Mechanical Ventilation Flashcards
Benefits of MV
facilitate lung expansion
improve gas exchange
decrease effort of ventilation
What is MV based on?
Pressure
volume
time and/or flow
Indications for MV
AFR
ARDS
hypoxemia
hypercapnia
airway protection
apnea/arrest
post op
What are 2 types of MV?
invasive and non invasive
What does invasive MV involve and why is it used?
ET-tube or trach
for prolonged respiratory support
What is non invasive MV and why is it used?
CPAP ( continuous positive airway pressure)
BiPAP (bilevel positive airway pressure)
for patients that can still breathe on their own but need resp support
Explain what FiO2 is?
Fraction of inspired oxygen
the concentration (%) of oxygen delivered to the patient
Why do you want the lowest possible FiO2?
avoid O2 toxicity
Explain tidal volume (Vt)?
Volume (amount) of air delivered to the lungs in one breathe
What is the typical range for Vt?
6-8 mL/kg
Why is choosing the correct Vt important?
to prevent lung trauma/injury
What can happen if Vt is too high?
Barotrauma or volutrauma
What can happen if Vt is too low?
atelectasis collapse of alveoli)
What is PEEP?
Positive End-Expiratory Pressure
pressure applied by the ventilator at the end of expiration to keep alveoli open
Typical range for PEEP
5-10
Purpose of PEEP
help improve oxygenation by preventing collapse of alveoli
maintains functional residual capacity
What is pressure support? When is it used?
Additional pressure applied during spontaneous breaths to reduce the work of breathing
when patients need extra help especially for weaning
What is the meaning of PaO2?
reflects how well oxygen is transferred from the lungs to the blood
PaO2 range
80-100
PaCO2 range
35-45
What are the volume controlled modes
Assist-control
synchronized intermittent mandatory ventilation
What are the pressure controlled modes?
pressure control and pressure support
Explain Assist-control MV mode?
delivers a SET tidal volume with each breath
patient can still initiate a breath
indications for assist-control?
pt can’t breathe or start breaths
pt cant protect their airway
ARF
post op
Reason for Assist-control?
ensure patient receives full tidal volume
Explain synchronized intermittent mandatory ventilation
delivers set number of breaths with PRESET Vt but allows spontaneous breathing
initiated breaths are not assisted
Indications for SIMV
weaning
pt cant breathe on their own but needs assistance to maintain adequate ventilation
Explain pressure-control ventilation
delivers breaths based on a set of inspiratory pressure
Vt will vary based on lung compliance
indications for PCV
ARDS
pt with high risk of barotrauma
pt with severe lung injury or high PEEP requirements
Explain pressure support mode?
only applies pressure during spontaneous breaths
indications for PSV
used to ASSESS patients readiness to wean
pt who may have muscle fatigue from breathing
Why is PSV used?
reduces work of breathing
Explain inverse ratio ventilation
inspiratory time is LONGER than expiratory time
higher risk of air trapping
indications for inverse ratio ventilation
Severe ARDS
patients with poor oxygenation
refractory hypoxemia
Why is IRV used?
to allow more time for gas exchange
keep alveoli open to improve V/Q
Explain Airway pressure release ventilation
A mode where pt breaths spontaneously while ventilator alternates between two levels of continuous positive airway pressure
Indications for ARPV
ARDS
refractory hypoxemia
pt at risk for ventilator induced lung injury
Reason for ARPV?
allows alveolar gas to be expelled by the lungs own natural recoil
allows maximum alveolar recruitment and oxygenation while allowing spontaneous breathing
Explain independent lung ventilation
each lung is ventilated separately using two ventilators double lumen
requires sedation and paralytics
indications for ILV
unilateral lung disease
ARDS in one lung
large lung abscess
single lung transplant
Reason for ILV
allows for tailored ventilation of each lung
Explain high frequency ventilation
uses very high respiratory rate
60-900 with low tidal volumes
pt must be sedated/NMB
breath sounds are hard to hear
indications for HFV
ARDS
severe lung injury in peds/neonate
Reasons for HFV
rapid rate for effective gas exchange
small Vt helps avoid overdistention of the alveoli
Nursing care for mechanical ventilation
continuous monitoring hourly
resp assessment
patient safety
suctioning
necessary medications
positioning
Signs of weaning intolerance
RR greater than 30 or less than 8
BP or HR changes
less than 90% SaO2
dysrhythmias
restlessness
What does low pressure alarms indicate and what do you do?
low exhaled volume
check for disconnection, cuff leak, or tube displacement
What do high pressure alarms indicate?
excess secretions
pt biting tube, kinks
coughing
PE
bronchospasm
pneumothorax
What do apnea alarms indicate and what do you do?
vent does not detect spontaneous breathing
check the vent, tube and patient
