Test 2 Study Guide Flashcards
In HFOV, 1 Hz = ____ breaths/min
60 breaths/min = 1 Hz
(usually between 3-15 Hz)
Pressure Volume Curve: Areas in green show ?
The oscillatory breaths and the region occupied within a pressure-volume curve.
Pressure Volume Curve: Areas in orange show?
Injury
Pressure Volume Curve: What can appear in the lower left region?
Atelectrauma (low compliance)
Pressure Volume Curve: What can appear in the upper right region?
Volutrauma (low compliance)
How does HFOV oxygenate?
FIO2 and mean airway pressure oxygenate
How does HFOV ventilate?
Frequency (Hz), amplitude, and I-time ventilate.
the gas exchange between the lung units with different time constant
Pendelluft
during normal bulk gas flow causes gas in the center of the airway to move more rapidly than gas near the airway walls due to frictional effects
Gas streaming
simply enhanced diffusion of gas caused by the rapidly oscillating gas stream reaching the small airways
Taylor-type dispersion
Method of triggering a ventilator breath which uses natural electrical discharge from the diaphragm during inspiration (EAdia)
Neurally Adjusted Ventilatory Assist (NAVA)
The _____ is the primary difference between (NAVA) and other modes of mechanical ventilation
inspiratory signal trigger
the inspiratory signal is detected using _____
diaphragmatic electromyography (EMGdia)
In NAVA, The ventilator can be set to cycle to expiration when diaphragmatic signal reaches ___% to ___ % of its maximum signal strength.
40% to 70%
The ventilator can be set to cycle to ___ when diaphragmatic signal reaches (40% to 70%) of its maximum signal strength.
expiration
The idea in NAVA is to cycle to expiration based on a _____
diminished inspiratory (EAdia)
Why is NAVA cycled to expiration?
to prevent continued inflation by ventilator when patient’s central respiratory control centers have switched to the expiratory phase
Disadvantages of NAVA
Esophageal catheter cost, catheter discomfort, catheter displacement, and apnea
Advantage of NAVA
Improve patient–ventilator synchrony.
In case of apnea (or absence of an EMGdia signal), NAVA ventilator will return to a ___ mode as a safety feature
pressure-controlled mode
As (NAVA) levels are increased, ___ and ___ will increase
peak pressure and tidal volume
Optimal (NAVA) support allows patient to choose a ___ and ___ to maintain an appropriate (PaCO2) while sufficiently unloading the respiratory muscles
respiratory rate and (VT)
NAVA graphics: What does the yellow line mean?
Actual Pressure delivery
NAVA graphics: What does the gray line mean?
estimated pressure delivery
Optimal Placement of the NAVA Catheter
second and third leads are highlighted in pink and (Edi) signal is present
NAVA: The ____ waveform is very useful in identifying the mode of ventilation, as well as (PIP), (Pplateau), and baseline pressure (PEEP or CPAP)
The “pressure-time waveform,” also known as the “pressure-time scalar,
(Can also provide a visual representation of the inspiratory time, expiratory time, and (I:E ratio))
NAVA: The ____ provide visual confirmation of the patient’s actual inspired and expired tidal volumes.
Volume-time curves
NAVA: The ____ provides a graphic display of the inspiratory and expiratory gas flow versus time
The “flow-time curve” or “flow-time scalar
Maneuver which briefly holds the inspired breath prior to exhalation to obtain an inspiratory plateau pressure (Pplateau).
Inspiratory Pause
represents the force required to distend the lung within the thorax at a point of no gas flow.
Plateau pressure
(Hold for (0.5 to 2 seconds)
Formula for calculating RAW
RAW = (PIP – Pplateau) ÷ inspiratory flow rate
Normal RAW in intubated patients
(5 to 10 cm H2O/L/sec)
(RAW) is the difference between ___ and ___
(PIP) and (Pplateau).
What increases RAW?
Bronchospasm, increased secretions, mucosal edema, mucus plugging, (ETT) occlusion
Calculate the RAW given the following:
FIO2: .60
Peak Pressure: 38
Vt: 600
Flow: 40 LPM
Rate: 12
Pplat: 29
PEEP: 5
First convert flow:
40 LPM/60 = .67 L/sec
PIP-Pplat/Flow: 38-29/.67 = 13.43
Formula for static compliance
(CST) = VT ÷ (Pplateau – PEEP).
Normal static compliance for nonintubated patients
60 to 100 mL/cm H2O.
Normal static compliance for intubated patients
40 to 60 mL/cm H2O.
____ is determined by the patients lung compliance and thoracic or chest wall compliance.
Static compliance
What will decrease lung compliance
Atelectasis, pneumonia, pulmonary edema, (ARDS), and pulmonary fibrosis
Will cause decreased thoracic compliance
Thoracic cage deformities, ascites, obesity, and pregnancy
During volume ventilation, how is the (PIP) affected by a decrease in compliance
the peak inspiratory pressure (PIP) will increase
During volume ventilation, how is the (PIP affected by an increase in airway resistance?
an increase in airway resistance will directly cause the Peak Inspiratory Pressure (PIP) to increase
With an increase in (RAW), how is the (PIP- Pplateau) difference affected?
An increase in airway resistance (Raw) will result in a higher than expected difference between the peak inspiratory pressure (PIP) and plateau pressure (Pplateau)
How is the (Pplateau) affected by a decrease in compliance?
When compliance decreases, the plateau pressure will increase
Simplified alveolar air equation
PAO2 = PIO2 – (PaCO2/0.80)
What is the (PAO2) of a patient breathing (60% oxygen), with a (PaCO2) of (45 mm Hg) at a (PB) of (760 mm Hg)?
PAO2 = .60 (713) - (45/.80)
PAO2 = 427.8 - 56
PAO2 = 371.8
(Normal value is 100)
Formula for oxygen delivery
DO2 = (CaO2 x 10) × ̇QT
(Normal oxygen delivery is 1000)
Things that will include PAO2
Increase (FiO2)
Increased (PB)
Decreased (PaCO2)
Alarm settings for low TV
(100 mL) below set tidal volume
Alarm settings for low MV
(20%) above and below average minute ventilation (2 L/min)
Alarm settings for PEEP
2 to 5 cm H2O below set (PEEP)
Alarm settings for Peak Inspiratory Pressure
(5 to 10 cm H2O) above observed (PIP)
Apnea Alarm setting
(20 seconds)
Alarm settings for Respiratory Rate
(10 breaths/min) above total rate.
Level ___ alarms require immediate attention, cannot be silenced, and are life threatening
Level 1
(patient should be immediately disconnected from mechanical ventilation and ventilated manually via resuscitation bag with (100% FiO2) until the problem can be identified and corrected.
Replacing the ventilator with another unit should be immediately considered if the problem cannot be readily identified)
Level ____ alarms may be life threatening, if left unattended
Level 2
Level ___ alarms are generally associated with patient ventilatory parameter fluctuations including volume loss or lung mechanics alteration
Level 3
Examples of Level 1 alarms
Power failure
Control circuit failure
High or low primary line pressure
Exhalation valve failure
Examples of Level 2 alarms
Humidification failure
High/Low PEEP
FIO2 blender control failure
Circuit leak
Circuit occlusion
Examples of Level 3 alarms
AutoPEEP
High or low Ve
High or low Vt
High or low peak pressures
Effects of mechanical ventilation on the pulmonary system
Support tissue oxygenation and removal of carbon dioxide without causing additional trauma
◦Ventilating chronic (CO2) retainers to achieve a normal (CO2) may result in unwanted alkalosis.
◦(FiO2) to (0.70) within two days, (0.50) or less within five days
Limit use of (100%) oxygen to less than (24h) to avoid oxygen toxicity, absorption atelectasis, ventilation depression in chronic (CO2) retainers, and retinopathy of prematurity in neonates.
Effects of mechanical ventilation on the immune system
triggers activation of the inflammatory cascade.
Patients who receive large tidal volume ventilation and low (PEEP) have higher concentrations of inflammatory mediators
Ventilator-associated pneumonia (VAP) is a form of hospital acquired pneumonia which develops (48 hours) or more after the initiation of mechanical ventilation.
Clinical findings often include a new or progressive lung infiltrate on imaging, fever, purulent sputum, leukocytosis, and deteriorating oxygenation status
Signs of ventilator-associated pneumonia
new or progressive lung infiltrate on imaging, fever, purulent sputum, leukocytosis, and deteriorating oxygenation status
Effects of mechanical ventilation on the cardiac system
