Desflurane

Question 1

What is type of drug the Desflurane (include chemically speaking)?

Answer 1

Volatile inhalation anesthetic

Fluorinated methyl ethyl ether

Question 2

What is the trade name for Desflurane?

Answer 2

Suprane

Question 3

Does Desflurane have lower or higher blood gas solubility? What type of surgery does this make it ideal for?

Answer 3

LOWER blood-gas solubility

Ideal for same day surgery

Question 4

What does it mean to have lower blood-gas solubility?

Answer 4

• Rapid uptake and elimination
• More precise control over the delivery of anesthesia
• More rapid recovery from anesthesia

Question 5

Is Desflurance considered a respiratory irritant? Why or Why not?

Answer 5

YES when used for mask induction in concentrations greater than 6%

Question 6

Is Desflurane good for inducing anesthesia? Why/why not?

Answer 6

Generally NOT used for inducing anesthesia in peds or adult populations b/c of respiratory irritant at >6%

Question 7

What is Desflurane primarily used for?

Answer 7

Maintenance Anesthesia

Question 8

What is the MOA? (the current theory they think it works by)

Answer 8

target proteins (most likely ion channels and/or receptors) are the site of action of the inhaled anesthetics. Separate sites of action for loss of consciousness and immobility have been proposed

Question 9

What is the Myer-Overton Hypothesis? Is this still a current theory of MOA for inhaled anesthetics?

Answer 9

Anesthetic action was attributed to the inhaled anesthetic dissolving into and distorting the lipid cell membrane.
-NO, this theory has largely been disproven

Question 10

What is the primary metabolism for Desflurane and what is it metabolized to?

Answer 10

• Oxidatively metabolized by the liver CYP450

- Acetylated liver protein adducts

Question 11

Tell me about the biodegradation of Desflurane.

Answer 11

• Strongly resists biodegradation; only a small amount is metabolized (0.02%)
• Highly stable and resists degradation by soda lime and the liver

Question 12

Is Desflurane a high risk for promoting Halothane Hepatitis?

Answer 12

No; low risk because it has the lowest level of adduct formation (<1% metabolized)

Question 13

How is Desflurane redistributed?

What is the Blood/Gas Co-efficient?

Answer 13

• Low blood/gas solubility sooooo……
• Blood/Gas partition co-efficient at 37 degree celsius and therefore has RAPID equilibration between inspired and alveolar concentrations

Question 14

How is Desflurane eliminated?

Answer 14

Almost entirely unchanged via exhalation from the lungs (Rapid decrease of alveolar concentrations during elimination also related to Blood/Gas solubility

Question 15

What is the Volume of Distribution of Desflurane?

Answer 15

Rapid uptake and elimination; uptake in the first minute of anesthesia is 146mL

Question 16

In general, what are the Cardiovascular Side Effects of Desflurane?

Answer 16

• Depresses myocardial contractility
• Associated with transient sympathomimetic activity (Tachycardia, HTN, myocardial ischemia) when used in high concentrations or when rapidly increasing the inspired concentration without opioid adjuvants to prevent this response
• Following transient SNS type activity arterial BP and SVR usually decreases with increase in HR (intact baroreceptor response)
• Reduces MAP, CO, CI in a dose dependent fashion via a reduction in SVR

Question 17

What happens to the CV system with high concentrations of Des/ or rapidly increased inspired concentration? How can you help to avoid such responses (hint a type of drug might help!)

Answer 17

• Associated with transient sympathomimetic activity (Tachycardia, HTN, myocardial ischemia)
• Give Opioid Adjuvants to prevent the response

Question 18

What are the Neuro/neuromuscular side effects of Desflurane?

Answer 18

• Increases CBF and ICP (particularly at 1 MAC or >)
• Decreases CPP (particularly at 1 MAC or>)
• Potentiates the effects of NMBs
• High rate of emergence delirium particularly in the pediatric population

Question 19

What does Des have as an effect with NMBs?

Answer 19

Potentiates!!!!

Question 20

What is something to be aware of with pediatric patients and Desflurane?

Answer 20

High rate of emergence delirium!

Question 21

What are the Respiratory side effects of Desflurane?

Answer 21

• Dose-related ventilatory depression
• typical: decreased Vt and increased RR
• Pungent and assoc. with adverse Respiratory events during inhalation induction
• Increases PaCO2 and decreases ventilatory response to CO2
• Reduces hypoxic pulmonary vasoconstriction at doses >1 MAC increasing the risk of hypoxia during one lung ventilation

Question 22

What Adverse Respiratory events is Desflurane associated with during inhalation induction? What is the typical concentration used for induction?

Answer 22

• Breath-holding
• Laryngospasm
• Bronchospasm/ resp tract irritation
• Coughing
• Increased Secretions with accompanying hypoxia
• Typical concentration used for induction is ~10%

Question 23

What are the GI/Liver side effects of Desflurane?

Answer 23

• Transient increase in LFTs following administration
• PONV
• Decreases hepatic blood flow and oxygen reserve capacity of the liver and small intestine

Question 24

What are the Contraindications with Desflurane?

Answer 24

• should NOT be used in Malignant Hyperthermia- susceptible patients
• Inhalation induction with children has reported high rates of airway reactivity and laryngospasm
• Use caution in pts at risk for CAD and myocardial ischemia, secondary to an increased myocardial oxygen demand and tachycardia with rapid concentration increases

Question 25

What are the drug interactions associated with Desflurane?

Answer 25

- Dose-related tachycardia, more pronounced in the presence of vagolytic drugs; may be attenuated in neonates and geriatric patients or by the concomitant use of opioids - Inhibits the frequency and amplitude of myometrial contractions induced by oxytocin in a dose-dependent manner

Question 26

What is the Dose of Desflurane?

Answer 26

MAC (37C) is 6% (Blood/Gas partition coefficient at 37C is 0.42; Oil/Gas partition coefficient at 37C is 18.7) **Doses vary according to patient status, age, procedure, and types of medications co-administered

Question 27

What are the Vapor pressure and boiling point of Des?

Answer 27

VP: 669mmHg (3-4x that of other inhaled anes.) BP: 22.8C

Question 28

What is the specially designated vaporizer used for Des?

Answer 28

Tec 6: electrically heated, pressurized device specifically designed to deliver desflurane

Question 29

What is a fun fact regarding CO and Des?

Answer 29

Deflurane produces high CO concentrations, resulting from degradation by the strong base present in desiccated CO2 absorbants