CH143 Bologna Anaesthesia

Question 1

3 parts of local anaesthetics

Answer 1

Secondary or tertiary amine end
Aromatic acid
Intermediate connecting chain containing either an ester or Amide

Question 2

Aromatic portion of anaesthetic is hydrophobic and lipophilic

Answer 2

True- this is essential to allow anaesthetic to diffuse through nerve cell membranes

Question 3

Local anaesthetics are weak organic bases

Answer 3

True

Question 4

Inflammatory response surrounding infection acidifies the site

Answer 4

True, reduces proportion of anaesthetic in the non ionised, lipid soluble form

Question 5

Metabolites are excreted by kidneys for both ester and Amide anaesthetics

Answer 5

True

Question 6

Local anaesthetic lidocaine must be used judiciously in premature due to cardiovascular effects

Answer 6

True

Question 7

Ester anaesthetics are risky in patients with deficiency of functional pseudocholinesterase

Answer 7

True, greater risk toxicity

Question 8

Local anaesthetics differ in speed of onset, duration of action and potency

Answer 8

True

Question 9

In a jaundiced newborn, parabens used as preservatives, can alleviate hyperbilirubinaemia

Answer 9

False, worsen due to displacing bilirubin from albumin . Thus only paraben-free anaesthetics should be used in newborns

Question 10

The vasoconstrictive effect of anaesthetic takes about 15 min to fully develop

Answer 10

True

Question 11

One part 8.4% sodium bicarbonate to ten parts lidocaine with epinephrine brings pH to a more physiologic 7-8 range

Answer 11

True

Question 12

Preservatives, particularly methylparaben and sodium metabisulfate have frequently been shown to be the cause of “local anaesthetic” allergy

Answer 12

True

Question 13

It is thought to be PABA (the metabolite of ester anaesthetics) that is thought to be responsible for the ester anaesthetic allergic reactions

Answer 13

True

Question 14

Switching class of anaesthetic and using preservative free solution is a reasonable options for those allergic to LA

Answer 14

True

Question 15

which allergens on Skin prick test can be performed to identify the offending agent

Answer 15

• ester anaesthetic
• Amide anaesthetic
• methylparaben
• sodium metabisulfite

Question 16

Other options to achieve cutaneous anaesthesia if patient is allergic

Answer 16

1% diphenhydramine

Normal saline with benzyl alcohol preservative will achieve brief anaesthesia

Question 17

Pt on erythromycin , ketaconazole and itraconazole can exhibit signs of lidocaine overdose at lower doses (these inhibit cypP450)

Answer 17

True

Question 18

Bupivacaine has a reduced risk of cardiac toxicity than lidocaine

Answer 18

False , increased

Question 19

EMLA is a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine

Answer 19

True

Question 20

Ocular anaesthesia - 1-2drops of 0.5% tetracaine achieves complete conjunctival anaesthesia after a few seconds of stinging

Answer 20

True

Question 21

Which nerves need to be blocked for a foot block

Answer 21

5 nerves
1 - posterior tibial - palpate posterior tibial artery and aim 3.8cm needle anterolaterally until bone is touched. Inject into groove between medial malleolus and Achilles’ tendon
2 - SURAL - inject in groove between LATERAL malleolus and Achilles
3 - superficial peroneal - inject from malleolus to malleolus along dorsum of the foot for 3 and 4
4 - saphenous -
5 - deep peroneal - insert 3.8cm needle lateral to extensor hallucis longus tendon (toward middle of foot) down to bone. Then pull back needle slightly and inject LA