ventilators and airway monitors

Question 1

stages of ventilation cycle

Answer 1

1 - inspiration
2 - transition from inspiration to expiration
3 - expiration
4 - transition from expiration to inspiration

Question 2

constant flow

Answer 2

• deliver constant insp gas flow regardless of a/w circuit pressure
• hi pressure gas source (5-50) allow stay sam regardless of changes in a/w resistance or compliance
• lo pressure (venturi) gas source varies to some degree w a/w pressure

Question 3

non constant flow

Answer 3

consistently vary flow w each insp cycle

Question 4

constant pressure generators

Answer 4

maintains constant a/w pressure throughout insp, irrespective of insp gas flow
gas flow ceases when a/w pressure equals the set insp pressure

Question 5

time cycled

Answer 5

• cycle tot the exp phase once predetermined interval elapses from start of insp
• TV product of set insp time and insp flow rate

Question 6

vol cycled

Answer 6

• terminate insp when preselected TV delivered (most are V cycled bu thane second limit on insp, pressure to guard against barotrauma)
• percentage of TV always lost to compliance of the system, 4-5cc

Question 7

pressure cycled

Answer 7

cycle into exp phase when a/w pressure reaches a predetermined level
TV & insp time vary

Question 8

flow cycled

Answer 8

BOTH pressure sand flow sensors that plow the vent to monitor insp flow at preselected fixed insp pressure
when flow reachers predetermined level, vent cycles from insp to exp

Question 9

power source

Answer 9

1 - compressed gas-gas only
2 - piston - power only (quiet, can’t hear things change)
3 - compressible bellows - gas & power ( most)

Question 10

drive mechanism

Answer 10

• double circuit bellows compressed by driving gas and pneumatically driven
• piston bellows comprised by electricity

Question 11

cycling mechanism in older machines

Answer 11

most vents are time cycled, electronically controlled w lvl limiting aspect

Question 12

bellows

Answer 12

direction of bellows movement during EXPIRATION determined classification

1 - ascending, ascend during exp
2 - descending, descend during expiration (gravity)

Question 13

pressure

Answer 13

impedance to gas flow rate
1 - breathing circuit
2 - pt airway and lungs

amt back pressure generated as result of airway resistance and lung thorax compliance (tube, elasticity)

Question 14

flow rate

Answer 14

rate at which gas vol delivered to pt, from pt connection of breathing system to pt,

vol change/time

Question 15

during expiration

Answer 15

• drive gas exits bellows chamber, pressure in bellows and pillot drop to zero, vent relief (ball) open
• exhaped pt gas fills bellows before any scavenging occurs (ball 2-3cm H2O), which occurs only after bellows filled completely
• relief valve only open during exp

Question 16

TV

Answer 16

10-15ml/kg

Question 17

RR

Answer 17

8-12

Question 18

flow rate

Answer 18

4-6/min vent

Question 19

MV

Answer 19

TV X RR

Question 20

I:E

Answer 20

• physiologic 1:2

Question 21

TI

Answer 21

TV/flow rate

500ml/30,000ml/min = .0167 X 60sec = 1 sec

Question 22

TE

Answer 22

determined by flow rate and RR/min
first figure out total tim elf ea vent for 1 min cycle…

60sec/12bpm = 5sec
exp time = 5-1 1:E = 1:4

Question 23

inspiratory pause

Answer 23

• inhalation time increased by 25%
• drive gas flow stops
• gas pressure in bellow housing system stays the same
• col of gas to pt is held inputs lungs until exhalation begins
• changes ratio to get exp you want (shorter exp)

Question 24

FiO2

Answer 24

delivery - COxO2 content

content - (hgb x %sat x 1.39) + (PaO2 x .0031)

Question 25

how much O2 to give?

Answer 25

- hypoventilation reduces PaO2 except when subject breathes enriched O2 mix -

Question 26

PaO2

Answer 26

PiO2 - PaCO2/ R+F ``` R = extraction ratio (0.8) F = correction factory (negligible) ``` each time you increase FiO2 by 10%, increase PaO2 by 50mmHg

Question 27

low pressure alarm

Answer 27

"disconnect alarm" | detected by drop in peak circuit pressure

Question 28

sub atm pressure alarm

Answer 28

pressure =/< -10 | pt starting to breath on mating, creating neg pressure

Question 29

sustained/continuing pressure alarm

Answer 29

15 for more than 10 sec

Question 30

high peak airway pressure alarm

Answer 30

normal 35-40 | detects excess pressure in system activated at 60 (or set by practitioner)

Question 31

vent setting alarm

Answer 31

vent inability to deliver desired MV set

Question 32

ETCO2 monitor

Answer 32

capnography is best for revealing disconnect

Question 33

O2 analyzers

Answer 33

most important monitor on machine calibrate at 21% in ambient air determine how much you're giving pt

Question 34

respirometer

Answer 34

vent setting, PAP monitors keep from delivering too much pressure - transducer cartrige and TV sensor clip - gas flow converted to electrical pulses - cartridge in exp limb - sensor clip snaps ionto transducer cartrige - exhaled vt expect to measure is... Vt = Vt set on vent + Vt fresh gas flow - Vt lost in system

Question 35

exhaled vol monitor

Answer 35

activated automatically once breaths are sensed and always active during mechanical vent

Question 36

reverse flow

Answer 36

alarm in flow toward patient

Question 37

apnea

Answer 37

if insufficient breath, based on TV setting, not achieved w/in 30sec

Question 38

ICU vs

Answer 38

- ICU vent more powerful, greater insp pressure & TV - CO2 absorber (pt rebreathing in OR) - ICU vent support more modes of vent - gas in ICU vent directly vent patient (OR, driving gas)

Question 39

CV

Answer 39

controlled ventilation by vent

Question 40

IMV

Answer 40

vent delivers preset vol at specific interval, while also providing cont flow of gas for spontaneous vent pt breaths spontaneously, while the vent delivers preset TV at predetermined interval through parallel vent circuit use as weaning technique fixed rate, NOT synch w pt

Question 41

SIMV

Answer 41

IMV, but synch w pts effort pt breaths spontaneously and at a predetermined interval the spontaneous breath is assisted by machine it times mechanical breath w the BEGINNING of spontaneous effort waking pt up in OR generates rest of breath for patient as soon as it detects pt breathing

Question 42

AC

Answer 42

intermittent mode of pos pressure vent pts insp effort creates sub baseline pressur ein insp limb of vent circuit that then triggers vent to deliver predetermined TV if pt rate drops below ppeset min rate, machine takes over w controlled vent mode all breaths pt takes are full assisted vent breaths can be pressure controlled or vol controlled

Question 43

pressure support

Answer 43

aid in normal breathing w predetermined level pos a/w pressure similar to IMV except than a/w pressure held constant throughout insp objective is to increase pt spon TV by delivering a/w pressure to achieve vol = 10-12 1- decrease work of breathing 2 - delay muscle fatigue

Question 44

high frequency vent

Answer 44

low total vol, less than dead space w high rate (60-300) typical settings 100-200bpm, IT 33%, drive pressure 15-30psi goal to maintain plum gas exchange at lower mean a/w pressures used in ESWL, ARDS must allow for exhalation

Question 45

pressure control

Answer 45

pt or time triggered pressure limited, time-ccyled mode of vent support gas flow decreases as a/w pressure rises and ceases when a/w pressure equals the set peak inflation pressure - TV not fixed - used in situation where pressure can be high - useful in neonates/premies

Question 46

CPAP

Answer 46

continuous pos pressure maintained during both insp & exp, only when pt is spent breathing can be provided w mask caution - if pressure > 15 can cause regurgitation & aspiration.