and tramadol are all examples of what type of drugs?
Opioids
Pure agonist, 10x more potent than morphine
Oxymorphone
This drug is an excellent choice for orthopoedic or very painful procedures
Oxymorphone
Agonist that is similar to oxy but less expensive and more available
Hydromorphone
What problems are associated with fentanyl?
Heat increases absorption, ingestion could lead to death due to resp depression, must be returned to clinic, takes a min of 12 hours to take effect
Opioid best used against mild-moderate soft tissue pain such as spays/neuters and mild disease.
Butorphanol (Torb)
Reversal agent for Torb
Naloxone
Agonist of Mu receptor
Buprenorphine
If given IV, _____ can cause hypotension
Morphine
Mu receptor agonist used for chronic pain
Tramadol
Combination of a tranq or sedative and an opioid
Neuroleptanalgesics
4 examples of neuroleptanalgesics
Ace/Torb
Ace/Oxy
Ace/Buprenorphine
Domitor/Torb
Decreased responsiveness of normal muscle reflexes
Hyporeflexia
General anesthesia ideally includes what 4 things?
Hypnosis, Hyporeflexia, muscle relaxation and Analgesia
What are the 4 components of anesthetic protocol?
- Preanesthesia
- Induction
- Maintenance
- Recovery
What stage of anesthesia can NOT be skipped?
Induction
The same drug is often used for _____ and _____
Induction and maintenance
When does recovery begin?
When the concentration of anesthetic in the brain begins to decrease
Inhalation anesthetics are removed during _____
respiration
What is the single most important factor in preventing serious anesthetic problems?
Monitoring
This stage of anesthesia begins immediately after the administration of an induction drug
Stage 1
What stage of anesthesia begins witht the loss of consciousness
Stage 2
What stage is “fighting anesthesia”?
Stage 2
This stage ends with signs of muscle relaxation, slowed respiratory rate, and decreased reflex activity
Stage 2
Stage 3 is divided into how many plans?
4
What is the surgical plane of anesthesia?
Stage 3 Plane 2
Minimum average heart rate for a dog under anesthesia
60 bmp
Minimum heart rate for a cat under anesthesia
100 bpm
What heart rate range is common during anesthesia?
60-120 bmp
___ is the force exerted by the flowing blood on arterial walls
BP
What can cause hypotension?
Excessive anesthetic depth
Vasodilation
Cardiac insufficiency
Blood loss
Systolic pressure: Highest Pressure ____
120
Diastolic pressure: Maintenance pressure ____
80
Mean Arterial BP: Average pressure ___-___
90-100
What are indirect methods of monitoring BP?
Doppler and Oscillometer
What amount of blood loss is acceptable?
5mL/lb
What percent blood loss has serious circulatory side effects?
>15%
Normal anesthesic respiratory rate
8-20 bpm
Inspiration followed by a prolonged period before expiration
Apneustic breathing
What is the most common complication in veterinary patients?
Hypothermia
Common reasons for hypothermia?
Stainless steel tables
Clipped/scrubbed patients
Decreased metabolic rate
Age
Open body cavity
Measure of oxygenation of RBCs
Systemic oxygenation
What can affect systemic oxygenation?
Blood loss, anemia, type of anesthetic used
What does direct monitoring of systemic oxygenation measure?
oxygen saturation, CO2 saturation, bicarbonate levels
Normal Oxygenation
90-100%
What oxygenation level is considered hyopxia?
less than 90%
What 2 factors indicate degree of oxygenation?
PaO2/SPaO2
During ____ CO2 is close to zero
Inspiration
During ____ CO2 rises to 32-40
Expiration
>40 mmHg CO2 indicates?
Hypercapnea
<30 mmHg CO2 indicates
Hypocapnea
Sensor at the end of the ET tube that monitors CO2 in breathed air
Capnograph
What is most commonly seen after the administration of alpha 2 agonists such as Medetomidine and Xylazine?
Heart Block
Degree of heart block where the P wave is seen with delayed QRS complex following
First degree
Degree of heart block where the P wave is present with an absent QRS complex
Second Degree
Degree of heart block where there is a series of P waves with no QRS complex?
Third degree
Occurs when electrical impulses that cause the heart to beat are not being transmitted properly through the heart
Heart block
An electrical impulse that arises from the ventricle, not the atria, and causes an uncoordinated and ineffective contraction
Premature Ventricular Contractions
What are some causes of PVC?
Hypoxia, Systemic diseases (GDV, heart disease), Epinephrine
Treatment for PVC
IV Lidocaine
Rapid, randomized, uncoordinated muscle twitching of the heart. May cause lack of circulation and loss of pulse.
Fibrillation
Valium/Xylazine ____ muscle tone
decrease
Ketamine/Tiletamine ____ muscle tone
increase
During what stage of anesthesia are pupils constricted then dilate as level increases?
Stage 2
Dilated central pupil with no light reflex may indicate what?
Dangerously deep anesthesia
Cats are prone to _____ therefore should be extubated as soon as possible.
Laryingospasms
Recovery period complications
Hemorrhage, aspiration, dyspnea, self trauma
In what percentage of procedures do complications arise?
10-15%
Average mortality rate for anesthesia?
5 per 1000
Geriatric patients are at a high risk for ______
Hypothermia
Geriatric patients can be easily _____
overhydrated
For geriatrics, reduce anesthesia ___-___%
30-50%
Fluid rates for geriatric patients should be kept ____
lower
What oxygen strategy can be used for geriatrics?
Pre-oxygenate with a mask or chamber for 5 minutes prior to induction
What should be avoided in neonates to prevent hypothermia?
Avoid using alcohol in surgery prep, avoid using Acepromazine because it lowers BP
For neonates ____ are preferred over injectables
inhalants
For neonates, administer ___ ____ in LRS via micro drip set
5% Dextrose
Fasting should be avoided in ____
neonates
For Brachycephalic breeds, ___ tubes will be necessary
smaller
For obese animals, dose according to ___ ___
ideal weight
For patients undergoing C-sections, ___ should be used instead of ketamine/valium
Propofol
For cardiovascular problems, patients should be given _____ to reduce pulmonary edema
diuretics
What blood work should be ran for hepatic failure strategies?
Profile, CBC, Clotting profile
____ agents are preferred for hepatic problems
inhalant
For patients with urinary obstruction, avoid IM ____
Ketamine
Treat hyperkalemia with ___
NaCl
To treat excessive anesthetic depth immediately ____ vaporizer and ____ O2 flow
decrease/increase
What should the adjustments be for a patient that is too awake?
Increase vaporizer setting and increase O2
What should the adjustments be for a patient that is too deep?
Increase O2 and decrease or turn off vaporizer, reversal drugs can be used.
Loose metatarsal pulse
<60
Loose femoral pulse
<40
What is the IV fluid rate for hypotension?
20 ml/kg for 15 mins (90 ml/kg/hr max)
What drugs should be used for shock?
Solu-delta Corteff
Dexamethasone SP
Dobutamine
Bicarb
What is asystole treated with?
epinephrine, atropine and bicarb
What is ventricular fibrillation treated with?
lidocaine and a defib
