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Close loop Ventilation

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Presented by Dr.J.M.Arnal

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Close loop Ventilation

  1. 1. Dr Jean-Michel Arnal Intensive Care Unit. Hôpital Font Pré Toulon France [email_address] Close loop ventilation in the ICU
  2. 2. Definition <ul><li>Conventional ventilation: </li></ul><ul><li>All the settings are done manually by the user </li></ul><ul><li>Closed loop ventilation: </li></ul><ul><li>Some settings are adjusted automatically according to parameters monitored </li></ul>
  3. 3. What parameter to close the loop? <ul><li>Non or little invasive </li></ul><ul><li>Accurate in most condition </li></ul><ul><li>Reproducible </li></ul><ul><li>Technology integrated in a ventilator </li></ul><ul><li>Not too expensive </li></ul>
  4. 4. What parameter to close the loop? <ul><li>Respiratory muscle support: patient effort </li></ul><ul><ul><li>RR, flow, EMG activity of diaphragm </li></ul></ul><ul><li>Ventilation: </li></ul><ul><ul><li>Expiratory time constant, E T CO 2 </li></ul></ul><ul><li>Oxygenation: SpO 2 </li></ul>
  5. 5. Positive close loop control C ontroller  = i’ x i Valves Signal: Flow= i’ Gain = i P insp Unstable Add complexity Act as auxiliary respiratory muscle Intrabreath
  6. 6. Negative close loop control C ontroller  = i– i’ Valves Signal: V T actual = i’ V T Target = i P insp Target can be achieved Fast response Adapts to external modifications Interbreath
  7. 7. Determination of the target C ontroller  = i– i’ Valves Signal: V T actual = i’ V T Target = i P insp Operator set Automatically determined
  8. 8. What is the target based on? <ul><li>Physiology: </li></ul><ul><li>Measurement of a physiologic parameter and algorithm that reproduces physiologic process </li></ul><ul><li>Knowledge: </li></ul><ul><li>Algorithm that reproduces expert clinical practice </li></ul>
  9. 9. Technical challenges <ul><li>Initiation of ventilation: the first breath problem </li></ul><ul><li>Manual adjustment of the target </li></ul><ul><li>Weaning: how to use close loop to wean faster? </li></ul><ul><li>Safety features: limits of settings, lost of signal… </li></ul><ul><li>User interface: avoiding the black box effect </li></ul>
  10. 10. Advantages <ul><li>Adapts timely ventilation delivered to lung condition </li></ul><ul><li>Increases safety </li></ul><ul><li>Helps to apply recommendations </li></ul><ul><li>Improves patient ventilator synchrony </li></ul><ul><li>Decreases weaning duration </li></ul><ul><li>Decreases workload </li></ul><ul><li>Decrease false alarms… </li></ul>
  11. 11. Disadvantages <ul><li>Avoids to apply recommendation </li></ul><ul><li>Increases weaning duration </li></ul><ul><li>Lost of knowledge, lost of practice </li></ul><ul><li>Hide the incident </li></ul>Define limits and contraindications Use a weaning protocol Use for teaching Adapt monitoring
  12. 12. Commercially available solutions Controlled mode Assisted mode Spont mode PAV NAVA SmartCare Adaptive Support Ventilation IntelliVent®
  13. 13. <ul><li>Pinsp regulated in proportion of patient inspiratory flow </li></ul><ul><li>PAV + : Automatic determination of compliance and resistances </li></ul><ul><li>Improve patient ventilator synchrony and sleep quality </li></ul><ul><li>Decreases numbers of manual adjustments </li></ul>Proportional assist ventilation Bosma. Crit Care Med 2007 Xirouchaki. Intensive Care Med 2009
  14. 14. <ul><ul><li>Pinsp regulated in proportion of EMG activity of diaphragm </li></ul></ul><ul><li>Improve patient ventilator synchrony in NIV using the helmet </li></ul><ul><li>Improve patient ventilator synchrony in neonatology </li></ul>Neurally adjusted ventilatory assistance Moerer. Intensive Care Med 2008 Beck. Pediatr Res 2009
  15. 15. Improve patient ventilator synchrony Terzi. Crit Care Med 2010 n = 11
  16. 16. Increase variability of ventilation Coizel. Anesthesiology 2010 n = 12 n = 12 Schmidt. Anesthesiology 2010
  17. 17. <ul><li>Knowledge based adjustment of pressure support </li></ul>SmartCare
  18. 18. Decreases weaning duration Lellouche. AJRCCM 2006 n = 144 patients, ventilation > 24 h
  19. 19. SmartCare n = 102 Rose. Intensive Care Med 2008 Weaning success: Control: 40 h (14 – 87) Smartcare: 43 h (6 – 169)
  20. 20. Adaptive Support Ventilation Ventilation Oxygenation Conventional ventilation ASV MV V T RR FiO 2 PEEP MV V T RR FiO 2 PEEP
  21. 21. Background The optimal respiratory rate 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0 0 10 20 30 40 50 WOB res WOB el WOB tot 1+2a* RCe *( VM -f*( V‘D/VD )) - 1 f -target = a* RCe Respiratory rate (cycle/mn) WOB (Joule/sec) Otis AB.J Appl Physiol 1950
  22. 22. <ul><li>Evaluation of patient </li></ul><ul><li>(RCexp and RRspont ) </li></ul>Clinician sets minute ventilation Calculation of target RR and V T The close loop algorithm Adjust Pinsp et RR reach the target
  23. 23. Ventilation delivered * p ≤ 0,05 versus normal Arnal. Intensive Care Med 2008 Normal COPD Chest wall stiffness ARDS n (d/patients) 706 / 140 217 / 40 54 / 13 136 / 36 RC exp (s) 0,78 ± 0,28 1,13  0,72* 0,41  0,16* 0,55 ± 0,21 * Vt/PBW (ml/Kg) 8,3  1,3 9,4  2,1* 7,1  1,1* 7,6  1,3 * RR (c/mn) 17  5 16  7 23  7* 20  6 * I/E 0,5  0,2 0,4  0,2* 0,5  0,2 0,63  0,27 *
  24. 24. Ventilation delivered Arnal. Intensive Care Med 2008
  25. 25. ASV in ARDS patients <ul><li>Study on model reproducing 108 simulated scenario: </li></ul><ul><ul><li>ASV delivers around 6 mL/Kg PBW for most of cases </li></ul></ul><ul><ul><li>Same plateau pressure than ARDSnet strategy </li></ul></ul><ul><ul><li>Lower V T for the most severe cases with lower Pplat </li></ul></ul><ul><li>Clinical study on 51 ARDS patients: </li></ul><ul><ul><li>V T delivered are in line with recommendations </li></ul></ul><ul><ul><li>Pplat was ≤ 28 cmH 2 O </li></ul></ul>Sulemanji. Anesthesiology 2009 Arnal. AJRCCM 2007 [abstract]
  26. 26. ASV and weaning Results: MV duration (h) n Control ASV p Sultzer Anesthesiology 2001 36 4,0 3,2 p < 0,02 Petter Anesth Analg 2003 34 3,2 2,7 NS Gruber Anesthesiology 2008 48 8,0 2,7 P < 0,05 Dongelmans Anesth Analg 2009 121 16,3 16,2 NS
  27. 27. ASV and weaning in COPD Kirakli. Eur Respir J 2011 n = 97
  28. 28. ASV and weaning in ICU <ul><li>Study in medical ICU </li></ul><ul><li>Weaning performed by RT </li></ul><ul><li>Comparison of two periods: PS and ASV </li></ul><ul><li>Extubation readiness on day 1: 20% in ASV, 5% in PS </li></ul><ul><li>Faster weaning in ASV: 1 day in ASV vrs 3 days in PS </li></ul>Chen. Resp Care 2011
  29. 29. IntelliVent Ventilation Oxygenation Conventional ventilation ASV IntelliVent ® MV V T RR FiO 2 PEEP MV V T RR FiO 2 PEEP MV V T RR FiO 2 PEEP
  30. 30. IntelliVent
  31. 31. IntelliVent
  32. 32. <ul><li>Randomized control trial: Provide an automatic weaning in post cardiac surgery patients with less manipulations and more time spent in optimal ventilation zones than PS. </li></ul><ul><li>Randomized cross-over study: Safe in ICU patients with less inspiratory pressure and V T than ASV with same gas exchanges. </li></ul>IntelliVent Arnal. Intensive Care Med 2010 [abstract] Lellouche. Intensive Care Med 2010 [abstract]
  33. 33. Limitations <ul><li>Patient’s response to changes in ventilator setting is hardly predictable </li></ul><ul><li>Different clinical situations: </li></ul><ul><li> Any algorithm won’t meet all the situations </li></ul><ul><li>Different practice: </li></ul><ul><li> Any algorithm won’t meet all the expectations </li></ul>
  34. 34. In practice <ul><li>Available and usable </li></ul><ul><li>For easy to ventilate patients or after the acute phase </li></ul><ul><li>Advantages: homogeneity in care, safety, less manipulation, improve organization… </li></ul><ul><li>But: </li></ul><ul><li>Learning curve: start with easy patients </li></ul><ul><li>Must be associated with a weaning protocol </li></ul>
  35. 35. Which one to choose? <ul><li>Patient ventilator synchrony: PAV or NAVA </li></ul><ul><li>Weaning duration: SmartCare </li></ul><ul><li>ASV: </li></ul><ul><ul><li>Individualized breath pattern </li></ul></ul><ul><ul><li>Automatic switch between control and assisted ventilation </li></ul></ul><ul><ul><li>Reduction of weaning duration </li></ul></ul><ul><li>IntelliVent… </li></ul>
  36. 36. Conclusions <ul><li>Available, usable and safe </li></ul><ul><li>Lot of potential interest: individual care, organization… </li></ul><ul><li>Different solutions with increasing complexity </li></ul><ul><li>Teaching and research tool </li></ul><ul><li>Clinical evidences are needed before large implementation </li></ul>Thank you… 

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