Exam 3- Anesthesia Machine II (7/13/23) Flashcards
A ventilator is an automatic device that will provide what two things to the patient?
- Patient ventilation
- Patient oxygenation
On the anesthesia workstation, ventilators essentially replace what component?
- The green reservoir bag
What ventilation mode was available from old ventilator models?
- Only offered volume-controlled ventilation
- No PEEP
- Couldn’t provide high enough PIP
Barotrauma is an injury that results from ______
- Injury resulting from high airway pressures
Compliance
- Ratio of a change in volume to a change in pressure (V/P)
Valve that opens to allow driving gas to exit the bellows housing
- Exhaust Valve
During INSPIRATION (Hint- I with E)
What is Fresh Gas Compensation?
- This is a way to prevent FGF from affecting tidal volume by measuring tidal volume and adjusting the volume of gas delivered by the ventilator.
The time during which lungs are held inflated at a fixed volume and pressure. (Inspiratory plateau)
- Inspiratory pause time
I:E ratio
- Ratio of the inspiratory phase time to the expiratory phase time
Normal I:E Ratio
- 1:2
- We spend more time expiring
Inverse ratio ventilation
- Inspiratory phase time is longer than the expiratory phase time
The sum of all tidal volumes in one minute
- Minute volume
Peak Pressure
- The maximum pressure during the inspiratory phase time
Spill Valve
- The valve in the ventilator that allows excess gases to be sent to scavenging system during exhalation
The energy that the patient/ventilator expends to move gas in and out of the lungs.
- Work of breathing
Factors that affect delivered tidal volume.
- Fresh gas flow
- Compliance
- Leak
On older vents, as FGF increases, what happens to tidal volume?
- Tidal volume increase
Newer vents have excess FGF divereted during inspiration
How do newer vents compensate for system compliance?
- Through pressure control - New vents will alter the volume delivered to compensate for system compliance (pressure control)
How does a leak affect delivered tidal volume?
- It will decrease tidal volume that can’t be compensated by the ventilator
Components to the ventilator.
- Driving gas supply & FGF (double circuit)
- Equal to Vm: if oxygen using flow control (1-2 L/min) + (4-5 L/min)
- Controls
- Alarms
- Pressure-limiting mechanism
- Bellows (accordion-like device)
- Housing
- Exhaust Valve
What does the driving gas do to the bellows?
- The driving gas is the gas external to the bellows that cause them to collapse.
What are the two standard alarms on the ventilator?
- Low-pressure alarm
- High-pressure alarm
What is the most common cause of low-pressure ventilator alarms?
- Disconnection of a circuit
What are examples of high-pressure ventilator alarms?
- Kinking of the ETT
- Occlusion of mask
What is a good set point for the pressure limit of the inspiratory pressure?
- 10 cmH2O above average inspiratory pressure
What is the housing of the anesthesia machine?
- Clear plastic cylinder
- Allows movement of bellows to be observed
- Has scale on side for rough estimation of tidal volume