Artificial Respiratory Suppport ✅ Flashcards
What can artificial respiratory support be classified into?
- Non-invasive respiratory support
- Invasive respiratory support
How is invasive respiratory support given?
Via a tracheal tube
What are the levels of support that can be given in artificial respiratory support?
- Single level support
- Intermittent positive pressure ventilation
Give 2 examples of single level respiratory support?
- CPAP (continuous positive airway pressure)
- HFNC (high flow nasal cannula)
What does single level respiratory support provide?
A form of distending pressure
Does single level respiratory support provide mechanical breaths?
No
Who is single level respiratory support suitable for?
Babies who are breathing spontaneous and have sufficient central drive
What is required if babies are not breathing spontaneously and show signs of respiratory failure?
Intermittent positive pressure ventilation
How can intermittent positive pressure ventilation be delivered?
Via a tracheal tube or nasal prong
What do the ventilatory needs of a patient depend largely on?
- Mechanical problems of respiratory system
- Type of abnormality in gas exchange
What drives the flow of gases in the lungs?
The pressure gradient between the airway opening and alveoli
What determines the pressure gradient necessary for adequate ventilation?
- Compliance
- Resistance
What does compliance describe?
The elasticity or distensibility of the lungs or respiratory system (lungs + chest wall)
How is compliance calculated?
Volume / pressure
What is the normal compliance of infants lungs?
3-5ml/cmH2O/kg
Give a condition that lowers the compliance of infant lungs
RDS
What is the compliance of an infants lungs in RDS?
0.1-1ml/cmH2O/kg
What does resistance describe?
The ability of the gas-conducting parts of the lungs or respiratory system to resist airflow
How is resistance calculated?
Pressure/flow
What is the resistance in normal infant lungs?
25-50cmH2O/L/second
Is resistance altered in RDS?
Not markedly
What can increase resistance in infants lungs?
Small endotracheal tubes
By how much can small endotracheal tubes increase the resistance in fetal lungs?
To 100cmH2O/L/second or more
What is meant by the time constant?
The time (milliseconds) necessary for the alveolar pressure (or volume) to reach 63% of a change in airway pressure (or volume)