Presentation of Dr. Dean Hess at 10th Pulmonary Medicine Update Course, Cairo, Egypt. Pulmonary Medicine Update Course is organized by Scribe : www.scribeofegypt.com

1. New Ventilator Modes Do They Help? Dean Hess PhD RRT Assistant Director of Respiratory Care Massachusetts General Hospital Associate Professor of Anesthesia Harvard Medical School Editor in Chief Respiratory Care

3. 1970s 1980s 1990s 2000 IMV PSV PCV Closed Loop

7. volume from ventilator = set tidal volume calculate new pressure limit pressure limit based on V T Trigger patient or ventilator Time = set inspiratory time cycle off yes yes no no same pressure limit PRVC, VC+, autoflow, APV (pressure-controlled breath) (first breath problem)

8. volume from ventilator = set tidal volume calculate new pressure limit pressure limit based on V T Trigger Pressure or Flow flow = % of peak flow cycle off yes yes no no same pressure limit Volume Support (pressure support breath) (first breath problem)

9. Adaptive Control: PRVC, AutoFlow, VC+ Effect of compliance increase (or effort increase) Branson, Respir Care 2005;50:187 Effect of compliance decrease (or effort decrease) The ventilator can take away support if patient effort increases! Tidal volume limitation is not guaranteed.

10. Tidal Volume with PRVC, AutoFlow, VC+, and VS Branson, Respir Care 2005;50:187

11. Effect of Increased Effort Jaber, Anesthesiology 2009; 110:620 APC (PRVC)

14. Adaptive Support Ventilation apnea Over-distention (pressure limit) auto-PEEP rapid-shallow breathing (4.4 mL/kg) Safety Box Determined by IBW -

15. Adaptive Support Ventilation ↓ P, ↑ rate ↓ P, ↓ rate ↑ P, ↑ rate ↑ P, ↓ rate Correct IBW setting important May overshoot tidal volume Role in complicated cases?

16. Proportional Assist Ventilation: Positive Feedback Control P = V/C + V R . ( proportion of assist adjustable) respiratory drive end-inspiratory and expiratory pause maneuvers of 300 ms every 4 to 10 s to estimate of R and C With neuromuscular disease, drive may not translate into flow

17. P AW = V E + V R . Support adjusted to normalize WoB . WoB = ∫ P × Vdt

18. Proportional Assist Ventilation Marantz, JAP 1996; 80:397

19. Crit Care Med 2007;35:1048

22. Neurally Adjusted Ventilatory Assistance (NAVA): Positive Feedback Control Sinderby, Nature Medicine 1999;5:1433

23. Effort/Drive support Volume Control PSV/PCV PAV/TC/NAVA APC/ASV

25. Airway Pressure Release Ventilation (APRV) Improved oxygenation, but is mortality improved? Transpulmonary pressure with spontaneous breaths? Alveolar ventilation Oxygenation

28. Transpulmonary Pressure: APRV Neumann, Intensive Care Med 2002;28:1742

30. 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.