Respiratory monitors and equipment Flashcards
___________ is the force that acts opposite to the relative motion of an object.
Resistance
______________ is the ability of the lungs to stretch and expand.
Compliance
What are the type types of pulmonary compliance?
static compliance
dynamic compliance
What is static compliance?
assesses the pressure required to keep the lung inflated to a given volume when there is no air movement
What is dynamic compliance?
assesses the pressure required to inflate the lung to a given volume when there’s airflow
Dynamic compliance is impacted by
airway resistance and the tendency of the lung/chest to collapse
What is peak inspiratory pressure?
the maximum pressure in the patient’s airway during inspiration
What is plateau pressure?
the pressure in the small airways and alveoli after the traget tidal volume is achieved
We can evaluate the PIP and PP to determine if alterations in pulmonary mechanics are due to changes in __________ or __________
compliance or resistance
Increased resistance manifests as ___________ PIP with ____________ PP
increased; normal
Examples of increased resistance include
kinked endotracheal tube & bronchospasm
Decreased pulmonary compliance manifests as ________ PIP and _______ PP.
increased & increased
Examples of decreased pulmonary compliance include
endobronchial intubation and pulmonary edema
What is the resistance equation?
Resistance= [P(airway)-P(alveolar)]/gas flow rate
What is the compliance equation?
Compliance= delta V/delta P
Compliance measures the
elastic properties of the lungs and chest wall
Things that influence compliance include
muscle tone
degree of lung inflation
alveolar surface tension
amount of interstitial lung water
pulmonary fibrosis
In the adult, normal static compliance is
35-100 mL/cm H2O
In the child, normal static compliance is
> 15 mL/cm H2O
What is the static compliance equation?
static compliance= tidal volume/ (plateau pressure-PEEP)
What is the dynamic compliance equation?
dynamic compliance= tidal volume/(Peak inspiratory pressure-PEEP)
Complications of an elevated plateau pressure include
ventilator associated lung injury, pneumothorax, pneumomediastinum, and subcutaneous emphysema
If barotrauma exists, you should aim to reduce plateau pressure by
reducing tidal volume, inspiratory flow & PEEP
sedation is also helpful
Examples of increased resistance include
kinked endotracheal tube
endotracheal tube cuff herniation
bronchospasm
bronchial secretions
compression of the airway
foreign body aspiration
Examples of decreased compliance include
endobronchial intubation
pulmonary edema
pleural effusion
tension pneumothorax
atelectasis
chest wall edema
abdominal insufflation
ascites
trendelenburg position
inadequate muscle relaxation
If you have increased PIP with no change in PP
resistance has increased OR inspiratory flow rate has increased
If you have increased PIP and increased PP
total compliance has decreased OR tidal volume has increased
Capnography measures the
end-tidal CO2 concentration over time
Capnography permits continuous assessment of
metabolism, circulation, and ventilation
An increased alpha angle suggests
expiratory airway obstruction
An increased beta angle suggests
rebreathing due to a faulty inspiratory valve
There are two methods of carbon dioxide analysis:
mainstream (in-line)
sidestream (diverting)
Where is end-tidal CO2 measured?
Point D on the capnograph
Describe Phase 1 or A-B on a capnograph.
exhalation of anatomic dead space
Describe phase 2 or B-C on a capnograph
exhalation of anatomic dead space + alveolar gas
Describe phase III or C-D on a capnograph.
exhalation of alveolar gas
Describe phase IV or D-E on a capnograph.
inspiration of fresh gas that does not contain CO2
hat is a normal alpha angle
100-110 degrees
The alpha angle is measured at
point C
An increased alpha angle signifies
an expiratory airflow obstruction such as COPD, bronchospasm or a kinked endotracheal tube
The beta angle is measured at
point D
Normal beta angle is
90-degrees
Benefits of a mainstream CO2 analysis include
provides a faster response time and doesn’t require a water trap or pumping mechanism
Because mainstream CO2 analysis is attached to the endotracheal tube, it
increases apparatus dead space as well as adds extra weight
With sidestream sampling, the device is located
outside of the airway
Sidestream sampling requires
a water trap to prevent contamination of the device
