The document discusses new modes of mechanical ventilation in anesthesiology. It questions whether new ventilation modes are needed to address old problems that were not solved or new problems that have emerged. Various new ventilation modes and technologies are presented, including proportional assist ventilation (PAV), neurally adjusted ventilatory assist (NAVA), biologically variable ventilation (BVV), fractal ventilation (FV), and adaptive support ventilation (ASV). The author argues that in anesthesia, simple solutions that can improve outcomes should be prioritized, such as using permissive hypercapnia with pressure support ventilation during deep muscle relaxation to increase blood pressure at the end of surgery and help identify bleeding.

1. 1 New modes of mechanical ventilation in Anaesthesiology Jan P Mulier MD PhD Sint-Jan Brugge-Oostende K U Leuven 1150 1850 1947 1977 2010 J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011

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3. Do we need New Ventilation Modes? Old problems not solved ? Atelectasis: peep & recruitment Synchronisation problems New patient population? Extreme age, size Neonati - very old – surgery less invasive Morbid obese - anorexia New insight in physiology? Volutrauma is more important than barotrauma Permissive hypercapnia, hypoxia instead of biotrauma J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 3 Measuring atelectasis Attention & Awareness Use of peep and recruitment

4. Do we need New Ventilation Modes? Old problems not solved or new problems? Ventilator associated tracheitis (VAT) to ventilator associated pneumonia (VAP) Synchronisation problems New patient population? Extreme age, size Neonati - very old – surgery less invasive Morbid obese - anorexia New insight in physiology? Volutrauma is more important than barotrauma Permissive hypercapnia, hypoxia instead of biotrauma J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 4

5. Do we need New Ventilation Modes? New problems or old problems not solved? Atelectasis problems, VAT to VAP Synchronisation problems Not a problem in anesthesia ? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 5

6. Do we need New Ventilation Modes? Old problems not solved or new problems? Ventilator associated tracheitis (VAT) to ventilator associated pneumonia (VAP) Synchronisation problems New patient population? Extreme age, size Neonati - very old – surgery less invasive Morbid obese - anorexia New insight in physiology? Volutrauma is more important than barotrauma Permissive hypercapnia, hypoxia instead of biotrauma J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 6

7. Do we need New Ventilation Modes? Old problems not solved or new problems? Ventilator associated tracheitis (VAT) to ventilator associated pneumonia (VAP) Synchronisation problems New patient population? Extreme age, size Neonati - very old – surgery less invasive Morbid obese - anorexia New insight in physiology? Volutrauma is more important than barotrauma Permissive hypercapnia, permissive hypoxia, prevention of biotrauma J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 7

8. Do we have New Ventilation Technology? Support matched with the patient demand: synchronisation problem: not for anesthesia Proportional assist ventilation (PAV) Neurally adjusted ventilatory assist (NAVA) Breath-to-breath variability: improves oxygenation: more physiologic in anesthesia? Biologically variable ventilation (BVV) Fractal ventilation (FV) Complex closed loop technology: ventilation is continuously adapted to the patient’s lungfunction: usefull in anesthesia? The adaptive support ventilation (ASV) J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 8

10. PMUS =R×V+E×VT +PEEPi−PAW

11. PAW=FA×V+VA×VT

12. An increased effort would correspond to increased support: the more the patient requests, the more the ventilator delivers.

14. Biologically variable or fractal ventilation BVV J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 11 Mimics spontaneous breath-to-breath variability, incorporating natural variable noise into a volume-targeted, controlled mode. The ventilator modulates respiratory rate and tidal volume while maintaining a fixed minute ventilation. alveolar recruitment achieved by high volumes exceeds the de-recruitment caused by small volumes

15. Adaptive Support Ventilation ASV J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 12 A closed-loop control mode that may switch automatically from a PCV-like behaviour to a PSV-like behaviour, according to the patient status. Pressure levels and ventilation rate are automatically adjusted according to measured lung mechanics at each breath. ASV provided a safe and effective ventilation in patients with normal lungs, restrective or obstructive diseases.

16. What do we need in anesthesia? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 13

17. Let us take something simple that improves outcome. First step Increasing blood pressure at end of surgery allows surgeon to find possible bleeding arteries and by clipping preventing post operative bleeding. J. Mulier Obes Surg 2007; 17: 1051 J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 14 110/57 145/78

18. ASA 2010 J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 15 A B

19. Let us take something simple that improves outcome. First step Increasing blood pressure at end of surgery allows surgeon to find possible bleeding arteries and by clipping preventing post operative bleeding. How can we increase blood pressure? Vasoconstriction or cardiac output increase? Preload-, heart rate- or contractility rise, afterload increase. Why not using hypercapnia: it stimulates sympathetic output, increasing heart rate and contractility, decreasing peripheral resistance. J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 16

20. Hypercarbia effects Bille-Brahe NE Acta Chir Scand Suppl. 1976; 472: 127-32. Cardiovascular effects of induced hypercarbia during halothane-nitrous oxide anaesthesia. Heart rate, cardiac index, systemic and pulmonary blood pressures rose as pCO2 was increased. Stroke volume, systemic and pulmonary vascular resistance remained unchanged. In conclusion the primary effect of hypercarbia was an increased heart rate and a resultant increase of cardiac output. The pressure changes merely reflect the effect on cardiac output. J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 17

21. Hemodynamic effects of Hypercapnia (vs hypoxia) Peripheral chemoreceptor contributions to sympathetic and cardiovascular responses during hypercapnia. Shoemaker JK Can J Physiol Pharmacol. 2002; 80: 1136. J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 18

22. Hypercapnic vs. hypoxic control of cardiovascular, cardiovagal, and sympathetic function. Steinback CD Am J Physiol Regul Integr Comp Physiol. 2009; 296: R402. J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 19

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24. Permissive Hypercapnia vs Normocapnia under general anesthesia in obese patients while giving ephedrine to elevate SAP J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 21 . J Mulier Anesthesiology ESA 2008 A174

25. Let us take something simple that improved outcome. Second step How do you increase blood pressure at end of operation to find surgical bleeding? Permissive hypercapnia But breathing against ventilator with elevated CO2. Deep NMB or support ventilation without NMB? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 22

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27. Let us take something simple that improved outcome. Second step How do you increase blood pressure at end of operation to find surgical bleeding? Permissive hypercapnia But breathing against ventilator with elevated CO2. Deep NMB or support ventilation without NMB? PSV is possible at partial NMB. To what depth of NMB is this impossible? TOF 1 or 0 ? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 24

28. To what depth of NMB is PSV possible? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 25 Profound muscle relaxation does not disturb pressure support ventilation. J Mulier 2009 PGA

29. PSV during infusion of total dose 2 mg/kg rocuronium over 10 minutes J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 26 Profound muscle relaxation does not disturb pressure support ventilation. J Mulier 2009 PGA

30. Is deep NMB usefull? Effect of deep muscle relaxation on IAP (intra abdominal pressure) with constant IAV (intra abdominal volume) Gradual pressure drop until flat line Max effect at TOF = 0/4 No need to drop until PTC = 0 J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 27 TOF 4/4 TOF ¼ PTC 10 PTC 5 PTC 0 J Mulier 2009 PGA

31. Effect of deep muscle relaxation on abdominal PV loop TOF > 90% TOF = 0/4 TOF 0/4 and PTC < 5 J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 28 J Mulier 2009 PGA

32. Let us take something simple that improves outcome. How do you increase blood pressure at end of operation to find surgical bleeding? Permissive hypercapnia Increase in cardiac output reduces wound infection! Hypercapnia reduces VILI, but peep needed But breathing against ventilator with elevated CO2. Support ventilation is possible during deep muscle relaxation Hypercapnic PSV allows faster awakening. Is support ventilation possible during NMB? Even at maximum depth, TOF 0 and PTC 0, PSV is possible! When is PSV not possible? Respiratory center depression? J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 29

34. Rocuronium infusion was given at 500mg/h till TOF and PTC were 0.

35. Then Rocuronium infusion was stopped en Sufentanil 25µg was given. PTC 1 TOF 0/4 PTC 1 TOF 4/4 TOF 1/4 Escape PCV RR Roc Suf

36. J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 31 Dosing sufentanil to maximum level without respiratory depression opens new method to optimize immediate post operative pain treatment Before after extra 5 ug Sufentanil I Casier, J Mulier ESA 2010

37. Effect of et CO2 on blood pressure J P Mulier New Ventilation modes Wintersymposium Leuven 8 1 2011 32

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