2 Points of Discussions Advanced Basics: Flow and Time Limit and cycling Rise TimeVolume vs Pressure ControlMandatory Modes of VentilationControlled Mandatory Ventilation (CMV or IPPV)Triggered Modes of VentilationContinuous Positive Airway Pressure (CPAP)Pressure Support Ventilation (PSV)Hybrid Modes of VentilationAssist Control Mode (A/C)Synchronized Intermittent Mandatory Ventilation (SIMV)
3 Triggered Modes of Ventilation CPAP and PSVVTriggered Modes of Ventilation
24 Points of Discussion Triggered Modes of Ventilation Volume Support (VS)Proportional Assist Ventilation (PAV or PPS)Hybrid Modes of VentilationVolume Assured Pressure SupportPressure Regulated Volume Control (PRVC)Auto mode: VS and PRVCAdaptive Support Ventilation: ASVBi-level Ventilation (APRV and Bi-vent)Mandatory Minute Ventilation (MMV)
25 New Modes of Ventilation Dual-Controlled Modes TypeManufacturer; ventilatorNameDual control within a breathVIASYS Healthcare; Bird 8400Sti and TbirdVIASYS Healthcare; Bear 1000Volume-assured pressure supportPressure augmentationDual control breath to breath:Pressure-limited flow-cycled ventilationSiemens; servo 300Cardiopulmonary corporation; VenturiVolume supportVariable pressure supportPressure-limited time-cycled ventilationHamilton; GalileoDrager; Evita 4Pressure-regulated volume controlAdaptive pressure ventilationAutoflowVariable pressure controlSIMVAdaptive support ventilation
27 VS (Volume Support)ApneaUpper Pressure limit5 cm H2OPressure5 cm H2O123456FlowConstant exp. Flow(1), VS test breath (5 cm H2O); (2), pressure is increased slowly until target volume is achieved; (3), maximum available pressure is 5 cm H2O below upper pressure limit; (4), VT higher than set VT delivered results in lower pressure; (5), patient can trigger breath; (6) if apnea alarm is detected, ventilator switches to PRVC
28 yesVolume fromVentilator=Set tidal volumeCalculate newPressure limitnoCalculatecomplianceFlow= 5% ofPeak flowyesTriggerPressure limitBased on VT/CCycle offnoControl logic for volume support mode of the servo 300
29 Pressure Limited Flow Cycled Ventilation Dual control breath to breath: Proportional Assist Ventilation(PAS)/Proportional Pressure Support (PPS)ControlTriggerLimitTargetCyclePressurePatientVolumeFlowPressure Limited Flow Cycled Ventilation
30 Proportional Assist Ventilation (PAV) Changing pressure support based on patient’s effortsPressureTimeFlowTimeRregulates the pressure output of the ventilator moment by moment in accord with the patient’s demands for flow and volume.Thus, when the patient wants more, (s)he gets more help; when less, (s)he gets less. The timing and power synchrony are therefore nearly optimal—at least in concept.
31 Proportional Assist Amplifies Muscular Effort Muscular effort (Pmus) andairway pressure assistance(Paw) are better matched for Proportional Assist (PAV) than for Pressure Support (PSV).
33 Dual Control within a Breath volume-assured pressure support TriggerLimitTargetCycleDualPressure/VolumePatientPressureFlow or volumeVolume Assured Pressure Support Ventilation
34 Switch from Pressure control to Pressure limitoverriddenSwitch from Pressure control toVolume/flow control40Set pressure limitPawcmH2-200.6Set tidal volume cycle thresholdTidal volumemetTidal volumenot metVolumeLInspiratory flowgreater than set flow60Inspiratory flowequals set flowFlow cycleSet flowFlowL/min60
35 Control logic for volume-assured pressure-support mode TriggerPressure atPressure supportnodelivered VT≥ set VTflow=25% peakyesyesnoInsp flow> Set flowCycle offinspirationyesnoSwitch to flow controlat peak flow settingnodelivered VT= set VTPAW <PSVsettingyesnoyesControl logic for volume-assured pressure-support mode
36 Dual Control Breath-to-Breath Pressure Regulated Volume Control TriggerLimitTargetCycleVolumePatient or TimePressureLowest pressurefor set volumeTimePressure-limited Time-cycled Ventilation
37 PRVC (Pressure Regulated Volume Control) Upper Pressure LimitPressure5 cm H2OTime123456FloeTimePRVC. (1), Test breath (5 cm H2O); (2) pressure is increased to deliver set volume; (3), maximum available pressure; (4), breath delivered at preset E, at preset f, and during preset TI; (5), when VT corresponds to set value, pressure remains constant; (6), if preset volume increases, pressure decreases; the ventilator continually monitors and adapts to the patient’s needs
38 PRVC Automatically Adjusts To Compliance Changes Pressure control VentilationPRVC
39 Trigger yes Volume from Ventilator= no Set tidal volume Calculate new Pressure limitCalculatecomplianceTime= setInspiratory timeyesTriggerPressure limitBased on VT/CCycle offnoControl logic for pressure-regulated volume control and autoflow
40 PRVC (Pressure Regulated Volume Control) IndicationsPatient who require the lowest possible pressure and a guaranteed consistent VTALI/ARDSPatient with the possibility of CL or Raw changes
41 Automode Mandatory Spontaneous PRVC VS Ventilator triggered, pressure controlled and time cycled; the pressure is adjusted to maintain the set tidal volumePatient triggered, pressure limited, and flow cycled.Apnea for 12 secondsTwo consecutive breaths
42 Dual Control Breath-to-Breath adaptive support ventilation
43 ASV (Adaptive Support Ventilation) A dual control mode that uses pressure ventilation (both PC and PSV) to maintain a set minimum E (volume target) using the least required settings for minimal WOB depending on the patient’s condition and effortIt automatically adapts to patient demand by increasing or decreasing support, depending on the patient’s elastic and resistive loads
44 ASV (Adaptive Support Ventilation) The clinician enters the patient’s IBW, which allows the ventilator’s algorithm to choose a required E. The ventilator then delivers 100 mL/min/kg.A series of test breaths measures the system C, resistance and auto-PEEPIf no spontaneous effort occurs, the ventilator determines the appropriate respiratory rate, VT, and pressure limit delivered for the mandatory breathsI:E ratio and TI of the mandatory breaths are continually being “optimized” by the ventilator to prevent auto-PEEPIf the patient begins having spontaneous breaths, the number of mandatory breaths decrease and the ventilator switches to PS at the same pressure levelPressure limits for both mandatory and spontaneous breaths are always being automatically adjusted to meet the E target
47 Mandatory Minute Ventilation A minimum minute ventilation is set by the operatorThe ventilator monitors the spontaneous MVThe part of the pre-selected MV that the patient is not able to accomplish is provided by the ventilator to make up the difference by automatically changing the breath rate
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