Invasive and non-invasive ventilation Flashcards
Ventilation
Theprocessofexchangeofair between
thelungsandtheambientair.
Gas exchnage
The biological process through which gases, specifically carbon dioxide C02 & oxygen 02
are transferred across a single cell membranes of the alveoli.
What is mechanical ventilation
Ventilation delivered by a machine/ventilation
Invasive ventilation is delivered via an Endotracheal Tube (ETT) which can be oral, nasal or via a Tracheostomy (Trachy).
Type I respiratory failure
is defined by;
- Hypoxia- PaO2 <8kPa
- With a normal or low CO2
- Caused by a V/Q mismatch
Type II respiratory failure
is defined by:
Hypoxia - PaO2 <8kPa
& Hypercapnia PaCO2 >6kPa
Caused by ventilatory failure
Type II respiratory failure ventilatory (Acute)
↑PaCO2
↓pH
↔HCO3
Chronic Type II
Respiratory Failure
Ventilatory
↑PaCO2
↔pH
↑HCO3
Acute on Chronic Type II
Respiratory Failure
Ventilatory
↑PaCO2
↓pH
↑HCO3
What causes respiratory failure?
Load (reps, RR) vs capacity
Disease processes that interfere with either central ventilatory control or the respiratory muscle pump (capacity) may cause ventilatory failure
Brain injury affecting control or NMD causing muscle weakness
Disease processes that increase the load on the respiratory muscle pump to the point it exceeds capacity will cause also ventilatory failure.
**COPD increased airflow obstruction, reduced lung compliance **
Acute indications for invasive ventilation
- Reversible organ/Multiorgan failure
- Protection of the airway
- Sedation
- GCS
- Trauma
- Post surgery
- pH <7.35 & PaCO2 >6kPa
Acute indiciaitons for non-invasive ventilation
- To avoid intubation
- As a therapeutic trial with a view to tracheal intubation if it fails
- Weaning from mechanical ventilation
- Long term respiratory support
- pH <7.35 but >7.1 & PaCO2 >6kPa
Aims of invasive mechanical ventilation
↓ work of breathing (WOB) – SURPORT MODE
Takes over ventilation completely–CONTROLED MODE
↑ or maintain adequate PaO2
↓ PaCO2
Normalise pH
Allow medical management time to work which can be of a single or multiorgan failure
What parameters can be change in a persons ventilation?
Tidal volumes
RR
Timed insp/expiration ratio
Flow rate
PEEP
Peak airway pressure/Peak inspiratory pressure
Humidification
Ramp or rise
Inspiration hold
FiO2
Pressure support
What do volume or pressure parameters augment…
A tidal volume facilitating ventilation
How does it work - PEEP?
PEEP splints the airways during exhalation, allowing for gas exchange and C02 washout. Increased PEEP will increase oxygenation.
Augmenting tidal volume
Target Tidal Volume based your height and ideal body weight not “real body weight”.
Range >6ml/kg &<8ml/kg IBW
When using a pressure mode PSV, PS, PCV, the tidal volume may vary and pressures should be adjusted to achieve an ideal tidal volume.
The compliance of the patients lungs will define the pressure required to achieve the target tidal volume.
Comfort paramater - RR
Set in assisted or control mode or a back up rate in support mode.
Comfort parameter - synchronising (Ti & ratio)
How long they breath in for 1:2, 1:3, 1:5
Comfort parameter - synchronising (Flow ramp/rise)
Flow rate gradual increase to achieve Peak Inspiration.
Mixed modes
Pressure Regulated Volume Control (PRVC):
Synchronized Intermittent Mandatory Ventilation (SIMV)
Bi-level ventilation
Non invasive ventilation
The provision of ventilation via a mask, nasal pillow or mouth piece to provide positive pressure during inspirations & expiration.
There are two main types of NIV used today CPAP and BiPAP with a third used in the acute setting only, Nasal High Flow.
CPAP
Continuous Positive Airway Pressure
BiPAP
Bi Level Positive Airway Pressure
IPAP
Inspiratory Positive Airway Pressure
