Anaesthetics

Question 1

side effects of propofol?

Answer 1

resp depression
cardiac depression
pain on injection

Question 2

side effects of volatile agents e.g. isoflurane?

Answer 2

nausea and vomiting
cardiac and resp depression
vasodilatation
hepatotoxicity

Question 3

why does anaesthesia cause a drop in BP?

Answer 3

results in vasodilatation, reducing TPR

Question 4

why are the eyes taped closed when under GA?

Answer 4

as loss of muscle power, so reduce risk of corneal abrasion

Question 5

CI to spinal blocks?

Answer 5

anticoagulation

local infection

Question 6

what to do at the end of anaesthesia?

Answer 6

change inspired gases to 100% O2 only
discontinue any anaesthetic infusions and reverse muscle paralysis
place ptnt in recovery position once spontaneously breathing, and give O2 by face mask.

Question 7

signs of LA toxicity?

Answer 7

perioral tingling and paraesthesia

progressing to drowsiness, seziures, coma and CR arrest.

Question 8

causes of post-op confusion?

Answer 8

hypoxia e.g. from atelectasis, pneumonia
drugs- opioids, sedatives
urinary retention
infection
MI/stroke
alcohol withdrawal
liver/renal failure

Question 9

why might ptnts BP be increased post-op?

Answer 9

pain
idiopathic hypertension e.g. missed medication
urinary retention
inotropic drugs

Question 10

what can precipitate decrease in Na+ post-op?

Answer 10

peri-op nausea, opioids, pain and chest infection

Question 11

agents used to reverse muscle relaxation?

Answer 11

anticholinesterase e.g. neostigmine

BUT cannot reverse blockage induced by suxamethonium, and would actually potentiate its action!

Question 12

how can therapeutic effect of local anaesthetic be prolonged?

Answer 12

injection of adrenaline- vasoconstriction and so reduce blood flow at site of LA injection to reduce rate of absorption of LA, reduce toxicity and extend duration of action.

Question 13

why are ptnts NBM pre-op ( at least 6 hrs for food, and 2 hrs for fluids)?

Answer 13

to reduce risk of regurgitation and aspiration of gastric acid at anesthesia induction
** if risk ptnt has eaten before op, must do rapid induction?**

Question 14

why must ptnt be sat upright in recovery room?

Answer 14

allow diaphragm to flatten to ease breathing and so maintain appropriate SpO2
reduce risk of regurgitation and aspiration

Question 15

which ptnts may be given antacids as premed to reduce risk of regurgitation and aspiration of gastric acid at induction of anaesthesia?

Answer 15

pregnant women- *progesterone, SM relaxation, increase reflux?
ptnts requiring emergency surgery
ptnts with hiatus hernia
morbidly obese ptnts

Question 16

rationale behind giving analgesia as a pre-med?

Answer 16

stop sensitisation of pain-conduction pathways that occurs with tissue damage during surgery, so postop pain will be reduced, AND prevent chronic pain.

Question 17

in which ptnts might antibiotics be given as a pre-med?

Answer 17

prosthetic or diseased heart valves
undergoing joint replacement
or bowel surgery

Question 18

thiopental can be used for rapid induction. what dose is given, speed of induction and duration of action?

Answer 18

2-6mg/kg, propofol= 1.5-2.5 mg
20.30s
lasts 9-10 mins

Question 19

considerations with use of thiopental for IV induction

Answer 19

ptnts may taste garlic or onions!

cumulative, delayed recovery after repeat doses

Question 20

why are barbiturates NOT used for TIVA?

Answer 20

prolonged recovery as accumulate in body e.g. thiopental

Question 21

why should LAs containing vasoconstrictors NOT be used around extremities e.g. fingers and penis?

Answer 21

risk of vasoconstriction causing tissue necrosis

Question 22

difference in speed of onset and duration of action between lidocaine and bupivacaine?

Answer 22

bupivacaine has slower onset but longer duration of action, widely used in nerve blocks, epidural and spinal anaesthesia, part. in obstetrics.

Question 23

define atelectasis *

Answer 23

state of lung collapse, can be partial or whole
alveolar collapse, usually due to bronchial secretions
prevent by physio pre and post op
+ve pressure ventilation may be required if severe