Neonatal consepts Flashcards
Discuss the transition from foetal to extrauterine life
Three major Cardiorespriatory chagnes
1) removal of fluid from the unexpanded alveoli to allow venilation
2) lung expansion and establishment of unctional residual capcity
3) redistribution of CO to provide lung perfusion
Placenta a temporary organ that supplied foetal nutrients and gas exchanged – very low systemic resistant and recieves 30% of total CO. Lung cvascular bed very high resistant recieves only 40% of RV output and 10 % of CO - rest of the blood is shunted from the pulmonary artery through the ductus arteriousis to the decending aorta
Rest is shunted the the FO
Reversal of these two shunts is necessary for successful transition to extrauterine life
Discuss Hypoxia in the newborn
Even in the uncompromised it can take 10 minutes for blood o2 saturation to reach normal extrauterine levels.
In utero or intrapartum asphyxia can precipitate a sequence of events that result in primary or secondary apnea
Primary apnoea- with intial hypoxia rapid gasps are followed by cessation of respiration – if prolonged can lead to bradycardia (almost always respiratory in nature). Simple stimulation is required at the onset of primary apnoea to stimulate ventilation and avoid bradycardia.
If nil stimulation and asphyxia persists the newborn takes severl final deep gasping breaths followed by cessation of respirations ( secondary apnoea) - this is accompanied by worsening bradycardia, refractory to simple stimulation and eventually hypotension.
Discuss hypothermia in the newborn
Newborns are unable to thermoregulate apporpiately and need to be dried and warmed.
Unable to shiver, low fat stores and have excess heat loss due to large surface to volume ration, exacerbated by elevated metabolic rates and being covered in fluid
Discuss hypoglycaemia in the newborn
Poor glycogen stores coupled with immature hepatic enzymes place the newborn at increased risk for hypoglycaemia.
Particualrly common in the premature infant and the small for gestational age child.
Discuss meconium stained amniotic fluids
MSAF - indicates potentially significant newborn stress prior to delivery.
aspiration of meconium and its consequences can be avoided or at least signifiantly limited by rapid intervention.
No longer indication for intrapartum suctioning or tracheal suctioning as a routine for meconium stained fluid.
Intubation indications are the same for any newborn.
Meconium aspiration should only be performed if indicated for signs of airway obstruction secondary to meconium that do not improve despite standard resuscitaitve measures including warming and drying and PPV.
Discuss with-holding or discontinuing resuscitation
Resus not recommended for neonates with a confirmed gestational age less than 23 weeks, those with birth wieght less than 400g andthose with confirmed anencephaly, trisomy 13 or 18
Neonates with no signs of life after 10 minutes have high mortality or severe lifelone developmental delay and resus should be terminated
Discuss special anatomic anomalies in the neonate
Diaphragmatic Hernia
- in addition to pulmonary hypoplasia neonates with diaphragmatic hernias have exquistiely reactive pulmonary vascular beds predisposing them to potentially fatal pulmonary vasospasm in the immediate and late postnatal period.
- Finding conerning for congenital diaphragmatic hernia include barrel chest, ipsilateral absence of breath sounds, tracheal or point of maxium cardiac impulse displacement.
- BVM will distend the stomach which is intrathoracic and can worsen respiratory distress
- Need to be emergently intubated
Myelomeningocele and omphalocele
- Infants with myelomeningocele should never be placed supine but instead by placed prone or on the side to avoid pressure on the defect.
- Resus should proceed from this modified position.
- spinal defect should be gently wrpaped with sterile gauze pads soaked in warm sterile water and enclosed in plastic wrap.
- Infants with gastroschisis or omphalocele should be resuscitated as needed and these with defects should be covered with an occlusive plastic wrap to avoid excess heat loss
- often need parenteral maintenence fluid, OG tube for decompression and IVAB prophylaxis
Choanal atresia (back of the nasal passage is blocked)
- because newborns are obligate nose breathes bilateral choanal atresia causes upper airway obstruction
- suspect if unable to pass nasal airway devise via either side
Pierre Robin sequence
- Profound micrognathia resulting in glossoptosis( retraction or downward placement of the tounge) and cleft palate
- Predispose to upper airway obstruction
- difficult ETT - fibre optics should be used
Congenital heart disease
- 5% for term newbornss - howevere critcal CHD occurs in only 50% of congential defects
Finding include blood pressure gradient between upper and lower limbs, weak femoral pulses, central cyanosis, pathological murmur and hepatomegaly.
-Many newbrons with CHD have ductal dependent lesions and are likley to have severe physioological decompensation on closure of the duct.
-PGE 1 should be used in lesions with duct dependance, dose starting at 0.05mic/kg/min can be increased to a max dose of 0.1mic/kg/min –> risk of apneoa increases with increasing doses of PGE1 infusion
Discuss duct dependent lesions
Ductal dependent pulmonary blood flow
- critical pulmonary stenosis or atresia
- severe tricuspid stenosis, atresia
- severe tetralogy of fallot
Ductal dependent systemic blood flow
- hypoplastic left heart syndrom
- crtical aortic stenosis
- interrupted aortic arch
- Total anomalies pulmonary venous return TAPVR
Discuss an equipment checklist of for neonatal resus
1) PPE
2) Timing device
3) blankets (warm and dry infant)
4) plastic wrap (for omphalocele, gastroschisis)
5) radiant warmer (neopuff)
6) bulb syringe
7) suction and suction cathetes
9) masks to fit premature and term infants
10) laryngoscope
11) ETT
12) co2
13) paediatric co2
14) meconium aspiraotr
15) umbilical catheters
Discuss ETT size and depth by birth weight and gestational age
<1 kg- <28 weeks –> uncuffed 2.5 at 7cm
1-2kg- 28-34 weeks –> uncuffed 3mm at 8 cm
2-3 kg 34-38 weeks –> uncuffed 3.5 at 9 cm
3+ kg 38+ weeks –> uncuffed 3.5-4 at 10cm
Discuss newborn resuscitation
Dry and warm all newborns immediatly - hypothermia increases metabolic demand and o2 consumption.
Supine neonate should be positioned to to maximize air entry and avoid obstruction of airflow.- Due to a relatively large occiput and anterior glottic opening, airway patency is best achieved with neck in slight extension. - Rolled small towel under shoulders
If patient is apnoeic or gasping or HR below 100/min PPV should be applied alongside ECG and spo2 monitoring - the first breath often require high pressures of 30-40mmhg to remove lung fluid - subsequent breaths require 20mm/hg PIP
Ventilation rates are of 40-60BPM – resus on RA initially than uptitrate as needed
Only if the newborn has poor tone, poor respiraotry effort or bradycardia after 1 minute of appopriate PPV should the trachea be suctioned wtih an ETT and meconium aspirator.
upper airway suctioning should be reserved only for newborns with the above signs as suctioning has been associated with decreased lung compliance brdaycardia and lowered cerebral blood flow.
If remaining under HR 100 consider intubation or LMA
If brady to <60 start chest compressions and increase fio2 to 100% –> compression 3:1 at 90compresisons/min with 30/min
Thearpeuitc hypothermia - those with moderate to severe hypoxic ischaemic encphalopathy therapeutic hypothermia to 33.5-34.5 can lower mortality and improve the likelihood fo normal neurolgoical outcome at 18 months.
Discuss APGAR scores
Routinely coutned at 1,5 and 10 minutes of life
Heart rate
- absent -0
- <100 -1
- > 100 -2
Respiration
- absent -0
- slow irregular -1
- good crying -2
Muscle tone
-limp 0
-some flexion -1
active good flexion -2
Reflex irritability
- no repsonse - 0
- Grimace -1
- Cough, sneeze - 2
Colour
-blue pale 0
-pink body, blue peripery -1
Pinl -2
Discuss vascular access in the neonate
Umbi, IO, intravascular
Discuss medications used in neonatal resus
Epi - 10mic/kg IV repeat every 3-5 minutes
Fluid expander - 10ml/kg of hartmans
Antibiotics
- most common bacterail pathogens implicated in neonatal sepsis includeGBS, Ecoli, klebsiella, enterbacter and listeria.
-Recomended neonatal AB 100mg/kg of ampi + 4mg/kg of gent
Glucose - 2ml/kg of 10%
Discuss risk factors for neonatal sepsis
Maternal risk factors
- Known GBS infection or cholinisation
- Chorioamnioinitis
- intrapartum maternal fever
- preterm delivery
- prolonged or premature rupture of membrnaes
- TORCH (herpes important)
- prenatal care or socioeconomic
- indigenous
Paeds
- Low birth weight
- premature
- invasive procedures during delivery
Environmental factors
- Home vs Hospital
- Nosocomial
