Test 5 Ch. 17 Concepts of MV Flashcards
What is the goal of MV ?
To reduce the WOB by providing adequate alveolar gas exchange with minimal damage to lung tissue (barotrauma) and/or interference with the circulatory system
Most common conventional neonatal ventilators use _____________- limited modes in order to protrct the newborn’s lungs from _______________.
pressure;
barotrauma
In pressure-limited modes, a mechanical positive pressure breath will be terminated once a
preset peak inspiratory pressure (PIP) has been reached
PIP is a ________ variable that will not allow the delivered breath to result in a pressure greater than the set PIP
limit
Pts with poor lung complaince require
higher PIP levels than those with good compliance to achieve the same tidal volume
PEEP levels are usually kept between
3 to 5 cm H20
Higher PEEP leads to…
increased Pmean which results in increased intrathoracic pressure and possible reduction of cardiac output
Frequency or rate is considered a trigger variable determined by the cycle time of each breath
**
The initial breath rate varies but should be started at ___ to ___ bpm
20 to 40
Preterm neonates may require rates as high as
60 bpm
inspiratory time (itime) is set by the operator and is a cycle variable that will
cycle the breath into exhalation once the preset IT is achieved
Mean airway pressure (MAP) is the average pressure exerted on the airway and lungs from the beginning of inspiration until the beginning of the next inspiration
**
MAP is the most powerful influence on oxygenation and must be carefully monitored because high levels of MAP lead to (3)
decreased cardiac output, pulmonary hypoperfusion, and increased risk of barotrauma
MAP levels above ___ have been associated with barotrauma
12 cm H20
The amount of gas inhaled in a single breath is called the
tidal volume
What are the 2 ventilator parameters that most directly affect the tidal volume in pressure control ventilation are
PIP and PEEP
Minute ventilation (VE) is tidal volume x RR
**
What vent changes can alter VE? (3)
- PIP
- PEEP (alters Vt)
- RR
VE is broken down into alveolar ventilation, the portion participating in gas exchange and dead space ventilation, the portion not participating in gas exchange
**
Deadspace is any gas that does not particpate in
gas exchange