PONV

Question 1

Nausea definition:

Answer 1

A feeling of sickness with theinclination to vomit

Question 2

Retching:

Answer 2

Spasm of the respiratory muscles against the glottis

Question 3

Vomiting:

Answer 3

Expulsion of gastric contents involuntarily and forecfully through the mouth and sometimes nose

Question 4

PONV?

Answer 4

Nausea and vomiting and retching within the first 24 hours post-operatively

Question 5

What are the complications of PONV?

Answer 5

1. Dehydration, metabolic derangements
2. oesophageal rupture/tear
3. bleeding, haematoma, wound dehiscence, clot disruption
4. tachycardia and hypertension
5. prolonged stay- more costs

Question 6

What are the 2 centres that causes vomiting?

Answer 6

1. chemoreceptor trigger zone(CTZ)

2. Vomiting centre in the medulla

Question 7

What are the 2 receptors that are found on chemoreceptor trigger zone?

Answer 7

1. Dopamine 2 receptor

2. 5-HT Receptors(serotonin)

Question 8

What is the receptor found on the vomiting centre in the medulla?

Answer 8

It is the muscarinic or ACh receptor

Question 9

What are the 4 stimulus of nausea and vomiting?

Answer 9

1. Pain, repulsive sight/smell, emotional factors
2. Motion sickness
3. Endogenous toxins/drugs
4. Stomach contents/pharynx

Question 10

In regards to motion sickness, where does the impulse come from? What receptors are found here?

Answer 10

1. The vestibular nuclei in the pons

2. It has histamine(H1 receptors) and muscarinic receptors

Question 11

Where does the impulse travel to after the vestibular nuceli?

Answer 11

To the chemoreceptor trigger zone and then to the vomiting centre zone

Question 12

What is the risk of post-operative nausea and vomiting based on in adults?

Answer 12

Apfel

Question 13

How is the Apfel risk of PONV classified?

Answer 13

1. female
2. non smoker
3. previous PONV
4. post-operative opiods
   - the risk for no risk factors is 10%, 1 risk factor 20%, 2 RF is 40%, 3 RF is 60% and 4 RF is 80%

Question 14

What are the things we can do to reduce the risk of PONV in high risk patients?

Answer 14

1. Give regional anaesthetic
2. Adequate Hydration
3. TIVA:propofol
4. Decrease use of post-operative opoids: ketamine, etomidate, neostigmine, N2O
5. Anxiolytics
6. acupuncture P6

Question 15

What are the 3 side effects of dopamine receptor antagonists? Droperidol

Answer 15

1. sedation
2. prolonged QT interval
3. extra-pyramidal side effects

Question 16

What are the side effects of anticholinergics?

Answer 16

1. dry mouth
2. tinnitus
   . sedation
   4.blurred vision

Question 17

Give an example of a steroid used in PONV

Answer 17

Dexamethasone

Question 18

What are the main side effects of antihistamines:

Answer 18

1. Drowsiness
2. sedation
3. blurred vision
4. dry mouth

Question 19

What would you give intra-op to patients that present with medium and high risk of PONV?

Answer 19

1. dexamethasone and droperidol

Question 20

What are the side effects of abtiseronerguc/5HT drugs?

Answer 20

Brain and GIT upset

They are very expensive