Mechanical ventilation, understanding modes.

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Rob Chatburn, RRT RRT-NPS, FAARC
Research Manager – Respiratory Therapy
Cleveland Clinic
Associate Professor
Case Western Reserve University

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Mechanical ventilation, understanding modes.

  1. 1. MechanicalVentilation<br />UnderstandingModes<br />RobChatburn,RRT-NPS,FAARC<br />ResearchManager–RespiratoryTherapy<br />ClevelandClinic<br />AssociateProfessor<br />CaseWesternReserveUniversity<br />1<br />
  2. 2. Overview<br />•Characteristicsofmodes<br />–Pressurecontrolvsvolumecontrol<br />–Graphicalrepresentationsofmodes<br />•Breathtypes<br />–Mandatoryvsspontanous<br />–Assistedvsunassisted<br />•Breathingpatterns<br />–Definitions,indications,examples<br />–Graphicalrepresentations<br />•Computercontrolofmechanical<br />ventilation<br />2<br />
  3. 3. CharacteristicsofaMode<br />1.BreathingPattern<br />–<br />–<br />Controlvariable<br />Breathsequence<br />2.ControlType<br />–<br />Setpoint,auto-setpoint,servo,adaptive,optimal<br />3.ControlStrategy<br />–<br />–<br />Phasevariables<br />Operationallogic<br />3<br />
  4. 4. ControlVariables<br />Pvent=ExV+RxV<br />Ventilatorcancontrolonlyonevariableatatime<br />Independentvariableiscontrolvariable<br />4<br />
  5. 5. VolumeControl<br />•Tidalvolumeandflowpreset<br />•Airwaypressurechangeswithlung<br />mechanics<br />•Advantage:<br />–Minuteventilationandgasexchangestable<br />•Disadvantage:<br />–Volumeandflowmaynotbeoptimal<br />5<br />
  6. 6. PressureControl<br />•Airwaypressurepreset<br />•Volumeandflowchangewithlung<br />mechanics<br />•Advantage:<br />–Betterpatientflowsynchrony<br />–Possiblybetteroxygenation<br />–Potentiallyreducedriskofvolutrauma<br />•Disadvantage:<br />–Gasexchangemaynotbestable<br />6<br />
  7. 7. Minute<br />Volume<br />Volume<br />Tidal<br />Volume<br />Control<br />Influence<br />Diagram<br />Rate<br />Cycle<br />Time<br />I:E<br />Inspiratory<br />Time<br />Expiratory<br />Time<br />Inspiratory<br />Flow<br />7<br />
  8. 8. Minute<br />Ventilation<br />Resistance<br />Pressure<br />Time<br />Constant<br />Ventilatory<br />Frequency<br />Tidal<br />Volume<br />Control<br />Influence<br />Inspiratory<br />Time<br />Expiratory<br />Time<br />Compliance<br />Diagram<br />I:ERatio<br />Pressure<br />Gradient<br />Continuous<br />FlowRate<br />(Affectsshape<br />ofpressure<br />waveform)<br />Peak<br />Inspiratory<br />Pressure<br />End<br />Expiratory<br />Pressure<br />Mean<br />Airway<br />Pressure<br />8<br />
  9. 9. Volume/FlowControl<br />PressureControl<br />Inspiration<br />Expiration<br />Inspiration<br />Expiration<br />Paw<br />Pressure<br />Volume<br />Paw<br />Plung<br />Flow<br />Time(s)<br />Time(s)<br />0<br />0<br />9<br />
  10. 10. DualControl<br />•VolumecontroltoPressureControl:<br />–Attemptstodeliveraconstanttidalvolumewhile<br />limitingpeakpressure<br />•PressurecontroltoVolumeControl:<br />–Attemptstolimitpeakpressurebutassurestidal<br />volumedelivery<br />•Disadvantage:<br />–Requireshighdegreeofunderstanding<br />–Difficulttoadjustandmaintain<br />10<br />
  11. 11. CharacteristicsofaMode<br />1.BreathingPattern<br />–<br />–<br />Controlvariable<br />Breathsequence<br />2.ControlType<br />–<br />Setpoint,auto-setpoint,servo,adaptive,optimal<br />3.ControlStrategy<br />–<br />–<br />Phasevariables<br />Operationallogic<br />11<br />
  12. 12. BreathTypes<br />Whatisthedifferencebetween<br />mandatoryandspontaneousbreaths?<br />12<br />
  13. 13. BreathTypes<br />Spontaneous<br />Mandatory<br />no<br />no<br />yes<br />Patient<br />Patient<br />controls<br />controls<br />Think<br />yes<br />start<br />size<br />13<br />
  14. 14. DefinitionofAssistedBreath<br />•Assisted<br />–Ventilatordoesworkonpatient.<br />•Un-Assisted<br />–Ventilatordoesnoworkonpatient.<br />•Loaded(workimposedonpatient)<br />–Patientdoesworkonventilator.<br />14<br />
  15. 15. IdentificationofAssistedBreaths<br />•Assisted<br />–Airwaypressurerisesabovebaselineduring<br />inspiration(orfallsbelowbaselineduring<br />expiration).<br />•Un-Assisted<br />–Airwaypressurestaysconstantduringinspiration<br />orexpiration.<br />•Loaded(workimposedonpatient)<br />–Airwaypressurefallsbelowbaselineduring<br />inspirationandrisesabovebaselineduring<br />expiration.<br />15<br />
  16. 16. AssistedSpontaneousBreaths<br />•<br />•<br />•<br />•<br />•<br />PressureSupport<br />VolumeSupport<br />AutomaticTubeCompensation<br />ProportionalAssistVentilation<br />SmartCare<br />16<br />
  17. 17. PotentialConfusion<br />•Anassistedbreathmaybe<br />spontaneousormandatory<br />•Aspontaneousbreathmaybe<br />assistedorunassisted<br />•Amandatorybreathisassistedby<br />definition<br />17<br />
  18. 18. CharacteristicsofaMode<br />1.BreathingPattern<br />–<br />–<br />Controlvariable<br />Breathsequence<br />2.ControlType<br />–<br />Setpoint,auto-setpoint,servo,adaptive,optimal<br />3.ControlStrategy<br />–<br />–<br />Phasevariables<br />Operationallogic<br />18<br />
  19. 19. ContinuousMandatory<br />Ventilation(CMV)<br />•Mandatorybreaths<br />–Machinetriggeredand/ormachinecycled<br />•Spontaneousbreaths<br />–Duringmandatorybreathsonly,notbetween<br />•Keyclinicalconcept<br />–Levelofsupportindependentoffrequency(if<br />patientisbreathing)<br />19<br />
  20. 20. IntermittentMandatory<br />Ventilation(IMV)<br />•Mandatorybreaths<br />–Machinetriggeredand/ormachinecycled<br />•Spontaneousbreaths<br />–Betweenandduringmandatorybreaths<br />•Keyclinicalconcept<br />–Levelofsupportisproportionaltosetfrequency<br />(ifspontaneousbreathsunassisted)<br />–Historicallyusedasamodeofweaning<br />20<br />
  21. 21. ContinuousSpontaneous<br />Ventilation(CSV)<br />•Allbreathsspontaneous<br />–Patienttriggeredandcycled<br />–Nobackuprateincaseofapnea<br />•Breathsmayormaynotbeassisted<br />–Fullsupportmaybeachieved(ifnoapnea)<br />21<br />
  22. 22. CharacteristicsofaMode<br />1.BreathingPattern<br />–<br />–<br />Controlvariable<br />Breathsequence<br />2.ControlType<br />–<br />Setpoint,auto-setpoint,servo,adaptive,optimal<br />3.ControlStrategy<br />–<br />–<br />Phasevariables<br />Operationallogic<br />22<br />
  23. 23. 8BasicBreathingPatterns<br />Control<br />Breath<br />Variable<br />Volume<br />Pressure<br />Dual<br />Sequence<br />ContinuousMandatoryVentilation<br />IntermittentMandatoryVentilation<br />ContinuousMandatoryVentilation<br />IntermittentMandatoryVentilation<br />ContinuousSpontaneousVentilation<br />ContinuousMandatoryVentilation<br />IntermittentMandatoryVentilation<br />ContinuousSpontaneousVentilation<br />Symbol<br />VC-CMV<br />VC-IMV<br />PC-CMV<br />PC-IMV<br />PC-CSV<br />DC-CMV<br />DC-IMV<br />DC-CSV<br />23<br />
  24. 24. VC-CMV<br />•Oftenreferredtoas“Assist/Control”<br />•Characteristics<br />–VCresultsinmoreevendistributionofventilation<br />amonglungunitswithequalresistanceandunequal<br />compliancethanPC<br />–Selectionofflowandsensitivityiscritical<br />•Indications<br />–Needfortotalventilatorysupport<br />–Needforpreciseregulationofbloodgases<br />•Example<br />–PreciseregulationofPaCO2inpatientswithtraumatic<br />braininjury<br />24<br />
  25. 25. A<br />B<br />C<br />Pressure<br />small<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />VC-CMV<br />Muscle<br />waveforms<br />reducedpressure<br />indicatespatient<br />effortthroughout<br />inspiration<br />Ventilator<br />Pressure<br />patient<br />machine<br />settidalvolume<br />triggered<br />triggered<br />Volume<br />setflow<br />25<br />Flow<br />
  26. 26. VC-IMV<br />•Characteristics<br />–Spontaneousbreathsmaybeassisted<br />–Selectionofmandatoryflowandspontaneous<br />pressuresupportcritical<br />•Indications<br />–Relativelynormallungfunction<br />–Rapidrecoveryfromsedationorrespiratoryfailure<br />–Recentdatasuggestitisworstchoiceforweaning<br />•Example<br />–TreatmentofneuromusculardiseaselikeGullian-<br />Barresyndrome<br />26<br />
  27. 27. A<br />B<br />C<br />VC-IMV<br />waveforms<br />Arespontaneous<br />medium<br />inspiratory<br />effort<br />setpressuresupport<br />Pressure<br />small<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />Muscle<br />Ventilator<br />Pressure<br />breathsassisted?<br />patient<br />machine<br />triggered<br />triggered<br />settidalvolume<br />Volume<br />setflow<br />27<br />Flow<br />
  28. 28. PC-CMV<br />•Characteristics<br />–PCresultsinmoreevendistributionofventilation<br />amonglungunitswithequalcomplianceandunequal<br />resistancethanVC<br />–Pressurecontrolresultsinhighermeanairway<br />pressureandearlierlungopeningthanVC<br />•Indications<br />–Problemswithoxygenationorsynchrony<br />•Example<br />–TreatmentofARDSpatientswithoxygenation<br />problems<br />28<br />
  29. 29. A<br />B<br />C<br />PC-CMV<br />waveforms<br />Pressure<br />small<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />Muscle<br />setpressurelimit<br />Ventilator<br />Pressure<br />Volume<br />timecycled<br />patient<br />triggered<br />Flow<br />machine<br />triggered<br />29<br />
  30. 30. PC-IMV<br />•Characteristics<br />–Relativelysimplemode<br />–Usedhistoricallyforinfants<br />–Spontaneousbreathsmaybeassisted<br />•Indications<br />–Problemswithoxygenationorsynchrony<br />–Adequateventilatorydrive<br />•Example<br />–TreatmentofprematureinfantswithRDS<br />30<br />
  31. 31. A<br />C<br />B<br />PC-IMV<br />waveforms<br />medium<br />inspiratory<br />effort<br />Pressure<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />Muscle<br />Ventilator<br />Pressure<br />Volume<br />Flow<br />31<br />
  32. 32. PC-CSV<br />•Characteristics<br />–Noassist=CPAP<br />–Assist<br />PressureSupport<br />ProportionalAssist<br />AutomaticTubeCompensation<br />•Indications<br />–Weaning<br />–Reduceworkofbreathingorstabilizeoxygenation<br />•Examples<br />–NasalCPAPforneonatesrecoveringfromRDS<br />–Noninvasiveventilationofadults<br />32<br />
  33. 33. A<br />B<br />C<br />Pressure<br />small<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />PC-CSV<br />Muscle<br />waveforms<br />Spontaneous<br />breathsarenot<br />assisted<br />(CPAP)<br />33<br />Ventilator<br />Pressure<br />Volume<br />Flow<br />
  34. 34. DC-CMV<br />•Characteristics<br />–Mandatorybreathsadapttochanginglung<br />mechanics<br />•Indications<br />–Unstablelungmechanicsorventilatorydrive<br />•Example<br />–Treatmentofpatientwithpneumoniaand<br />intermittentsecretionproblems<br />34<br />
  35. 35. A<br />B<br />no<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />DC-CMV<br />Pressure<br />Muscle<br />waveforms<br />pressurelimit<br />setpressurelimit<br />setvolumetarget<br />over-ridden<br />volumetarget<br />pressure-to-volume<br />BirdVAPS<br />Ventilator<br />Pressure<br />volumecycled<br />notmet<br />volumemetbefore<br />flowdecaystosetlimit<br />Volume<br />inspiratoryflow<br />equalsflowlimit<br />flowcycled<br />setflowlimit<br />switchfrompressurecontrol<br />tovolumecontrol<br />Flow<br />patient<br />triggered<br />35<br />
  36. 36. A<br />B<br />Pressure<br />DC-CMV<br />waveforms<br />volume-to-pressure<br />small<br />inspiratory<br />effort<br />plateau<br />pressure<br />Muscle<br />setPmax<br />Ventilator<br />Pressure<br />Dräger<br />PressureLimited<br />Ventilation<br />plateau<br />pressure<br />volumelimited<br />timecycled<br />settidalvolume<br />volume<br />limited<br />timecycled<br />Volume<br />Flow<br />switchfromvolumecontrol<br />topressurecontrol<br />36<br />
  37. 37. A<br />C<br />B<br />DC-IMV<br />Pressure<br />Muscle<br />waveforms<br />setPmax<br />setPmax<br />Ventilator<br />Pressure<br />plateau<br />pressure<br />settidalvolume<br />Volume<br />setflow<br />timecycled<br />timecycled<br />Flow<br />37<br />
  38. 38. PressureSupport<br />•Pressureorflowtriggered,pressure<br />limited,inspiratoryflowcycled<br />•Levelofventilatorysupport<br />determinedbypressurelimit<br />•Sometimessettoapproximately<br />supportresistiveworkofbreathing<br />(throughendotrachealtube)<br />38<br />
  39. 39. A<br />B<br />C<br />PC-CSV<br />waveforms<br />Pressure<br />small<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />Muscle<br />setpressurelimit<br />Ventilator<br />Pressure<br />Spontaneous<br />breathsare<br />assisted<br />pressurerise<br />time<br />increased<br />Volume<br />flowcyclethreshold<br />flowcycled<br />patient<br />triggered<br />39<br />Flow<br />
  40. 40. ProportionalAssist<br />Pmus=Enormal×volume+Rnormal×flow<br />Pmus=(Enormal+Eabnormal)×volume+(Rnormal+Rabnormal)×flow<br />Pmus=(normalload)+(abnormalload)<br />Pmus+Pvent=(normalload)+(abnormalload)<br />Pvent=abnormalload=Eabnormal×volume+Rabnormal×flow<br />operatorsettings(volumeandflowamplificationfactors)<br />40<br />
  41. 41. A<br />B<br />C<br />PC-CSV<br />small<br />inspiratory<br />effort<br />large<br />inspiratory<br />effort<br />no<br />inspiratory<br />effort<br />Pressure<br />Muscle<br />waveforms<br />Spontaneousbreaths<br />areassisted<br />(ProportionalAssist)<br />41<br />Ventilator<br />Pressure<br />Volume<br />Flow<br />
  42. 42. AutomaticTube<br />Compensation<br />Pvent=abnormalresistiveload=Rtube×flow<br />2<br />operatorsetstubediameter<br />ventilatorcalculatesresistancefactor<br />42<br />
  43. 43. CharacteristicsofaMode<br />1.BreathingPattern<br />–Controlvariable<br />–Breathsequence<br />2.ControlType<br />–Withinbreaths<br />–Betweenbreaths<br />3.SpecificControlStrategy<br />–Phasevariables<br />–Operationallogic<br />43<br />
  44. 44. EvolutionofVentilatorControlTypes<br />TacticalControl(within-breaths)<br />setpoint(PC-IMV)<br />Patient<br />Ventilator<br />Operator<br />auto-setpoint(Pmax)<br />servo(AutomaticTubeCompensation)<br />operator-selected,staticsetpoints<br />StrategicControl(betweenbreaths)<br />adaptive(CMV+AutoFlow)<br />Model<br />Operator<br />optimal(ASV)<br />ventilator-selected,dynamicsetpoints<br />staticmodel<br />Patient<br />Ventilator<br />IntelligentControl(betweenpatients)<br />knowledgebased<br />artificialneuralnetwork<br />ventilator-selected,dynamicsetpoints<br />Model<br />dynamicmodel<br />abilitytolearnfromexperience<br />Patient<br />44<br />Ventilator<br />
  45. 45. TacticalControl<br />•Allthemodesdiscussedsofar<br />•Allrequiretheoperatortoset<br />–<br />–<br />–<br />–<br />Pressure(PIP,PEEP)<br />Volume(tidalvolume,minuteventilation)<br />Flow(peakinspiratoryflow)<br />Time(inspiratorytime,frequency,I:E)<br />45<br />
  46. 46. StrategicControl<br />•Characteristics<br />–BreathingpatternmaybePC-CMV,PC-IMV,PC-CSV<br />–Pressurelimitautomaticallyadjustedtocompensatefor<br />changesincompliancetomeettargettidalvolume<br />•Indications<br />–(Self)Weaning<br />–Reduceworkofbreathingorstabilizeoxygenation<br />–Reduceclinicianworkload<br />•Examples<br />–Post-operativepatientswithnormallungs<br />–MixedICUpatients<br />–COPDexacerbation<br />46<br />
  47. 47. A<br />no<br />inspiratory<br />effort<br />B<br />C<br />Adaptive<br />Control<br />large<br />inspiratory<br />effort<br />Pressure<br />Muscle<br />pressurelimit<br />automaticallyreduced<br />volumeovershoot<br />volumetarget<br />timecycled<br />Ventilator<br />Pressure<br />Volume<br />Flow<br />patient<br />triggered<br />machine<br />triggered<br />47<br />
  48. 48. HamiltonGalileoAdaptiveSupportMode<br />•Optimumcontrol<br />•Clinicianenters<br />–Patientidealbodyweight<br />–Percentofpredictedminuteventilationtosupport<br />•Ventilatormonitors<br />minuteventilation<br />lungmechanics(expiratorytimeconstant)<br />•Automaticallyadjustsminuteventilation<br />mandatorybreathfrequency<br />pressurelimit<br />inspiratorytime<br />•SetsfrequencytominimizeWOBasif<br />patientwasbreathingspontaneously<br />48<br />
  49. 49. “Anymedical<br />instrumentationthat<br />requiresconstant<br />inputfromahuman<br />operatorisobsolete”<br />HamiltonMedical<br />49<br />
  50. 50. IntelligentControl<br />•Characteristics<br />–Classificationofpatientcondition<br />Manual(eg,bydiagnosis)<br />Fuzzylogic<br />–Rulebasedexpertsystemorartificialneuralnetwork<br />•Indications<br />–Weaning<br />–Respiratoryfailureofvarioustypes<br />–Trauma<br />•Examples<br />–Post-operativepatientswithnormallungs<br />–MixedICUpatients<br />–Emergencydepartment<br />50<br />
  51. 51. CommercialExample<br />•SmartCare(DrägerEvitaXL)<br />–KnowledgeBasedControl<br />1.Automaticallyadjustpressuresupport:breathingrate,tidal<br />volumeandendtidalCO2.<br />2.Automaticallytestpatienttoleranceofalowerpressure<br />supportlevelwithoutleavingthecomfortzone.<br />3.Attempts“extubation”withPSatresistiveWOB.<br />•<br />•<br />Artificialintelligence<br />–Fuzzylogicinterpretspatientcondition<br />–Rulebasedexpertsystemtreatscondition<br />Operatorsets<br />–patientweight<br />–history(neuroorCOPD)<br />–typeofairway<br />51<br />
  52. 52. CharacteristicsofaMode<br />1.BreathingPattern<br />–Controlvariable<br />–Breathsequence<br />2.ControlType<br />–Setpoint,auto-setpoint,servo,adaptive,optimal<br />knowledgebased<br />3.SpecificControlStrategy<br />–Phasevariables<br />–Operationallogic<br />52<br />
  53. 53. ModeDescriptionUtility<br />•Describethedifferenceinmodes<br />–PressureSupport<br />–VolumeSupport<br />•Describethedifferenceinventilators<br />–Pressuresupport(PB7200)<br />–Pressuresupport(Servo-i)<br />53<br />
  54. 54. ModeDescriptionSummary<br />(withoutthebrandjargon)<br />•PressureSupport<br />–OnlyLevel1needed<br />PC-CSV<br />•VolumeSupport<br />–RequiresLevel2<br />PC-CSVwithadaptivecontrol<br />54<br />
  55. 55. AdaptivePressureControl<br />•<br />•<br />•<br />•<br />PressureRegulatedVolumeControl<br />AutoFlow<br />VC+<br />PC-SIMV+VolumeGuarantee<br />55<br />
  56. 56. ModeDescriptionSummary<br />(withoutthebrandjargon)<br />•Level3PressureSupport<br />•PB7200<br />–Cannotadjustrisetime(limitvariable)<br />–Cannotadjustcyclethreshold(cycle<br />variable)<br />•Servo-i<br />–Adjustablerisetime(limitvariable)<br />–Adjustablecyclethreshold(cyclevariable)<br />56<br />
  57. 57. Resources<br />•Getthebook<br />–collegeleveltextbook<br />–300pages<br />–www.aarc.org/store<br />TrainingSoftware<br />–www.VentWorld.com<br />–www.Amazon.com<br />57<br />
  58. 58. TooComplicated?<br />58<br />
  59. 59. FinalThought<br />“Ifyouexplainsomethingso<br />simplythatevenafoolcan<br />understandit,thenonlya<br />foolwillunderstandit."<br />FPPrimianoJr<br />59<br />

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