NLS

Question 1

Describe the 11 stages of the physiology of acute perinatal hypoxia

Answer 1

1. if subjected to sufficient hypoxia in utero, the fetus attempts breathing movements
2. fetus eventually loses consciousness due to low o2
3. the neural centres in brainstem cease to function due to lack of o2
4. Fetus enters period of absent respiratory effort (primary apnoea)
5. Heart rate decreases to about half the normal rate as myocardium reverts to anaerobic metabolism.
6. Lactic acid (a by-product) released, worsening the acidosis.
7. Circulation to non-vital organs reduces in order to preserve vital organs.
8. Shuddering agonal gasls (rate of about 12/min)
9. Enters secondary/terminal apnoea with no further spont breathing.
10. Worsening acidosis and on-going anoxia begins to impair cardiac function.
11. Heart eventually fails.

Question 2

How long does the process of perinatal hypoxia take in a term fetus?

Answer 2

up to 30 mins

Question 3

What is the most urgent requirement for a severely hypoxic fetus?

Answer 3

lungs aerated effectively

Question 4

What is classed as very slow, slow, fast heart rate?

Answer 4

very slow- < 60 bpm
slow- 60- 100 bpm
fast- > 100 bpm

Question 5

What 2 manoeuvres can be done to open the airway?

Answer 5

1. Hold head in neutral position- place towel under shoulders
2. Double-handed jaw thrust

Question 6

When giving inflation breaths, what pressure is used for a term baby?

Answer 6

30cm of water and air for 2-3 secs (repeated 5 times)

Question 7

When giving inflation breaths to a premature baby, what pressure is used?

Answer 7

25cm of water and 21-30% oxygen

Question 8

Which inflation breath would you expect to see the chest move?

Answer 8

4/5th as first 2-3 replace the fluid with air without changing the volume of the chest

Question 9

How would you know the inflation breaths have worked?

Answer 9

heart rate will increase

Question 10

How are ventilation breaths different to inflation breaths?

Answer 10

only last approx 1-2 secs (1 sec on, 1 sec off)
performed for 30 secs

Question 11

Once at stage of performing chest compressions, what should happen to the oxygen?

Answer 11

increase oxygen to 100%

Question 12

Why is it important not to clamp and cut the cord too short when a baby is born in compromised conditions?

Answer 12

venous access is obtained by inserting a catheter through the umbilical vein

Question 13

Which drugs are used in NLS and what are their purposes?

Answer 13

BAD
sodium Bicarbonate to reverse intracardiac acidosis
Adrenaline to increase blood pressure and heart rate
Dextrose as the heart cannot work without glucose and the glycogen stores might be depleted.

Question 14

In community, at what point in NLS should you transfer?

Answer 14

as soon as 1st set of inflation breaths is unsuccessful

Question 15

If a baby is < 32 weeks needing NLS, how do we maintain their temperature?

Answer 15

Plastic bag

Question 16

If a baby is > 32 weeks needing NLS, how do we maintain their temperature?

Answer 16

Space blanket

Question 17

What should be done after NLS?

Answer 17

• Analyse cord gases within 20 min
• update parents and debrief
• debrief team
• complete documentation and incident form
• recommend early feeds