IV induction agents

Question 1

Induction agents:

Answer 1

Propofol
Benzodiazepines
Barbituates
Etomidate
Ketamine

Question 2

Opioids:

Answer 2

Morphine
Fentanyl
Codeine
Tramadol
Remifentanyl

Question 3

Which drugs cause apnoea?

Answer 3

Propofol
Barbituates
(Etomidate has brief hyperventilation then brief apnoea)

Question 4

Uses of propofol?

Answer 4

Induction, sedation and maintenance
Anti-emetic
Prevents seizures
Increases duration of midazolam (CY3A4)

Question 5

Cardiac effects of propofol?

Answer 5

Reduced CO, SVR, BP and myocardial blood flow

Question 6

What is propofol infusion syndrome?

Answer 6

Asystole
Metabolic acidosis
Rhabdomyolysis
Fatty liver disease
Hyperkalaemia

Question 7

Use of barbiturates?

Answer 7

Cerebral protection
Seizure suppression
Anxiolysis

Question 8

Respiratory effects of propofol?

Answer 8

Reduced tidal volume
Increased respiratory rate
Apnoea

Question 9

Use of benzodiazepines?

Answer 9

Anticonvulsant (increases seizure threshold)
Induction and sedation
Midazolam = short for paeds
Tamazepam and lorazepam = intermediate
Diazepam = long

Question 10

Cardiac effects of benzodiazepines?

Answer 10

Stable agent on the heart

Question 11

Respiratory effects of benzodiazepines?

Answer 11

Decreased hypoxic and hypercapnic response

Question 12

Use of ketamine?

Answer 12

Opiod sparing analgesia

Induction and sedation

Question 13

Cardiac effects of ketamine?

Answer 13

Increased BP, CO, HR, symp and O2 consumption

Question 14

Respiratory effects of ketamine?

Answer 14

RR interval maintained - good for paeds

No apnoea but potentially cause pulmonary hypertension

Question 15

Contraindication for ketamine?

Answer 15

Do not use with a head trauma patient as the drug increases cerebral blood flow, cerebral oxygen consumption and intracranial pressure
(also cause increased muscle tone vivid dreams and hallucinations)

Question 16

Cerebral effects of barbiturates?

Answer 16

Reduce cerebral O2 consumption, ICP and cerebral blood flow

Question 17

Use of etomidate?

Answer 17

Similar to propofol

Good for kidney patients as liver metabolises to inactive metabolites

Question 18

Cardiac effects of etomidate?

Answer 18

Increased BP and PR interval

Question 19

Respiratory effects of etomidate?

Answer 19

Brief hyperventilation then brief apnoea

Decreased hypercapnic response

Question 20

Use of dexmedetemide?

Answer 20

alpha-2 agonist
Opiod-sparing analgesic used for withdrawal
Used for neuromonitoring in brain/spine
Neuro-blockade, decreased CBF

Question 21

Cardiac effects of dexmedetemide?

Answer 21

Bradycardia
Initial rise in BP
Decreased CO

Question 22

Use of morphine?

Answer 22

Peri-operative analgesic
Vagal stimulation so causes constipation and biliary SM constriction
Pruritis and N+V

Question 23

Cardiac effects of morphine?

Answer 23

Bradycardia

Question 24

Respiratory effects of morphine?

Answer 24

Respiratory depression

Question 25

Use of fentanyl?

Answer 25

80-100x potency of morphine
Peaks 5 minutes after IV
Less histamine

Question 26

Codeine features:

Answer 26

Pro-drug

Risk to neonate if mother is a rapid metaboliser and is breast feeding

Question 27

Use of tramadol?

Answer 27

50% potency of morphine also 5HT/NA-ergic
Safer cardiac/respiratory profile than morphine
Risk of serotonin syndrome

Question 28

Use of remifentanyl?

Answer 28

Potent mu agonist with t1/2 of 3.7 minutes
Ultra-rapid onset and offset with end of infusion
Used for sedation in ICU, PCA in obstetrics and pain relief in surgery
Total IV anaesthesia (TIVA)

Question 29

Which drugs are TIVA?

Answer 29

Propofol and remifentanyl

Question 30

Benefits of TIVA?

Answer 30

Improved CV profile, reduced N+V and improved tube tolerance