SS25 MAC & Volatile Properties (Exam 3) Flashcards
1
Q
0.1 MAC
A
↓ hypoxic response by 50% - 70%
2
Q
0.25 MAC
A
Ischemic Pre-conditioning Protection (brain/heart/renal)
3
Q
0.4 MAC
A
↓ CMRO₂ & cerebral activity begins
4
Q
> 0.5 MAC
A
- Nitrous PRO-emetic
- Halothane LOST Autoregulation
5
Q
> 0.6 MAC
A
↑ Cerebral BF
6
Q
- > 0.8 MAC
- Volatile of choice?
A
- ↑ ICP by 7 mmHg
- Sevo = Volatile of choice
7
Q
< 1 MAC
A
To avoid Nitrous gas diffusion into air-filled space
8
Q
1 MAC
A
- N₂O 60% + 0.5 MAC volatile = adequate SSEP/MEPs monitoring (synergistic)
- 50% of patients won’t move with supra-maximal stimuli
9
Q
> 1 MAC
A
- SEVO: PRESERVES Autoregulation up to 1 MAC
- SEVO LOST Autoregulation AFTER 1 MAC (so 1.1 MAC & up)
10
Q
1 - 2 MAC
A
NO CHANGE in baseline pulm resistance in absence of bronchospasm
11
Q
1.1 MAC
A
- ↓ hypoxic response by 100%
12
Q
1.5 MAC
A
- Burst suppression
13
Q
> 1.5 MAC
A
- Sevo causes tachycardia only at MAC greater than 1.5
14
Q
2 MAC
A
- Electrical silence
- ↓HPV response 50%
15
Q
> 2 MAC
A
Enflurane: proconvulsant
16
Q
0.3 - 0.5
A
Awake Anesthesia
17
Q
0.5 - 1
A
DECREASED uterine smooth muscle contraction
18
Q
0.5 - 1.5
A
- Iso + Des LOST Autoregulation
- SSEPs & MEPs unreliable: ↓ amplitude/ ↑ latency
19
Q
1 - 1.5
A
- ↑ Hepatic Portal Vein
Be careful; there are 2 “HPV”
20
Q
1.5 - 2.0 MAC
A
- APNEA
21
Q
1.7 - 2.0
A
- MACBAR: Blunt Autonomic reflexes
22
Q
Which volatile causes the most dose-dependent CV depression?
A
- Halothane “Halo = Heart”
- ↓MAP, contactility, SVR, CO
23
Q
T/F: Nitrous causes CV depression.
A
- FALSE
- All volatiles cause CV depression EXCEPT nitrous oxide.
24
Q
Which volatile causes mild ↑ in Cardiac Output?
A
- Nitrous
- Sympathomimetic
25
Which volatile(s) increase refractoriness of accessory pathways?
- Isoflurane (Forane)
26
Volatile of choice: bronchospasm risk
- Sevo
27
List volatiles in order of increasing respiratory airway resistance (bronchospasm).
(highest risk to lowest)
1. Des (esp. smokers)
2. Thiopental
3. Iso
4. Halothane
5. Sevo
28
T/F: Nitrous does not cause skeletal muscle relaxation
TRUE
29
Which volatiles have anticonvulsant properties at high concentrations w/ hypercarbia?
The Big 3
- Des
- Iso
- Sevo
30
Which volatile has the least vasodilatory effects?
SEVO
31
Which volatile has the worst vasodilatory effects?
Halothane
- ↑CBF, ICP
- Avoid in neuro patients
32
- Which volatile(s) blunt autonomic response?
- Which volatile(s) blunt hypercarbic response?
- all **INLCUDING** Nitrous
- all **EXCEPT** Nitrous (less depression Des + N₂O > Des + O₂)
33
Which volatile causes severe tachycardia?
- How?
- Des even at low MAC
- Over-pressurization
34
Volatile of choice for ablation?
SEVO
35
Which volatile decrease hepatic BF?
- Halothane "H = Hepatic"
- ↓ O₂ delivery
36
Which Volatiles (3) metabolize to Acetyl Halide from greatest to least?
- Significance?
- Enflurane > Iso > Des
- Can cause Antibody reaction
37
Which Volatile(s) metabolize to Vinyl Halide from greatest to least?
- Significance?
- Trick! **SEVO** only
- Unable to form antibodies
38
Volatile that causes Fluoride toxicity
Methoxyflurane
39
What volatile forms Compound A?
- Sevo (+ CO₂ absorbents)
40
Nitrous: Metabolic effects (3)
Think **"BMP"**
- B₁₂ deficiency
- Megaloblastic bone marrow suppression
- Plasma homocysteine Increase
41
Which volatile increases analgesia for uterine contrations?
- Nitrous
42
Order of CO absorbent degradation from highest to lowest?
1. Desflurane (Suprane)
2. Enflurane
3. Isoflurane (Forane)
4. Sevoflurane (Ultane)
43
Halothane concerns:
Think **COPD**
- **C**atecholamine-induced arrythmias
- **O**ccasional **h**epatic necrosos
- **P**edi brady-arrythmias
- **D**ecomposition to HCL acid (thymol preservative added)
44
Which volatiles enhance dose-dependent skeletal relaxation? (most to least effect)
1. Des (most enhancement)
2. Sevo
3. Iso
