gas notes - special cases

Question 1

What is Rapid Sequence Intubation (RSI)?

Answer 1

A technique designed to minimise the time between loss of consciousness and tracheal intubation.

Question 2

In which patients is RSI most useful?

Answer 2

Patients at high risk of aspiration (e.g. pregnant and unfasted patients).

Question 3

What distinguishes RSI from conventional induction?

Answer 3

Premedication is often omitted and there is no bag-mask ventilation.

Question 4

Why is bag-mask ventilation omitted in RSI?

Answer 4

It inflates the stomach.

Question 5

What role does cricoid pressure play in RSI?

Answer 5

An assistant applies cricoid pressure to hold the oesophagus closed.
this is controversial - some practitioners skip this step

Question 6

How much cricoid pressure is applied while the patient is awake?

Answer 6

10 N (the weight of one kilogram).

Question 7

How much cricoid pressure is applied once the patient is asleep?

Answer 7

30 N (the weight of three kilograms).

Question 8

What medication is given immediately after induction in RSI?

Answer 8

Suxamethonium.

Question 9

What alternative to Suxamethonium can be used in a modified RSI?

Answer 9

High-dose rocuronium.

Question 10

What is emphasized about the first attempt at intubation in RSI?

Answer 10

Your first shot at intubation should be your best shot.

Question 11

What is the awake fibreoptic intubation ideally suited for?

Answer 11

High-risk patient who is still awake and protecting their own airway.

Question 12

What is the first step in the process of awake fibreoptic intubation?

Answer 12

A lubricated endotracheal tube is loaded onto a fibreoptic bronchoscope.

Question 13

Through which anatomical structures is the fibreoptic bronchoscope guided?

Answer 13

Nose (or mouth), pharynx, and vocal cords.

Question 14

What mixture is used to topicalise the airway before inserting the fiberoptic bronchoscope?

Answer 14

Lignocaine and phenylephrine (co-phenylcaine).

Question 15

What is the role of lignocaine in awake fibreoptic intubation?

Answer 15

Suppresses coughing.

Question 16

What effect does phenylephrine have during the procedure?

Answer 16

Reduces mucosal bleeding.

Question 17

What is obesity associated with in the context of anaesthesia and surgery?

Answer 17

Virtually every complication, including death.

Question 18

What is a major airway implication of obesity for anaesthesia?

Answer 18

High incidence of difficult intubation.

Question 19

What complication is associated with bag-mask ventilation in obese patients?

Answer 19

Difficult bag-mask ventilation.

Question 20

How does obesity affect access to the front of the neck?

Answer 20

Obscured front of neck access.

Question 21

What conditions increase the risk of aspiration in obese patients?

Answer 21

GORD and gastroparesis.

Question 22

What respiratory issue is common in obese patients post-operatively?

Answer 22

More post-operative respiratory problems.
Reduced chest wall compliance.
educed functional residual capacity

Question 23

What cardiovascular complication can arise from obesity?

Answer 23

Co-morbid heart disease.
Propensity for venous thromboembolism.
Mechanical aorto-caval compression.
co morbid heart disease
Difficult IV access.

Question 24

How does obesity affect drug dosing?

Answer 24

Increased glomerular filtration rate.
Unpredictable distribution of anaesthetic drugs.

Question 25

What is a practical complication of obesity during surgery?

Answer 25

Long surgery time due to operative complexity. Poor ultrasound views for regional anaesthesia.

Question 26

Is surgery and anaesthesia generally safe for the mother and baby during pregnancy?

Answer 26

Yes, but should be avoided unless it’s an emergency ## Footnote Surgery and anaesthesia are considered safe at any stage of pregnancy.

Question 27

What airway changes can be expected in a parturient at full term?

Answer 27

Oedema and engorgement of the upper airway, higher incidence of unexpected difficult intubation ## Footnote These changes can complicate airway management.

Question 28

What breathing changes occur in a parturient at full term?

Answer 28

Reduced chest wall compliance, reduced functional residual capacity (FRC) ## Footnote These changes can affect respiratory function during anaesthesia.

Question 29

What cardiovascular changes are observed in a parturient at full term?

Answer 29

Aorto-caval compression by the uterus, 50% increase in cardiac output, 40% increase in blood volume, slight reduction in haematocrit, torrential and unpredictable hemorrhage ## Footnote A left-lateral tilt can alleviate aorto-caval compression.

Question 30

What is the practical consideration for anaesthesia in parturients?

Answer 30

Lots of neuraxial anaesthesia, 30% decrease in MAC, anaesthetist needs to ooze confidence ## Footnote Neuraxial anaesthesia is commonly used due to its effectiveness and safety.

Question 31

What is one solution to the problem of induction in children?

Answer 31

Gas inductions because they don't like needles

Question 32

Are gas inductions as safe as IV inductions?

Answer 32

No, they’re not as safe as an IV induction

Question 33

What is the concentration of sevoflurane used during induction?

Answer 33

High-concentration (8%) sevoflurane

Question 34

How many breaths does it typically take for a child to fall asleep with sevoflurane?

Answer 34

Within ten breaths

Question 35

What should be secured quickly once the child is asleep?

Answer 35

IV access and an airway

Question 36

Is propofol licensed for use in children?

Answer 36

No, but everyone uses it

Question 37

What is more common and deadly in children during anaesthesia?

Answer 37

Laryngospasm

Question 38

Why is the safe apnoeic time shorter in children?

Answer 38

Because of their high V’O2 and low FRC