How Flow Can You Go
Ex Machina
I've Got The Vapors
Take My Breath Away
Under Pressure
100
Which statement about the production of compound A during sevoflurane anesthesia is MOST likely true?
a. It is produced by metabolism of sevoflurane in the liver.
b. It results in increased serum creatinine levels.
c. Low fresh gas flow rates (<2 L/min) are associated with increased levels of the compound.
d. Compound A production is unaffected by the type of CO2 absorbent used.
C. Low fresh gas flow rates (<2 L/min) are associated with increased levels of the compound.
BONUS: What compounds found in CO2 absorbers will affect compound A production?
100
Which statement about the Pin Index Safety System is MOST likely true?
a. It prevents turning on two vaporizers at the same time.
b. It prevents interchanging the connections for different gases from the wall outlet to the anesthesia machine.
c. It is designed to prevent administration of an hypoxic gas mixture.
d. It couples the nitrous oxide and oxygen flowmeters.
c. It is designed to prevent administration of a hypoxic gas mixture.
100
Protocol for cleaning up volatile spill:
Do not wipe it up, you use SUCTION
Isolate it in sealed container, label it, waste disposal
Can also use the powder absorber that solidifies liquid wastes in OR
If patient in the room, prepare for transport to another room (they are protected if on the vent, but staff in OR exposed)
100
National Institute for Occupational Safety and Health (NIOSH) recommends limiting the room concentration of halogenated agents to ___
2ppm
100
*A PaO2 of 60mmHg corresponds to a saturation of:
What is 90%?
200
In a circle system, where is dead space located?
dead space in a circle system is limited to the area distal to the point of inspiratory and expiratory gas mixing at the Y-piece.
Unlike Mapleson circuits, the circle system tube length does not affect dead space. Like Mapleson circuits, length does affect circuit compliance and thus the amount of tidal volume lost to the circuit during positive-pressure ventilation.
200
*What does red indicate on color doppler on ultrasound? (i.e. flow direction, frequency)
Source moving TOWARD probe = HIGHER frequency
200
What is the second gas effect?
- If 50% of an anesthetic is taken up by pulmonary circulation, an inspired concentration of 20% (20 parts anesthetic per 100 parts gas) will result in an alveolar concentration of 11% (10/90=11; 10 parts of anesthetic remaining in a total volume of 90 parts of gas).
- If the inspired concentration is raised to 80% (80 parts of anesthetic per 100 parts of gas), the alveolar concentration will be 67% (40 parts of anesthetic remaining in a total volume of 60 parts of gas).
- More significant with nitrous; A high concentration of nitrous oxide will augment (by the same mechanism) not only its own uptake, but theoretically that of a concurrently administered volatile anesthetic.
200
National Institute for Occupational Safety and Health (NIOSH) recommends limiting the room concentration of nitrous oxide to ___
25ppm
200
*Decreased temperature does this to saturated vapor pressure (of volatile anesthetic).
SVP decreases as the temperature of an anesthetic decreases. Vaporization draws heat from the liquid anesthetic and is a cooling process. Since vaporization is temperature dependent, we need the vaporizer to compensate by adding heat or else vaporizer output would decline.
300
*List a disadvantage of assist-control ventilation.
Barotrauma, respiratory alkalosis*, (hyperventilation), breath stacking/auto-PEEP (dec venous return -> hypotension)
300
*The point of maximum amplitude corresponds to this during an oscillometric blood pressure cuff measurement.
What is... MAP?
These devices directly measure MAP
300
A sevoflurane vaporizer is filled with isoflurane and the vaporizer dial is set at 1%. What will happen?
Overdose
More than 1% isoflurane will be delivered
300
Recommendations for maximal allowable trace anesthesia gases are based on
a. achievable levels with modern scavenging systems
b. data from animal studies
c. evidence for an association with spontaneous abortion in operating room personnel
d. evidence for an association with malignancy in anesthesiologists
a. It's what our machine scavenging can achieve
300
Your patient has recently had a vitrectomy for retinal detachment repair. Which of the following statements regarding nitrous and recent intraocular surgery is TRUE?
a. It is safe to use nitrous 10 minutes prior to intraocular gas
b. It is safe to use nitrous 7 days after the patient received a filtered room air bubble
c. It is safe to use nitrous 7 days after the patient received a sulfur hexafluoride bubble
d. It is safe to use nitrous 7 days after the patient received a perfluoropropane bubble
b. It is safe to use nitrous 7 days after the patient received a filtered room air bubble
-D/c nitrous >15min before
-Air bubble lasts 7 days
-SF6 lasts 10d-1month
-C3F8 lasts 6-8weeks
400
*What property of helium makes it beneficial to a patient with postop stridor?
Its low density
-Heliox reduces work of breathing and decreases airway resistance by facilitating laminar flow (because turbulent flow is dependent on gas density.)
-Can treat upper airway obstruction, post-extubation stridor, COPD, asthma.
400
*Error will increase when using doppler to evaluate an artery under ultrasound when this is changed.
-Angle of transducer
-Probe frequency
-Color
What is...Angle. (If your angle is above 60 degrees, the probe cannot compensate as well and error increases)
400
*Rank these anesthetics in order of CO production in presence of dry CO2 absorbent, from MOST to Least:
Desflurane, Isoflurane, Sevoflurane
*desflurane > isoflurane > sevoflurane
400
*What is Boyle's law?
PV=P'V' or, Volume of gas is inversely proportional to pressure at constant temp
400
*The desflurane percentage delivered from a vaporizer at high altitude will be ___ to the desflurane delivered from a vaporizer at sea level.
A. Decreased
B. Same/unchanged
C. Increased
What is B, the same/unchanged?
500
Define critical temperature.*
Above this temperature, no more vapor can be produced despite how much pressure is applied (because it is all already vapor).
-The pressure at this temp is called the critical pressure.
-This is why we weigh nitrous cylinders, because it's critical temp is above room temp (so some is existing as a liquid)
500
During general anesthesia administered through a circle system, the soda lime absorbent is exhausted. No fresh soda lime is available for use. Which of the following is the most appropriate next step to prevent hypercapnia in this patient?
a. Decreasing the dead space of the circle system
b. Discontinuing nitrous oxide
c. Increasing the fresh gas flow
d. Increasing tidal volume
e. Switching to spontaneous ventilation
c. Increasing the fresh gas flow
500
Which of the following is the most appropriate action after an anesthetic vaporizer (Tec4) is tipped?
a. Return to the manufacturer for recalibration
b. Flush the vaporizer with oxygen at 5 L/min for 24 hours
c. Store the vaporizer for 24 hours at room temperature
d. Set the vaporizer at high concentration and flush with oxygen at 10 L/min for 30 minutes
d. Set the vaporizer at high concentration and flush with oxygen at 10 L/min for 30 minutes
Tipping may flood the bypass area and lead to dangerously high anesthetic concentrations because liquid anesthetic is much more potent (1ml liquid sevo produces 184ml vapor!)
500
How will an under-dampened arterial line affect blood pressure values?
UnderDamp overshoot SBP, underestimate DBP, MAP accurate
500
Oxygen 100 ml/min is bubbled through a vaporizer containing an anesthetic with a vapor pressure of 150 mmHg, and this mixture is added to a fresh gas flow of 5 L/min. The delivered anesthetic concentration is
a. 0.25%
b. 0.5%
c. 1%
d. 2.5%
e. 5%
b. 0.5%
SVP/atmP= x/(x + carrier ml)
SVP/atmP=150/760=
=x/(x+100ml), solve for x (which is anes in mL)
=~25ml of gas
25mL/5000mlx100= gas percent of total flow =0.5%