Mechanical Ventilation Flashcards
What are the two types of mechanical ventilation?
-Negative pressure (not used in acute care setting)
-positive pressure (pushes air in)
What are the two subgroups of positive ventilation?
-Volume ventilation (predetermined tidal volume (Vt) is set. Pressure is determined by the pt and vent together and varies w/each breath.)
-pressure ventilation (peak inspiratory pressure & the volume is determined by the pt/vent w/each breath)
pressure vent is for inhale only & helps prevent alveoli collapse by keeping the pressure up
What are the two volume assisted vent MODES?
-A/C Vent (assist-control,*max support)
•preset tidal volume & RR
•Pt can initiate own breath but vent will do all work & deliver set volumes.
•used commonly in resp failure, ARDS, Paralysis
-SIMV (Synchronized intermittent mandatory vent)
•preset tidal volume & RR but Pt can initiate own breath W/own tidal volume
•commonly used for Pt weaning or strengthening lungs/WOB.
Pressure support vent setting
•won’t have preset volume
•Pt must be able to initiate own breath
•positive pressure is added to inspiration
•typically used for Pt weaning
•flow rate of + pressure is greater than the force of spontaneous breath —>
^ o2 reaches alveoli
Pressure control vent setting
PCV: gives breath w/set pressures. Pt can control RR & volume
Pressure control inverse ratio
PC-IRV:
•”last ditch effort setting”-Renteria
•extra inspiratory time than expiratory time allows for increased alveolar oxygenation
•short expiratory cycle keeps alveoli open
•need deep sedation d/t abnormal breathing pattern
•used commonly w/ARDS Pt’s who are hard to oxygenate
Airway pressure release ventilation
APRV:
•”not as much sedation/gentler setting” -Renteria
•allows spontaneous breathing but has preset CPAP
•no set Vt
•Delivers set of rapid inspiratory pressures (extra puff -think eye Dr test)
•good for Pt’s w/collapsed alveoli
Pressure regulated volume control
PRVC:
•dual modes together - full support (preset pressure & volume)
•sedation needed but it’s a gentler mode
Ancillary vent settings
“Peep those alveoli open” 🫁
-PEEP:
• + pressure applied at end expiration
•opens alveoli/prevents collapse
•range is 3-20cm h2O (5cm is natural occurring/healthy person)
•main goal of PEEP: improve oxygenation while decreasing the Fio2
- Warning* -increased PEEP levels Can cause barotrauma to alveoli and hemodynamic instability
warning the higher the peep the higher risk for decreased BP d/t intrathoracic pressure on the heart
Alternatives to Vents: CPAP
Continuous positive airway pressure :
•similar to PEEP but delivers continued expiratory pressure
•maintains 5cm H2O
•common uses: sleep apnea, CHF, COPD exacerbation
*caution in Pt’s w/cardiac impairment
Alternatives to Vents: BiPAP
Bilevel positive airway pressure:
•two levels of support (considered life support)
•high inspiratory & low expiratory pressures
•common Pt’s: COPD, CHF, RF, sleep apnea
•last ditch effort to prevent intubation
*contraindications: need to be conscious, not vomiting, no facial trauma or recent head sx
Hi-flow NC
•fills dead space
•delivers set flow rates
•less risk of mucosal damage
•can achieve peep (1cm H2O for Q 10L)
•similar to Bi-pap w/o claustrophobia
Vent complications (alveolar)
Alveolar hypoventilation: leaking cuff, low pressures, increased secretions or obstruction
Alveolar hyperventilation: Pt hyperventilating over set rate, tidal volume set too high or rate set too fast
Nursing considerations: Vent
•pain control/sedation
•reposition Q2hr/PRN
•oral care/suction
•maintaining alarms
•trach care
•monitor trends/vitals/labs
•participate in weaning trails/sedation vacations
Indications for intubation
•Resp distress is #1 indicator
•prolonged period of apnea (TBI, sleep apnea, drugs)
•Trauma/airway obstruction
•high risk aspiration/ineffective airway clearance(overdose/drunk)
