Potential Conflicts of Interest Received research grants from Hamilton, Covidien, Drager, General lel Electric, Newport, and Cardinal Medical Received

Transcription

1 How Does a Mechanical Ventilator t Spain Work? Bob Kacmarek PhD, RRT Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts

2 Potential Conflicts of Interest Received research grants from Hamilton, Covidien, Drager, General lel Electric, Newport, and Cardinal Medical Received honorarium for lecturing from Covidien, Hamilton and Maquet Medical Consultant for Newport and KCI

3 Morch Volume Ventilator

4 Engstrom volume ventilator

5 Application of PEEP - Ashbough, Petty Lancet 1967

6 Second Generation Assist/ Control Ventilation Simple monitoring Basic alarms External IMV At end of period Demand valves Integrated IMV or SIMV

7 Seimens Servo 900

8 Desautels, Bartlett Respir Care 1974;19:74

9 Third Generation Microprocessor Controlled Increased responsiveness Triggering effort improved Widespread Introduction of Pressure Ventilation i Extensive alarms Expanded monitoring

10 Puritan Bennett 7200

11 Forth Generation Dramatic increase in ventilators at all levels Introduction of non-invasive ventilators Introduction of new modes Waveforms Extensive monitoring data provided Upgradeability Management/Assessment packages P-V curves Open lung Tool Weaning tools

12 PB 840

13 Maquet Servo i

14 Viasys Avea

15 expiratory valve (PEEP) atmosphere filter electrical power Microprocessor (mode and breath delivery) monitors & alarms PATIENT air filter O 2 inspiratory valve(s) (flow, volume, pressure, FIO 2 ) humidifier

16 expired gas suction dead space bias flow filter patient ventilator humidifier Aerosolized drug (nebulizer or MDI)

17 Breath Delivery: Phase Variables Trigger: initiates inspiration Ventilator (time) or patient (pressure or flow) Control: what the ventilator controls during the inspiratory phase Flow (volume) or pressure Cycle: initiates iti t exhalation Time, flow, volume, or pressure Baseline: present throughout the cycle PEEP or CPAP or EPAP

18 Pressure-triggered breath Flow-triggered breath trigger flow trigger flow beginning of patient effort pressure beginning of patient effort pressure trigger Modern triggers are sensitive s Trigger Difficulty: - auto-peep: increase PEEP setting - weakness: increase rate setting Auto-Trigger: - water in circuit - cardiac oscillations

19 Ventilator Breath Types Mandatory: either triggered or cycled by the ventilator (back-up rate) Volume control Pressure control Adaptive control (pressure varies to keep volume constant) Spontaneous: triggered and cycled by the patient (no back-up rate) Continuous positive i airway pressure Pressure support ventilation Adaptive (pressure varies to keep volume constant)

20 Pressure vs Volume Ventilation Tidal Volume Peak Alv Press Peak Air Press Pressure Variable Constant Constant Volume Constant Variable Variable Flow Pattern Decelerating Preset Peak Flow Inspir Time Minimum Rate Variable Preset Preset Constant Preset Preset

21 flow inhalation constant flow ramp flow 0 pressure Control/ normal time auto-peep exhalation

22 pressu ure Fast rise time Pressure control ventilation Slow rise time PIP Constant flow volume control ventilation Patient trigger PEEP time

23 Decelerating; inspiratory time fixed flow rectangular Decelerating; fixed peak flow time

24 Volume Ventilation Tidal Volume set Inspiratory Time set Flow Waveform set Peak Flow set Pressure Ventilation Pressure Level set Inspiratory Time set (PA/C only) Tidal Volume dependent upon Pressure level andinspiratory Time Patient lung and chest wall compliance Patient inspiratory demand

25 Volume Controlled Ventilation constant t descending ramp Pressure (cm H2O) Flow (L/min) Fixed flow and inspiratory time Fixed volume Pressure varies with lung mechanics or patient effort Vol lume (ml) Pressure (cm H2O) Flow (L/min) Volume (ml)

26 Pressure Controlled Ventilation Fixed pressure and fixed inspiratory time Variable inspiratory flow Flow (volume) varies with lung mechanics and patient effort low (L/min) 2O) Fl sure (cm H 2 L) Press Volume (ml time

27 Ventilator Modes Continuous mandatory ventilation (assist/control) [backup rate] VCV, PCV, adaptive control Continuous spontaneous ventilation [no backup rate] CPAP, PSV, PAV, adaptive control Synchronized intermittent mandatory ventilation VCV, PCV, adaptive control pressure support

28 spontaneous breath mandatory breath SIMV spontaneous breaths flow volume airway pressure esophageal pressure

29 Why New Modes? More safely assist patient! Less likelihood lih of ventilator t associated lung injury. Less hemodynamic compromise More effectively ventilate/oxygenate! Improve patient - ventilator synchrony! More rapid weaning!

30 Ventilator Modes Continuous Mandatory Ventilation (CMV) Continuous Spontaneous Ventilation (CSV) Intermittent Mandatory Ventilation (SIMV) VCV PCV CPAP PSV PAV NAVA VCV PCV MMV Dual Control PCIRV APRV Dual Control Automode ASV Dual Control Bilevel

31 New Modes Volume Assured Pressure Support Pressure Regulated Volume Control/ Volume Support Proportional Assist Ventilation Automatic Tube Compensation Smart Care Adaptive Support Ventilation Airway Pressure Release Ventilation/ Bi-level Pressure Ventilation Neurally Adjusted Ventilatory Assist

32 PRVC and VS Pressure regulated volume control and Volume support Both target a preset V T and adjust the level of pressure ventilation needed to ensure delivery of the V T PRVC -set rate, inspiratory i time, minute ventilation/v T and pressure limit VS - set minute ventilation/v T and pressure limit

33 Adaptive Support Ventilation, Calculates Optimal Breath Pattern: Least Work of fb Breathing Vt in ml 2'000 1'500 1' b a c d Frequency in breaths per minute Avoid: a: apnea b: volu/barotrauma c: AutoPEEP d: excessive V D /tachypnea

34 Lellouche, Brochard AJRCCM 2006;July 13th CDPW system operational rules: PSV 2-4 cmh 2 2O Osepses steps establish s a comfort o zone RR 15 to 30 breaths per min, 34 COPD V T > 250 ml or 300 ml based on size P ET CO 2 < 55 or < 65 if COPD When PSV minimal, SBT at minimal settings: Trach + HH = 5 cmh 2 O Trach + HME = 10 cmh 2 O ETT + HH = 7 cmh 2 O ETT + HME = 12 cmh 2 O Ventilator indicates if patient passed SBT Pt extubated if P/F > 200 and PEEP < 5 cmh 2 O

35 Proportional Assist Ventilation PAV based on the equation of motion: Paw + Pmus = V xr+ V VxE Increases or decreases ventilatory support in proportion to patient t effort Similar in concept to Power Steering Tracks changes in patient effort and adjusts ventilator t output t to reduce work Introduced by Younes in 1992 Younes M, ARRD 1992;145:121

36 Neurally Adjusted Ventilatory Assist Sinderby Nature Med 1999;5:1433

37 Categories of Ventilators ICU Ventilators Mid-level, sub-acute ventilators Home care ventilators Transport Ventilators Non-invasive ventilators

38 What is Needed Protocolized approaches to providing mechanical ventilation Coordination and correlation of monitored data Identification of existent or potential problems Smart Alarms Modes of ventilation????

39 Intelligent Ventilator Alarms and Enhanced Monitoring Should the ventilator alarm every time the high pressure or low tidal volume limit is reached? Alarms should incorporate: Up/down counting algorithms! Alarms should reset if condition corrected! td! Alarm level associated with criticality of alarm!

40 Anesthesiology 2006;104:39

41 Crit Care Med 2007;35:260 VAP Crit Care Med 2007;35:260 Closed suction is cost-effective, the same catheter can be used multiple times for multiple days.

42 Humidification Prevents water and heat loss Active heated humidification Passive heat and moisture exchanger (artificial nose): less effective; adds dead space and resistance

43 Crit Care Med 2007; 35:2843

44 Chest 2005; 127: Both nebulizers and MDIs can be used to deliver Bt Beta 2 -agonists to mechanically ventilated t patients. t Careful attention to details of the technique employed for administering i i drugs by MDI or nebulizer to mechanically ventilated patients is critical, since multiple technical factors may have clinically important effects on the efficiency of aerosol delivery.

45 Goals When Setting The Ventilator Avoid alveolar over-distension: volume and pressure limitation Apply PEEP to maintain alveolar recruitment or counter-balance auto-peep Provide adequate gas exchange Promote patient-ventilator synchrony Avoid auto-peep Use the lowest possible FIO 2

46 Ventilator-Induced Lung Injury Gas Exchange Setting the Ventilator t Patient Comfort Hemodynamics

47 Thank You