Review of Mechanical Ventilation

1. In The Name of GOD Review of Mechanical Ventilation Mohsen SavaieMD, CCM Anesthesiologist, Intensivist Assistant Professor

2. Mechanical Ventilation Support Gas Exchange Manage Work of Breathing Avoid Lung Injury 2/28

3. Abbreviations VT :Volume of each respiration FiO2 : Fraction of inspiratory O2 (%) RR : Respiratory Rate Ti:Inspiratory Time MV : Volume that is inhaled or exhaled per min Te: Expiratory Time PEEP :Positive End-Expiratory Pressure I:E Ratio :Ti/Te CPAP : Continuous Positive Airway Pressure PIP : Peak Inspiratory Pressure IPPV : Intermittent Positive Pressure Ventilation Flow : Inspiratory Flow Rate (Lit/Min) Trigger :Factor that Start Inspiration (T, P, Flow) 3/28

4. Pressure Graph of Mechanical Ventilation P Peak Pressure PlattuePressure PEEP t t 4/28

5. Timing of Mechanical Ventilation Respiratory cycle time Inspiratory time Expiratory time Inspiratory pause time Volume Inspiratory flow time Time 5/28

6. Timing of Mechanical Ventilation 3 secs 2 secs 1 sec  Respiratory rate withoutchanging Inspiratory time orinspiratory flow 0.5 s Flow Volume Set: RR, Insp Time, Flow rate Time 6/28

7. Timing of Mechanical Ventilation 3 secs 1 sec 2 sec 0.5 s Volume Time Set: RR, Insp Time, Flow rate 7/28

8. Modes of Mechanical Ventilation • Volume Controlled • (A)CMV : (Assisted) Controlled Mechanical Ventilation • (S)IMV :(Synchronized) Intermittent Mandatory Ventilation • MMV :Mandatory Minute Ventilation • Pressure Controlled • PCV :Pressure Controlled Ventilation • (P) SIMV :Pressure SIMV • Spontaneous • PSV (ASB) :Pressure Support Ventilation (Assisted Spontaneous Breathing) • Other Modes • APRV, PRVC, BIPAP, NAVA, Smart, NIV, VAPS, ASV, PAV, HFPPV, HFJV, HFOV 8/28

9. Control Mandatory Ventilation (CMV) P • TidalVolume • Respiratory Rate • Flow : 40-60 lit/min • PeakPressure t 9/28

10. Assist Control Mechanical Ventilation (ACMV) • VolumeControl(Maquet) • IPPV (Drager) • S-CMV(Hamilton) P • TidalVolume • Respiratory Rate • Trigger : 1-5 • Flow : 40-60 lit/min • PeakPressure t 10/28

11. SIMV Mandatory breath Mandatory breath Pressure support breath Pressure PEEP Time Flow Time Trig Trig Trig Trig Setting : TV, RR, Trigger : 1-5, Flow : 40-60 lit/min, Peak Pressure, Pressure Support, PEEP, T insp (I/E) 11/28

12. P aw cmH 0 2 (Auto flow Ventilation) PRVC (Pressure Regulated Volume Control) P • Deliver a set TV at the minimum pressure level necessary, according to the airways/lung/thorax mechanics. • Constant pressure during the entire inspiration. 60 t SEC 1 2 3 4 5 6 -20 120 12/28

13. Pressure Control Ventilation (PCV) • Fio2 • PeakInsp Pressure • Respiratory Rate • PEEP PC above PEEP Pressure PEEP Time Flow Time Volume Time 13/28

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15. Set % of max inspiratory flow Pressure Support Ventilation (PSV)=Assisted Spont Breathing (ASB) • Fio2 • Trigger : 1-5 • Pressure Support 6-20 • PEEP • VSV ? PS above PEEP Pressure PEEP Flow Volume 15/28

16. BIPAP Bi-Level Positive Airway Pressure Allows Spontaneous Breathing during the Mandatory Breaths Spontaneous Breathing BIPAP PCV 16/28

17. BIPAP Bi-Level Positive Airway Pressure Pinsp Rise Time The time it takes to achieve Pinsp PEEP Ti Ti - Inspiratory phase lungs are maintained distended at set Pinsp Te Te–Expiratory phase Lungs are prevented from complete collapse by set PEEP 17/28

18. BIPAP Bi-Level Positive Airway Pressure BIPAP and Synchronisation with Spontaneous Breathing P Exp. Trigger t Insp. Trigger Exp.Trig. Window Insp.Trig. Window Dual PAP Ventilation (BIPAP+PS) 18/28

19. VentilatoryFailure Oxygenation Failure Increase PEEP and Pinsp Increase delta Pinsp – Peep( Increase TV) Change Tinspor RR Increase frequency (RR) 19/28

20. Airway Pressure Release Ventilation (APRV) • Continuouspositive airway pressure (Inspiration) with regular, brief, intermittent releasesin airway pressure (Expiration). • Positive pressure drives oxygenation. • The timed releases of pressure aid in CO2 clearance. • It is the primary mode of choice for patients with ARDS. 20/28

21. Airway Pressure Release Ventilation (APRV) In diseased lung they become important 21/28

22. APRV Setting • P High : = PlattuePressure • P Low (Release) : = 0 • T High : = 4 -15 seconds (0.5-2 each times) • T Low : = 0.5–0.8 seconds • Frequency should always be less than 12 • Patient must be encouraged to breathe spontaneously during APRV 22/28

23. Adaptive Support Ventilation (ASV) • Very easymode presented by Hamilton corporation. • You set only the patients weight or height and percent of calculated minute volume that must be delivered by machine, then lventilator automatically set best RR and TV to provide minute ventilation. 23/28

24. Volume vs Pressure Modes ? Volume Modes • TV is constant • Inspiratory pressure varies • Inspiratory flow is constant Pressure Modes • TV varies • Inspiratory pressure is constant • Inspiratory flow varies 24/28

25. Which Mode is Better ? Apnoeic patient : Control of minute ventilation important → → Volume Assist Control Control of peak pressure important → → Pressure Assist Control Intermittent spontaneous breaths → → SIMV Regular spontaneous breaths and improving condition → → PS 25/28

26. Problem Solving Low O2 Saturation • Increase FiO2 • Check Patient and Circuit • Increase PEEP • Increase Inspiration Time High PCo2 • Check Patient and Circuit • Increase TV • Increase RR Other Problems ? 26/28

27. Clinical Pearls • Ventilator kills your patient unless you prevent it from doing so! • Thebest mode is the most suitable and comfortable mode for patients (not for you). • Patient fight with your mistakes not with the ventilator! • Calm your patient with opioids & Hypnotics, not relaxants. • ‌Nebulizers &Humidifiers are your guardian angels. • Use lab. tests to conform diagnosis not to diagnose. • Plan and order nutrition professionally. • Plan for and manage the stress of ETT & IPPV. 27/28

28. Thanks for your attention