Neonatal resuscitation part 1 by dr.javeria

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Transcript of Neonatal resuscitation part 1 by dr.javeria

NEONATAL RESUSCITATION(INTRODUCTION)

Pakistan has the world’s third highest number of newborn

deaths .

Neonatal deaths, account for around half (47 %) of under-five

deaths in Pakistan.

three-quarters (74 %) of deaths occur in the first week of life.

More than one quarter of deaths occur in first 24 hrs of life.

Bir th asphyxia

“ failure to initiate and sustain breathing at birth.”

Brain damage, it causes is the major concern.

Cause of arrest/ collapse--- primarily respiratory arrest.

Upto 50% babies who require resuscitation have no

identif iable r isk factors before birth.

Resuscitation must be anticipated at every bir th.

The transition from intrauterine to extrauterine life occurs

without incident in approximately 90% of all births.

10% of newborns will require some assistance with

breathing at birth.

1% will need extensive resuscitative measures in order

to survive.

The outcome of newborns can be improved by the use of

ef fective neonatal resuscitative measures .

At term, the fetal lung is filled with approximately 20 ml of

fluid

This lung fluid maintains lung volume at about the functional

residual capacity (FRC) and is a determinant of normal lung

growth.

80-90% of FRC is established within the first hour of birth in

term neonates with spontaneous respirations.

At the onset of labour,

i. HORMONAL SURGE from the mother and baby cause

the secreting cells within baby’s lung to switch from

secretion to absorption.

ii. THORACIC SQUEEZE during birth process(25-33%).

Babies are thus prepared by labour for this step.

Babies born via caesarean section, before labour are

more likely to have respiratory problems in the first few

hours after birth.

New born initiates breathing in response toi. Cord obstructionii. Physical discomfortiii. Cold air

FIRST BREATHS ----push out fluid in the airways

resting lung volumeCONCERN IF i) only partially achieved

ii) not achieved at all

Fetal "breathing" (ie, chest wall and diaphragmatic movement)

begins at approximately 11 weeks of gestation and increase in

strength and frequency throughout gestation.

low PaO2 in utero --- the mechanism that inhibits continuous

breathing.

The centre responsible for NORMAL breathing (higher

centre) has two functions,

i. To initiate and maintain normal regular breathing

ii. To suppress the more primitive spinal centre (lower

centre) responsible for gasping.

When the higher respiratory centre is put out of action, the

lower respiratory centre ,initiates the gasping.

Still if no oxygen is delivered to the lower respiratory centre

then this primitive form of breathing cannot be maintained

and it stops (terminal apnea).

fetus undergoing asphyxia exhibit an altered respiratory

pattern.

Breathing movements gradually becoming more desperate

With continuing low PaO2 ---- breathing stops (PRIMARY

APNEA)

After few minutes of apnea fetus tries to breathe again---

GASPING BREATHS gradually increasing frequency &

vigor & then decrease

Continuing low /falling PaO2 ---- stops gasping (TERMINAL

APNEA).

The PaCO2 is increasing throughout, when PaO2 is falling.

The heart rate increases under the stress of initial insult in first minute or so, but then suddenly drops to about half its normal rate after about 4 minutes.

The baby’s heart has adequate glycogen stores & thus able to revert to anaerobic respiration, during low PaO2 .

During the effective uterine contractions there is very little effective gas exchange occuring at the placenta and the baby is likely “holding breath” & the heart is managing to maintain a reasonable rate by means of anaerobic respiration.

The price of reverting to anaerobic respiration is that

this will produce lactic acid in large quantities.

Contributes to falling pH.

• Blood pressure, though gradually falling, is well maintained

for some time despite the low heart rate.

• By shutting down circulation to non-essential areas and thus

maintain a reasonable circulation to the most important

organs.

• Thus, there is sufficient functioning circulation during

this period.

After a pause of a minute or two the baby will start gasping.

If the airway is open, air is drawn into the lungs & as the circulation

is still functioning, the blood will become oxygenated .

As soon as the oxygenated blood reaches the coronary arteries the

heart will revert to aerobic metabolism (energy efficient), and

the hear t rate will rapidly rise.

After a few gasps, oxygenated blood will have reached the higher

respiratory centre in the brain resulting in recovery of its function

thus initiate normal breathing as well.

The result is a self resuscitating baby .

The baby will gasp and provided the airway is clear the baby

will again recover itself.

However, because this baby has had a longer period of

asphyxia it may take longer for the brain to recover i.e. the

period of gasping may be longer and normal breathing

may be interspersed with gasping for a bit longer.

• The baby will make no breathing efforts, the hear t rate and

blood pressure will gradually fal l .

• No spontaneous breathing effort of any sort will arise from

the baby.

• By this point, there is no reserve left and though the

circulation may still be just functioning , it is rapidly

fai l ing.

• In the absence of some external intervention this

baby wil l die.

• A baby delivered in terminal apnea, needs help i.e.

resuscitation.

• If we inflate the lungs, baby’s heart may still be functioning

sufficiently to maintain circulation.

• Thus some blood still flowing though the lungs, will become

oxygenated & perfuse the heart .

• The heart will then revert to aerobic metabolism and will

almost immediately increase its rate.

• Increase in hear t rate is an indicator that the lungs have

been inflated ef fectively .

If delivery occurs a little later in terminal apnea, lung inflation is not followed by an improvement in heart rate.

The heart has deteriorated so much that it cannot maintain circulation and thus requires chest compressions to establish it again.

A brief period of chest compressions manages to bring some oxygenated blood back to the heart rate while waiting for the baby to recover.

After a period the baby will star t to gasp. Once oxygenated blood has reached the higher respiratory centre it will also respond and normal breaths wil l begin.

PRIMARY APNEA, responds to stimulation with

reinstitution of breathing.

SECONDARY / TERMINAL APNEA

does not respond to tactile or noxious stimulation

require positive-pressure ventilation (PPV) to restore

ventilation

Primary and secondary apnea cannot be clinically

distinguished.

Therefore, if an infant does not readily respond to

st imulation, PPV should be initiated .

Babies can withstand asphyxial process of normal

delivery.

Circulation can continue reasonably well despite about

20 mins of anoxia.

If baby is not breathing at birth

THE MOST IMPORTANT TASK IS TO

AERATE THE BABY’S LUNGS

In few cases, babies who have further asphyxial insult,

lung aeration & a brief period of chest

compressions is required for recovery.

Neonatal resuscitation primarily focuses on

revival of RESPIRATORY FUNCTION