Acute Respiratory Distress Syndrome

Mark Griffiths

St Bartholomew’s Hospital

Imperial College London

ARDS for Physicians

What is ARDS?

Why should you care?

Should you change?

Date of download: 2/9/2016 Copyright © 2016 American Medical

Association. All rights reserved.

From: Acute Respiratory Distress Syndrome: The Berlin Definition

JAMA. 2012;307(23):2526-2533. doi:10.1001/jama.2012.5669

Acute non-cardiac pulmonary oedema with respiratory failure

Pulmonary oedema

↓

Surfactant dysfunction

↓

Collapse

Loss of Hypoxic Pulmonary

Vasoconstriction

Hypoxic respiratory

failure + =

Acute Inflammation

Pneumonia Aspiration

Noxious inhalation

Sepsis Embolisation

TRALI

Alcoholism Diabetes Smoking Obesity

ARDS for Respiratory Physicians

Diagnosis

ARF & diffuse pulmonary infiltrates

Not ARDS

Cardiac Respiratory

ARDS

Causes of ARDS

Cardiac

Acute LV failure

Right to left shunts

P. Vascular

PE, Sickle lung, Veno-Occl dz

Diffuse alveolar haemorrhage

Malignancy

BA Carcinoma, Lymphangitis

Acute leukaemia, lymphoma

Cryptogenic

Acute Interstitial Pneum

Cryptogenic Organising Pneum

Acute eosinophilic pneum

Differentials – non-ARDS / DAD

Imaging Echo

Bronchoscopy Micro

Immunology Cytology

ARDS for Physicians

“Not my problem”

Lung SAFE Bellani, G., et al. JAMA, 2016. 315(8): 788-800

• 459 ICUs, 50 countries, 5 continents

• 29,144 ICU admissions

• 10.4% developed ARDS

• 25% patients supported with IMV

• Unrecognised, diagnosis made in 50%

mild ARDS

• High mortality (35-40%)

Clinical risk conditions for ALI in ICU and hospital ward: a prospective observational study

Ferguson ND et al. Critical Care 2007;11(5):R96

28%

Clinical risk conditions for ALI in ICU and hospital ward: a prospective observational study

Ferguson ND et al. Critical Care 2007;11(5):R96

Eight-year trend of ARDS: a population-based study in Olmsted County, Minnesota

Li et al. Am J Respir Crit Care Med 2011;183:59-66

• ↓ ARDS incidence from 82.4 to 38.9 per 100,000 – incr severity of acute illness,

– more comorbidities,

– incr prevalence of predisposing conditions

• ↓Mortality, hospital and ICU los

• Resulting from changes in practice?

Predisposing conditions LIPS

points

Shock 2

Aspiration 2

Sepsis 1

Pneumonia 1.5

High-risk surgery

• Orthopedic spine 1

• Acute abdomen 2

• Cardiac 2.5

• Aortic vascular 3.5

High-risk trauma

• Traumatic brain injury 2

• Smoke inhalation 2

• Near drowning 2

• Lung contusion 1.5

• Multiple fractures 1.5

Risk modifiers LIPS

points

Alcohol abuse 1

Obesity (BMI > 30) 1

Hypoalbuminaemia 1

Diabetes mellitus -1

Chemotherapy 1

FiO2 > 0.35 or > 4

litres/minute

2

Tachypnoea RR > 30 1.5

SpO2 < 95% 1

Acidosis (pH < 7.35) 1.5

Score >4 points sensitivity for ALI 0.69 (95% CI 0.64-0.74),

specificity 0.78 (95% CI 0.77-0.79),

Can ARDS be prevented?

• Identifying a pre-ARDS population

– Where are they? >25% aren’t in AICU

• Time to intervene median lag 2-4 days

• Identifying at risk populations

– Epidemiology i.d. at risk groups - LIPS

– Biomarkers

ARDS for Physicians

Effective interventions

Study Patients Mean Tidal

Volume Vt ml/kg

Mean Plateau Pressure

cmH2O

PEEP cmH2O

Mortality %

P C P C P C P C p

Stewart 120 6.8 10.1 20 28.6 9.6 8.0 50 47 NS

Brower 52 7.3 10.2 24.9 30.6 Not given 50 46 NS

Brochard 116 7.4 10.7 24.5 30.5 9.6 8.5 47 38 NS

ARMA ARDS Network

861 6.5 11.4 26 37 8.1 9.1 31 40 0.007

Ventilator Associated Lung Injury

National Center for Health Statistics 10 lives / day saved in USA!

0 5 10 15 20

Thousand deaths / year

Asthma

AIDS

Emphysema

ARDS

In terms of QALYs gained, if an average ICU spent $10,000 per ARDS patient in order to achieve >90% adherence to low tidal volume ventilation the intervention would still be cost effective Cooke et al. Chest 2009; 136:79-88

Fluid And Catheter Treatment Trial (FACTT) ARDS Network N Engl J Med 2006;354:2564-75

• 1000 ALI pts within 48hrs of ALI diagnosis

• Protocolised fluid Mx in for 7 days

• Protective ventilation strategy

• Factorial design - CVC vs PAC

• Cumulative 7 day fluid balance

o Liberal 6992 ± 502 ml

o Conservative -136 ± 491 ml

Outcome Conservative Liberal P value

Death @ d60 25.5 28.4 0.30

Ventilator-free days from d1-28

14.6 + 0.5 12.1 + 0.5 <0.001

Lung injury score 2.03 + 0.07 2.27 + 0.06 0.001

ICU free days: Days 1-7 0.9 + 0.1 0.6 + 0.1 <0.001

Days 1-28 13.4 + 0.4 11.2 + 0.4 <0.001

Renal RT: Prevalence 10% 14% 0.06

Days of RRT 11.0 + 1.7 10.9 + 1.4 0.96

Transfusing ARDS patients

• Western Europe (ABC ‘02) & US (CRIT ‘04) trial 35-45% ICU pts transfused ~5u RBC

• Dose-dependent relationship between RBC utilization & ARDS incidence Gong et al CCM ’04

• Transfusion incr mortality, leukocyte depleted blood less injurious Netzer et al. Chest ’07

• Nosocomial infection: bacteraemia & VAP – TRIM

• Post SHOT, 2/3 decrease in TRALI

Mind the 2nd translational gap!

Young et al. Crit Care Med. 2004 Jun;32(6):1260-5.

Limiting ventilator-induced lung injury through individual electronic medical record surveillance

Herasevich V et al. Critical Care Medicine 2011;39:34-39

ARDS for Respiratory Physicians

After you have failed….

Neutral fluid balance Transfusion @ 7 g/dL Antimicrobials Nutrition Rehab Psychology Out-patient services

Management of ARDS

Summary • Overall

Diagnose & treat the disease!

Avoid iatrogenic injury

Drugs (don’t hold your breath)

• Opportunity for prevention Your patients

Scoring - LIPS

Effective interventions

• Quality improvement Education, cohesive practice and audit

IT/ automated surveillance - “sniffer”

Challenge! 60 yr publican in HDU, d1 after

type B thoracic aneurysm repair

• Hypotensive, oliguric, T 37.8o

• Extubated requiring NIV, fiO2 0.5, CXR fluffy

• Confused

• Hb 80

According to AECC 1994

In the United States, there are estimated to be 190,000 cases and 74,000 deaths annually from ARDS.

Strong +ve Weak +ve Equipoise Weak -ve Strong -ve

Steroids X

NMB X

Inh vasod X

Low Vt X

Proning X

ECCOR X

APRV X

Recrtmt M

HFOV X

High PEEP X

-ve FB X

ECMO X

Analysis of Evidence

Strong +ve Weak +ve Equipoise Weak -ve Strong -ve

Steroids RCT required

NMB Cisatr, 48hr, mod/severe

Inh vasod iNO

Low Vt X

Proning >16hr, mod/severe

ECCOR RCT required

APRV X

Recrtmt M

HFOV X

High PEEP mod/severe

-ve FB X

ECMO X

ICS GDG Recommendations

Wythenshawe Glenfield Papworth GSTT Royal Brompton

London

NHS England adult respiratory ECMO centres

Indications

Activity

Parameter N

Referrals 105

Admissions ECMO 29 AV-ECCO2R 1 HFOV 2

37

Patients not admitted Futility 44 “Too well” 13 Lack of capacity 9 Wrong area 1 Referrer wants to keep 1 Referral for cardiac ECMO 0

68

Survival for patients admitted

Time point N 2014 2013-4

End of NSCT pathway 42 37 (88.1 %) 74.3%

Discharge from RBH ICU 42 32 (76.2 %) 68.8%

VA ECMO 4 3 (75 %)

Deaths

G. 33 year old male, pulmonary tuberculosis • IF drug user • Diagnosed with pulmonary TB two weeks previously • Directly observed therapy but defaulted after 1 week • Represented with 2 day history of breathlessness, Pseudomonas identified from

sputum • Ventilated and referred on day 2 (pH 7.10; pO2 7.9 kPa) • 25 min cardiac arrest due to tension pneumothorax whilst ECMO team en route

• Mobile VV-ECMO

• Acute liver dysfunction (hypoxic and Hepatitis E) • Acute kidney injury • Very significant sedation issues

Deaths

G. 33 year old male, pulmonary tuberculosis

• Recurrent pneumothoraces, torrential air leak • Relentless clinical decline • ECMO withdrawn day 16 • Referred but unsuitable for donation after cardiac death

Deaths

C. 67y male, community acquired pneumonia • Severe hypoxaemic respiratory failure • Left lower lobe consolidation • Empirical thrombolysis for PE • Transferred for consideration of ECMO

• Unequal pupils noted • CT head –no neurosurgical option • CT pulmonary angiogram – no PE • Not for escalation of therapy, died on day 2

• Hospital post-mortem

Intracranial haemorrhage

Last three years data

Non-ECMO • 3/39 (7.7%) ECMO patients • 7/49 (14.3%) No difference (p=0.506, Fisher’s Exact) 4 out of 10 patients survived to discharge home Prediction of outcome difficult

ELSO

~ 3.9 %

Australia

~ 8.8 %

• Avalon cannula may obstruct venous drainage • Smaller cannulae • Neutral head position

• Lower heparin doses

• Slower reductions in arterial CO2 at onset of

ECMO

• Observational study in preparation • Brain oximetry • Biomarkers • Correlated with time/events/outcome