Full term neonatal disease Flashcards
(44 cards)
How does PPHN cause hypoxemia?
Pulmonary vasculature remains constricted after birth despite clearance of amniotic fluid from lungs and decrease in PVR
Define persistant pulmonary hypertension of the newborn
- Abnormal transition from fetal to extrauterine life
Is persistent pulmonary hypertension a right to left shunt or left to right shunt?
Right to left shunt, blood continues to flow through the ductus arteriosus despite clearance of fluid from the infants lungs
what are the risk factors associated with PPHN?
- Oligohydramnios
- high maternal BMI
- Maternal diabetes
- pre-eclampsia
- smoking
- SSRIs
NSAIDS
What are the proposed etiologies for PPHN?
- repeated intrauterine closure of ductus with redirection of blood flow into the high resistance fetal pulmonary vasculature
- repeated intrauterine hypoxia which stimulates hypertrophy of medial smooth muscle which surround pulmonary arterioles
When does PPHN typically present?
- Full or post term infant
- Dystocia (difficult labor)
How does PPHN present?
- Refractory hypoxemia
- Low APGARS
- Mild respiratory distress to moderate tachypnea
How is PPHN diagnosed?
- Cardiac echocardiogram
- Clear CXR
3 Normal heart
What should you try to rule out before diagnosing PPHN?
- Meconium aspiration
- Congenital heart disease
- Group Be strep PNA
What would indicate the presence of PPHN after reviewing the echocardiogram and CXR?
- Severe hypoxemia
- No parenchymal disease
- Evidence of left to right shunting
What are the 3 categories of PPHN physiology?
- Maladaption
- excessive muscularization
- Hypoplastic vasculature
Describe how PPHN can be caused by maladaption?
structurally normal but abnormally constricted vasculature caused by lung parenchymal disease such as MAS, group b strep or RDS
Describe how excessive muscularization can cause PPHN
normal parenchyma but increased smooth muscle cell thickness and extension of smooth muscle to distal ends of pulmonary vessels
How does hypoplastic vasculature contribute to PPHN?
underdevelopment of the pulmonary vasculature may result in vessels that are small and incapable of carrying the appropriate volume of blood
What IV medications may be used on infants with PPHN?
- Sedatives-fentanyl
- Paralytics - vecuronium
- Magnesium - muscle relaxers
What strategies is employed when mechanically ventilating infants with PPHN?
mild hyperventilation
What respiratory medications can be given to infants with PPHN?
Inhaled Nitric oxide
Flolan
What is the formula for the oxygenation index?
OI = (Paw x FiO2) / PaO2
What is the oxygenation index used for?
Used to measure the disease severity
What is a normal Oxygenation index value?
Normal < 10
What oxygenation index supports the initiation of HFOV or iNO?
> 20
What oxygenation index score supports the initiation of ECMO?
> 40 on conventional ventilation supports ECMO
60 on HFOV supports ECMO
Describe the 20-20-20 rule for initiation of nitric oxide
When OI is 20
Dose 20 ppm
Response if the P/F ration increases by greater than 20 mmhg
What is the 60-60-60 rule for weaning iNO?
When? 60 minutes after demonstrating response if FiO2 is less than 60% and PaO2 is greater than 60 mmHg