MV: strategies for managing asynchronies

Insp flow mismatch

1. increase flow

2. decrease resp drive

3. assess sedation + analgesia

4. check for dyspnea

short or prolonged cycling

1. increase or decrease Ti

2. turn OFF cycling in PS

3. use proportional modes

double triggering

1. increase Ti

2. try PS

3. titrate flow termination to improve synchrony

double triggering due to reverse triggering

1. decrease sedation

2. check RR

exp muscle contraction due to prolonged cycling

lower Ti by checking cycling OFF and VT

ineffective inspiraotry efforts

1. check trig sens + excessive iar trapping

2. check excessive assistance (too high of RR, Ti and/or PS)

3. counterbalance aPEEP w/ PEEP

4. check for dyspnea

auto triggering

1. check trig sens

2. check for leaks + water in circuit

exp muscle contraction during expiration

1. check for excessive assistance

2. check air trapping + aPEEP

trigger delay definition, causes + solutions

asynchrony b/w resp drive + insp trigger as there is a time lag b/w onset of pt. effort and onset of flow delivered by vent. This is caused by low sens or RR drive or presence of aPEEP or obstruction in tubing

1. adjust trigger sensitivity

2. +PEEP to counter aPEEP

3. replace HME/ETT/NIV interface

ineffective efforts

asynchrony b/w resp drive + insp trigger, or b/w neural Ti and vent cycling variable as vent is unable to detect pt’s neural effort despite presence of insp effort. This is caused by low trigger sens, weak drive, aPEEP or delayed cycling

1. adjust trig sens

2. reduce sedation/prevent depletion of RR drive

3. reduce support

4. fix pH

5. increase PEEP to counter aPEEP

6. shorten Ti

auto-triggering

asynchrony b/w resp drive + insp trigger, being a mech breath not triggered by pt. insp effort beyond mandatory breath. This is caused by high trig sens, leaks or random noise in circuit

1. adjust trig sens

2. reduce noise

3. remove leaks

double-triggering

asynchrony b/w vent need + control variable gas delivery or b/w neural Ti and vent cycling variable, being 2 mandatory breaths that may/may not be separated by very short Te. This is caused by short cycling due to insufficient assistance, short cycling due to high exp trigger threshold in PSV mode w/ low compliance and high drive

1. increase Ti

2. increase flow

3. optimize pressure rise time in PSV mode

4. remove cause of reverse triggering

reverse-triggering

vent cycling variable synchrony where vent insufflation triggers diaphragmatic muscle contraction. This is caused by over assistance or deep sedation

1. reduce assistance

2. reduce sedation

cycling asynchrony

asynchrony b/w neural Ti + vent cycling variable, being a mismatch b/w pt. resp neurological output + vent’s Ti. This is caused by neural time being greater than vent Ti or vice versa.

1. adjust Ti

2. check for excessive assistance

3. reduce leak

flow asynchrony

asynchrony b/w vent need + control variable gas delivery as vent’s delivered gas flow is less than pt’s insp flow demand. This is caused by low gas flow or pressure rise time is too low

1. increase gas flow

2. adjust insp flow

3. decrease resp drive w/ drugs

4. increase pressure rise in PC mode.

Low shit? (VT, Ve, P)

think leak!

1. circuit (heater, pressure line)

2. tube (too high, cuff leak)

3. pt. (chest tube, TE fistula)

low BP?

1. tension pneumo

2. aPEEP

3. increased intrathorcaci pressure

4. MI

high peak, normal plat?

resistance!

1. circuit (water, HME or filter overload w/ moisture)

2. tube (mucous plug, biting)

3. patient (bronchospasm, obstruction)

high peak, high plat?

compliance!

1. circuit, tube (right mainstem)

2. patient (increased secretions, pulm. edema, ARDS, aPEEP, pneumonia, decreased CW comp)

hypoxia w/o vent clues?

1. DS

2. fluid shift

3. cardiac shunt

DOPES

Displacement
Obstruction
Pneumo
Equipment failure
Secretions/stacking/synchrony

DOTTS

Disconnect
O2
Tube
Tweak (alarms? more Te? new mode?)
Scan (CXR, etc.)