Esophageal Pressure Monitoring in the ICU

1. Esophageal Pressure Monitoring in the ICU Transpulmonary Pressure Measurements: Case Studies: Similar airway pressures, different transpulmonary pressures

4. As the lung inflates� Airways = Red Arrows Lung = Black Arrows Chest Wall = Green Arrows

5. Compliance: CRS = CL + CCW The compliance of the respiratory system can be viewed as 3 components: Lung compliance Chest wall compliance Respiratory system compliance combination of chest wall and lung compliances

6. Airway Pressure Graphic The airway pressure scalar can be divided into the following components:

7. AVEA: Enhanced Patient Monitoring ARDSnet 6ml/kg target Vt Keep Airway Plateau Pressures < 30 cmH2O

8. AVEA: Enhanced Patient Monitoring Why monitor Transpulmonary Pressures? Ptp = Paw - Pes Keep Transpulmonary Plateau Pressures < 30-35 cmH2O

9. Increased Abdominal Pressure � Lung Sequela

10. How common is this syndrome? Malbrain et al, Intensive Care Med (2004) 30:822�829

11. Lung Stretch Pressure = Ptp How are Transpulmonary Pressures clinically significant?

12. Assessments of Transpulmonary � Insp & Exp Holds

13. Assessments of Transpulmonary � Insp & Exp Holds

14. Lung Stretch Pressure = Ptp ARDS Goal: Manage Stress caused by over stretch and collapse of the lung tissue �Transpulmonary Pressure�

15. Can we differentiate between a stiff lung and a stiff chest wall? Which is the larger contributing factor to the overall decrease in Respiratory System Compliance? Esophageal Pressure Monitoring Stiff Lung or Stiff Chest Wall?

16. Esophageal Pressure Measurements Esophageal Catheter Insertion Lower third of the esophagus

17. Transpulmonary Pressure During an inspiratory hold, the airway pressure equilibrates with the alveolar pressure and the pressure being measured by the ventilator (Paw) is the total respiratory system plateau pressure, i.e. the chest wall and lung pressure Transpulmonary Pressure: Once an inspiratory or expiratory hold is performed, the chest wall pressure, B, can then be subtracted from the total pressure of the respiratory system, A, to give the transpulmonary pressure, C

18. Chest Wall Compliance Pes Measurement: Less compliant lungs (stiff lung tissue)? lower the rise in Pes Less compliant chest wall (Stiff chest wall)? higher the rise in Pes

20. Lung Recruitment Potential Primary ARDS vs. Secondary ARDS Pulmonary ARDS vs. Extra-pulmonary ARDS Intra-alveolar debris vs. Interstitial edema Non-recruitable vs. Recruitable

21. Clinical Presentation 64 yr old male Previously healthy, developed progressively worsening SOB over 2-3 days, fever, malaise Visited the ER and was diagnosed with CAP Prescribed a course of antibiotics, sent home Patient returned to community hospital by ambulance 3-days later. X-Ray showed diffuse patchy infiltrates, and bilateral opacifications. Difficult to ventilate and oxygenate CXR: consolidation w/ basilar predominance Prophylactic bilateral chest tubes-no leak Trials of iNO, and HFOV ? no success Day 9 of ventilation, inserted esophageal catheter to assess transpulmonary pressures Difficult to ventilate and oxygenate CXR: consolidation w/ basilar predominance Prophylactic bilateral chest tubes-no leak Trials of iNO, and HFOV ? no success Day 9 of ventilation, inserted esophageal catheter to assess transpulmonary pressures

22. Patient deteriorated required intubation and mechanical ventilation; respiratory failure Subsequently developed ARDS, Sepsis, ARF Transferred to a university hospital for hemodialysis Vent-day 7. The patient was received chemically paralyzed, sedated, with a sodium bicarbonate infusion.

23. Admission to University Hospital AVEA ventilator; Pressure A/C Mode Insp. Pres: 18 cmH20 PEEP: 20 cmH20 RR: 23 bpm Ti: 0.9 sec FiO2: 1.0 Issues: High PIP & High PEEP/FiO2, VT(7 ml/Kg) Transfer ABG: pH 7.26 HCO3 33 mEq/l PaCO2 77mmHg SaO2 90% PaO2 69 mmHg

24. Patient continued to deteriorate requiring fluid resuscitation & inotropes to stabilize BP Subsequent ABG: pH 7.08 HCO3 30 mEq/l PaCO2 108mmHg SaO2 81% PaO2 67 mmHg Trial of paralytic agent to optimize conventional ventilation Trials of iNO (20ppm) and HFOV (MAP28) ? not able to wean FiO2 from 1.0 Prophylactic bilateral chest tubes inserted

26. Inspiratory Hold Maneuver Inspiratory Hold performed Transpulmonary Plateau Pressure measured to assist in improving ventilation strategy

27. Expiratory Hold Maneuver Transpulmonary End-expiratory Pressure assessed to measure distending pressure of lung Note: Peso pressure only rises from 6 on expiration to 7 at end inspiration The lungs are extremely stiff, (non-compliant) the Pes tracing remain very diminished. The Ptp reflects the true distending pressure felt by the lungs during inspiration and reflects the degree of elastance caused by the fibrotic lung changes associated with the pneumonia process.The lungs are extremely stiff, (non-compliant) the Pes tracing remain very diminished. The Ptp reflects the true distending pressure felt by the lungs during inspiration and reflects the degree of elastance caused by the fibrotic lung changes associated with the pneumonia process.

28. Assessed Loops Transpulmonary P/V and Esophageal P/V Note: virtually no pressure change is seen on the Pes/V loop Machine Peep=20, Pes=6 Severe decrease in lung compliance Pressure-Volume Loops

29. Case Study#2 ARDS 2o to Pancreatitis Elevated Abdominal Pressure (?Ccw) Case Study: Secondary ARDS � Ptp Low

30. Lung Recruitment Potential Primary ARDS vs. Secondary ARDS Pulmonary ARDS vs. Extra-pulmonary ARDS Intra-alveolar debris vs. Interstitial edema Non-recruitable vs. Recruitable

31. Clinical Presentation 62 y.o female, Dx: ARDS 2o to pancreatitis Morbid Obesity Difficult to ventilate and oxygenate Emergency surgical decompression of enlarged abdomen Post Op - still difficult to ventilate and oxygenate Paralyzed, sedated, on HCO3 drip

32. Clinical Presentation AVEA ventilator; Pressure A/C Mode Insp. Pres: 24 cmH20 PEEP: 20 cmH20 RR: 24 bpm Ti: 1.0 sec FiO2: 0.80 Subsequent ABG: pH 7.21 HCO3 26 mEq/l PaCO2 78 mmHg SaO2 81% PaO2 57 mmHg Day 6 of ventilation, inserted esophageal catheter to assess transpulmonary pressures

33. Inspiratory Hold Maneuvers

34. Expiratory Hold Maneuvers Transpulmonary End-expiratory Pressure assessed to measure distending pressure of lung Note: Peso pressure rises from 24 on expiration to 31 at end inspiration; negative Ptp

35. Pressure-Volume Loops

36. Ptpexp of -4 indicated that Airway PEEP was inadequate. Potential PEEP required ~ 25 - 30cm H2O Clinicians more comfortable with HFOV strategy Started on HFOV, LRM performed (40 cmH2O for 40 sec) Settings: MAP 32 cmH20 f = 4 Hz Power = 9 Ti = 33, FiO2 = 0.6 Pt responded nicely. FiO2 was weaned to < 0.30. Patient survived and was discharged from hospital.

37. Discussion� Are airway pressures adequate for interpreting lung stress in ventilated patients? Gattinoni - Crit Care 2004 Vol. 8, pp 350-355 High Ptp trigger of VILI

38. Discussion�

39. Discussion� Do airway pressures adequately reveal the role of chest wall involvement in ventilation? Talmor - Crit Care Med 2006 Vol. 34, No.5 Ranieri - AJRCCM 1997 Vol. 156, pp 1082-1091 Benditt - Respir Care 2005;50(1):68 �75 (Discussion)

40. Discussion�

41. Summary� One Paw - Two different pictures

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