IV and inhalational anaesthetics Flashcards Preview

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Flashcards in IV and inhalational anaesthetics Deck (31)
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1

What drug is used for induction and maintenance using IV drugs alone?

Propofol

2

Which drug has:

- anti-emetic properties?

- what is it used for?

Propofol 

- anti-emetic properties 

- used for maintaining sedation on ITU, total IV anaesthesia, day case surgery

 

 

3

Which agent has a rapid sequence of induction?

- what are the disadvantages?  

Sodium thiopentone 

- marked myocardial depression 

- metabolites accumulate quickly 

- little analgesic effect 

- unsuitable for a maintenance 

 

4

Ketamine 

- what is it used for? 

- what are its advantages? 

- what is its disadvantage?

Ketamine

 

Use: may be used as induction 

Advantages:

- has moderate - strong analgesic properties

- produces little myocardial depression (useful in haemodynamically unstable patients) 

 

Disadvantage: 

- may produce dissociative anaesthesia -> nightmares, hallucinations, agitation (as a drug wears off) 

 

5

Etomidate

- advantage (1)

- disadvantages (3)

Etomidate

Advantage: has a good cardiac profile (very little haemodynamic instability)

Disadvantages: 

- no analgesic properties

- may result in adrenal suppression (even short use) -> therefore not used for maintenance

-  post-op vomiting is common

 

 

6

Components of checklist before introduction of anaesthesia (7)

Before the induction of anaesthesia, the following must have been checked:
 

  • Patient has confirmed: Site, identity, procedure, consent
  • Site is marked
  • Anaesthesia safety check completed
  • Pulse oximeter is on patient and functioning
  • Does the patient have a known allergy?
  • Is there a difficult airway/aspiration risk?
  • Is there a risk of > 500ml blood loss (7ml/kg in children)?

7

Mechanism of action of propofol 

Not yet fully understood, thought to act on GABAA receptors and sodium channels on the reticular formation

8

What allergies predispose the patient to anaphylactic reaction with propofol use?

Egg and soy -> as propofol is mixed with the substances containing these components (poor solubility in the water) 

9

Propofol infusion syndrome

- cause

- clinical features

- management

Propofol infusion syndrome

Etiology: high doses and prolonged administration of propofol

Clinical features: severe metabolic acidosisrhabdomyolysis, renal failure, and/or cardiac failure (often fatal)

Management: discontinue propofol immediately, symptomatic treatment (catecholamines, fluid resuscitation) 

10

Mechanism of action of Etomidate 

Etomidate 

MoA: GABA receptors in reticular formation

11

What's Etomidate good for? Why?

Etomidate 

It has the least effect on CVS (it does not cause depression of the myocardium) 

* therefore used in anaesthesia of the patients with myocardial instability 

 

 

12

Mechanism of action of Ketamine 

Ketamine 

MoA: NMDA receptor antagonist (type of glutamate receptor)

13

What's the advantage of Ketamine over other anaesthetics in an emergency setting?

- it can be administrated IM (apart from IV) -> so if IV access is difficult we still can give it

 - good for polytrauma and hypotensive patients -> it does not induce CV depression

 

14

What type of procedure Ketamine is good for? 

What is other use of Ketamine (aside from surgeries)?

 

Ketamine 

- short and painful procedures e.g. fracture reduction 

*Ketamine used in treatment of resistant asthma

15

Mechanism of action of barbiturates 

 

Barbiturates 

 

MoA: enhance GABA action -> via increased duration of Cl channels opening -> hyperpolarisation of post-sympathetic neurones -> reduced neural excitability 

16

What's disadvantage of barbiturate use?

They are highly lipid soluble -> have high potency with narrow therapeutic index

Rapid onset of action and recovery

17

Examples of barbiturates (name few) 

18

Side effects of barbiturates

  • Hypotension (dose-dependent)
  • Respiratory depression and/or apnea (dose-dependent)
  • Laryngospasm, bronchospasm (histamine release)
  • Myoclonus
  • Painful injection
  • Dependence
  • Cytochrome P450 induction
  • Contraindicated in porphyria

19

Indications for barbiturate use

20

Barbiturate overdose

 

- clinical features

- management

Barbiturate overdose

Clinical features: impaired consciousness, coma, respiratory failure, cardiovascular depression

Management

- Secure airways, oxygenation, monitoring

fluid resuscitation

ECG: monitor for arrhythmia

21

What are inhalational anaesthetics used for?

  • induction and maintenance of general analgesia
  • sedation

 

22

  • What are the three most commonly used inhalational anaesthetics?

 

  • Which one of these is MOST COMMONLY used?

 

Sevoflurane is the most commonly used -> due to its rapid onset of action and also patient recover quickly from it

23

Which one of the inhaled GA is the most commonly used?

Sevoflurane is the most commonly used -> due to its rapid onset of action and also patient recover quickly from it

24

What are the physiological effects of the use of inhalational anaesthetics?

- respiratory depression

- decrease in arterial blood pressure

- decrease in cerebral metabolic demand

- increase in cerebral blood flow

 

25

What is the disadvantage of the use of inhalational anaesthetics?

They do not provide post-op pain relief

26

How do inhalational anaesthetics are taken up into the blood?

Passively, via diffusion

27

How are inhalational anaesthetics eliminated?

They are eliminated via the lungs 

28

Can Nitrous Oxide be administrated on its own?

  • Nitrous oxide is not effective on its own
  • it would be often administrated with another inhalational anaesthetic 

Nitrous oxide increases the speed of onset of action of the other anaesthetic 

 

29

Sevoflurane 

- advantages

Sevoflurane is the most commonly used inhalational anaesthetic 

 

- rapid onset of action -> narcosis can be achieved within one minute 

- rapid onset of recovery 

- good for induction 

 

*also can be given via mask -> very good for paediatric surgery 

30

General side effects of inhalational anaesthetics

General side effects

  • Nausea/vomiting → inhalational anesthetics are contraindicated in patients who are not sober 
  • Risk of malignant hyperthermia
  • Postoperative shivering