Test 2 Ch.3 Flashcards
The signal measured by the ventilator that is associated with a specific breath
Phase variable
Begins inspiration
trigger variable
Limits the value of pressure, volume , flow or time duration inspiration
limit variable
Ends inspiration
cycle variable
Volume triggered
Establishes the baseline during expiration before inspiration is triggered
baseline variable
The mechanism the ventilator uses to begin inspiration is the
triggering mechanism
Delivers a mandatory breath after a set Time has elapsed
Time triggering
The set time is based on the
total cycle time (TCT)
What is the equation for TCT (I:E)
TCT= TI+TE
The pt can trigger the machine based on pressure, flow, or volume changes
Patient triggering
Occurs when the ventilator detects a drop in flow through the circuit during exhalation
Flow triggering
Which triggers are most common?
pressure and flow
Occurs when the ventilator interprets a drop in volume as a patient effort
volume triggering
The sensitivity for pressure triggering is usually set to
-1 cm H20
The machine triggers a breath w/o the pt making an effort
auto-trigger
_______________ is timed from the beginning of inspiratory flow to the beginning of expiratory flow
Inspiration
The maximum value that a variable (pressure, volume, flow or time) can attain
limit variable
Allows pressure to rise to a certain value but not exceed it
pressure limiting
When the ventilator reaches the high-pressure limit, excess pressure is
vented through a spring-loaded pressure release, or pop off valve
Controlled by an electronically operated valve that measures the flow passing through the ventilator circuit during a specific interval _____________ limiting
volume limiting
The clinician can set the volume of gas
the ventilator delivers
If gas flow from the ventilator to the pt reaches but does not exceed a maximum value before the end of inspiration the ventilator is ________ limited
flow limited
Is used to prevent excessive pressure from damaging a pt lungs ; safety mechanism
Maximum safety pressure
Typically set to value of 10cm H20 above the average peak inspiratory pressure (PIP)
Maximum safety pressure
Most adult ventilators pressure cycle (end inspiration) when set maximum safety pressure has been
reached; as if pt coughs or obstruction in Ventilatory tubing
Inspiration ends when a set pressure threshold is reached at the mouth or upper airway
Pressure- cycled ventilation
An advantage is that they limit peak airway pressures which may reduce the damage
that can occur when pressures are excessive
Designed to maintain air the lungs at the end of inspiration before the exhalation valve opens
Inflation Hold (Inspiratory Pause)
The pressure reading on the manometer peaks at the ______ of _______________ and then levels to a plateau (plateau pressure)
end of insufflation
The inflation hold maneuver is sometimes referred to as (3)
- inspiratory pause
- end- inspiration pause
- inspiratory hold
The period from the end inspiration to the beginning of the next breath
Expiratory phase
During MV expiration begins when inspiration ends the
expiratory valve opens and expiratory flow begins
If an adequate amount of time is not provided for exhalation……
Leading to a phenomenon called
air trapping and hyperinflation can occur; auto-PEEP or intrinsic PEEP
If auto-PEEP happens than you should
extend exhalation TIME
Current MVs have a mode that allows the clinician to control TI and expiratory time (TE)
Time- limited expiration
A maneuver transiently performed at the end of exhalation
Expiratory holder end expiratory pause
An accurate reading of end- expiratory pressure is impossible to obtain if a pt is
breathing spontaneously
Two methods of applying continuous pressure to the airways have been developed to improve oxygenation in pts with refractory hypoxemia
continuous postive airway pressure (CPAP) and PEEP
Application of continue pressure to the airways to improve oxygenation in pts w/ refractory hypoxemia
CPAP
Applying positive pressure to the airway throughout the respiratory cycle
PEEP
Two types of MV breaths can be described
spontaneous and mandatory breaths
Are initiated by the pt and volume delivery is determined by the pt
Spontaneous breaths
The volume and flow delivered are based on the pt demand rather than on a valve
set up by the ventilator operator
The ventilator determines the start time (time triggering ) or tidal volume (VT) or both
Mandatory breaths
