Modes of Mechanical Ventilation: The Essentials
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The document discusses the essential aspects of mechanical ventilation, emphasizing safety, efficacy, and patient comfort. It outlines various mechanical ventilation modes, including pressure-cycled ventilation (PCV) and volume-cycled ventilation (VCV), along with their specific variables and characteristics. The importance of clinician skills in utilizing these ventilation strategies effectively is highlighted, along with a cautionary note that new ventilator modes must be assessed critically against traditional lung-protective strategies.
Modes of Mechanical Ventilation: The Essentials
- 1. Modes of Mechanical Ventilation: The Essentials Lluis Blanch MD, PhD Senior Critical Care Department Director Research and Innovation Corporació Sanitaria Parc Tauli. Sabadell. Spain. Universitat Autònoma de Barcelona. Spain. 22-23 January 2014 Cairo, Egypt
- 2. Objectives MV • Safety • Efficacy – Oxygenation – Ventilation – Work of Breathing • Comfort / Synchrony – Surveillance of Flow & Pressure
- 3. Modes of Mechanical Ventilation: Relationship between possible breath types and inspiratory-phase variables Phase variables that define inspiration: trigger variable limit variable: pressure, flow or volume cycle variable that ends inspiration Gas delivery: pressure, volume, flow, time or dual control Breath type: mandatory or spontaneous
- 4. PCV & VCV Waveforms PCV Rectangular Pressure Waveform VCV VCV VCV Rectangular Flow Waveform Ascending Ramp Flow Waveform Descending Ramp Flow Waveform VCV Sinusoidal Flow Waveform
- 5. Pressure vs Volume Control • Volume Control • Pressure Control - Set VT - Set Pressure - Set Flow waveform - Set Inspiratory Time - Set Flow rate - Variable VT - Set Inspiratory Time - Variable Flow waveform - Variable pressure - Variable Flow rate - Linear Rate/VE - Non-linear Rate/VE
- 6. Daily Use of Modes of Mechanical Ventilation 1998 VCV PCV PSV Esteban A et al. JAMA 2002;287:345-55
- 7. Daily Use of Modes of Mechanical Ventilation 2010 VCV PSV PCV Esteban A et al. Am J Respir Crit Care MedJ 2013;188:220-30
- 8. VCV. Effects of an End-Inspiratory Occlusion Time
- 9. Assist/Controlled Ventilation Hess DR, Kacmarek RM. Essentials of Mechanical Ventilation. 2on Ed. McGraw Hill. 2002.
- 10. Variations in Crs in VCV (square flow) High Crs Intermediate Crs Low Crs Corretger E, Murias G,… Blanch L. Med Intensiva ((2011 Oct 17)
- 11. Variations in Rrs in VCV (square flow) Low Rrs Intermediate Rrs High Rrs Corretger E, Murias G,… Blanch L. Med Intensiva (2011)
- 12. AutoPEEP Generation: Lengthen Ti at equal Ttot (Airflow decreased for a similar VT) 1.0 0.5 Airflow (L/s) AutoPEEP 0.0 -0.5 -1.0 0 1 2 3 4 Time (s) Blanch L, Bernabe F, Lucangelo U. Respir Care 2005;50:110-123
- 13. Progressive increase of inspiratory pause during VCV Lucangelo U, Bernabè F, and Blanch L. Resp Care 2005; 50 : 55-65
- 14. VCV with progressive increase of inspiratory time, but with constant pause Lucangelo U, Bernabè F, Blanch L. Resp Care 2005; 50 : 55-65
- 15. Patient WOB during Triggered Ventilation Marini JJ et al. Am Rev Respir Dis 1988; 138:1169-79
- 16. VCV Increased Work of Breathing
- 17. Georgopoulos D et al Intensive Care Med 2006;32:34-47 (on line suppl)
- 19. Variations in Crs in PCV High Crs Intermediate Crs Low Crs Corretger E, Murias G,… Blanch L. Med Intensiva (2011 Oct 17)
- 20. Variations in Rrs in PCV Low Rrs Intermediate Rrs High Rrs Corretger E, Murias G,… Blanch L. Med Intensiva ((2011 Oct 17)
- 21. PCV: Effect of AutoPEEP Marini JJ & Amato MB. Principles & Practice of Mechanical Ventilation. Tobin M, ed. 2007
- 22. PCV: Effect of ↑Resistance High Raw = Low VT Marini JJ & Amato MB. Principles & Practice of Mechanical Ventilation. Tobin M, ed. 2007
- 23. PCV: Effect of ↓Compliance Low Crs = Low VT Marini JJ & Amato MB. Principles & Practice of Mechanical Ventilation. Tobin M, ed. 2007
- 24. Effect of Inspiratory Flow on Work of Breathing Cinnella G. Am J Resp Crit Care 1996; 153:1025-33
- 25. Suggestion for settings ACV - VT about 6 - 8 mL/kg (AVOID Pplat > 28 and large VT) - Inspiratory flow 60 L/min - Ti /Ttot PCV - Inspiratory pressure (for a VT of 6-8 ml/kg) (AVOID Ppaw > 30) - Ti / Ttot Common for ACV & PCV - FiO2 for Sat ≥ 90% and < 97%. Avoid FiO2 1 if possible. - PEEP 5-10 cmH2O - Back up Rate 12 - 15 x’ Then, titrate according to individual patient’s clinical condition (gas exchange, mechanics, patient/ventilator interactions)
- 26. flow cycle pressure limit Spontaneous breath type • patient triggered (no set rate) • pressure limited • usually flow cycled patient trigger Volume (mL) Pressure (cm H2O) Flow (L/min) Pressure Support Ventilation Hess D. Respir Care 2005; 50:166-186 time
- 27. Pressure Support Ventilation Hess DR, Kacmarek RM. Essentials of Mechanical Ventilation. 2on Ed. McGraw Hill. 2002.
- 28. PSV: Expiratory Trigger Setting
- 29. PS 20 cm H2O Rise time (τ) 0.01 s Neural inspiratory time 1.0 s 120 Peak flow 100 L/min flow (L/min) 100 80 60 Flow termination 25% peak flow 40 20 R 10 cm H2O/L/s, C 0.02 L/cm H2O 0 0 0.2 0.4 0.6 0.8 1 time (s) Peak flow 60 L/min flow (L/min) 60 40 R 20 cm H2O/L/s, C 0.05 L/cm H2O 20 0 0 0.2 0.4 0.6 0.8 1 time (s) Hess D. Respir Care 2005; 50:166-186
- 30. PSV: Autotriggering Flow (L/s) Can occur when: - too sensitive inspiratory trigger Paw (cmH2O) - end-expiratory leaks Pes (cmH2O) Time (s) Brochard L. Principles & Practice of Mechanical Ventilation. Tobin M, ed. 2007
- 31. PSV: Ineffective Efforts Flow (L/s) Can occur when: - too much PSV Paw - presence of autoPEEP (cmH2O) Pes (cmH2O) Time (s) Brochard L. Principles & Practice of Mechanical Ventilation. Tobin M, ed. 2007
- 32. Adaptative Pressure Control Modes: It is a pressure-controlled breath that utilized closed-loop control of the pressure to maintain a minimum delivered tidal volume Commercial Names for Adaptative Pressure Control Modes: Branson RD & Chatburn RL. Respir Care 2007;52:478-488
- 33. Implementation of AutoFlow on the Drager Evita 4 Ventilator Paw (cmH2O) Flow (L/s) VT (mL) PCV Breaths VCV Breath Adaptative PCV until target VT is reached Crs Increases and VT exceeds the target, Paw is reduced until VT reaches the target
- 34. Airway pressure delivered during the inspiratory phase in relation to patient effort in different modes of ventilation
- 35. VCV Normal respiratory effort PSV PCV ASV PAV NAVA SmartCare IntelVent Paw Ppl Paw Increase respiratory effort Ppl Murias G, Villagrá A, Blanch L. Minerva Anestesiol 2013;79:434-44
- 36. Adaptive Support Ventilation: Negative Feedback Control Target minute ventilation: 100 ml/min/kg (IBW) % Min Volume: 20 – 200% Rate based on Otis minimal work equation (1950) All combinations of rate/VT calculated Te = 3 RC (I:E ratio) PRVC or VS depending upon whether or not the patient is actively breathing Available on Hamilton ventilator
- 37. Working principles of Adaptive Support Ventilation (ASV) to maintain the target minute ventilation.
- 38. Arnal JM et al ICM 2012
- 40. Level of pressure delivered with PSV & PACV and with NAVA & PAV two cycles with different inspiratory efforts.
- 41. PAV: The bases
- 42. PAV % Patient Effort
- 43. Crit Care Med 2007;35:1048
- 44. Neuro Ventilatory Coupling Ideal Technology Central Nervous System Phrenic Nerve Diaphragm Excitation New Technology Ventilator Unit Diaphragm Contraction Chest Wall & Lung Expansion Airway Pressure, Flow & Volume Current Technology
- 45. NAVA (Neural Adjusted Ventilation Adaptation)
- 47. Neurally Adjusted Ventilatory Assistance (NAVA): Positive Feedback Control Sinderby, Nature Medicine 1999;5:1433
- 48. Running in NAVA mode
- 50. The Evidence for New Ventilator Modes … It’s not the ventilator mode that makes a difference … … It’s the skills of the clinician that makes the difference. Any ventilator mode has the potential to do harm! High level evidence is lacking that any new ventilator mode improves patient outcomes compared to existing lung-protective ventilation strategies. Dean Hess 2010