Ventilators And Airway Monitors Flashcards
Modern vents
4 phases
Classified by what
Inspiration, transition to expiration, expiration, transition to inspiration
Inspiratory phase characteristics, method of cycling
Expiration depends on what
Doesnt depend on vent, is passive, depends on airway resistance and lung compliance
Inspiratory characteristics Constant flow Delivers what regardless of what High p gas source Low p gas source
Constant ins gas flow regardless of circuit pressure
Ins flow constant despite changes w resistance or compliance
Varies to some degree w airway pressure
Non constant flow charac
Varies flow w inspiratory cycle
Constant pressure generators do what, flow stops when
Maintains constant airway pressure through inspiration regardless of insp gas flow. Flow ceases when airway pressure equals set insp pressure
Time cycled
What it is
How to calculate TV
Cycles from exp phase once time interval elapses from start of insp
Tidal volume is product of ins time and ins flow rate
Volume cycled
What it is
TV affected how
Terminates ins when preset TV is delivered. Most adult vents are set to this but have another limit on ins pressure to prevent barotrauma
%always lost to compliance of system. Usually 4-5cc/cmh2o
Difference between anesthesia and icu vents
Anesthesia: gas never reaches pt, modes are what drives vent not the gas
In icu gas that drives vent is what reaches pt
Power source
3 types
Compressed gas only
Piston power only
Compressible bellows gas and power
2 types of drive mechanisms
Types of bellows and what drives them
Double circuit bellows compressed by driving gas and pneumatically driven
Piston bellows compressed by electricity
Most vents are ___ cycled, ___ controlled, with a __ __ aspect
Timed, electronically, volume limiting
Bellows
Direction of bellows during __ determines classification
Ascending vs descending
Expiration
Ascending ascend on exp
Descending descend on exp
What kind of bellows aren’t safe
Hanging bellows, gravity
Volume expressed in what, what for minute volume
Avg for small or normal person
Mls, Ls
400-500, 600 mls
Pressure
Defined as what
Where its encountered
Expressed in what
Impedance to gas flow rate: breathing circuit, pt airway/lungs
Backpressure: airway resistance, lung-thorax compliance
Cmh20, mmhg, kpa
Flow rate What it is Where it is Referees to \_\_\_change/time Expressed in what
Rate at which gas volume delivered to pt
Pt connection of breathing system to the pt
Volume
L/sec, LPM
Bellows separate what
During ins phase the driving gas enters ___ and does what
Driving gas from pt gas circuit
Chamber, increases pressure
Increase in pressure during ins phase:
What 2 things happen
Ventilator relief valve closes so no gas can escape into scavenger
Bellows compressed and gas in bellows delivered to pt
During expiration
Drive gas exits where, what happens to pressure and relief valve
Bellows chamber, decreases to zero, opens
During expiration
Exhaled pt gas fills ___ before any ___ occurs because valve ball does what, scavenging only occurs when
Bellows, scavenging, produces back pressure, bellows filled completely
Relief valve is only open when, and what happens at this point
Expiration, scavenging
How to calculate pt tv through bellows
TV bellow + fresh gas flow - compressed circuit volume
Tidal volume
__ ml/kg
Rr __-__
Flow rate = what
10-15
8-12
4-6 x minute ventilation
How to calc minute ventilation
How to calc time spent on inspiration
TV X RR
TV/flow rate
How to calc TE
- Breaths per min, then find how many sec per 1 breath
2. Do that many seconds - ins time
Inspiratory pause/sigh
- does what
- what happens
- volume of gas to pt held in lungs until what
Inhalation time increased by 25%
Flow of drive gas stops, pressure in bellows stays same
Until exhalation
Set inspiratory pressure limit to what
35-40
Fio2
How to calc oxygen delivery
Co x o2 content
How to calculate oxygen content
Hgb x%sat x 1.39 ml o2
+ pa02 x .0031 ml 02
Hypoventilation: reduces ___ except when pt breathes oxygen
Pao2= \_\_\_-\_\_\_/ \_\_+\_\_ R= what F= what
Pao2
Pio2- paco2/ r + f
R= extraction ratio (0.8) F= correction factor, small
Every time you increase ___ by __% you increase pao2 by ___mmHg
FiO2, 10
50
Low pressure alarm detected by a drop in __ __ pressure
Sub atmospheric pressure alarm of ___ cm h20
Peak circuit
-10
Alarm for sustained pressure alarm of ___ cm h20 for more than __ secs
-15, 10
High peak airway pressure alarm detects excess pressure in system activated by ___ cm h20 or set by practitioner. What if kid
60, 35
Low ___ __ alarm
Ventilator setting alarm, vents inability to deliver desired __
Oxygen supply
MV
What is best for revealing a disconnect, and gold standard for how much you’re ventilating
ETCO2
Etco2 ___ what’s happening in blood
Underestimates
What is most imp monitor on the machine, calibrate at what
Oxygen analyzer
21% o2
Respirometer
___ __ and tidal volume __ __
Gas flow converted to what
Cartridge in which limb
Transducer cartridge, sensor clip
Electrical pulses
Expiratory
Exhaled vt to expect to measure is
Vt= ___ + ____ - ___
Vt set on vent
+ vt fresh gas flow
- vt lost in system
Which monitor activated once breaths sensed, always active while mechanically venting
Exhaled volume
Reverse flow alarms when
Apnea alarms when
Flow toward pt
If insufficient breath based on TV setting not achieved in 30 sec
ICU vents more ___ than OR ones. Allow for greater __ __ and ___ __
Other changes
Powerful
Inspiratory pressures and tidal volumes
Co2 absorber, more modes, gas supplied by vent directly vents pt in icu
Icu vents: ___ essential in anesthesia ones and not as much in icu
Bellows
Modes of ventilation
2
CV- controlled vent
IMV- vent delivers preset volume at specific interval, continuous flow of gas for spont vent
AC mode does what
Intermittent positive pressure. Pts insp effort creates sub baseline pressure in insp limb of vent that triggers vent to deliver a predetermined TV
AC- all breaths are what, can be controlled how
Full assisted vent breaths
Pressure or volume
How pressure support did from IMV
What goal of PS is
Airway pressure held constant in inspiratory pressure
Increase pt spont TV by delivering pressure to achieve 10-12 ml/kg volumes. Decreases WOB and muscle fatigue
High frequency vent
Low __ __, less than __ __, rate __-__
Typical settings
Tidal volumes, dead space, 60-300
100-200 BP
IT 33%
15-30 PSI drive pressure
Goal of high freq vent
Maintain pulm gas exchange at lower means airway pressures
Pressure control vent
__ or __ triggered, __ limited, __-cycled
Pt or time, pressure, time
Pressure control vent
__ __ decreases as airway pressure rises and creases when airway pressure = the set peak __ __
__ not fixed
When its used
Gas flow, inflation pressure
TV
Pressures can be high, neonate and premies
CPAP
In 1 lung anesthesia, giving CPAP to which lung and PEEP to which
Cpap to up lung, peep to down lung
If pressures greater than what cpap can cause regurg and aspiration
15 cm h2o
