Neonatology Flashcards
What is the definition of Apnea of prematurity
Cessation of breathing for at least 20 minutes or a briefer episode with one of the following:
- Bradycardia
- Cyanosis
- Pallor
What is apnea od prematurity related to?
Underdevelopment of the brainstem
What other causes must be ruled out before diagnosing with apnea of prematurity?
CNS disorders Decreased oxygen delivery to brain Infection Metabolic disorders Thermal instability
What are the nonpharm tx for apnea of prematurity?
Supplemental O2 (O2 sat b/n 85-95%) RBC transfusion (increases O2 carry capacity) Positions (opens upper airways) Tube removal (Removed airflow impedance) Environment (maintain temp) Ventilation (assists O2 delivery and airway maintenance)
What are methylxanthines?
Caffeine
Theophylline
Aminophylline
What are the hypothesized MOAs of methylxanthines?
Stimulates CNS Increases CO sensitivity Enhances diaphragmatic contraction force Increases CO Increases HR Decreases vascular resistance
What are the known MOAs of methylxanthines?
Inhibits:
Adenosine which normally depresses central respiratory drive
Phosphodiesterases which normally decrease number of cyclic monophosphates
What are the ADRs of Methylxanthines?
Increased UO
Jitteriness
Dose limiting effect of coffeine is tachycardia
Hypotension (less common)
What is the half-life of caffeine citrate?
52-96 hours
What is the therapeutic concentrations for caffeine citrate?
8-20
What is the toxic concentrations for caffeine citrate?
> 50
What are the loading doses for caffeine citrate?
20-25 mg/kg/dose
10-12.5 mg/kg/dose (base)
What are the maintenance doses for caffeine citrate?
5-15 mg/kg/dose
2-2.5 mg/kg/dose (base)
What is the dosing interval for caffeine citrate?
Q24h
What is the half-life of theophylline/aminophylline?
17-43 h
What is the therapeutic concentrations for theophylline/aminophylline?
6-12
What is the toxic concentration for theophylline/aminophylline?
> 15
What is the loading dose for theophylline/aminophylline?
5-6 mg/kg/dose
What is the maintenance dose of theophylline/aminophylline?
2-6 mg/kg/dose
What is the dosing interval of theophylline/aminophylline?
Q8-12h
What is the definition of respiratory distress syndrome?
Surfactant deficiency in lungs of premature neonates
What is surfactant
Provides surface tension at alveoli level in lungs
“Holds” alveoli open for gas exchange
What are the signs of surfactant deficiency?
Delay in normal respirations Grunting during expirations Flaring of the nares Cyanosis in room air Retraction of intercostal and sternal muscles Tachypnea Radiographic findings: -Reticulograndular, ground-glass pattern -Air bronchograms
What are the treatment outcomes for RDS?
Improved lung compliance
Improved oxygenation
Lower O2 requirement
What are the components of surfactant?
Phospholipids
Proteins (A-D)
What is protein A?
Hydrophilic protein regulating pulmonary surfactant turnover
What is Protein B?
Hydrophobic protein improving surfactant surface activity
What is Protein C?
Protein improving surfactant surface activity and fluidity
What is Protein D?
Protein involving bacterial opsonization
What are the animal derived surfactants?
Beractant (Bovine)
Calfactant (Bovine)
Poractant (Pork)
What are the synthetic surfactants?
Colfosceril (does not contain protein)
Lucinactant
How do we prevent RDS?
Antenatal steroids (to mother) Early surfactant administration (to baby)
How do antenatal steroids work in RDS?
Increases rate of fetal lung maturation
When do we treat with antenatal steroids in RDS?
24-34 week gestation with risk of delivery within 7 days
Under 32 weeks gestation with premature rupture of membranes
When do we prophylax with early surfactant administration?
High risk patients:
Patients less than or equal to 30 week gestation and/or patients that are NOT exposed to antenatal steroids
What is PDA?
Patent ductus arteriosus
Ductus arteriosus remaining open after birth
What can untreated PDA lead to?
CHF (Edema, hepatomegaly, tachycardia, tachypnea)
Hypoperfusion (Brain, intestines, kidneys)
What is used to clinical diagnosis of PDA?
Systolic murmur: Bounding palmer pulses Hyperdynamic precordium Increased pulse pressures Pulmonary hemorrhage Refractory hypotension Signs of CHF
What is a definitive diagnosis for PDA?
Echocardiogram with left-to-right flow
What are the causes of PDA?
Decreased prostaglandin (from the placenta) metabolism (pre-term) Decreased arterial oxygen concentration (pre-term)
What are the treatments for PDA?
Medical
Surgical (uncommon)
Pharmacologic
How do we medically treat PDA?
Manage CHF:
Fluid restriction
Diuretics (Lasix can increase prostaglandin synthesis. If PDA is not closing fast enough, lasix may be the problem)
When is surgical treatment of PDA recommended?
Pharmacologic treatment failure
Pharmacologic treatment contraindication
What medications are used for treatment of PDA?
Indomethacin
Ibuprofen
What are indomethacin/ibuprofens MOA?
Decrease prostaglandin synthesis resulting in vasoconstriction
What are indomethacin/ibuprofens ADRs?
Acute kidney damage
Bleeding
Necrotizing enterocolitis
How do NSIADs cause bleeding problems?
NSAIDs cause platelet inhibition
How do NSAIDs cause necrotizing enterocolitis?
Vasoconstriction does not allow growing gut to be supplied with nutrients, gut becomes necrotic and becomes colitis
How is indomethacin typically dosed?
3 dose course
0.2 mg/kg IV x1
Next dose depends on age
Every 12-24 hours
What are specific ADRs for indomethacin alone?
Decreased UO
Increased SCr
How is ibuprofen typically dosed?
3 dose course
10 mg/kg IV x 1
5 mg/kg IV x 2
Every 24-48 hours
Why would we maintain PDAs?
Some congenital heart defects require/need a PDA for patient survival
What medication is used for maintaining PDAs?
Prostin VR
What is the Loading dose for Prostin VR?
0.05-0.1 mcg/kg/minute continuous infusion
What is the maintenance dose for Prostin VR?
Titrate between 0.1-0.4 mcg/kg/minute
What are the ADRs for Prostin VR?
Apnea
Fever
Flushing
