1. Proportional Assist ™ Ventilation (PAV ™ +)

2. Objectives State the clinical description of PAV+. Understand how PAV+ determines WOB. Learn how PAV+ amplifies effort. Learn how to adjust PAV+ settings. Review literature associated with PAV+.

3. 24% of mechanically ventilated patients exhibit patient- ventilator asynchrony in > 10% of their respiratory efforts during AVC and PS ventilation (ineffective triggering and double triggering). Patient-ventilator asynchrony during assisted mechanical ventilation Intensive Care Med. 2006;32:1512 Patient-ventilator Asynchrony Arnold W. Thille, Pablo Rodriguez, Belen Cabello Francois Lellouche, Laurent Brochard

4. 1. Kollef M et al. Chest. 1998;114:541–548. 2. Levine S et al. NEJM.2008;358:1327-1335. 3. Rello J et al. Chest.2002;122:2115-2121. Length of Stay Asynchrony Sedation Prolonged ventilation time 1 Possible muscle atrophy 2 and VAP 3 Weaning is delayed

5. Cost of an Intensive Care Unit Day: The Contribution of Mechanical Ventilation Setting: 253 diverse US hospitals Sample: 51,000 patients 36% of patients were ventilated at some point Average cost for a ventilated ICU patient = $3,968 PAV ™ + Software Option Support and Literature Dasta J et al. Crit Care Med. 2005;33:1266-1271.

6. [ 24% ] [ 18 days ] [ $72,000 ] 1. Thille A et al. Intensive Care Med. 2006;32:1512. 2. Dasta J et al. Crit Care Med. 2005;33:1266-1271. 24% of ICU patients exhibit asynchrony in greater than 10% of their breaths. 1 Asynchrony contributes to 18 extra days on the ventilator. 1 Average cost per day in the ICU for a patient receiving mechanical ventilation is $4,000. 2 Ventilator Asynchrony Prevalence and Cost

7. Rapid Disuse Atrophy of Diaphragm Fibers in Mechanically Ventilated Humans* *Levine et al., Rapid Disuse Atrophy of Diaphragm Fibers in Mechanically Ventilated Humans, NEJM 2008 358: 1327-1335

8. The combination of 18 to 69 hours of complete diaphragmatic inactivity and mechanical ventilation results in marked atrophy of human diaphragm myofibers. These findings are consistent with increased diaphragmatic proteolysis during inactivity. *Levine et al., Rapid Disuse Atrophy of Diaphragm Fibers in Mechanically Ventilated Humans, NEJM 2008 358: 1327-1335

9. Patient Clinician Ventilator True Closed-Loop Control

10. Patient Ventilator True Closed-Loop Control

11. [ RATE ] [ DEPTH ] [ PATTERN ] Now the patient’s respiratory center is in charge.

12. Closed loop –Thermostats –Cruise Control Open loop –Volume Control Ventilation (VCV) Close Loop Applications vs. Open Loop

13. Closed-loop ventilation based on work of breathing (WOB). Now the patient’s respiratory center in the brain is in charge of all aspects of ventilatory rate, depth, pattern and ABGs.

14. Flow VolumeCompliance Resistance PAV+ Measurements and work estimates Impedance Demand Total Work

15. WOB Assessment Vent continuously assesses total WOB. 300 millisecond end-inspiratory pause. Estimates compliance and resistance. 4 to 10 breaths randomly. Continuous Measurement

16. PAV+ uses the flow and volume information collected every 5 milliseconds to know what the patient wants. PAV+ combines this data with the %Supp information input by the clinician to determine how much pressure to supply to the system. PAV™+ Software Option Clinical Description

17. One Simple Setting

19. How does the clinician know where to set the “%Support”? Sound clinical assessment Work of Breathing (WOB) bar

20. Vital signs ABG Signs of respiratory distress –Respiratory rate > 40 breaths/minute PLUS… –Marked use of accessory muscles –Diaphoresis –Abdominal paradox –Marked complaint of dyspnea –Etc… Sound Clinical Assessment.

21. Pt=25% of work Vent=75% of work % Supp 75 % WOB Bar

22. Suppose there is an improvement in compliance. Vent=60% of work.Pt=40% of work. Suppose there is an increase in airway resistance % Supp 75 % % Supp 70 % % Supp 65 % % Supp 60 % % Supp 65 % % Supp 70 % Vent=70% of work.Pt=30% of work.

23. Feedback

24. New Monitored Values

25. Muscle effort Amplifier

26. High at High Levels 95% Support 20:1 50% Support 2:1 20% Support 1.25:1 Low at Low Levels Effort Amplification AMP= 1 1-%Supp

27. Clinical Assessment “Normal” is the GREEN ZONE Identifies and Isolate excess WOB PAV+

28. PCV 15 cmH 2 O PAV+ at 75% P T P T P T P T P T P T Improved Synchrony

29. Comfort. Lower peak airway pressure. Less need for paralysis and/or sedation. Less likelihood for over ventilation. Preservation and enhancement of patient’s own control mechanisms such as metabolic ABG control and Hering-Breuer reflex. Improved efficiency of negative pressure ventilation. PAV Potential Benefits PAV ™ + Software Option Clinical Description M Younes. Proportional Assist Ventilation, A New Approach to Ventilatory Support. Theory. Am Rev Respir Dis 1992;145:114- 120.

30. Muscle activity (i.e. movement) Changes in pH Agitation Sleep/wake cycles Feeding Fever Ventilatory demand will change over time

31. Ventilatory Demand

32. Airway Resistance

33. Increase Support Sedate The practitioner’s typical response to an increase in demand is what? Ventilatory Demand These can lead to disuse atrophy of the respiratory muscles or lowering of the CO 2 set point. Or

34. Start patients at 70% and wean back to stabilize When disease process has sufficiently reversed, decrease %Support over 2 hr intervals On average, patients will breathe at 7 mL/kg; some may want less while others may want more Some patients have a high rate normally, so a high rate on PAV+ may or may not reflect distress; check other signs; try increasing assist to see if rate goes down Don’t be surprised if respiratory rate climbs when switching from other modes Management tips from Dr. Magdy Younes, inventor PAV™+ Software Option Clinical Description Dr. Younes is the inventor of Proportional Assist/PAV. The tips in this presentation are his suggestions and are not necessarily those of Tyco Healthcare/Puritan Bennett. Proportional Assist and PAV are trademarks of The University of Manitoba and are used under license by Puritan Bennett.

35. Tube size: 6.0–10.0. Ensure no large leaks are present (affects R and C). Do not use silicone breathing circuits. Ideal body weight is > 25 kg (not for neonates). No external nebulizers which add flow. Conditional Requirements 12 3 4 5

36. PAV+ is NOT recommended for… Low drive due to meds. Abnormal breathing pattern. Extreme air trapping. Large mechanical leaks (TEF).

37. PAV+: Higher Demand = Higher Support

40. Clinical picture Accessory muscle use Air trapping ABG Minute ventilation Total work Respiratory drive Does all this mean extra coffee breaks for clinicians? PAV™+ Software Option Clinical Description

41. PAV ™ + Software Technical Description Pertubation Maneuver

42. Equation of Motion This equation represents the pressure required for the patient to move his diaphragm. This is patient effort without an artificial airway. PAV™+ Software Technical Description

43. Effort could then be estimated at each 5 millisecond interval if flow, resistance and lung volume were known (840 measures these values). PAV ™ + Software Technical Description

44. This equation finds the pressure at the wye and factors in the %supp set by the clinician. PAV™+ Software Technical Description

45. Four breath start-up. Each includes an end-inspiratory maneuver that yields patient’s compliance and resistance. First breath is delivered using the predicted resistance for the artificial airway and a conservative estimate for a patient’s resistance and compliance based on IBW. NOTE: IBW must be correct! Each valid measurement is then factored in until the fifth breath, which is the first PAV+ breath. Measurements for compliance and resistance are then taken randomly every 4-10 breaths. Flow and volume is assessed every 5 milliseconds. Policing every breath you take Algorithm PAV ™ + Software Technical Description

46. PAV ™ + Literature

47. Ambrosino N, Rossi A. Proportional Assist Ventilation (PAV) a significant advance or a futile struggle between logic and practice? Thorax. 2002;57(3):272-276. “PAV is the only mode of ventilation designed on a physiological basis where the technical solutions offered by ventilators did not come first…it allows the patient to attain whatever ventilation and breathing pattern that best fits the ventilatory control center.”

48. What is This?

49. Comparing Pressure Support and PAV+ PS Targets percent work with variable pressure Breath terminates when inspiratory flow (effort) stops PAV+ Preset pressure, unknown patient work An all-or-nothing breath type Breaths terminate based on several criteria (level of pressure, compliance and resistance of patient, rate of pressure rise, cycling criteria)

50. 1.0 Diaphragm Pressure (cmH 2 O) Airway Pressure (cmH 2 O) Flow (l/sec) Volume (l) 0 0.5 0 0 25 10 0.1 sec/div RC= Time constant = Resistance*Compliance Shorter RC Longer RC

51. P aw PDIPDI VTVT Flow 0.2 sec/div PSVPAV

52. P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) Volume (l) PAV 0.2 sec/div P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) 1. 2 0 20 0 30 0 0 0. 8 1. 2 0 20 0 30 0 0 0. 8 Volume (l) PSV

53. P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) Volume (l) PAV 0.2 sec/div P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) 0 20 0 30 0 1.2 0 0.8 0 20 0 30 0 1.2 0 0.8 Volume (l) PSV BPM patient=60 BPM vent=20

54. 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PAV 0.2 sec/div 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PSV

55. 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PAV 0.2 sec/div 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PSV BPM patient=60 BPM vent=20

56. PS vs PAV+ Comparison Play Movie

57. P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) Volume (l) PAV 0.2 sec/div P di (cmH 2 O) P aw (cmH 2 O) Flow (l/sec) 0 20 0 30 0 1.2 0 0.8 0 20 0 30 0 1.2 0 0.8 Volume (l) PSV Giannouli et al. Response of ventilator dependent patients to different levels of pressure support and proportional Assist. AJRCCM 1999; 159:1716-1725. As a consequence: Minimal, if any, ineffective efforts Ineffective Efforts (min -1 ) Assist LevelPAVPSV Min0.31.0 20.64.0 31.010.0 Max1.213.0

58. 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PAV 0.2 sec/div 0 20 P di (cmH 2 O) 0 30 P aw (cmH 2 O) 0 1.2 Flow (l/sec) 0 0.8 Volume (l) PSV T TOT Pat. T I VENT

59. Improved hemodynamics 3 Less invasive than other technologies Improved sleep architecture 4 Potential Benefits 1. Younes M. Am Rev Respir Dis. 1992;145:114-120. 2. Xirouchaki N et al. Intensive Care Med. Published online July 2008. 3. Patrick W, et al. Am J Respir Crit Care Med. 1993;147:A611. 4. Bosma K et al. Crit Care Med. 2007;35:1048-1054. Improved patient comfort 1 Lower peak airway pressures below 30 cm H 2 0 2 Physiologic control mechanism 1 May reduce need for paralysis/sedation 1 Less likelihood of over-ventilation 1

60. PAV No C and R Traditional vs. Modern PAV PAV+ Updates Compliance and Resistance every 4–10 breaths.

61. “…a software option has been developed (PAV+) that continuously and automatically adjusts the flow and volume gain factors so as to represent constant fractions of the measured values of resistance and elastance of the respiratory system. This feature not only considerably increases the efficiency of this mode but greatly simplifies the application of PAV in critically ill patients…” Current Status of Proportional Assist Ventilation Georgopoulos, et. al. Current Stautus of Proportional Assist Ventilation. International Journal of Intensive Care. Autum 2007: 19-26.

63. Proportional Assist Ventilation with Load-Adjustable Gain Factors in Critically Ill Patients: Comparison with Pressure Support Aim of Study Explore the use of PAV+ in CRITICALLY ILL patients 208 patients with severe illness such as: –ALI/ARDS –CHF/Cardiogenic shock –COPD exacerbation –Sepsis Randomized into PAV+ and PSV groups once ability to breathe spontaneously was achieved. Used pre-determined algorithms for sedation and vent management to prevent investigator bias. N. Xirouchaki, E. Kondili, K. Vaporidi, G. Xirouchakis, M. Klimathianski G. Gariilidis, E. Alexandopoulou, M. Plataki, C. Alexopoulou, D. Georgopoulos Intensive Care Med (2008) 34:2026–2034

64. 1.Xirouchaki N et al. Inten Care Med. Published online July ‘08. 2.Georgopoulos D et al. Internatl J Int Care. 2007;14(3),74-83. “…airway pressure…remained below 30 cm H 2 O in 98.2% of measurements and below 26 cm H 2 O in 94%…” 1 “…simple clinical algorithms…” 2 “…continuously and automatically adjusts…this feature not only considerably increases the efficiency of this mode but greatly simplifies the application…” 2 Implementation “…a useful mode of support in critically ill patients.” 1

65. Proportional Assist Ventilation with Load-Adjustable Gain Factors in Critically Ill Patients: Comparison with Pressure Support N. Xirouchaki, E. Kondili, K. Vaporidi, G. Xirouchakis, M. Klimathianski G. Gariilidis, E. Alexandopoulou, M. Plataki, C. Alexopoulou, D. Georgopoulos Intensive Care Med (2008) 34:2026–2034 Ventilating pressure remained below 30cmH 2 O in 98.2% of measurements in PAV+ group. PAV+ PSV Failure RateAsynchrony Rate PAV+ PSV

66. Respiratory load compensation during mechanical ventilation-proportional assist ventilation with load- adjustable gain factors versus pressure support Objective: to assess, in critically ill patients, the short-term steady-state response of respiratory motor output to added mechanical respiratory load during PAV+ mode and during pressure support 10 patients with acute respiratory failure Esophageal catheter placed Patients initially on PS and PTP was calculated after 30 minutes Patients then placed on PAV+ option and %Support adjusted to give comparable PTP. Eumorfia Kondili, George Prinianakis, Christina Alexopoulou, Eleftheria Vakouti, Maria Klimathianaki, Dimitris Georgopoulos Intensive Care Med DOI 10.1007/s00134-006-0110-0 Sandbags applied to entire surface of the anterior chest and abdominal wall to affect elastance by 30%

67. Respiratory load compensation during mechanical ventilation-proportional assist ventilation with load- adjustable gain factors versus pressure support Results With load application, inspiratory effort per breath was considerably lower due to continuous adaptation of the degree of ventilatory assistance to the changes in respiratory mechanics. Minute volume was maintained in PSV with smaller tidal volumes and higher rates. Eumorfia Kondili, George Prinianakis, Christina Alexopoulou, Eleftheria Vakouti, Maria Klimathianaki, Dimitris Georgopoulos Intensive Care Med DOI 10.1007/s00134-006-0110-0

68. Younes M, Am J Respir Crit Care Med. 1993;147:A611 Improved Cardiac Performance with Proportional Assist Ventilation *In this example, “PAV” refers to proportional assist ventilation. It does not refer to Puritan Bennett’s PAV+ software option, which features a closed loop algorithm that automatically adjusts to patient demand. Response of peak airway pressure (left) and cardiac output (right) to alternation between volume-cycled assist/control (A/C) ventilation and proportional-assist ventilation (PAV).

69. PAV*PSV Arousals/hr 916 Awakenings/hr 3.55.5 REM Sleep 9%4% Slow Wave Sleep 3%1% K Bosma et al. Patient-ventilator interaction and sleep in mechanically ventilated patients: Pressure support versus proportional assist ventilation. Crit Care Med 2007 Vol. 35, No. 4 *This study examined traditional PAV not PAV+ Reduced asynchrony and better overall sleep quality. Improved Sleep with Proportional Assist Ventilation

70. Innovation – PAV+ Mode with the Patient in Mind Tidal Volume Flow Rate Inspiratory Time Set Respiratory Rate Volume Control Volume Control+ Pressure Control PS PAV+ Medical Doctor Patient Brain Resp Therapist

71. PAV+: Higher Demand = Higher Support

72. Ventilator asynchrony is costly PAV+ software improves patient-ventilator synchrony PAV+ software is easy to use in critically ill patients and for weaning Conclusion

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