Practical Review Flashcards
Describe the ASA Physical statuses of a patient
ASA - American Society of Anesthesiologists
1 - Minimal Risk/Normal healthy patient (elective procedures)
2 - Low risk / Mild systemic disease ( Neonatal, geriatric, obese)
3 - Moderate risk / Severe systematic disease (Anemia, moderate hydration)
4 - High risk / severe systemic disease (ruptured bladder, pyometra)
5 - Extreme risk / Moribund patient cannot survive without operation ( severe head trauma)
When would you use Crystalloid / Colloid ? Hypertonic saline?
Crystalloid - routinely used in most anesthetized patients (except those with low blood protein, low RBC mass or low platelet count)
Hypertonic - used in hypovolemic, traumatic, or endotoxic shock
Colloid solutions - used during preoperative period to support the expansion of blood volume and blood pressure
What is the difference between maintenance and anesthetic fluid flow rates?
Anesthetic flow rate = 5 ml/lb/hr
Maintenance = 30-40 ml/lb/day
What is the calculation for fluid replacement in a dehydrated patient?
Maintenance + Dehydration + Ongoing losses
M (30-40ml/lb/day) +
D (kg x % dehydration) +
O (estimation of what’s seen)
What 4 parts are included on every anesthetic machine?
- Compressed gas supply
- Anesthetic vaporizer
- Breathing circuit
- Scavenging system
What are the differences between the rebreathing and non-rebreathing systems?
Rebreathing - in this system, exhaled gases minus carbon dioxide are recirculated and rebreathed by the patient, along with variable amounts of fresh oxygen and anesthetic
*** appropriate for most patients over 2.5-3 kg (Really for everyone)
Nonrebreathing - in this system, little or no exhaled gases are returned to the patient but are instead removed from the circuit by used of approximately high flow rates of carrier gas and evacuated by scavenger connected to a pressure-limiting valve or other exit port
*** for patients under 2.5-3 kg (Not for everyone)
What is the minimum oxygen flow rate in any anesthetic system?
500 ml**
What is the minimum pressure you need in your oxygen tank?
500 psi
Induction / maintenance / recovery flow rates
Partial Rebreathing ( Ind = 3 L/min, Maint = 10-20 L/lb/min, Recovery 3 L/min) Nonrebreathing (Ind = 3 L/min, Maint = 1.5-2x (TV(5xlb) x RR ml/min) Recovery 3 L/min
Function of the Oxygen Pressure Gauge
indicates the amount of gas/pressure left in the tank
Function of the Pressure Reducing Valve
located near the tank pressure gauge; reduces the pressure of the gas to a constant safe operating pressure (40-50psi)
Function of the Oxygen Flushvalve
A button or lever that rapidly delivers a large volume of pure oxygen (at a flow rate of 35-75 L/min) directly to the common gas outlet or breathing circuit of a rebreathing system, by passing the anesthetic vaporizer and oxygen flow meters
Function of the Oxygen Flowmeter
further reduces the pressure of the gas in the intermediate-pressure line from ~50 psi - 15psi (slightly above atmospheric pressure)
Function of the Precision vaporizer
convert liquid anesthetic to a gaseous state and add controlled amounts of vaporized anesthetic to the carrier gases
Function of the Unidirectional Valves
(aka one way valves); control the direction of gas flow through the rebreathing circuit, cause the gases to travel a one-way modified circular path through the breathing circuit
Function of the Carbon dioxide Absorbing Canister
exhaled gases are filtered here and returned to the patient. Absorbent + CO2 –> Calcium carbonate + heat + water and decreased pH
Function of the Pop-off Valve
the point of exit of the anesthetic gases from the breathing circuit; acts as a vent to prevent the buildup of excessive pressure
Function of the Scavenger
evacuates gas from the system
difference between passive and active?
What are parts A, B, C, D, E?
A - Valve with syringe attached B - Balloon (inflation or pilot) C - Machine end D - Connector or Adaptor E - Tie
What are parts F, G, H, I, J?
F - Measurement of length from patient end in cm
G - Measurement of internal diameter in mm
H - cuff
I - Patient end
J - Murphy eye
Considerations and sizing of the ET tube
Considerations : tube should be no longer than the distance between the most rostral aspect of the mouth and the thoracic inlet
Sizing : By weight, palpate the trachea, nasal septum
How to find the rebreathing bag size
TV x 5 (mls) ** round up
Bag sizes : 0.5, 1, 2, 3, 5 L
What does stimulation of the parasympathetic ANS cause?
- increased saliva
- slows heartbeat
- constricts bronchi
- stimulates peristalsis and secretion
- stimulates release of bile
- contracts bladder
- Pizza party, let out a breath and pee
What does stimulation of the Sympathetic ANS cause?
- Dilates pupil
- Inhibits flow of saliva
- Accelerates heartbeat
- Dilates bronchi
- Inhibits peristalsis and secretion
- Conversion of glycogen to glucose
- Secretion of adrenaline and noradrenaline
- Inhibits bladder contraction
- ** scary monster
Pain-related physiologic changes (cardiovascular, respiratory, Ophthalmic)
Cardio - Hypertension, tachycardia, tachyarrhythmia, peripheral vasoconstriction (pale mucosae)
Resp - Tachypnea, shallow breathing, exaggerated abdominal component, panting (dogs), open-mouth breathing (cats)
Ophthalmic - mydriasis
(Specifics by species?)
What does giving IV to effect mean?
Intravenous injection of an ultrashort-acting agent to effect is a technique used for short procedures that require less than 10 min of anesthesia. This way anesthetic depth typically increases rapidly over 15 sec to a few min after initial injection, then decreases gradually over 10-20 min
This technique allows the anesthetist to control the peak effect and can increase anesthetic depth rapidly by giving additional boluses of the drug
What are the stages of anesthesia?
1 - patient begins to lose consciousness; beginning of induction period
2 - fights anesthesia; middle of induction period
3 - HR, BP, RR decrease; surgical anesthesia (can be divided into light stage 3/ stage 3/ deep stage 3)
4 - continued anesthetic depth, dramatic drop in HR and BP, Anesthetic overdose
How to assess anesthetic depth
Respiration, HR, BP, MM, CRT
What do the complexes do the colors on this ECG correspond with?
pink - P (contraction/depolarization of the Atria)
green - QRS ( contraction of the ventricles; depolarization and repolarization)
blue - T (repolarization of the ventricles
How does electrical current flow through the heart?
Sinoatrial node, Atrioventricular node, Bundle of His, L/R bundle branch, Purkinje fibers
What causes Tachycardia and how to fix it?
Causes - inadequate anesthetic depth, drug reactions and surgical stimulation
Fixes -
What causes Bradycardia and how to fix it?
Causes - excessive anesthetic depth, drug reactions, hypothermia, and hyperkalemia
Fix -
What causes low Sp02 and how to fix it?
-
What causes low BP and how to fix it?
-
What causes High EtCO2 and how to fix it?
-
What causes Low EtCO2 and how to fix it?
-
What are important elements of CRP to keep in mind
CPR cycle length
How fast to do compressions - 100-120 bpm
How often to give a breath to an intubated animal - 10/min (every 6 seconds)
How do different chest shapes impact how compressions are done?
- A one-handed-technique directly over the heart may be considered in small dogs and cats (lateral recumbency)
- Two-handed compression directly over the heart in a lateral direction may be considered in keel chested breeds (such as sighthounds) (lateral recumbency)
- Two-handed compression on the sternum directly over the heart (while in dorsal recumbency) may be considered in barrel-chested breeds (such as English bulldogs)
When to give low/high dose epinephrine?
Low dose - every 2 min (every other BLS cycle x3)
High dose - prolonged CPR (last resort)
(BLS - Basic Life support)
Monitors used during CPR
ECG and End Tidal CO2 (ETCO2)
What hazards are Vet Techs exposed to when acting as anesthetist?
- waste anesthetic gas : fixed by good understanding of duration of anesthesia/build up, flow rate of carrier (waste), machine maintenance, effective scavenging system, room ventilation
- handling of compressed gas cylinders : cradle
- potent injectable agents : caping precautions
