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Flashcards in Perioperative anaelgesia Deck (32)
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1
Q

What’s anaesthesia triad?

A
  • muscle relaxation
  • anaesthesia
  • hypnosis
2
Q

Analgesic ladder

A
3
Q

What drugs are used to provide intra-operative analgesia?

A

Stages 2 and 3 are most commonly used to provide intraoperative analgesia

  • Stage 2 e.g. diclofenac or ibuprofen
  • Stage 3 e.g. morphine or fentanyl
4
Q

Is simple analgesia of any use in the provision of analgesia during surgery?

A

Simple analgesics, such as paracetamol, and NSAIDs, such as diclofenac and ibuprofen, may provide sufficient analgesia for short, day-case analgesia, sometimes in combination with local anaesthesia

5
Q

What’s the most commonly used intraoperative analgesia for more painful surgery?

A

Opioid → Fentanyl

It is useful to combine simple analgesics and NSAIDs with fentanyl to reduce the total dose of opioid required, and provide a degree of postoperative analgesia, as well as to limit unwanted effects of opioids

6
Q

What happens to the opioid dose requirement if local or regional anaesthesia is used?

A

The opioid requirements will be markedly reduced

7
Q

What’s the difference between ‘opiate’ and ‘opioid’?

A

Opiate → naturally-occurring opioid e.g. morphine

Opioid → synthetic drugs e.g. fentanyl

8
Q

How are syringes containing opioid drug identified?

A

By blue labels

9
Q

What’s more potent: morphine or fentanyl?

A

Fentanyl is about 100 times more potent than morphine

10
Q

When an initial dose of Fentanyl is given (in terms of surgery)?

A

At induction because:

  • it takes 5 mins to be effective
  • it reduces the response to laryngoscopy

(if endotracheal intubation is planned)

11
Q

How long does Fentanyl analgesic effect last?

A

15-30 minutes in usual doses (50-100 µg intraoperatively)

* it may be repeated (depending on the duration of surgery, analgesic plan, painful surgical stimulation)

12
Q

Where is fentanyl metabolised?

A

in the liver

13
Q

Side effects of fentanyl

- intraoperative

  • post-operative
A

Intraoperative:

  • bradycardia
  • fall in BP
  • respiratory depression (due to a reduction in respiratory rate)

Postoperative:

  • nausea and vomiting
  • urinary retention
  • constipation and itching
14
Q

When and how to use morphine + fentanyl in combination?

A
  • Morphine has a slower onset time than fentanyl
  • It is more common to use fentanyl initially
  • then use morphine intraoperatively if further analgesia is required, particularly if severe pain is anticipated in the early postoperative phase in recovery
15
Q

How long does analgesic effect of morphine last?

A

For the usual intraoperative dose of morphine (2-5 mg bolus) it last 30-40 min

*repeated-dose usually needed

16
Q

Can we give morphine 10 minutes before surgery ending?

A

The longer onset time to peak effects means that the timing of intraoperative morphine requires to care

if given within 10 min of surgery ending → respiratory depression may slow recovery

*In a surgery that is anticipated to be very painful postoperatively, an intravenous bolus dose of morphine of 0.1-0.15 mg/kg can be given about 45 min before the end of surgery.

17
Q

Where does the metabolism of morphine occur?

A

In the liver

18
Q

What’s morphine-6-glucuronide?

A
  • an active metabolite of morphine
  • it is more potent than morphine
  • it is only important in patients with renal failure who receive repeated doses of morphine
19
Q

Side effects of morphine

A
  • bradycardia
  • fall in BP
  • Respiratory depression
  • Nausea and vomiting postoperatively
  • Urinary retention
  • Constipation
  • Itching

*Morphine can also cause histamine release; in asthmatics bronchospasm may be triggered

20
Q

How can Diclofenac be given intraoperatively?

A

IV or suppository

(consent must be gained for suppository)

21
Q

Can we combine NSAIDs + Paracetamol + Fentanyl?

A

It is useful to combine NSAIDs with paracetamol and fentanyl in theatre, since the NSAIDs have a further opioid-sparing effect that not only allows less fentanyl to be used, but also reduces the postoperative opioid requirements by 20-30%

22
Q

How can Paracetamol be given intraoperatively?

A

IV or suppository

Usually 1g for an adult person

23
Q

How does IV Paracetamol should be given?

A

the vial contains 1 g of paracetamol as a solution in 100 ml; this should be given intravenously over about 20 min

24
Q

When should suppository Diclofenac or Paracetamol be given?

A

It should be placed per rectum after induction of anaesthesia and before surgery starts to allow time for absorption

25
Q

Do we prefer to give intraoperative simple analgesia by IV or suppository routes?

A

The rectal route is less reliable than the intravenous route for drug administration, but is sometimes preferred for very short duration surgery

26
Q

Do we need to repeat paracetamol dose intraoperatively?

A

The duration of action of paracetamol is much longer than for the intravenous opioids; a repeat dose is rarely used unless surgery takes more than 6 h.

27
Q

Contraindications to Ibuprofen use

A
  • Previous or existing upper GI ulcers
  • Avoid in asthmatics who are intolerant of aspirin
  • Use with care in patients with renal impairment
28
Q

Side effects of Ibuprofen

A

The most common side-effects are upper GI tract bleeding and inhibition of platelet aggregation.

29
Q

Contraindications to Diclofenac use

A
  • Previous or existing upper GI ulcers
  • Avoid in asthmatics who are intolerant of aspirin
  • Use with care in patients with renal impairment
  • Porphyria
30
Q

Side effects of Diclofenac

A

Like ibuprofen, the most common side-effects of diclofenac are upper GI tract bleeding and inhibition of platelet aggregation

31
Q

How often morphine could be administrated to a patient on patient-controlled analgesia (PCA) device?

A
  • 1-2 mg (whichever is preset by the anaesthetist) to be given on demand with a 5 min lockout period

*The lockout period may be set by the anaesthetist and is to prevent overdose, which carries the risk of respiratory depression

* Close and charted observation is required if PCA is prescribed

32
Q

Can strong opioids be used in day cases?

A

NO

If NSAIDs are not tolerated and it is anticipated that a stronger analgesic than paracetamol is needed, then codeine phosphate may be prescribed for a limited period: usually enough for 72 h. The dose of codeine phosphate is 30-60 mg every 4 h