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RESPIRATORY DISTRESS SYNDROMEBy Dr. Gacheri Mutua
DEFINITIONAlso known as Hyaline Membrane
DiseaseIs a respiratory disorder that
affects newbornsMore common in premature
infants especially born 6wks or more before their due date
Their lungs have insufficient surfactant, necessary to maintain lung compliance
Disease is exacerbated by:◦Cold stress◦Hypoxia◦Acidosis◦Sepsis
Natural history- clinical signs develop within 6hrs of life with progressive worsening over the first 48 to 72hrs of life
Predisposing factors Prematurity Male gender and are more likely to die from the
disease Caucasian > black Caesarean section Low APGAR score Maternal diabetes Congenital hypothyroidisim Familial predisposition Twins Postnatal hypothermia Maternal malnutrition Intrauterine growth retardation Hemolytic disease of the newborn
DIAGNOSIS◦ Clinical:-
tachypnoea grunting respirations intercostals recession, sternal indrawing nasal flaring cyanosis increased oxygen requirements deranged cardiovascular parameters: HR, BP
◦ Radiological features:- Air bonchograms with characteristic ground glass
appearance
◦ Haematological:- anaemia Thrombocytopenia
◦ Blood gas measurements Mixed metabolic and respiratory acidemia
PREVENTION
Prevent premature deliveryAntenatal steroid therapyDrugs to mature surfactant
synthetic pathways: aminophyllinePrevent asphyxiaAvoid drugs that cause respiratory
depressionThe course of the disease is
altered by exogenous surfactant therapy and assisted ventilation
MANAGEMENTNon-respiratory
◦Temperature control◦Avoid enteral feeding◦ IV therapy 5% or 10% dextrose◦Closely monitor blood glucose◦Antibiotics: penicillin, gentamicin◦Assess the baby's circulatory status by
monitoring heart rate, peripheral perfusion, and blood pressureAdminister blood or volume expanders, and use appropriate vasopressors to support circulation where necessary.
Respiratory◦Airway- place infant in lateral or
prone posture rather than supine◦Repeated suctioning of pharynx is
not required and may cause apnoea and hypoxia
Oxygen ◦Administer humidified oxygen at
flow rates of 6-8l/min◦Monitor arterial blood gases, aim to
keep pO2 between 50 and 80mmHg◦Desired range of monitored pulse
oxymeter for infants <34weeks gestation is 88 to 95% but for more mature infants 88 to 100%
INTUBATION AND IPPVIPPV- Intermittent Positive
Pressure Ventilation
Indications:◦Cyanosis that persists in spite of
maximal oxygen therapy◦Severe recurrent apnoea◦Respiratory failure (pCO2 >70 and
pH <7.2)
CPAPContinuous Positive Airway Pressure is
used to treat preterm infants whose lungs have not yet fully developed such as in RDS or bronchopulmonary dysplasia
It’s functionally similar to PEEP, except that PEEP is an applied pressure against exhalation and CPAP is a pressure applied by a constant flow
CPAP:-◦ improves survival◦decreases the need for steroid treatment for
their lungs◦decreases the need for IPPV
Surfactant ventilator settings
Ventilator rate 60 breaths per minute
Inspiratory time 0.3sec; expiratory time 0.7sec
PEEP 5cmOxygen set to maintain
saturations of 88 to 95%Peak inspiratory pressure (PIP)
20-30cm water
SURFACTANT ADMINISTRATION
Premature neonates with surfactant deficiency and respiratory distress syndrome have an alveolar pool of about 5mg/kg. Full-term animal models have pools of 50-100mg/kg.
Recommended dosages of clinically available surfactant preparations are 50-200mg/kg, approximately the surfactant pool of term newborn lungs
Rapid bolus administration of surfactant after adequate lung recruitment with 3-4cm of positive end-expiratory pressure (PEEP) and adequate positive pressure may improve its homogeneous distribution.
Most neonates require 2 doses; however, as many as 4 doses, given at 6-hour to 12-hour intervals, were used in several clinical trials.
◦NB: Dosages could be given as a rapid bolus or
intermittent administration. Prophylactic doses can be given soon after delivery
If the patient rapidly improves after 1 dose, respiratory distress syndrome is unlikely.
Conversely, in infants who have a poor or no response, patent ductus arteriosus (PDA), pneumonia, and complications of ventilation (air leak) should be excluded, especially before subsequent surfactant doses are given.
SUDDEN DETERIORATION
In spontaneously ventilating:◦ pneumothorax◦ failure of oxygen supply◦ increase in severity of the underlying disease
In a ventilated infant:◦ pneumothorax
◦ endotracheal tube blockage or displacement
◦ mechanical failure with the ventilator
◦ increase in the severity of the underlying lung disease
◦ massive intraventricular haemorrhage
◦ necrotizing enterocolitis, especially if perforation has occurred
◦ patent ductus arteriosus
FAMILY PSYCHOTHERAPYStaff members (preferably a
physician and a nurse) should keep the patient’s parents well informed by frequently talking to them, especially during the acute stage of respiratory distress syndrome
THANK YOU!!