Module 1 Exam: Classifications of Ventilation Flashcards
List the powering mechanisms
Electric, Pneumatic, and combined
How do you know if a machine is powered?
Look at machine to tell how its powered
What is the purpose of pneumatically powered vents?
To supply a gas that controls gas flow
What is the purpose of driving mechanisms?
Controls the direction of pressure/flow seperately
What vents are required for MRI?
Pneumatics and Fluidics
List the driving mechanisms
Pnuematic: clutch-valve, Servo, Solenoids, regulator, fluidics (not commonly used any longer)
Piston (electrically powered)- Linear Rotary
Bellows- driven by compressed gas source, may use one way valve, and compressed springs or weight if in a sealed chamber.
Microprocessor- all modern-day ventilators pneumatic controlled drive battery back-up
What is a control variable?
The variable measured by the ventilator control circuit and used feedback signal to control ventilators output.
List the control variables
Volume, pressure, flow and time is controlled by the vent during inspiration
In volume ventilation what variables change from breath to breath?
Pressure and flow
In pressure ventilation what variable changes
volume and flow
Control variables are responsible for inspiration or expiration?
Inspiration
List the cycles of ventilation
flow, pressure, volume or time
Define cycle?
When to stop inspiratory flow
Define limit?
Maximum amount of cycling of flow, time, pressure, and volume can attain.
List 5 phase variables
Trigger (pressure- set-1 to -2, flow-1 to 3LPM, manual) limit, cycle, baseline, and conditional variable
What are to ways to ventilate a patient?
Pressure and Volume
What are 3 things set on a pressure vent?
Pressure, flow, and rate
Define positive pressure ventilation
Set pressures being delivered to the airway that is higher than alveolar spaces.
What are some positive pressure vents?
Drager V500, PBI80 and PB 840, LTV 1200, and Evita
What are some negative pressure vents?
Iron lung and Chest cuirass
Define double circuited?
Ventilators that have 2 gas flows one to patient and one to machine. (1 limb)
Define single circuited?
ventilators in which the gas supply that powers the machine is the same gas to the patient. (2 limbs)
Define tubing compliance?
The amount of gas that is compressed in the circuit for every cmH2O generated during inspiration
Define compressed volume?
Amount of volume lost in the circuit due to tubing compliance - volume varies depending in the type of circuit.
Define internal resistance?
How well the flow pattern and pressure pattern can be maintained in the presence of back pressure
What is the flow wave patterns?
Square- a constant, depending on internal resistance to determine if it changes with back pressure
Sine- gradually increase flow until mid-inspiration due to action of rotary piston
Accelerating- gradually accelerates to peak and levels off
Decaying- reaches peak flow immediately, then gradually decelerates (air-mix)
What are the pressure patterns?
Reticular- due to square wave
Sigmoidal- due to sine wave
Exponential- due to accelerating wave
Parabolic- due to decaying
What determines shape of a waveform?
internal resistance
What are the alarms for ventilators?
O2 disconnect
high pressure/low pressure
high/low volume
fail to cycle
High/low PEEP
Time (I:E ratio)
Apnea
Pressure patterns are determined by.
Flow patterns
High/Low alarms indicate?
High alarms indicate- Obstruction /blockage
Low alarms indicate leaks/disconnect
What type of alram is O2 disconnect?
Low alarm/ low pressure limit, peep/cpap
What can cause low pressure alarms?
Disconnect, cuff leak, increased patient demand
What can cause high pressure alarms?
Cough, Biting ETT tube, Fighting VENT, needs suctioning, or kinked ETT tube
What can cause apnea alarm?
Disconnect or true apnea event (20 seconds)
What causes I:E ratio alarms?
Duration of inspiration is 50% or > OF TCT
When is low peep are activated?
Presence of leak in the patient ventilator circuit
Define trigger?
What initiates the start of inspirations
What controls the I:E ratio setting?
The respiratory rate
What is the purpose of PEEP?
To keep the alveoli, open during expiratory phase to allow gas exchange
What are the hazards of PEEP?
Air trapping and barotrauma
What is control mode?
All WOB is taken over by ventilator
Sedation required
Useful with ARDS when inversed ratio is required
Pressure varies
Patient cannot trigger breath
Preset volume and rate
What is A/C- V/C mode?
Constant preset volume
Pressure varies with each breath
Patient can trigger breath
Machine performs majority WOB
No spontaneous volumes
Sedatives administered to prevent hyperventilation
What is SIMV mode?
Set VT and RR
pt. can breathe spontaneously between breaths
Weaning and short term
What mode is PSV?
Delivers kick of pressure at the beginning of inspiration to help overcome increased resistance
Patient can trigger breath
Positive pressure set
Pt. can set own RR, VT, and flow
Used with CPAP and SIMV
Helps reduce WOB by ETT and tube
What mode is CPAP?
Pt. control RR, VT, AND FLOW
What mode is MMV?
Replaced by ASV Adaptive Support Ventilation
What mode is BIPAP?
Similar to CPAP but applies high pressure during inspiration and lower pressure during exhalation
Obstructive sleep apnea
Severe air rapping
Study advanced modes
