Wk 5: Respiratory distress and neonatal sepsis Flashcards
What are some signs of respiratory distress and wha are they signaling?
Tachypnoea- a compensatory reaction to hypoxia
Chest wall restraction, grunting, poor air entry-> due to lung mechanics
Central cyanosis- L) to R) cardiopulmonary shunting
Peripheral cyanosis beyond 24hrs of life-> poor tissue oxygenation due to acidosis, heart failure, shock or hypothermia
How is grunting created?
caused by the neonate partially closing their epiglottis at the end of each breath in order to maintain positive pressure in their lungs. It’s essentially the neonate trying to maintain his own functional residual capacity (FRC).
What are some differential diagnoses of resp distress in newborn?
- Mec aspiration syndrome
- Respiratory distress syndrome
- Neonatal pneumonia
- Transient tachynea of the newborn
- Persistent pulmonary hypertehsion of the newborn
- Pneumotherax
- Congenital heart disease
- Congenital diaphragmatic hernia
- Pulmonary congenital defects
What is transient tachypnea of the new born?
= tachypnoea as a result of pulmonary odema due to excess fluid in the lungs that wasn’t cleared at birth.
aka wet lung
What are some risk factors for TTN?
- Infants <39wks
- Infants born via c/s without labour
- Male infants
- Infants born to mother with GDM
- excessive fluid administration to mother during labour
- precip
- second twin
- LGA or SGA
- cord prolapse
- DM
- asthma (maternal)
What are some symptoms of TTN?
- tachypnea= >60 breaths/min
- Nasal flaring
- Grunting
- Retractions
- Clear lung fields or crackles
- cyanosis
- Cyanosis which resolves with O2 administration of <40%
- Barrel chest in some neonates (symetrical hyperinflation)
How does TTN resolve?
- usually its self over time
- usually resolves in 24- 48 hours of age, though for some neonates up to 72 hours of age.
- if resolves in 2-6 hours may be considered ‘delayed transition’
- As symptoms are due to slow absorption of lung fluid
Define neonatal pneumonia
= transfer of infection from mother though infected amniotic fluid that the baby practice breaths with or transplacenta though the blood.
What are some risk factors for neonatal pneumonia?
- prem
- maternal chorioamnionitis
- ROM >18hrs
What can cause neonatal pneumonia?
GBS
Herpies simplex virus
Kelebsiella
E. coli
What are some symptoms of neonatal pneumonia?
- Respiratory distress
- Poor feeding
- Apnea
- Tachycardia
- Poor perfusion
What are some key points of late onset pneumonia?
Often hospital acquired
Major risk factors: receipt of respiratory support
Chlampdia which as long incubation person and causes infection around 4 wks
Define respiratory distress syndrome
= deficiency of pulmonary surfactant in the immature lung
*surfactant production commences in labour
What is a risk factor for RDS?
- <37 weeks
What are some symptoms of RDS?
- Tachypnea >60
- Nasal flaring
- Grunting-> create positive pressure so alveoli stay open
- Retractions
- Cyanosis
- General increased WOB
- Apnoea
- Cyanosis
- Increased oxygen requirements of >60% to maintain target Sp02 is not uncommon and therefore transfer to tertiary neonatal unit is common
What is the management of RDS?
- can be reduced with pre birth maternal corticosteroids
- can be given surfactant via NGT
- manage thermoregulation
- oxygenation
enteral feed should be avoided with infants with RDA requirements >35% - FBC and cultures
- IM antibiotics in these circumstances
- minimal handelig
Define meconium aspiration syndrome (MAS)
=clinical diagnosis when a neonate has birthed through meconium stained liquor and has respiratory distress, appearances on chest x-ray of MAS and no other diagnosis for respiratory distress.
- Release of cytokines and proinflammatory factors
- Obstruction of air ways
- Distal gas trapping
- Alveoli rupture
- Deactivation and decreased synthesis of surfactant
What are some symptoms of MAS?
- Tachynea
- Retractions
- Grunting
- Nasal flaring
- Cyanosis
*develop immediately after birth
Explain some of the key pathological points of RDS
- Surfactant is produced and stored by the epithelial lining of the alveoli from approximately 22 weeks gestation
- it reduces alveoli tension and keeps them open.
What may exacerbate RDS?
- sepsis (most common)
- Cold stress
- Hypoxia
- Acidosis
- Disease causing secondary surfactant deficiencies e.g. meconium aspiration syndrome, pneumonia, infant of diabetic mother
Explain the pathophysiology of MAS
How mec is released
- In utero hypoxia and acidosis can cause a vagal response leading to increased peristalsis and a relaxed anal sphincter resulting in meconium passage.
- Intra-uterine distress (at any time in gestation) may initiate gasping in utero -> may result in amniotic fluid and particulate matter to be inhaled into the large airways.
When a mec particle is aspirated
1. physical obstruction of airway-> Chemical pneumonitis-> surfactant dysfunction and inflammation-> further leads to parenchymal disease
2. Mec causes a ball valve effect in airways resulting in complete obstruction-> collapse or atelecatasis or over expansion due to trapping and air leak.
3. Air leaks from being trapped in alveoli and into plural space-> Pneumomediastinum.
4. Pneumonitis: inflammation of lungs
5. Inactivation of surfactant-> stoped it from working
6. Infection potential-> provides potential for infection breeding
Mec is potential activator of inflammatory mediators which not only leads to lung dysfunction (pneumonitis) but also causes systemic inflammatory response.
What are the complictions of MAS?
- the initial reason the baby was stressed
- resp distress or hypoxia
- PPH
- infection
What are some risk factors for MAS?
- post dates (Due to or in the presence of placental insufficiency syndrome= stress and the older placenta cant meet the needs of the older baby)
What is the risk of MAS?
3-12% of the neonates born with meconium stained liquor will develop Meconium Aspiration Syndrome
