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