Commonly Monitored Ventilator Settings Flashcards
What is the goal tidal volume for a patient on a positive pressure ventilator?
the maximum volume allowed to keep the peak airway pressure less than 30 mmHg while maintaining adequate ventilation
What increases as tidal volume or peak alveolar pressure increases?
the risk of lung injury
What is plateau pressure?
a reflection of the lung compliance
What does low lung compliance mean?
the lung is stiff
What does high lung compliance mean?
the lung has less ability to recoil
What kind of lung compliance is seen with conditions such as: emphysema or COPD?
high lung compliance
What kind of lung compliance is seen in patients with fibrosis or ARDS?
low lung compliance
How high does the tidal volume have to be to cause barotrauma?
more than 10mL/kg
Why does a tidal volume greater than 10mL/kg cause barotrauma?
it may overdistend the alveoli, increasing pressure, which my result in injury or rupture the alveolar space
What happens when volutrauma occurs?
overstretching the alveolar cells triggers release of inflammatory mediators and stimulation of the inflammatory response
What does volutrauma increase?
the permeability of the lungs’ microvasculature, which may result in pulmonary edema
What plateau pressure needs to be maintained for ventilation of the lungs?
pressure of less than 30 cm H2O
If a patient has a pulmonary disease that prevents them from being adequately ventilated, what may be used?
permissive hypercapnia
How does permissive hypercapnia work?
This technique deliberately allows hypoventilation by using low tidal volumes, and the healthcare team must determine goals for the PaCO2 and pH
What is the FiO2 at sea level?
.21
What range of FiO2 can a ventilator provide?
.21-1
What is FiO2 commonly set at during an acute decompensation event?
.5 to 1
Prolonged use of FiO2 greater than __ may cause complications associated with oxygen toxicity?
.6
What drug can increase the risk of hyperoxia-mediated lung injuries?
amiodarone
What is the normal range for minute ventilation for ventilator settings?
5 to 7 L/min
How is normal minute ventilation calculated?
Tidal volume multiplied by respiratory rate
Why is positive end expiratory pressure set?
to provide pressure at the end of expiration, to prevent alveolar collapse
Why would cardiac output decrease as PEEP levels increase?
because of the increase in intrathoracic pressure and decreasing venous return
What does the level of PEEP depend on?
the severity of the lung injury
When is assist control mode commonly used?
as a resting mode, particularly in patients with acute respiratory failure or respiratory muscle fatigue
What is the major disadvantage of using assist control mode on a ventilator?
it may cause muscle atrophy or ventilator-induced diaphragm dysfunction from the ventilator performing the work of breathing
What occurs when synchronous intermittent mandatory ventilation mode is used?
the patient spontaneously breathes through the ventilator circuit, maintaining much of the work of breathing
What are the benefits of using synchronous intermittent mandatory ventilation?
It decreases the risk of hyperventilation and provides a better ventilation-perfusion distribution, and it may reduce sedation needs as there is more synchrony with ventilation for the patient
What does pressure support ventilation mode do?
it is an adjunct weaning mode that enhances spontaneous inspiratory effort by application of positive pressure
How does pressure support ventilation decrease the work of breathing?
by overcoming increased airway resistance
What are the factors that determine the patient’s tidal volume?
the preset pressure support level, the degree of patient effort, and the level of airway resistance and lung compliance
Common range for PSV levels of cm H2O
5-15
What is pressure regulated volume control mode?
a dual control mode of ventilation where the pressure readjusts on a breath-to-breath basis to achieve the set tidal volume
If a patient is receiving ventilation that combines high respiratory rates, greater than 4 times the normal and tidal volumes smaller than anatomical dead spaces, what kind of ventilation is the patient receiving?
High-frequency oscillating ventilation
What is a potential consequence of high-frequency oscillating ventilation?
the requirement of sedation and neuromuscular blockade
When would a high frequency percussive ventilator be indicated?
with severe respiratory failure
When is airway pressure release ventilation indicated?
ARDS
When is the use of airway pressure release ventilation contraindicated?
in severe COPD
Why is the use of airway pressure release ventilation contraindicated in patients with COPD?
the hyperinflation may induce barotrauma
When is extracorporeal membrane oxygenation indicated?
severe lung injuries
What is considered a desirable PIP (peak inspiratory pressure) in an adult?
less than 40 cm H2O
Why are high PIP levels not ideal?
they greatly increase the risk of barotrauma and have negative effects on other body systems
What does a low exhaled volume alarm indicate?
a loss of tidal volume or a leak in the system
How can a cuff leak be checked?
by feeling for air leaking out of the nose and mouth
What should precede cuff deflation and why?
deep oral suctioning to prevent flooding the airway with contaminated secretions from the upper airway
What kind of alarm will sound in the event of coughing, biting on the ventilator tubing, secretions in the airway, or water in the tubing?
high pressure alarm
What needs to be checked following the initiation of mechanical ventilation?
ABGs
Barotrauma is associated with which ventilator setting?
High tidal volumes
What can a low minute ventilation cause?
Acute respiratory acidosis
PEEP affects the alveoli by doing what?
Maintaining them open at end expiration
What does an increasing PIP most commonly indicate?
Increasing airway resistance and/or decreasing lung compliance
