NLS Flashcards
Why is delivery through the birth canal an anoxic event?
Respiratory exchange by the placenta is interrupted for the 50-75 second duration of the average contraction
For how long can the heart of the newborn baby function despite anoxia?
20-30 mins
When does fluid resorption in the neonates lungs begin?
During labour
How much fluid do babies born vaginally at term still have in their lungs?
100ml
What proportion of babies born at term will initiate spontaneous respirations?
85% - within 10-30 seconds
What is the crucial intervention in NLS?
The aeration and ventilation of babies
How quickly will the remaining fluid in the average 3.5kg baby be cleared from the lungs?
Within a matter of minutes, unaided
How much warmer is the human fetus than its mother?
0.5 oC
How low can a baby’s temperature fall within 5 minutes if left naked and wet?
33 oC
By what degree does risk of mortality increase in very low birth weight babies for every 1 oC below the 36.5 oC baseline?
28%
What should be assessed in the baby whilst the umbilical cord is still attached?
Colour
Tone
breathing
Heart Rate
How should colour be assessed in a newborn?
By looking at the trunk, lips and tongue
Is the cord pulsation a reliable indicator of heart rate?
If >100 pulsations a minute - likely all i well, but if pulsations less than this, it is not necessarily an indicator of true heart rate, and thus should be assessed with a stethoscope
What is the fetal circulation fed by?
Both the right and left ventricle - 55% by the right ventricle, 45% by the eft ventricle
What is the combined ventricular outfit in the near-term fetus?
465ml/kg
75% of the right ventricle output supplies what?
Through the ductus arteriosus to supply the abdomen, lower body and placenta
75% of the left ventricle output supplies what?
Perfuses the upper body - the head, neck and arms
What is the total fetal lung fluid in a near-term infant?
20-30ml/kg (equivalent of functional residual capacity)
What would happen should there be insufficient amniotic fluid (and thus fetal lung fluid)?
Adversely affected fetal lung development, causing pulmonary hypoplasia
What is it about labour that bring about the cease in production of lung fluid secretion from the fetus’s alveolar cells?
Adrenaline production by the fetus
Thyrotropin production by the mother
What is it that bring about loss of fetal lung fluid?
Primarily = the hydrostatic pressures generated by inspiration + secondarily, postural changes imposed on the fetus during uterine contractions > than the ‘vaginal squeeze’ affect
How do the hydrostatic pressures generated by inspiration work?
Spontaneous inspiratory movements by the fetus generates a transepithelial pressure gradient between the interstitial tissue and airway lumen, the lung fluid being drawn from the proximal airways into the distal ones, which is then cleared across the distal airway wall into the surrounding interstitial tissue space
How many breaths is it before gas exchange typically occurs?
7 - before carbon dioxide is detected on exhalation
When does exhaled carbon dioxide peak after birth?
Within the first 2-3 minutes of birth
Why do newborns recover from periods of oxygen deprivation more so than adults?
- Conservation of energy by shutting down circulation to all but vital organs in response to hypoxia
- Activity of automatic spinally generated gasping activity following primary apnoea
- Anaerobic respiration, the newborn’s heart utilising glycogen, as an alternative fuel to maintain circulation
At what saturation would you NOT start inspired oxygen?
> /=95%
At <28/40 gestation, what concentration of inspired oxygen would you start with?
30%
At 28/40-32/40 gestation, what concentration of inspired oxygen would you start with?
21-30%
At >32/40 gestation, what concentration of inspired oxygen would you start with?
21%
How long minimum of adequate ventilation should be performed before chest compression be started if inadequate HR?
30 seconds
What concentration of oxygen would you give if chest compressions need to be started?
100%
What are the acceptable R arm saturations 2 minutes after birth?
65%
What are the acceptable R arm saturations 5 minutes after birth?
85%
What are the acceptable R arm saturations 10 minutes after birth?
90%
What is the usual HR in term and well pre-term babies after 2 mins?
> 100
What are the different methods of assessing heart rate during resuscitation?
Stethoscope
Pulse oximetry
ECG monitoring
Why are oximetry readings take in the R arm of newborn infants?
Measurements are pre-ductal. Pre-ductal saturations represent the oxygen going to the brain
What pressures of inflation should be started with with a term infant for inflation breaths?
30cm of water, 2-3 seconds inspiratory time
What pressures of inflation should be started with with an infant <32/40 for inflation breaths?
25cm of water
At what rate should ventilation breaths be performed?
30 breaths/minute, 25cm of water, 1 second inspiratory time
What response suggests the infant had been suffering with terminal apnoea?
Gasping in nature
How long does it usually take for the heart to respond to chest compressions?
Usually, only 20-30 seconds
How is access achieved in a newborn infant?
Umbilical vein catheter or IO
How often should adrenaline be given if CPR is be performing?
Every 3-5 minutes
What may be going on if the HR is still not improving after CPR?
Hypovolaemia
Tension pneumothorax
Diaphragmatic hernia
Complete heart block
What are the fetus antenatal RFs for neonatal resuscitation at delivery?
- Prematurity
- IUGR
- Multiple pregnancy
- Serious congenital abnormality
- Oligo/poly-hydramnios
- Fetal anaemia, including hydrops
What are the maternal antenatal RFs for neonatal resuscitation at delivery?
- High BMI
- Short stature
- PET
- Lack of intrapartum steroids in pre-term
- PIH
- GDM
- Maternal sepsis
What are the intrapartum RFs for neonatal resuscitation at delivery?
- Evidence of fetal compromise - e.g. pathological CTG
- Meconium-stained liquor
- Vaginal breech
- Instrumental delivery
- Significant maternal PPH
- C-section before 39/40
- Emergency section
- GA
What is near enough the only condition that requires early intubation?
Congenital diaphragmatic hernia
What special consideration should be given to neonates with abdominal wall defects?
- Passing an NG tube when positive pressure ventilation is required in order to minimise intestinal distension
- IO may be required for access as umbilical vein catheterisation may be impossible
What can be done in relation to the umbilical cord if DCC is not practicable, but immediate cutting is not required?
Cord milking
At what gestation should cord milking NOT be performed?
<28 weeks gestation
What are the benefits of DCC in a term infant?
- Avoidance of bradycardia
- Improved early haematological; indices
- Improved iron stores in infancy
What are the benefits of DCC in pre-term infants <34/40?
- Improved survival
- Improved early haematological indices
- Improved cardiovascular stability in first 24 hours - improved BP and lower use of inotropes
- Reduce need for blood transfusions and reduced total number of transfusions
When may DCC NOT be advisable?
- Cases with interruption of the placental blood flow/oxygenation - e.g. maternal haemorrhage/seizure/arrest, placental abruption, vasa praevia, cord avulsion
- TTTS
- Fetal hydrops, any underlying cause
How much additional blood is conveyed to the infant during cord milking?
3-5 ‘milks’ = 50ml
What are the reasons for difficulties with breathing at birth?
- Loss of respiratory drive
- Mechanical obstruction of airway
- Inability to breathe
What causes a loss of respiratory drive in neonates?
Congenital brain abnormality
Acquired depression of the neurological centres - e.g. infection, drugs, perinatal stress and hypoxia
What causes a mechanical obstruction of the airway in neonates?
Foreign body - e.g. mec or vernix
Anatomical abnormality of the airway - Pierre-Robin sequence
Loss of muscular tone affecting patency of the airway - unconscious baby
What causes an inability to breathe in neonates?
Neurological and muscular disorders
Lung immaturity
What are the 2 manoeuvres that open a neonate’s airway?
- Head in neutral position, supporting chin and jaw
2. Moves the jaw forward using a two-handed jaw thrust
How can the head be kept in a neutral position without holding it?
There is a tendency for the neonates neck to be flexed due to the prominence of the occiput - this can be overcome, holding the head in neutral position by a 2cm pad being placed under the shoulders
Which pieces of equipment can be used to deliver positive pressure ventilation?
- T-piece
or - Self-inflating bag
How do you minimise face mask leaks?
3 P’s:
POSITION - rolling the mask on to the face
PRESSURE - balancing the pressure exerted on the mask by the finger and thumb
PULL - lifting or pulling the jaw up in to the mask
What size face mask should be used for 23-26/40?
35mm
What size face mask should be used for 27-28/40?
35mm or 42mm
What size face mask should be used for 29-32/40?
42mm
What size face mask should be used for 33-36/40?
42mm or 50mm
What size face mask should be used for 37/40?
50mm
What size face mask should be used for term IUGR/38 weeks?
50mm or 60mm
What size face mask should be used for >39/40 or LGA?
60mm
When would you expect the chest to start moving on giving inflation breaths?
4th or 5th breath
If needed, at what rate should ventilation breaths be given?
30/min
When can an iGel or LMA be used?
In those >2000g or >34/40
What size laryngeal mask (LMA or iGel) should be used in neonates, and how should it be inserted?
Size 1
Should be inserted with a laryngoscope (unlike in adults)
How should the head be positioned when inserting a laryngeal mask?
With the neck in a slightly extended position
What do you do if inflation breaths do not work?
Consider obstruction - consider using laryngoscope to inspect the oropharynx and a large bore suction catheter to relieve the obstruction
What are intubation rates in neonates in the UK?
0.4-2%
What are the chest compression rates in neonates in the UK?
0.3%
What proportion require adrenaline?
0.05% - 1 in 2000
What is the technique for two-thumbed chest compressions?
Overlapping thumbs, lower third of the sternum, in the centre of the chest, just below the imaginary line between the nipples
At what rate should CPR be performed in neonates?
3:1 - 90 chest compressions:30 breaths (120 events)/minute
What drugs should be given with prolonged resuscitation?
Glucose and sodium bicarbonate
How often should adrenaline be given whilst CPR is ongoing?
Every 3-5 minutes
What is the preferred route of adrenaline in neonates?
IV, but IO can be used
What is the recommended dosage of adrenaline IV or IO in resuscitation?
20 microgram/kg
What is the recommended dosage of adrenaline when given intra-tracheally in resuscitation?
100 microgram/kg
What level of CPAP should be used to stabilise pre-term infants if needed?
5-8cm water
What is the appropriate PEEP for a ventilated pre-term infants if needed?
5cm
What is the first sign of recovery from terminal apnoea?
Once the circulation is restored, agonal gasps, occurring every 5-8 seconds is the first sign
What is the cause of primary apnoea?
Unclear airway
