Mechanical Ventilation Flashcards
What are the 2 different driving mechanisms for ventilators?
- Bellows - pneumatic
2. Piston - electric
What is the waste gas scavenging system?
- Prevents atmospheric contamination
- Collects all the extra gas and vapor from the system so you don’t get contamination of the air with volatile agents, etc.
The Bellows type ventilator is pneumatically driven. What does this mean?
- a pneumatic force compresses the bellows, which empties its contents (gas from flowmeters and vaporizer) into the circuit
- Gas goes into the bellow and fills it up and then gas comes outside the bellows and drives it down.
For the bellow type ventilator, what drives the bellows?
- Have to have an external gas source to drive the bellows
- The driving gas is oxygen, air, or a venturi mix of O2 and air
What drives the piston type ventilators?
- They do not need a driving gas
- They are electronically controlled and pneumatically driven
Bellows ventilators will not work without…?
Electrical power
All ventilators have backup batteries, how long will they last?
30 min
For ascending bellows, they go ______ during exhalation and _______ during inhalation.
up, down
Describe “hanging bellows” or descending bellows.
- Same concept as ascending bellows except they are upside down
- During exhalation they fall down due to a weight.
What is a possible safety hazard with “hanging bellows” or descending bellows?
- The bellows fall no matter what because of the weight, so if you have a disconnection or leak in the system you would not know
In ascending bellows, filling is dependent on ______…?
- exhaled gases from a tight circuit
Piston ventilators do not require _____…?
- A driving gas
Piston ventilators are driven by ________…?
- Compression from an electric motor
In regards to piston ventilators, tidal volume =?
- The surface area of the piston X the distance the piston moves to ventilate the patient
What are 4 advantages/disadvantages of piston type ventilators?
- Quiet
- No baseline PEEP
- Greater precision
- No gas needed to drive it
What is an advantage of bellow type ventilators?
- Able to see and detect disconnection from bellows falling
What is physiological PEEP?
3 or so
What does mandatory ventilation mean?
- Means that the patient will get ventilated no matter what, it doesn’t sense what the patient is doing
What are the 3 modes of mandatory ventilation?
- Volume control
- Pressure control
- Pressure control volume guarantee
What do you set for Volume Control?
- you set the tidal volume and respiratory rate
What varies in Volume Control?
Peak pressures (due to patient compliance)
What remains constant in Volume Control?
Minute ventilation remains constant
How should tidal volume be calculated?
8-10 cc per Kg of the ideal body weight
What do you set for Pressure Control Ventilation?
- You set the peak pressure and RR
What varies in Pressure Control?
- Tidal volume
- Minute ventilation
What is Pressure Control - Volume Guarantee?
- “Smart mode” that delivers the desired tidal volume with the lowest possible pressure using a decelerating flow pattern
- The ventilator automatically adjusts the pressure to achieve the volume that you would like to achieve
Specifically, how does Pressure Control - Volume Guarantee work?
- The first breath is a volume control breath, the patients compliance is determined and then the inspiratory pressure level is established for the subsequent breaths.
- It is anesthesia ventilation tailored to the patient’s compliance
What is Synchronized Intermittent Mandatory Ventilation (SIMV)?
- Combination of spontaneous breathing and mandatory ventilation
- Machine breathes are delivered to the patient at set intervals
- Meant to supplement patient’s own respiratory efforts - mechanical breaths are “synchronized” with respiratory effort
What are the 2 SIMV modes?
- SIMV - VC: you set the TV and RR
- SIMV - PC: you set the pressure and RR
What is Pressure Support Ventilation (PSV)?
- Used for patients who are spontaneously breathing
- You set the pressure support for the machine to deliver during spontaneous breathing
- Once the ventilator senses an inspiratory effort from the patient, the ventilator provides constant pressure to the airway to relieve work of breathing.
What is PSV- Pro?
- Back up ventilation incase patient stops breathing (30 sec apnea alarm)
- Back up mode is SIMV-PC + PS
- You set a minimum mandatory RR and pressure
- In between mandatory breaths, the patient receives pressure support
