Niv ventilatory modes

Noninvasive Ventilation

1. NIV Ventilatory Modes
Mostafa Elshazly
Professor Of Pulmonary Medicine
Chairman Of PCCU
KasrAlainySchool Of Medicine
Cairo University
[email protected]

3. •NPPVmustbeconsideredasarationalartandnotjustasan
applicationofscience,whichrequirestheabilityofcliniciansto
bothchoosecase-by-casethebest“ingredients”fora“successful
recipe”(i.e.patientselection,interface,ventilator,interface,etc.)
andtoavoidadelayedintubationiftheventilationattemptfails.

5. •TheuseofNPPVtotreatacuterespiratoryfailure(ARF)
hasexpandedtremendouslyovertheworldinthepasttwo
decadesintermsofthespectrumofdiseasesthatcanbe
successfullymanaged,thelocationsofitsapplicationand
theachievablegoals.

6. •NPPVhasbecomethefirst-choiceventilatortechniquein
•AE-COPD,
•Cardiogenicpulmonaryedema,
•Severehypoxemiainimmunosuppressionconditionsand
•Weaningfrominvasivemechanicalventilation(IMV).

8. •Infact,clinicianswhodonotapplyNPPVinthese
“golden”clinicalindicationswithintherighttime-frame
andsettingmaybebannedformalpractice

9. NPPVofferthesamephysiologicaleffectsofIMVdeliveredvia
endotrachealintubation(ETI)
•Respiratory muscle unloading,
•Gas exchange improvement and
•Augmentation of alveolar ventilation but
•Avoiding the life-threatening risks correlated with the use of an artificial airway

10. Avoiding the life-threatening risks correlated with the use of
an artificial airway
•Eliminates the risks associated with upper airway trauma,
•Reduces patient discomfort and
•Minimizes risk of conditions such as VAP and the need for
sedation;
•It preserves airway clearance and swallowing and

11. Avoiding the life-threatening risks correlated with the use of
an artificial airway
•Allows oral patency and intermittent ventilation so that
normal eating, drinking and communication are
permitted; additionally,
•Breaks from ventilation can be used for nebulized
medication, physiotherapy and expectoration.

12. Theoretically, NIV could be delivered using all the
modalities used for invasive ventilation
But, in real life, most ventilators used for NIV deliver
either volume or pressure-targeted ventilation.
Recent Ventilators use Hybrid Modes

13. NIV has two unique characteristics:
•Non-hermetic nature of the system.
•Ventilator-lung assembly cannot be
considered as a single compartment
model

15. •Unintentional leaks are very common in NIV
•It may be External or Internal
•Leaks can affect ventilator triggering,
pressurization, volume delivered, rate of
inspiratory pressuring and cycling function .
Non-hermetic
nature of the
system.

16. •During NIV a variable resistance
constituted by the UA is interposed
between the ventilator and the lungs.
•The UA may change its resistance to
airflow, compromising the delivery of
an effective tidal volume to the lungs.
Ventilator-lung
assembly cannot be
considered as a
single compartment
model

17. NIV has two unique
characteristics:
•Non-hermetic nature of the
system.(Leaks)
•Ventilator-lung assembly cannot be
considered as a single compartment
model (UA)
Both situations may
compromise the
delivery of an
effective tidal
volume.
As a consequence,
increasing the
delivered volume or
the delivered
inspiratory pressure
during NIV does not
necessarily result in
increased effective
ventilation reaching
the lungs

18. Modes Of Ventilation
•Theoretically, NIV can be delivered using all the modalities used in
invasive ventilation.

19. In this modality the ventilator
delivers a fixed volume during a
given time and will generate
whatever pressure is necessary to
achieve this, regardless of the
patient contribution to ventilation.
Advantage
•Strictdelivery,inthe
absenceofleaks,ofthe
presetvolume.
Disadvantage
•Amajordisadvantageis,precisely,
thatdeliveryofthisfixed
ventilatoryassistancedoesnot
allowtakingintoaccountthe
patient’svaryingrequirements
Volume-Targeted Mode

20. In this modality the ventilator
delivers a fixed volume during a
given time and will generate
whatever pressure is necessary to
achieve this, regardless of the
patient contribution to ventilation.
Advantage
•Strictdelivery,inthe
absenceofleaks,ofthe
presetvolume.
Disadvantage
•Ifthereisaleak,therewillbeno
increaseinflowratetocompensate
foritandthegeneratedpressure
willbelower,sothattheeffectively
deliveredvolumewillbereducedin
proportion.
Volume-Targeted Mode

22. Pressure-targeted ventilation
In this modality the ventilator is set to deliver airflow by generating a
predefined positive pressure in the airways for a given time. Airflow is
therefore adjusted in order to establish and maintain a constant Paw.
Flow is brisk at the beginning of inspiration when the gradient between the
circuit pressure and the pressure target is large. As this gradient narrows the
flow decelerates until driving pressure no longer exists and flow ceases .
Advantage of PTV is the ability to compensate for mild to moderate leaks

25. NIV: Volume or Pressure Targeted?
Most of the initial studies concerning NIV used VTM ventilators .
PTM ventilators were increasingly prescribed and surpassed VTM ventilators at
the end of the 1990s.
AlthoughstudiespublishedshowednosignificantdifferencesintermsofclinicalefficacyorABGs
results,aEuropeansurveyshowedthatmorethan75%ofhome-ventilatedpatientsusePTM
ventilatorsandthat,infact,VTMindicationswererestrictedtopatientswithneuromuscular
disease

27. A limitation of pressure ventilation is that it cannot
guarantee a tidal volume delivered to the patient.
Volume targeting is a feature available in some new
ventilators that could allow this limitation to be
overcome.

28. Volume-targeted pressure ventilation
A limitation of pressure ventilation is that it cannot
guarantee a tidal volume delivered to the patient.
Volume targeting is a feature available in some new
ventilators that could allow this limitation to be
overcome.

29. Volume-targeted pressure ventilation
This hybrid modality combines features of pressure
and volume ventilation.
The ventilator estimates the delivered tidal volume
and adjusts its parameters to ensure a
predetermined target tidal volume.

30. Volume-targeted pressure ventilation

31. Volume-targeted pressure ventilation

32. Common Setting Parameter
•Appropriatesettingsaredecisivetoobtainoptimalpatient
ventilatorsynchrony.

33. Common Setting Parameter

34. Common Setting Parameter
➢Pressure-based’ trigger
(Old, Closed circuit)

35. Common Setting Parameter
➢Flow-based’ trigger,
➢(Recent, shorter delay)

36. Common Setting Parameter
➢Leaks

37. Common Setting Parameter
➢The newer technologies
(microprocessors, servo valves
and fast blowers) have
substantially improved trigger
responses.

38. Common Setting Parameter
➢Ascorrectpressurizationisessential
todecreaseinspiratoryeffortand
improvesynchronization,during
thisphaseinspiratoryflowshouldbe
sufficienttomatchinspiratory
demand.

39. Common Setting Parameter
➢Afasterrisetimehasbeen
showntounloadrespiratory
musclesmorecompletely.

40. Common Setting Parameter
➢HighPFRmayincreasethe
sensationofdyspnoea,induce
doubletriggering,andleadto
highpeakmaskpressure,
favoringleaks.

41. Common Setting Parameter
➢Astheslopebecomesflatter,
themachinedeliverslower
flowratesandthepatient’s
workofbreathingincreases.

42. Common Setting Parameter
➢The inspiratory pressure level is
one of the main determinants
of the efficaciousness of NIV.

43. Common Setting Parameter
➢Optimallevelistheresultof
balancingtwoopposingaims:
➢Thedesiretoprovideeffective
MV
➢Minimizeleaksanddiscomfort

44. Common Setting Parameter
➢Time-cycled or
➢Flow-cycled
Cycling should coincide with the end of
patient effort. mainly determined by
respiratory mechanics ( ILD-COPD)
leaks may also delay.

45. Common Setting Parameter
➢Time-cycled or
➢Flow-cycled
Fixed (old) PFR
recent ventilators offer adjustable values

46. 25% of Insp. Flow
F
L
O
W
Time
Ventilator TI
25%
Peak

47. 50% of Insp. Flow
F
L
O
W
Time
Ventilator TI
50%
Peak

48. 75% of Insp. Flow
F
L
O
W
Time
Ventilator TI
75%
Peak

49. Common Setting Parameter
➢Time-cycled

50. Common Setting Parameter
➢Flow-cycled

51. Common Setting Parameter

52. Common Setting Parameter
ExpiratoryPositiveAirway
PressureThepr.deliveredby
theventilatorwhilepatientis
exhaling

53. •EPAPassistswiththemaintenanceofupperairwaypatencyin
sleep,whichmaybeimportantinpatientswithanunstable
upperairway(e.g.inOSA)andhelpstorecruit/maintainlung
volume,improvingoxygenation.
•Inobstructivelungdisease,EPAPhelpstoovercomethe
inspiratorythresholdloadwhenintrinsicPEEPispresent,
reducingtheWOBandmaximizingeffectivetriggering

54. How Do I Determine The Optimal EPAP Value?
•EPAPassistswiththemaintenanceofupperairwaypatencyinsleep,
whichmaybeimportantinpatientswithanunstableupperairway(e.g.in
OSA)andhelpstorecruit/maintainlungvolume,improving
oxygenation.

55. How do I determinethe optimal EPAP value?
•EPAP: Expiratory Positive Airway Pressure
•Maintainingan expiratoryflow throughtubing mandatory to washoutexpired CO
2
fromsingle tube circuits and masks
•EPAP increasesFRC (improvesventilation in obese subjects)
•EPAP preventscollapse of upperairwaysin subjectsproneto sleepapnea-hypopnea
syndrome («Pneumaticsplint»)
•EPAP counteractsthe negativeeffectof PEEP
Ion workof breathing

56. How do I determinethe optimal EPAP value?
•Overlapsyndromesandpatientswithsleepapnea-hypopnea
syndromes:EPAPvaluesmustbeadjustedtostabilizeupper
airway
•PEEP
I:rarely>4cmH
2OinCOPD(butreportedbygroup
ofNicholasHartaspotentiallyreaching6-8cmH
2O);PEEP
I
alsopresentinsevereobesity(OHS)
Some ventilators enable the clinician to set an EPAP range that adjusts the level of
PEEP applied in response to patient-related changes (auto-EPAP)

57. Common Setting Parameter
Inspiratory Positive
Airway Pressure( IPAP) The
pr. delivered by the ventilator while
patient is inhaling

58. How do I set the IPAP value?
•IPAP: InspiratoryPositive Airway Pressure
•IPAP –EPAP= Pressure support (or PS)
•PS = pressure support providedto the respiratorymuscles to compensatefor
theirweaknessand correct alveolarhypoventilation
•In a givensubject, relationshipbetweenPS and tidal volume (V
T) islinear
•Limits: leaks, tolerance, glotticclosure

59. •Titration of PS must aimto:
-normalizePCO
2(Arterialbloodsampleor PtcCO
2) and/or
•-obtaina targetV
Tof 7-8 ml/kg of idealbody weight
•NB: Reliabilityof estimation of tidal volume (V
T) by ventilatorsoftwares varies
considerablyfromone deviceto another, and dependson pressure levelsand
leaks
How do I set the IPAP value?

60. Common Setting Parameter
PressureSupport(PS)
The difference between IPAP And
EPAP (PS= IPAP-EPAP)

62. Common Setting Parameter
Risetime
Itistimetakentoreach
IPAPafteronsetof
inspiratoryphase

63. Flow
Pressure
Inspiration
Expiration
IPAP
EPAP
0
0
PS
Inspiration Expiration
Rise time

64. ➢Thefastertheramptime,thelesseffortthepatient
makes.
➢Thisisparticularlyimportantinthefirststagesof
ventilation,whenthepatienthasahighdriveandis
hungryforair.
➢Itisofnocoincidencethatthepatientundergoing
NIVcomplainsinthesephasesthat‘‘notmuchair
reachesme.’’
➢Themostinstinctivebehaviorwouldbetoincrease
theinspiratorysupport,butinfactitmightbe
sufficienttoincreasetheflowrate.

65. ➢Thefastertheramptime,thelesseffortthepatient
makes.
➢Thisisparticularlyimportantinthefirststagesof
ventilation,whenthepatienthasahighdriveandis
hungryforair.
➢Itisofnocoincidencethatthepatientundergoing
NIVcomplainsinthesephasesthat‘‘notmuchair
reachesme.’’
➢Themostinstinctivebehaviorwouldbetoincrease
theinspiratorysupport,butinfactitmightbe
sufficienttoincreasetheflowrate.

66. Rise time range: 100 –900 msec
•Shorterrisetimesallowashorterinspiratorytime(TI),anda
morefavorableI:Eratioinobstructiveconditions
•ShorterrisetimesareassociatedwithalowerWOB.
•inCOPD,risetimesettingisusually100or150msec;almost
never>250msec;
•inrestrictivedisorders,risetimemaybeabitlonger

67. Common Setting Parameter
Ti
Thetimeoverwhichthe
pressureismaintained,from
beginningtoendofinspiration

68. Common Setting Parameter
TiMax
Maximuminspiratorytimelimit
Itlimitstimespentininspiration

69. Common Setting Parameter
TiMin
Minimuminspiratorytimelimit
Itensuresadequatetimeisspentatinspiration

70. Pressurisation and cyclingwindow
•TI
MIN:
•Determinesminimal duration of pressurisation;
•TI
MAX:
•Determinesmaximal duration of pressurisation;
•Is a securityfeaturein case of important leaks: allowsthe ventilatorto cycle even
if the presetcyclingcriterion(percentage of PIF) isnot detectedby the
ventilator
•CyclingimperativelyoccursbetweenTI
MINand TI
MAX
•In COPD, TI
MAXmust be set to allow an I:E ratio of 1:3; in restrictive
disorders, computeTI
MAXfor an I:E ratio 1: 1.5 or 1:1

71. Flow
Pressure
Inspiration
Expiration
IPAP
EPAP
0
0
PS
Inspiration Expiration
PIF
Ti
MIN
Ti
MAX
Cycling occurs between
TI
MINand TI
MAX

72. NB: TI
MINmust be higherthanrise time!
Respiratory
Rate (BPM)
I:E= 1:2
(reference)
I:E= 1:3
(Obstructive
disorders)
I:E= 1:1
(Restrictive disorders)

73. Common Setting Parameter
Falltime
The time taken for inspiratory pr.
To fall to EPAP after ventilator
cycles into expiration

75. Common Ventilatory Modes
•CPAP
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

76. Common Ventilatory Modes
•CPAP
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

77. Common Ventilatory Modes
•CPAP
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

78. Common Ventilatory Modes
•S (Sponteous)
•In this mode, only available in PTV, the patient controls the beginning and
end of inspiration.

79. Common Ventilatory Modes
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)
➢The pressure is
maintained as long as a
minimal preset
inspiratory flow is
occurring.
➢End of inspiratory
assistance (eg, cycling
from inspiration to
expiration) occurs when
inspiratory flow reaches a
predetermined
percentage of peak
inspiratory flow

80. Common Ventilatory Modes
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)
In this mode,
a targeted inspiratory
pressure,
inspiratory trigger
sensitivity and
a percentage
threshold of peak
flow for cycling to
expiration (must be
selected).

81. Common Ventilatory Modes
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)
Apnea

82. Common Ventilatory Modes
•S (Sponteous)
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

83. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•Inthisparticularmode,cyclingfrominspirationtoexpirationisflow-
limitedinpatient-triggeredcyclesandswitchestotime-limitedwhenthe
patient’sspontaneousRRfallsbelowtheback-upRR,andalsowhenthe
inspiratorytimeexceedsapredeterminedmaximallengthduringS
cycles.C(PressureAssistControl)
•T (Timed)

84. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

85. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)
Pt. triggered
Machine triggered

86. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

87. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)

88. Common Ventilatory Modes
•S/T (Sponteous-Timed )
•PAC (Pressure Assist Control)
•T (Timed)
Flow Cycled Time cycled

89. Common Ventilatory Modes
•T (Timed) ,Control mode (C)
•In the control mode there is a preset automatic cycle based on time.
•The ventilator controls the beginning and end of inspiration and thus the RR.
•With this mode, the entire work of breathing is supposed to be performed by
the ventilator.

90. Common Ventilatory Modes
•T (Timed)

91. Common Ventilatory Modes
•T (Timed)

92. Common Ventilatory Modes
•PAC (Pressure Assist Control)

93. Common Ventilatory Modes
•PAC (Pressure Assist Control)

94. Common Ventilatory Modes
•PAC (Pressure Assist Control)

95. Common Ventilatory Modes
•PAC (Pressure Assist Control)

96. Initiating NIPPV
Initial settings:
•Spontaneous trigger mode with backup rate
•Start with low pressures
-IPAP 8 -12 cmH
2O
-PEEP 3 -5 cmH
2O
•Adjust inspired O
2to keep O
2sat > 90%
•Increase IPAP gradually up to 20 cm H
2O (as tolerated) to:
-alleviate dyspnea
-decrease respiratory rate
-increase tidal volume
-establish patient-ventilator synchrony

97. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
Everything Must be Ready, and Everything Must be Familiar

98. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Patientshaveindividualandunpredictableresponsesandsothe
commonpracticeistousetheventilatorandthemethodthatenables
thepredeterminedtherapeuticaimtobereachedatthelowest
humanandfinancialcosts,withthefewestundesiredeffectsforthe
patientandwiththebestcomplianceandtolerance.
There is No Such Thing as the Best Method of Ventilation

99. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•
Choose the Ventilator According to the Patient’s Need

100. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Itisimportanttohaveasbroadarangeoftypesandsizesof
interfacesaspossible,consideringthatallthishasacostforour
administrators,butthatontheotherhand,usingNIVavoidsother
moresubstantialexpensessuchasantibioticstotreatcasesof
intubationassociatedpneumonia.
There is no Single Interface Valid for All Patients

101. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Whenapatientisintubated,onlytheclinician’sbrainisworking,
whereaswhenweapplyNIVthisbecomesameansofinteraction
betweentheclinician’sbrain(throughtheventilator)andthatofthe
patient.
•Thepatientisthereforeanactiveandnotpassivepartofthe
ventilatoryprocessduringNIV
Explain What You Want to Do to the Patient

102. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•OneofthetrickstofacilitatethesuccessofNIVistoexplainthe
techniquetopatients,especiallythosewithoutgrosschangestothe
sensorium,beforeusingit.
Explain What You Want to Do to the Patient

103. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Restingthemaskonthepatient’sface,holdingittherewithahand,
butnotattachingitwithelasticsorheadpiecesandinthemeantime
switchingontheventilatoratalowpressureinordertodemonstrate
whatwearegoingtodo.
•Itmustbesaidthatsometimesaminimumofpsychologicalwarfare
cancomeinhand,forexample,recountingtheprocedureof
intubationanditspotentialsideeffectsiftheNIVisnotaccepted
Explain What You Want to Do to the Patient

104. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•NIVisnotatreatmentgivenbyasingleperson,buttheworkofa
team.
•Theearliestperiodisthemostcriticaloneandthesupportofatleast
twopeopleisoneofthekeystosuccessfulNIV
Never Work Alone

105. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Thetimefactoriscrucialinmedicine.
•Aclinician’sgreatestskillisthatofclearlyunderstandinghowfarhe
canpushwithoutharmingthepatient.
Be Aware of Your Limits

106. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•ThereareobjectivelimitstohowfaratrialofNIVcanbe
pushed;
Be Aware of Your Limits

107. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Everytherapyworthyofthenamemustbeevaluatedthrough
objectiveparameters.
•ThefortuneormisfortuneofNIVisthatitssuccessorfailureis
quicklypredictableinmostcases
•TheprobableimprovementsduringNIVareseenwithinafew
minutes.
Monitor and Record What You Do

108. Eight Rules To Remember When
Ventilating A Patient Non-Invasively
•Wemust,knowwhichparametertomonitor,whentomonitorit
andaboveallwhytomonitorthatsign.
•Remembertokeeptrackofwhathasbeendoneandrecord,write
anddocumenttheinformation,forthepersonwhowilllookafter
yourpatientwhenyouarenolongerthere.
Monitor and Record What You Do