Early Protective Mechanical Ventilation is key to ARDS outcomes

The Lungsafe study demonstrated that protective ventilation is not consistently applied, reflecting the need for more accessible and effective bedside tools for identification of the lung at risk ^[1]. This important study concluded that ARDS is underrecognized, undertreated, and still associated with a high mortality rate.

How to prevent excess dynamic lung stress and diaphragm injury?

Of patients with ARDS, developed it in the first 48 hours of invasive ventilation.

Received a PEEP of less than 12.

Received a tidal volume above 8 ml/kg of PBW.

Suffers from diaphragm weakness associated with poor outcomes.

See reference ^[1]

Lung and diaphragm protective ventilation

The goal of mechanical ventilation in patients with ARDS is to maintain gas exchange while avoiding the complications such as ventilator-induced lung injury (VILI), ventilator-associated pneumonia (VAP), or ventilation-induced diaphragm dysfunction (VIDD). ^[2]

Learn more about VIDD

Protective ventilation strategies proposed as standard of care are prescribing low tidal volumes per predicted bodyweight (PBW), and limited plateau and driving pressures in order to reduce risk for ventilation induced lung injury (VILI) ^[3].

Timely recognition and prompt adherence to protective ventilation may be important for maximally reducing ICU mortality in patients with ARDS ^[4].

Flowchart with two main goals: Maintain adequate gas exchange and Minimize atelectasis, detailing methods.

Flowchart on lung stress management: avoid excess stress with low tidal volumes and optimal inspiratory effort.

Why driving pressure?

Driving pressure (ΔP) is an indirect measurement of lung strain. It is been defined as the ratio of tidal volume by total respiratory system compliance (ΔP = VT/C_RS) and can be routinely calculated for patients who are not making inspiratory efforts as the plateau pressure minus PEEP (ΔP = Pplateau - PEEP).

Amato et al identified ΔP as the main determinant of ventilator-induced lung injury (VILI), and the ventilator parameter most strongly related to mortality, particularly at ΔP values >14 cm H₂O ^[1]^[3]. Targeting ΔP as means to minimize lung injury appears to be reasonable approach to improve patient outcome.

Learn more about Servo-u and the lung protective tools

Gattinoni L and Presenti A. The concept of baby lung” ICM 2005

Tidal volume 6 ml/kg PBW protective

Patients with ARDS have dependent atelectasis and this atelectasis exacerbates lung injury during mechanical ventilation by reducing the size of the lung available for tidal ventilation and increasing lung stress, even when using "safe" tidal volumes.^[6]

The Open Lung Approach (OLA)

The Open Lung Approach (OLA), including lung recruitment maneuvers and PEEP titration, may dramatically improve oxygenation, while reducing lung injury.^[2] ^[6] In the OLA trial oxygenation and driving pressure were improved, without detrimental effects on mortality, ventilator-free days or barotrauma ^[7]. This trial showed also one of the lowest reported mortality rates for patients with established ARDS: 25% .

Graphic reference ^[7]

Is there value in lung recruitment maneuvers (RM)?

Hexagonal chart with benefits: improve oxygenation, reduce mortality, no increased barotrauma, no hemodynamic issues.

Recruitment maneuvers in ventilation strategies

A recent systematic review and meta-analysis of randomized trials comparing mechanical ventilation strategies with and without RMs, showed RMs to be safe and well tolerated ^[8].

Learn more about Servo-u Open Lung Tool™ (OLT)

Maintain optimal inspiratory efforts and protect the diaphragm

Why Diaphragm Protection?

Diaphragm weakness is prevalent (23–84%) in ICU patients and consistently associated with poor outcome ^[12]. 29% of patients experience weaning failure due to diaphragm dysfunction and it extends time on mechanical ventilation by up to 16 days ^[13].

Edi Monitoring

Prevention of disuse atrophy and high breathing effort are the cornerstone of diaphragm-protective mechanical ventilation, where Edi monitoring is proposed as a method to target physiological loading of the diaphragm. ^[14]^[15]

Learn about Edi monitoring and NAVA

Impact on clinical

The presence of diaphragm weakness significantly increases the risk of difficult weaning, prolonged weaning and hospital mortality, says Dr Ewan Goligher, referencing a recent study on the topic.^[16]

Watch this video to learn more

All references

1. Bellani, et al Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries JAMA. 2016;315(8):788-800. doi:10.1001/jama.2016.0291.
2. Fan E, Brodie D, Slutsky AS. Acute Respiratory Distress Syndrome: advances in diagnosis and treatment. JAMA 2018; 319(7): 698-710. Doi: 10.1001/jama.2017.21907.
3. Amato MB, Meade MO, Slutsky AS, et al.Driving pressure and survival in the acuterespiratory distress syndrome. N Engl J Med. 2015;372(8):747-755.
4. Needham et al.: Timing of Tidal Volume and ICU Mortality in ARDS, ATS Journal 2015
5. Yoshida T et al. Spontaneous Breathing during Mechanical Ventilation: Risks, Mechanisms, and Management (FIFTY YEARS OF RESEARCH IN ARDS). Am J Respir Crit Care Med Medicine Volume 195 Number 8 | April 15 2017
6. Fan E, Del Sorbo L, Goligher EC, et al. American Thoracic Society, European Society of Intensive Care Medicine, and Society of Critical Care Medicine. An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. 2017 May 1;195(9):1253-1263.
7. Kacmarek RM, et al. Open Lung Approach for the Acute Respiratory Distress Syndrome:A Pilot, Randomized Controlled Trial. Crit Care Med. 2016 Jan;44(1):32-42.
8. Goligher EC, Hodgson CL, et al. Lung Recruitment Maneuvers for Adult Patients with Acute Respiratory Distress Syndrome. A Systematic Review and Meta-Analysis. Ann Am Thorac Soc. 2017 Oct;14 (Supplement_4):S304-S311.
9. Colombo D, et al. Efficacy of ventilator waveforms observation in detecting patient–ventilator asynchrony. Crit Care Med. 2011 Nov;39(11):2452-7.
10. Schepens T, et al. The course of diaphragm atrophy in ventilated patients assessed with ultrasound: a longitudinal cohort study. Crit Care. 2015 Dec 7;19:422.
11. Blanch L, et al. Asynchronies during mechanical ventilation are associated with mortality. Intensive Care Med. 2015 Apr;41(4):633-41.
12. Dres M, Goligher EC, Heunks LMA, Brochard LJ. Critical illness-associated diaphragm weakness. Intensive Care Med. 2017 Oct;43(10):1441-1452.
13. Kim et al. Diaphragm dysfunction (DD) assessed by ultrasonography: influence on weaning from mechanical ventilation. Crit Care Med. 2011 Dec;39(12):2627-30
14. Heunks L, Ottenheijm C. Diaphragm Protective Mechanical Ventilation to Improve Outcome in ICU Patients? Am J Respir Crit Care Med. 2017.
15. Colombo D, et al. Efficacy of ventilator waveforms observation in detecting patient–ventilator asynchrony. Crit Care Med.2011 Nov;39(11):2452-7.
16. Blanch L, et al. Asynchronies during mechanical ventilation are associated with mortality. Intensive Care Med. 2015 Apr;41(4):633-41.