How to Ventilate on VV ECMO? And Why?

Ibrahim Fawzy Hassan, MD ECMO Program Director – Hamad General Hospital Assistant Professor of Medicine – Weill Cornell Medical College in Qatar

Disclosure  I have no actual or potential conflict of interest.

Objectives • • • • • •

Lung zones in ARDS and VILI Early vs late course of the lung on ECMO Ventilation strategies during different courses Recommendation from various networks Pplat and TV, PEEP and ∆P Summary

Lung Zones in ARDS Normal Lung Potential for Derecruitment

Consolidated Lung

Ventilator Induced Lung Injury Normal Lung

O2 Toxicity

Volum-trauma Baro-trauma

Potential for Derecruitment

Atelecto-trauma Bio-trauma

Consolidated Lung

Ventilator Induced Lung Injury Over-distention

O2 Toxicity

Volum-trauma Baro-trauma

De-recruitment

Atelecto-trauma Bio-trauma

Atelectasis

Bio-trauma

Overdistention “Safe” Window

Derecruitment and Atelectasis

Injurious Ventilation leads to MODS Brain Swelling and Ischemia

Cardiovascular instability

↑peak pressure, VILI

Anuric acute renal failure

↑Gut ischemia and impending necrosis

Worsening of the acidosis

Safe Ventilator Strategy in ARDS

O2 Safe Toxicity FiO2

Volum-trauma Low TV Baro-trauma Safe Pplateau

Atelecto-trauma Optimum PEEP Bio-trauma

↓Over-distention Over-distention ↓De-recruitment De-recruitment

Enhance Atelectasis recruitment

Very Severe ARDS H1N1 PNA  FiO2 :100%  PEEP : 20  Pplat : 45  TV : 5 mL/kg

PEEP : 10

ABG  pH : 6.9  PaO2 : 42  PaCO2 :120  SaO2 : 70%

PEEP : 40

H1N1 PNA  FiO2 :100%  PEEP : 20  Pplat : 45  TV : 5 mL/kg  RR : 35

Very Severe ARDS on ECMO  FiO2  PEEP  Pplat  TV  RR

:100% : 20 : 45 : 5 mL/kg : 35

ABG  pH : 7.35 6.9  PaO2 : 70 42  PaCO2 ::120 40  SaO2 : 98% 70%

What are the Ventilation Options?  FiO2  PEEP  Pplat  TV  RR FiO2? PEEP? Pplat? TV? RR?

:100% : 20 : 45 : 5 mL/kg : 35

Continue the same ventilation? Protective lung ventilation? Ultra-protective lung ventilation? Extubation?

ABG  pH : 7.35  PaO2 : 70  PaCO2 : 40  SaO2 : 98%

ECMO Course Early Course (Inflamed Lung)     

First few days to week Severe lung inflammation Uncontrolled source Systemic inflammation Encephalpathy

Late Course (Lung Recovery)     

Second week Lung recovery Source eradicated Less systemic inflammation Weaning

Early Course (Inflamed Lung)

Optimize ECMO flow and O2 delivery

Optimize Native Lung Function

Early Diagnosis and aggressive treatment of the cause

Decrease the risk of VILI

What are the Ventilation Options?  FiO2 v :100%  PEEP : 20  Pplat : 45  TV : 5 mL/kg  RR v : 35 FiO2? PEEP? Pplat? TV? RR?

Continue the same ventilation? Protective lung ventilation? Ultra-protective lung ventilation? Extubation?

ABG  pH : 7.35  PaO2 v : 70  PaCO2 v : 40  SaO2 : 98%

What are the Ventilation Options?  FiO2  PEEP  Pplat  TV  RR

PEEP? Pplat? TV?

:100% : 20 : 45 : 5mL/kg PEEP : 35  Pplat  TV

Protective lung ventilation? Ultra-protective lung ventilation?

: High : < 30 : 4-6 mL/kg

 PEEP  Pplat  TV

: High : < 20 : 1-3 mL/kg

Recommendation and Data

The use of VV ECMO for ARDS

• RR :3-5 breaths per minute • Peak inspiratory pressures 35 - 45 cmH2O • PEEP:15 and 25 cmH2O

ELSO • Managing MV “at low settings to allow lung rest”. • “A common mistake is to try to recruit lung volume during the acute inflammatory stage early in ECMO.” • “PEEP: any level, usually 5-15 cmH2O”.

Cesar Trial • • • •

PCV, peak inspiratory pressure < 20 cmH2O PEEP of 10 cmH2O Respiratory rate of 10 breaths/minute FiO2 30% Conventional Ventilation or ECMO for Severe Adult Respiratory Failure

Italian ECMO Network • TV • PEEP • RR

: 3 - 6.3 mL/kg (PBW), median 4.6mL : 16 cmH2O, median value : 10 (8-12) breaths/min

Pplat and TV?

Summary of randomized controlled trials of Volume- and Pressure- Limited mechanical ventilation VT (ml/kg)

Study

High

Low

6

12

31.8

ARDSnet (n = 861)

6.2

11.8

Stewart (n = 120)

7.2

10.8

22.3

26.8

Brower

(n = 52)

7.1

10.3

24.9

30.6

Brochard (n = 116)

7.1

10.3

25.7

31.7

Amato

Low

Mean Pplat (cm H2O)

(n =53)

< 32

25

High 34.4 33

>32

< 32

Mortality (%) Low

High

38

71

31

40

50

47

50

46

47

38

10

The available data from each of these assessments do not support the commonly held view that inspiratory plateau pressures of 30 to 35 cm H2O are safe.

Mortality Proportion

9 8

We could not identify a safe upper limit for plateau pressures in patients with ALI/ARDS.

7 6 5 4 Retrospective evaluation of the ARDSnet database suggested that VT reduction would have improved outcome, even in patients who already had pPlat < 30 cm H2O.

3 2 1 0

20

40

60

Day 1 Plateau Pressure (cm H2O)

80

Tidal volume reduction in patients with acute lung injury when plateau pressures are not high. Hager DN, Am J Respir Crit Care Med. 2005 Nov 15

Tidal volume lower than 6 ml/kg enhances lung protection: role of extracorporeal carbon dioxide removal. Terragni PP,, Anesthesiology. 2009.

“ARDSNet” strategy: 25