Inhaled Anesthetics Part 2 (Exam III) Flashcards
need to separate concept with inhaled gas info
What are the purposes of the anesthesia circuit?
- Delivery of O₂ and inhaled anesthetics
- Maintenance of temperature & humidity
- Removal of CO₂ and exhaled drugs
S2
What types of gas delivery systems are there?
- Rebreathing (Bain system)
- Non-rebreathing (BVM system)
- Circle systems (Anesthesia machine)
S2
What type of system is depicted below?
Where is the aPL valve located on this system?
- Bain Circuit
- Blue circle depicts aPL below.
S3
In the figure below, what portion of the anesthesia circle system is indicated by 1?
Inspiratory Unidirectional Valve
S5
In the figure below, what portion of the anesthesia circle system is indicated by pink arrow?
Fresh Gas Inlet (O₂ & medical air)
S5
In the figure below, what portion of the anesthesia circle system is indicated by 2?
CO₂ Absorber
S5
In the figure below, what portion of the anesthesia circle system is indicated by 3?
Bag/Ventilator Selector Switch
S5
In the figure below, what portion of the anesthesia circle system is indicated by 4?
APL Valve
S5
In the figure below, what portion of the anesthesia circle system is indicated by 5?
Expiratory Unidirectional Valve
S5
In the figure below, what portion of the anesthesia circle system is indicated by 6?
Expiratory Limb
S5
In the figure below, what portion of the anesthesia circle system is indicated by 7?
Y-Piece
S5
When fresh gas flow (FGF) exceeds V̇T then you have _________________.
High Flow Anesthesia
S6
When V̇T exceeds fresh gas flow (FGF) then you have _________________.
Low Flow Anesthesia
S6
When would one see lack of rebreathing, wasteful volatile use, and cool dried air?
High flow anesthesia
S6
When would one see lower volatile use, less cooling/drying of air, and slow changes in anesthetics?
Low flow anesthesia
S7
Do volatiles cause bronchostriction or bronchodilation?
Bronchodilaton
S10
How do volatiles cause bronchodilation?
- Blockage of VG Ca⁺⁺ channels
- Depletion of SR Ca⁺⁺
S10
Is the bronchodilatory effect of volatiles still present in someone with reactive airway disease?
- No (or very little effect). Bronchodilatory effects of volatiles require an intact epithelium, normal inflammatory processes, etc.
S10
Will volatiles cause bronchospasm on their own (in a patient with no history of bronchospasm)?
No
Histamine release or vagal afferent stimulation needed to cause spasm.
S10
In a patient without history of bronchospasm, how much would you anticipate PVR to change with 1-2 MAC?
PVR would be unchanged in patient with no history of bronchospasm.
S10??
What risk factors increase risk of bronchospasm?
- COPD
- Coughing w/ ETT in place
- <10 years old
- URI
S10
What anesthetic is generally the best at bronchodilating?
- Halothane (1st)
- Sevoflurane (2nd)
S11
Which anesthetic can function as a pulmonary irritant (especially in smokers)?
Desflurane
S11
Which volatile anesthetic in the graph below caused the greatest increase in airway resistance?
Lowest?
- Desflurane = ↑ airway resistance
- Sevoflurane = ↓ airway resistance
S11
Inhaled anesthetics engender a dose-dependent skeletal muscle relaxation. T/F?
True
S12
Which volatile gas has no effect on the relaxation of skeletal muscles?
N₂O
S12
Will volatiles potentiate or inhibit NMBD’s? How?
Potentiate via sensitization of nACh receptors at NMJ.
S12
How do volatile anesthetics cause skeletal muscle relaxation as a solo agent?
Volatiles cause skeletal muscle relaxation via enhancement of glycine at the spinal cord.
S12
What is ischemic preconditioning?
With people who are susceptible of having M.I., there’s a thought that if you expose them to a little of anesthetic gas, it preconditions them and decreases their likelihood from getting M.I.
S13
Ischemic preconditioning with volatile anesthetics can occur as low as ______ MAC.
0.25
S13
Why does ischemic preconditioning happen?
- ↑ PKC activity
- Phosphorylation of ATP sensitive K⁺ channels
- Production of ROS (Reactive Oxygen Species)
- Better regulation of vascular tone.
S13
What molecule mediates ischemic preconditioning?
Adenosine
S13
What does ischemic preconditioning prevent?
- Reperfusion injuries
- Cardiac dysrhythmias
- Contractile dysfunction
- Delays MI’s in CAD patients.
S13
At what dose does volatile depression of CMRO₂ begin?
0.4 MAC
S15
At what MAC would we see EEG burst suppression?
What about total electrical silence?
- 1.5 MAC = burst suppression
- 2 MAC = EEG silence
S15
Which volatile causes the most EEG suppression?
Trick question. They all affect EEG’s the same.
S15
Which volatiles have anticonvulsant activity?
Des, Sevo, & Iso at high concentrations & with hypocarbia.
S16
Which volatile is a proconvulsant?
Enflurane
S16
Give an example of a somato-sensory evoked potential (SSEP).
Stimulation of the foot evoking an electrical response in the CNS.
S16
Give an example of a motor-evoke potential (MEP).
Direct stimulation of the brain eliciting a twitch response in the hand.
S16
You have a case where SSEPs and MEPs need to be monitored, what general anesthetics options do you have?
- TIVA
- N₂O 60% and 0.5 MAC volatile.
S16
What specific effects will volatile agents have on SSEPs and MEPs?
Dose-dependent (0.5 - 1.5MAC):
- ↓ amplitude
- ↑ latency (delayed frequency)
S16
What occurs with cerebral blood flow with volatile administration?
Dose dependent:
- ↑ CBF due to dilated vessels
- ↑ ICP
S17
At what MAC would you expect to start to see an increase in CBF due to volatile administration?
At > 0.6 MAC
S16
Which volatile has less vasodilatory effects?
Sevoflurane
good for neuro patients
S16
Which volatile has the greatest effect on increasing CBF? (and thus ICP)
Halothane
S17
How much Nitrous to give due to potent vasodilating effect?
< 1 MAC
S17