Chapter 36 – Resuscitation of the Newborn




Abstract




The primary reason for resuscitation in the newborn infant differs from that in adults. While most adults requiring resuscitation will have a cardiac event, the newborn infant’s heart is healthy and it will usually be a respiratory (hypoxic) event that will have compromised the newborn. Particular attention to management of the Airway and Breathing is therefore imperative.


The fetal lung is filled with fluid (approximately 30 mL/kg, which equates to about 100 mL in an average term baby). This is absorbed rapidly soon after birth due to various adaptive processes, the lung becomes aerated and a functional residual capacity (FRC) established. In compromised hypoxic infants this may not occur and the onset of breathing may be delayed. These babies need intervention.





Chapter 36 Resuscitation of the Newborn


Sadaf Bhayat , Louise Davidson , Siromi Gunaratne and Nigel Kennea




Key Facts


Resuscitation is one of the most frequently performed procedures in the neonatal period. It is therefore important that procedures are evidence based and frequently updated. In 2015, the Resuscitation Council (UK) issued new guidelines on newborn resuscitation, accredited by the National Institute for Health and Care Excellence. The changes in approach in the 2015 guidelines are outlined in Table 36.1.




Table 36.1 Expansions on 2010 Neonatal Resuscitation recommended in NLS Current Guidance (2015)


































Cord clamping Delay cord clamping in infants not needing resuscitation.Cord clamping should be delayed for at least 1 minute from delivery of baby.Stripping or milking of the cord is not recommended.
Temperature The temperature of newly born infants is actively maintained between 36.5°C and 37.5°C after birth unless a decision has been taken to start therapeutic hypothermia.
Monitoring Pulse-oximetry should be used for patient assessment during neonatal resuscitation.
Oxygen or air

It is best to start resuscitation of term infants in air and subsequently guided by pulse-oximetry.


For preterm infants, a low concentration of oxygen (21–30%) should be used initially for resuscitation at birth.

Cardio-pulmonary resuscitation

Recommended chest compression: ventilation ratio is 3:1.


There should be 30 seconds of adequate ventilation breaths prior to starting compressions.


Recommended dose of adrenaline is 10–30 mcg/kg IV.

Capnography Detection of exhaled carbon dioxide is recommended to confirm endotracheal tube placement but may not be helpful in circulatory arrest.
Meconium

Routine suction in active infants is not recommended.


There should be no unnecessary delay in commencing inflation breaths.

Resuscitation of preterm infants Preterm babies less than 28 weeks’ gestation should be covered up to neck with food grade plastic bag/wrap without drying, and stabilised under a radiant header. Early Use of nasal continuous positive airway pressure should also be considered in those spontaneously breathing preterm infants.
Hypoxic ischaemic encephalopathy For birth asphyxia in term or near-term infants, to treat with therapeutic hypothermia (33.5–34.5°C) within 6 hours after birth


From [1].



Physiology


The primary reason for resuscitation in the newborn infant differs from that in adults. While most adults requiring resuscitation will have a cardiac event, the newborn infant’s heart is healthy and it will usually be a respiratory (hypoxic) event that will have compromised the newborn. Particular attention to management of the Airway and Breathing is therefore imperative.


The fetal lung is filled with fluid (approximately 30 mL/kg, which equates to about 100 mL in an average term baby). This is absorbed rapidly soon after birth due to various adaptive processes, the lung becomes aerated and a functional residual capacity (FRC) established. In compromised hypoxic infants this may not occur and the onset of breathing may be delayed. These babies need intervention.


Physiological studies, performed more than 50 years ago, evaluated the fetal responses to hypoxia–ischaemia. During labour uterine contractions lead to compromise in placental gas exchange and so the fetus is exposed to hypoxia The first response of the fetus to hypoxia is to breathe more deeply and rapidly; after a few minutes, regular breathing cease due to lack of oxygen (primary apnoea). If the hypoxic insult continues, primitive spinal centres produce whole body gasps at a rate of about 12/minute. Soon after this, the fetus enters a further phase known as terminal apnoea. Without further intervention at this point, the baby would die.


A baby who is not breathing at birth could be in primary apnoea, about to gasp, or in terminal apnoea. It is not possible to distinguish this at the time and therefore any baby not breathing at birth should have resuscitation initiated.



Practical Considerations



Anticipation of Resuscitation


Anticipation and adequate preparation are critical for successful neonatal resuscitation. At every delivery there should be at least one person trained in neonatal resuscitation, whose primary responsibility is the newborn. Preparation for early management of a newborn infant should include a review of obstetric notes and handover from colleagues regarding any possible complications at delivery.



Equipment and Environment


It is important to prepare the environment and the equipment before delivery of the baby. Resuscitation should take place in a warm, well-lit, draught-free area with a flat resuscitation surface below a radiant heater.


Apart from air and oxygen sources, the recommended minimum set of equipment include warm towels (to dry and stimulate the newborn), air-oxygen blender, face masks, T-pieces/self-inflating bags, suction apparatus and tubing, laryngoscope with different sizes of straight blades, tracheal tubes, laryngeal airways and drugs. A stethoscope, pulse oximetry and carbon dioxide detectors are used for monitoring.



Initial Steps and Evaluation



Cord Clamping


Clamping of the umbilical cord before the first breath is associated with reduced cardiac filling and may induce bradycardia. By delaying clamping, studies have shown that cardiovascular output is maintained and there is a smoother transition between fetal and neonatal circulation. Delayed cord clamping is associated with better haematological indices in term babies. In preterm infants delayed cord clamping reduces the need for blood transfusion and the risk of mortality. It has not been shown in the most recent meta-analysis to have an effect on neonatal morbidities such as necrotising enterocolitis, intraventricular haemorrhages, but the analyses were underpowered and require looking further into individual patient data. It is therefore recommended to delay clamping of cord for 1 minute in all babies not requiring resuscitation. However, if immediate resuscitation is required then this should take priority.



Temperature Management


Newborn babies are covered in fluid and have a large surface area. They can suffer significant heat loss leading to hypothermia. Exposure of the newborn to cold stress will lower arterial oxygen tension and increase metabolic acidosis. Hence, an essential early step in neonatal resuscitation is the prevention of hypothermia.


Term babies should be dried immediately, the wet towel discarded and the baby wrapped with warm, dry towels. If the baby needs resuscitation then place the baby on a warm surface under a preheated radiant heater, leave the baby wrapped in towels and expose only necessary parts for resuscitation: chest and, if needed, umbilicus.


In preterm babies, hypothermia is associated with increased morbidity and mortality. Hence babies less than 28 weeks of gestation should be immediately placed into a plastic bag, ensuring that they are completely covered up to the neck without drying. A hat should be applied and the infant placed on a warm surface under preheated radiant heater. They should remain wrapped in the plastic bag until their temperature has been checked in the NICU and the incubator is sufficiently heated. The delivery room temperature should be maintained at a minimum of 26°C.


The effect of postnatal hyperthermia has not been studied extensively but maternal fever has been shown to be associated with neonatal respiratory distress, encephalopathy and increased mortality. It is unclear whether these morbidities are secondary to hyperthermia or an underlying disease process. Also, in babies with newborn encephalopathy and hypoxic brain injury, hyperthermia is associated with adverse outcome. For this reason, it is advised to avoid neonatal hyperthermia during resuscitation.



Initial Infant Assessment


As soon as the baby is born, a clock should be started or the time noted. The baby should be dried and wrapped; this will not only provide stimulation but will also allow time to assess tone, breathing and respiration. It is important to reassess these observations regularly at 30-second intervals throughout the resuscitation.


On the basis of the initial assessment, the baby can be placed into three groups:




  1. 1. Vigorous breathing or crying, good tone, heart rate >100/minute. This baby does not require any intervention other than drying and wrapping.



  2. 2. Breathing inadequately/apnoeic, normal or reduced tone, heart rate <100/minute. Dry and wrap. This baby may improve with mask inflation, but may need further interventions if the baby does not respond



  3. 3. Breathing inadequately/apnoeic, floppy, low or undetectable heart rate and pale (suggesting poor perfusion). Dry and wrap. This baby is likely to need further resuscitation. The initial steps remain the same of inflating the lungs with inflation breaths, followed by ventilation breaths. Resuscitation is initiated in air, in this case the FiO2 may be increased depending on the response and pulse oximetry, If there is no improvement in the heart rate despite adequate lung expansion, the baby will need chest compressions and potentially drugs such as adrenaline if there is still no response.


The heart rate of baby is best judged by listening with a stethoscope or using a pulse oximeter, as a slow heart rate measured by palpating the umbilical cord may not be indicative of the true heart rate.


Neonatal resuscitation should be commenced if assessment shows that the baby has failed to establish adequate regular normal breathing or has a heart rate of <100/minute. Opening the airway and successfully inflating the lungs is usually all that is necessary. Further interventions will be futile unless these two first steps have been successfully completed.



Approach to Resuscitation


The systematic approach to newborn resuscitation is demonstrated in Figure 36.1. It uses the Airway, Breathing, Circulation, Drugs (A, B, C, D) approach.





Figure 36.1 Neonatal resuscitation algorithm.


(Reproduced with the kind permission of the Resuscitation Council, UK.)


Airway


The first step in successful resuscitation is to ensure there is a patent airway. If the airway is not open and clear then the rest of the resuscitation will be futile.


Newborn infants have a large occiput and when placed onto the resuscitaire or a hard surface there is the tendency for their head to flex forward, obstructing the airway. To overcome this, the head should be placed in the neutral position with the neck neither flexed nor extended (Figure 36.2). This simple manoeuvre is sometimes all that is needed in order to assist the newborn’s respiratory effort. If it is not sufficient, there are further airway manoeuvres one can apply (see later).





Figure 36.2 Newborn infants have a large occiput and when placed onto the resuscitaire or a hard surface there is the tendency for the head to flex forward thereby obstructing the airway (A). Placing the infant’s head in the ‘neutral position’ opens the airway (B). Care must be taken not to over-extend the head.


If, having placed the head in the ‘neutral position’, the baby’s respiratory effort remains poor or absent, with a heart rate that is slow (<100 beats/minute) the infant will need five inflation breaths. The idea of inflation breaths is to establish a residual volume and displace lung fluid. Therefore these breaths are given with pressures set at 30 cm H20 for term babies (20–25 cm H20 for preterm babies) each lasting 2–3 seconds. These should be given preferably with a pressure-limited T piece, ‘Neo-puff’ or, if not available, a bag and mask. The reason for five breaths is that the initial two or three breaths may only help in pushing lung liquid out of the alveoli and not expand the lungs with air. It is important to watch for chest wall movement as the inflation breaths are given.


To give these breaths effectively, the right sized mask should be used, that is, one which covers the nose and mouth but does not go over the end of the chin or encroach onto the eyes. Once these five inflation breaths are given, further assessment is necessary to see if the infant has responded. While assessing tone and respiratory effort, the first and most important sign of effective inflation breaths is a rise in the heart rate.


If there is no rise in the heart rate and the chest was not seen to move while giving inflation breaths it is likely that the lungs have not been inflated. The following manoeuvres can then be tried:




  • Applying chin lift and jaw thrust – helpful in floppy babies.



  • A two-person jaw thrust – one applying jaw thrust and other giving inflation breaths.



  • Placing some support under shoulders – this will prevent flexion due to the prominent occiput. Direct visualisation of larynx and vocal cords, with suctioning if an obstruction is visible. For suspected tracheal obstruction, intubation and use of the tracheal tube as a suction device.



  • If there is no obstruction on visualisation, placing an appropriately sized oropharyngeal airway using the laryngoscope.


Following these manoeuvres, five inflation breaths should be repeated. If there is good chest wall movement and the heart rate improves then the baby has responded. If, using these manoeuvres, the chest wall moves with the inflation breaths but there is no rise in heart rate, then there is a need to undertake chest compressions. Ventilation breaths should be given for 30 seconds before commencing chest compression and if there is still no response in heart rate, chest compression should be started.


If the attendant is appropriately trained and skilled, one option at this point is to intubate the baby using an appropriately sized endotracheal tube (ET). The advantage of being able to insert an ET is that the airway is secured and in an extended resuscitation the hands can be freed to concentrate on circulatory resuscitation.



Points to Note for Airway


When Amniotic Fluid Is Clear

There is evidence that suctioning of the nasopharynx can create bradycardia during resuscitation. Hence it is recommended that routine suctioning immediately following birth should be avoided and should be reserved for babies who have obvious obstruction or who require positive pressure ventilation.



When Liquor Is Meconium Stained

A multicentre randomised control trial has shown that routine elective intubation and suctioning of vigorous infants at birth did not reduce the incidence of meconium aspiration syndrome. Another randomised study has shown that suctioning the nose and mouth of such babies on the perineum and before delivery of shoulders (intrapartum suctioning) is also ineffective.


Current recommendations state that when presented with a floppy and apnoeic baby with meconium stained liquor, it is reasonable to inspect the oropharynx rapidly to remove potential obstruction. However, if the baby is bradycardic then inflation breaths should be instigated within the first minute of life without delay. If the resuscitator is experienced in endotracheal intubation, then tracheal intubation and suctioning may be useful. However, if attempted intubation is prolonged and unsuccessful this should be abandoned in order to prevent delay in starting inflation breaths.



The Importance of the Correct Size Face Mask

Successful neonatal facemask ventilation requires an airtight seal between the face and mask. Achieving this can be difficult. Leakage is a common reason for failure of ventilation. Ensure the mask is adequately covering the nose and mouth but does not go over the end of the chin or encroach onto the eyes.



Confirmation of ET Placement

A prompt increase in heart rate is the best indicator that effective ventilation is being provided via the ET tube. In addition, detection of exhaled carbon dioxide can be used to confirm ET tube placement, although it is worth noting that in the absence of spontaneous circulation use of exhaled CO2 detectors is unreliable. Clinical parameters such as chest rise, bilateral air entry on auscultation and response of heart rate remain important indicators of successful ET placement.



Laryngeal Masks

Laryngeal masks have been used successfully in resuscitation at birth although this is not common practice. They are potentially useful airway adjuncts, particularly if mask ventilation or intubation is problematic in term or near-term infants (weighing more than 2000 g or of greater than 34 weeks’ gestation). Their use in more preterm infants has yet to be established and is not currently recommended.

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May 9, 2021 | Posted by in OBSTETRICS | Comments Off on Chapter 36 – Resuscitation of the Newborn
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