Introduction to Ventilator Graphics Flashcards
Advantages of graphing
- allow view of machine-patient interaction
- troubleshooting before trouble
- identify pathophysiological changes
Basics of graphing
- machines display real time view of patient’s pressure, flow and volume
- scalar graph
- six basic shapes of scalar
- loops
What are the four flow patterns?
- square
- decelerating
- accelerating
- sine
True/false: no matter the flow pattern, the area under the curve must be equal for each pattern.
true
The relationship of pressure, flow, volume and time is based on what?
- VT = flow x Ti
- flow depends upon pressure gradient between machine and inside lungs
- flow = VT/ Ti
- pressure created depends upon the patient’s compliance and airway resistance
Volume ventilation (with constant flow)
- high driving force
- high internal resistor inside - lowers pressure
- high driving pressure ensures delivery
Normal VT breath
500 mL
Normal compliance
100 mL/cmH2O
What can’t you do if a patient is breathing?
an inspiratory pause. must wait until flow is 0.
What is the power source to a patient’s lungs and what must it be?
pressure gradient; must be super high
Volume curve
- no plateau
- no rest period
- active expiration is much longer
- amount of exhalation time is same
- expiratory flow decreases
How do you tell if someone is in PSV or PCV?
look at itime. PCV will have a set itime when PSV does not
What mode is considered a stand alone mode?
PSV
PCV
- pressure wave is constant
- pressure wave not affected by C or R
- flow varies, C changes in lung characteristics, set pressure and inspiratory effort
- flow wave rises rapidly at beginning and then decreased during insp
What happens if you decrease the support level?
machine work goes down and patient work level goes up
