Volatile agents Flashcards
Desflurane (Suprane)
Class/ Category, use, MOA (how many florunes)
Class: volatile agent
use: maintenance of general anesthesia
MOA: unknown
Desflurine
MAC (adult)
6.6%
Desflurane
Blood: gas
0.42
Desflurane
CV effects
-Dose-dependent ↓ MAP (via ↓ SVR)
-Dose-dependent ↓ contractility
-Dose-dependent ↓/↔ CO
-↑ HR 5-10% from baseline, even at low concentrations (Des > Iso)
-Rapidly increased concentration → ↑ SNS and RAAS activity → ↑ MAP and HR*
Desflurane
% metabolism
0.02
Desflurane
vapor pressure
669
Desflurane
Pulm effects
-Dose-dependent ↑ RR
-Possible apnea at 1.5-2 MAC
-↓ Vt, ↓ MV
-↑ PaCO2, ↓ ventilatory response to PaCO2
-May promote bronchoconstriction, especially in smokers
Desflurane
CNS effects
-↓ CMRO2, ↑ CBF, ↑ CBV
-↑ ICP (especially if space-occupying lesion)
-Maintains CBF autoregulation up to 1 MAC
-Dose-related EEG changes; burst suppression at > 1.2 MAC
most pungent PIA and what does it cause
Desflurane
-promotes airway irritation, salivation, breath holding, coughing, or laryngospasm when > 6% given to awake patient
Degradation in a ____ CO2 absorber produces ______
(in what order of VA)
Desiccated, CO
Des>Iso»Sevo
signs of CO poisoning (carboxyhemoglobinemia)
Desflurane
↓ SpO2, mixed gas or Enflurane reading on gas analyze
T or F provides skeletal muscle relaxation
desflurane
True
Dose-Dependent potentiation of ____ by ____-____%
Order of volatile agents
NMBs by 30-40%
Des>Iso>sevo
Desflurane is a ____trigger and may be undesirable in pts with ____
MH, CAD
Des required vaporizor
Tec 6
Desflurane boiling point
22.8 C
Tec 6 heated to____, pressurized to ____
39C, 2 atm (1500psi)
What volatile agent requires vaporizor with power
Desflurane
T/F Isoflurane is MH trigger
true
Sevoflurane
Class/ Category, use
-volatile inhaled agent
-inhalation induction; maintenance of general anesthesia
Sevoflurane
MAC (adult)
2%
Sevoflurane
Blood:gas
0.65
Sevoflurane
% metabolism
2-5
Sevoflurane
Vapor pressure
157
Sevoflurane
CV effects
-Dose-dependent ↓ MAP (↓ SVR)
-Dose-dependent ↓ CO (at 1-1.5 MAC)
-Dose-dependent ↓ contractility
-↑ HR at 1-1.5 MAC
Sevoflurane
Pulm effects
-Dose-dependent ↑ RR
-Apnea at 1.5-2 MAC
-↓ Vt, ↓ MV
-↑ PaCO2, ↓ ventilatory response to PaCO2
-Promotes bronchodilation
Sevoflurane
CNS effects
-↓ CMRO2, ↑ CBF (for up to 4 hrs after stopping), ↑ CBV
-↑ ICP
-No alteration of CBF autoregulation
-Dose-related EEG changes, burst suppression at > 1.2 MAC
-Possible proconvulsant effect at high concentrations (1.5-2 MAC)
List 4 things different about Sevo (than Des/Iso)
-non-pungent
-minimal odor
-sweet-smelling
-least/no airway irritation
Degradation in desiccated CO2 absorber produces _______ rxn leading to ____and ____
exothermic, fire, carbon monoxide
When sevo breaks down in CO2 absorber can cause what? with what side effect
Compound A, nephortoxicity
how to prevent compound A (MAC hours, FGF, and LPM)
Exposure should NOT exceed 2 MAC hours at FGF 1-2 LPM, increase FGF >2LPM after 2 MAC hours
what does Sevo metabolize into and what is a potential concern
inorganic fluoride, nephrotoxic
T/F Sevo does NOT cause skeletal muscle relaxation
false
T/F Sevo has risk factor for emergence delrium
True
T/F Sevo is not MH trigger
False
Isoflurane
Class/ Category, use
volatile inhaled agent, maintenance of general anesthesia
Isoflurane
MAC
1.2%
Isoflurane
Blood:gas
1.46
Isoflurane
% Metabolism
0.2
Isoflurane
Vapor Pressure
238
Isoflurane
CV effects
-Dose-dependent ↓ MAP (↓ SVR)
-Dose-dependent ↓ contractility
-Dose-dependent ↓/↔ CO
-↑ HR 5-10% from baseline, even at low concentrations (Des > Iso)
-Rapidly increased concentration → ↑ SNS and RAAS activity → ↑ MAP and HR
Isoflurane
Pulm effects
-Dose-dependent ↑ RR up to 1 MAC (ceiling effect)
-↓ Vt, ↓ MV
-↑ PaCO2, ↓ ventilatory response to PaCO2
-Bronchodilator
Isoflurane
CNS effects
-↓ CMRO2, ↑ CBF,↑ CBV
-↑ ICP
-Maintains CBF autoregulation up to 1 MAC
-Dose-related EEG changes, burst suppression at > 1.5 MAC, isoelectric at 2 MAC
-Anticonvulsant properties, does not evoke seizures
Describe coronary steal syndrome and what VA is associated
-diversion of blood from myocardial bed with limited or inadequate perfusion to a bed with greater perfusion
-Isoflurane
Isoflurance is less ____than ____ and can cause_____
Pungent, Des, airway irriation
Nitrous Oxide (N2O)
class/ category, use, MOA
-Inorganic inhaled agent
-adjuvant for general anesthesia/ sedation/ analgesia
-NMDA antagonist
Nitrous Oxide
MAC
104%
Nitrous Oxide
Blood:gas
0.46
Nitrous Oxide
% metabolism
0.004
Nitrous Oxide
Vapor pressure
38,770 mmhg/ 745psi
Nitrous Oxide
CV effects
-↑/↔ BP
-↑ CO
-↔ SVR
-↑ SNS activity
Nitrous Oxide
Pulm effects (5)
-↑ RR (equal or more than PIAs),
-↓ Vt (less than PIAs)
-No change or ↑ PaCO2 (less than PIAs)
-↑ PVR
-Lacks bronchodilator effect
Nitrous Oxide
CNS effects
-↑ CMRO2,↑ CBF,↑ CBV
-↑ ICP
Nitrous Oxide is a good choice for what patient population
and when?
Obstetrics (3rd trimester)
Odorless to sweet smelling inhaled agent
Nitrous Oxide
Nitrous Oxide is non-flammable but is still a fire risk because?
supports combustion
____activity of Vit B12 dependent enzymes by irreversibly oxidizing the cobolt atom, which effects ____ and ____ synthetase
Nitrous oxide decreases, methionine, thymidylate
T/F Nitrous Oxide can cause spontaneous abortion/ fetal effects/ cogential abnormalities
true
May cause bone marrow suppression and neurological disturbances
Nitrous oxide
What can Nitrous oxide do to air filled spaces and causes risk for what?
-expands airfilled spaces, ↑ pressures, high-volume absorption into gas-filled spaces 34x faster than N2 can escape
-risk for expansion of air-filled spaces, emboi
What can occur when discontinuing nitrous oxide
Diffusion hypoxia for 1-5 min following discontinuation may transiently lower alveolar O2 and CO2 concentration
Which inhaled agen can increase risk of PONV, and after how long
nitrous oxide, >6 hours
which trimesters is N2O contraindicated
first and second
List potential toxicity from expansion of gas-filled spaces from N2O
-Emphysema, pneumothorax, pneumocephalus, middle ear surgery, air embolus, bowel obstruction
T/F N2O used in tympanoplasty
false
T/F-Increased ICP and cerebral ischema can be caused by N2O
True
relative contraindications for nitrous oxide
Pulm HTN, foreign body aspiration, thoracic anesthesia
which inhaled agents do not cause MH
N2O and Xe
Which inhaled agent has modest acute analgesic effect
Nitrous oxide
Which inhaled agent does not provide skeletal muscle relaxation (potentiation of NMBs)
Nitrous oxide
what does nitrous oxide do when combined with volatile agents
reduces MAC of volatile agents
T/F nitrous oxide promotes uptake of second gas
true