2. 2
Regardless of which operating mode is selected, it should
achieve four main goals: provide adequate ventilation and
oxygenation, avoid ventilator-induced lung injury, provide
patient-ventilator synchrony, and allow successful weaning
from mechanical ventilation
12. 12
The patient can breath
spontaneously without any
support or augmentation.
It can used for T-piece method
for SBT during weaning.
it can be used with PEEP.
It is associated with increased
WOB.
Apnea Backup ventilation
In the event of apnea, backup ventilation is recalled (set range
15-20 seconds), it deliver predetermined values according to
mode VC or PC
13. 13
It maintains a continuous level of
positive airway pressure PAP in
a spontaneous breathing.
Expiratory PAP > inspiratory PAP
> zero baseline.
Recruitment and Oxygenation
It may be helpful in refractory hypoxia and atelectasis;
preservation of FRC and reduction of WOB
14. 14
It applies a preset pressure
plateau to airways for the
duration of spontaneous breath.
Starting spontaneous breath, it is
augmented by preset limited
pressure, and ends the breath
when flow is reduced when
reduction by 10-25% of PIFR.
Importance
PSV augments patient’s inspiratory efforts, increasing tidal volume and
reduction of WOB
15. 15
Importance
PSV needs a competent drive and
adequate efforts.
It can not be used in deeply
sedated nor paralyzed patients,
and in ARDS/shocked patients.
It is commonly used as a recovery
mode; with SIMV and mode of
weaning.
PSV level is titrated until spontaneous tidal volume 10 ml/kg and frequency
less than 25 b/m; add-on PEEP.
Once PSV level is less than 10 cmH2O with adequate effort; it is time for
weaning SBT.
18. 18
Mandatory solo MV doses all of
the work; preset start of breath ,
target variables (VC or PC), and
end of breath, without any
patient effort
Patient Criteria
The patient is properly medicated with sedation and NMBAs
19. 19
Indications
CMV (with sedation and
NMBAs) is indicated for patients
fighting the MV.
Also in status epilepticus with
complete anesthesia/anti-
epileptic infusions, or in cases of
crushed chest injury or impaired
ventilatory drive or pump.
Complications
As the patient is totally dependent on MV; there is apnea and hypoxia when
accidently MV-patient disconnection, and prolonged difficult weaning due to
diaphragmatic disuse atrophy and oxidative injury.
20. 20
The patient may increase MV assisted frequency (patient triggered) in
addition to the preset MV controlled frequency (time triggered).
AC dose not allow the patient to take the whole spontaneous alone
21. 21
The patient starts breath, then
the MV delivers the breath
achieving preset targets
variables, and breath ends by MV
preset data.
With adequate patient
ventilatory drive of 12/min,
minimum control frequency is
10/min.
Indications
As a resting mode, MV provides full ventilatory support while permits the
patient (when able) to trigger MV into inspiration; used in ARDS, ACPO,
shock, and multisystem trauma, or impaired ventilatory drive or pump.
22. 22
Advantages
Reduction WOB, and the patient
is allowed to control RR and
minute volume according to his
demand and efforts.
Disadvantages
With patient rapid breathing, it causes alveolar hyperventilation with
alkalosis, and hyperinflation with auto-PEEP.
23. 23
Intermitting Pattern
periodic VC/PC mandatory
breaths and PSV supported
spontaneous breaths in between.
It is not continuous mandatory
nor spontaneous breathing
The patient can decide his own
frequency of supported breaths, in
addition MV gives a set number
of mandatory breaths to
supplement patients won efforts
24. 24
The mandatory AC breaths are synchronized with the spontaneous
breaths efforts to avoid breath-stacking double-triggering (associated
with high alveolar volume and overdistension-volutrauma, or high
AW pressure and barotrauma)
25. 25
During this window
If there is patient inspiratory effort, the
MV is patient-triggered to deliver
assisted mandatory breath.
If there is no patient inspiratory effort,
the MV is time-triggered to deliver
controlled mandatory breath.
Synchronization Window
In-between these windows
The patient is permitted to take
supported spontaneous breaths,
depending on his demand/effort
26. 26
Indications
The primary indication for SIMV is to provide partial ventilatory
support; keeping the patient actively involved in providing part of the
minute volume. It was introduced as a method for weaning.
VC-SIMV with PSV PC-SIMV with PSV
27. 27
Advantages
It maintains respiratory muscles
strength by avoiding their
atrophy, and it decreases mean
AW pressure, plus it facilitates
weaning.
Disadvantages
Early use of SIMV can lead to
increased WOB of spontaneous
breaths, and muscle fatigue with
weaning failure.
28. 28
Conventional modes
Variables are affected by
patient effort and demand
plus ventilatory drive and
mechanics
To be adjusted, they need
input from the clinician
The ventilator dose not
adapt to dynamic changes
Smart modes
Variables with dual control
change in proportion to
patient effort and demand
plus ventilatory drive and
mechanics
Automatic and adaptive
achievement of preset
targets and limits
29. 29
Guaranteed Adequate MV
with Limited Safe Pressures
Computerized FB
systems make online
smart automatic
adjustments in tidal
volume, frequency,
airway pressures, and
timing of the
respiratory cycle
Improved
Patient-Ventilator Synchrony
Limited
VILI and HD instability
Improved
VQ matching and Vent-Oxyg
Reduced
WOB and sedation
30. 30
Pressure-limited Time-cycledbreath-to-breath
PC-ACV VC-ACV
Smart ventilator compares the delivered Vt/MV with the
preset Vt/MV
The physician presets Vt target, and the ventilator delivers a
pressure-limited breath, until that preset Vt is achieved
The ventilator adjusts Vt target , and Ti/I:E values, plus limit
of IP, with RR according to patient-A or MV-C
The IP is automatically adjusted or to deliver a preset Vt;
according to change of mechanics R/C
If delivered Vt is equal, there is no action
If delivered Vt is low, it increases IP on the next breath
If delivered Vt is high, it decreases IP on the next breath
PRVC – APV – VC+
31. 31
Pressure-limited Flow-cycled breath-to-breath
PSV VC-SIMV
Smart ventilator compares the delivered Vt/MV with the
preset Vt/MV
The physician presets Vt target, and the ventilator is triggered
to a pressure-limited breath according to patient spontaneous
effort, until that preset Vt is achieved
The ventilator adjusts Vt target plus limit of IP, and RR plus
Ti/I:E values according to patient spontaneous effort
The PS is automatically adjusted or to deliver a preset Vt;
according to change of mechanics R/C
If delivered Vt is equal, there is no action
If delivered Vt is low, it increases PS on the next breath
If delivered Vt is high, it decreases PS on the next breath
VSV – MMV
32. 32
Pressure-limited Flow-cycled within-breath
PSV VC-ACV
Smart ventilator compares the delivered Vt with the preset Vt
The physician presets Vt target, and the ventilator is triggered
to a pressure-limited breath according to patient spontaneous
effort, until that preset Vt is achieved
The ventilator adjusts Vt target, plus limit of IP, and RR plus
Ti/I:E values according to patient spontaneous effort
Each breath is automatically shifted to and from VC-ACV
If delivered Vt is equal, there is no action
If delivered Vt is low, it forms constant inspiratory flow to
reach preset Vt
VAPS
33. 33
Variable Support-Control Automode/Adaptive
PSV/PC-ACV VC-SIMV/ACV
Automatic shift from supported to assisted breaths of dual-
control nature, plus Adaptive manner to meet needed MV
If there is no spontaneous effort, the ventilator is set up in
PRVC mode (time-cycle)
If there are adequate spontaneous breaths, the ventilator
shifts to VSV mode (flow-cycle)
Proportional Assist Ventilation PAV
No preset limits or targets
This mode supports patient spontaneous breathing in
proportion to his effort/demand and change in mechanics
Constant WOB regardless changing effort/demand
34. 34
Dual control with Time-cycling
Depends on ventilator delivery/triggering
Not for weaning
Dual control with Flow-cycling
Depends on adequate patient spontaneous efforts
Self weaning mode
Variable support-control
Automatic weaning from ventilator delivery/triggering to adequate
patient spontaneous effort
Proportional support
Depends on adequate patient spontaneous efforts
Variables are delivered in proportion to effort/demand
Guaranteed Adequate MV with Limited Safe Pressures
36. 36
The lowest possible IP is
used to deliver preset Vt/MV
With PC-ACV
If delivered Vt is equal, there is
no action.
If delivered Vt is low, it increases
IP on the next breath; to achieve
preset Vt
If delivered Vt is high, it
decreases IP on the next breath;
to achieve preset Vt
Automatic adjusting IP for VC breath by
altering PIFR and Ti; in response to
mechanical AW and lung changes R/C
PC-ACV VC-ACV
37. 37
Disadvantages
It may result in air-trapping and
auto-PEEP, and it may be poorly
tolerated in non-sedated patients.
Test for
compliance and
set IP limit
Delivery at
previous measured
values
Modify PIFR
and Ti to deliver
target Vt and
under-limit IP
Indications
Guaranteed Vt with preset lowest
PIP in ARDS or asthma and
COPD; allowing adequate alveolar
ventilation plus oxygenation.
38. 38
Compare delivered Vt with
desired preset Vt
No set for RR or Ti
If delivered Vt is equal, there is
no action.
If delivered Vt is low, it increases
PS on the next breath; to achieve
preset Vt
If delivered Vt is high, it
decreases PS on the next breath;
to achieve preset Vt
If apnea, it is shifted to PRVC
PSV VC-SIMV
39. 39
Compare actual patient effort
MV with desired preset MV
With PSV actual MV ≥ preset
MV; no action.
With PSV actual MV < preset
MV; activation of MMV,
operating with SIMV with
adjusted AC Vt and frequency
to reach preset MV.
Once adequate recovery of
spontaneous drive; return to
baseline PSV.
Partial Full Partial
Automatic smartly ensuring adequate preset MV; preventing hypoventilation
and hypercapnia
PSV SIMV
40. 40
Compare delivered Vt with
desired preset Vt
With PSV delivered Vt ≥ preset
Vt; no action.
With PSV delivered Vt < preset
Vt; activation of VAPS,
operating with VC-AC to adjust
inspiratory flow and time; to
reach preset Vt.
Partial Full Partial
Providing optimal inspiratory flow and
tidal volume with targeted pressure;
reducing WOB and adequate ventilation.
It may prolong inspiratory time,
resulting in air-trapping in COPD
PSV VC-ACV
41. 41
Compare delivered effort
MV with desired preset MV
Passive patients; the ventilator
adjusts the appropriate values
of Vt/RR/Ti/I:E plus limited IP;
to maintain preset MV; PC-
ACV plus guaranteed MV
Active patients trigger
ventilator to decrease PC
breaths, and to increase PSV
level until preset Vt/RR;
maintaining preset MV
Excellent mode for ventilation Initiation ----- Support ----- Weaning
ASV is adaptive to patient demand/effort and dynamic mechanics/drive
More PSV breathing ----------------- Less PC-ACV breathing
Guaranteed minute volume with Limited safe inspiratory pressure
PSV SIMV or PC-ACV VC-ACV
42. 42
Clinician Input
Limit of IP/PEEP/FiO2 ,and
patient IBW, plus desired
target MV (100 ml/kg/min)
Ventilator Analysis
Dynamic compliance
Ventilator Adjustment
Vt/RR and Ti/I:E plus limit
of IP
Final Adaptation
Reach to guaranteed MV
with PC or PSV
Used as full support in
ARDS/COPD, and for
facilitated weaning
44. 44
Automatic shift from
supported to assisted breaths
of dual-control nature, plus
Adaptive manner to meet
needed MV
If there is no spontaneous
effort, the ventilator is set up in
PRVC mode (time-cycle)
If there are adequate
spontaneous breaths, the
ventilator shifts to VSV mode
(flow-cycle)
Excellent mode for ventilation Initiation ----- Support ----- Weaning
It is adaptive to patient demand/effort and dynamic mechanics/drive
More PSV breathing ----------------- Less PC-ACV breathing
Guaranteed minute volume with Limited safe inspiratory pressure
VSV PRVC
45. 45
Amplification of patient
effort, without preset
limits or targets, with
constant WOB
Measurement of flow/Vt pulled
by the patient
Calculation of respiratory
elastance and resistance
Determination of proportional
support to overcome E/R
Delivery the needed pressure
This mode supports patient
spontaneous breathing in
proportion to his effort/demand
and change in lung mechanics
47. 47
PC-IVR allowing biphasic
spontaneous CPAP
Inhalation phase high pressure and
time is more than exhalation phase
low pressure and time.
High period is for constant alveolar
recruitment and oxygenation.
Low period is for release and
ventilation; avoided derecruitment as
it is short period.
During high and low phases
If there is enough effort, it allows
Bi-CPAP spontaneous breathing.
If there is no respiratory effort, it
becomes a form of inversed ratio
pressure limited ventilation.
PC-IRV Bi-CPAP
48. 48
It allows lung protective strategy,
alveolar recruitment, and improves
oxygenation and hemodynamics in
ARDS, plus allowing spontaneous
breathing and patient-ventilator
synchrony, so less sedation/NMBAs.
It may be complicated with potential
volutrauma due to dynamic
hyperinflation, and increased WOB.
49. 49
PC-AC allowing biphasic
spontaneous CPAP or PSV
Inhalation phase high pressure and
time is and exhalation phase low
pressure and time.
High period is for constant alveolar
recruitment and oxygenation.
Low period is for release and
ventilation.
During high and low phases
If there is enough effort, it allows
Bi-CPAP or Bi-PSV spontaneous
breathing.
If there is no respiratory effort, it
becomes a pressure limited
ventilation.
Bi-level
PC-AC CPAP/PSV
50. 50
APRV
PC-IRV Bi-CPAP
The patient spends most of time
at level of high pressure.
BIPAP
PC-AC Bi-CPAP or bi-PSV
The patient spends most of time
at level of low pressure.
52. 52
IRV mode
Improved oxygenation
Prolonged inspiration allows
alveolar recruitment, and
shortened expiration allows for
auto-PEEP and prevention of
decruitment.
Constant volume alveoli
Improved VQ plus reduced
shunt.
Indication
In ARDS with sedation/NMBAs
I:E > 1:1 (2:1 – 4:1)
Disadvantages
Overdistension and barotrauma,
and increased trans-vascular fluid
shift with APO, and it needs
sedation with NMBAs
53. 53
PC-IRV
Increasing Ti increasing
inspiration time-cycling
VC-IRV
Slowing PIFR increasing
inspiratory time flow-cycling
Inspiratory pause increasing
inspiratory time time-cycling
57. 57
CPAP with a wiggle
Time-cycled very high rate breaths with
small Vt, oscillating around a steady AW
pressure
No overdistension Nor derecruitment
58. 58
Advantages
Uniform Steady AW and
alveolar inflation pressures,
with constant recruitment and
prevented decruitment.
Reduced risk of Volutrauma,
Barotrauma, Biotrauma, and
Atelectrauma.
Improved VQ and gas exchange.
Indication
As a rescue treatment in ARDS
refractory to ventilation and prone
position; when ECMO is not
available nor suitable
Disadvantages
Hemodynamic instability, and
increased ICP, need for
sedation/NMBAs, and frequent
suctioning of AW to reduce
obstruction.
