module 2 quiz Flashcards
What are the main types of flow patterns?
Constant = square
Decelerating
Ascending
Sine
What is the equation for determining what FiO2 you should put a patient on who is receiving mechanical ventilation?
Desired FiO2 = Desired PaO2 x Known FiO2 / Known PaO2
What are the risks associated with high FiO2s?
Oxygen toxicity
Absorption atelectasis
Describe absorption atelectasis
Nitrogen is washed out of the alveoli by excess oxygen, oxygen dissolves into the blood resulting in a low partial pressure in the alveoli causing atelectasis
What is extrinsic PEEP?
Level of PEEP set on the ventilator
What is intrinsic PEEP?
Amount of pressure in the lungs at the end of exhalation
What is total PEEP?
Extrinsic PEEP + Intrinsic PEEP
A pulse oximeter reading of 90% indicates a PaO2 of what?
At least 60 mmHg
What are the functions of PEEP?
maintain/restore FRC
Enhance tissue oxygenation
Recruit alveoli and maintain them in an aerated state
What is the minimum level of PEEP set on most patients?
2-6 cm H2O
PEEP usually set to 5
When is PEEP considered therapeutic?
When it is greater than 5 cm H2O
When considering patient oxygenation, when should you increase FiO2 and when should you increase PEEP?
Patient with a low PaO2 on less than 60% = increase FiO2
Patient with a low PaO2 on more than 60% = PEEP
When performing a vent check, what should you check on the vent and in the room as part of the routine check?
Alarm settings
External alarm connection
Air and oxygen connections
Power supply
Resuscitation bag and mask
Suction
ETT secure
What are the two options for humidifying air on a ventilator?
Heat moisture exchangers
Heated humidifiers
What is a normal range for triggering a breath using pressure on a ventilator?
-0.5 to -2.0 cm H2O
How is a breath triggered with flow?
Ventilator has bias flow which is the amount of flow available in the circuit and can recognize when there is an absence of flow due to patient effort
What is auto PEEP and when does it occur?
Auto PEEP is air trapping
Occurs in patients with a prolonged expiratory phase
What effect can a leak in the circuit have?
A leak in the circuit will cause a pressure change which can result in false or auto triggering of breaths
What issues can auto PEEP create?
Will make triggering a breath more difficult for the patient
Where is rise time found?
Only found in pressure breaths
PCV
CSV
PRVC
BiPAP
What is rise time?
The time in which airway pressure builds to the maximum pressure value set
What are the benefits of a longer Itime?
Larger tidal volume
More lung recruitment
Increased mean airway pressure
What are the cons for longer Itime?
Shorter time for exhalation can lead to air trapping
Not comfortable for patient
What is the relationship between flow and Itime?
Faster the flow = shorter the Itime
Slower the flow = longer the Itime
What is a closed loop mode?
Vent takes information it receives from the patients and alters how it delivers the breath
What factors can affect PIP?
Itime
Tidal volume
Flow
Compliance and resistance of patient lungs
What is an open loop mode?
Mode delivers a breath based on the information entered by the RT and does not respond to input from the patient
Define a set point targeting scheme
RT instructs the ventilator to deliver a certain breath, the vent delivers a breath as it was instructed
What are examples of modes with set point targeting schemes?
PC-CMV
AC-CMV
Define an adaptive targeting scheme
The delivered breath is monitored and the delivery of the next breath will be influenced by the previous breath
Define an optimal targeting scheme
Uses an algorithm to determine the best way to deliver breaths based off the patient
What are examples of modes with adaptive targeting schemes?
PRVC
What are the disadvantages of setpoint targeting?
High PIPs
Low tidal volumes
Vigilant monitoring with lots of adjustments