ARDS for Physicians

Mark Griffiths Royal Brompton Hospital Imperial College London

ARDS for Physicians

What is ARDS? Why should I care?

Should I change what I do?

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

Pneumonia Aspiration

Noxious inhalation

Sepsis Embolisation

TRALI

Alcoholism Diabetes Smoking Obesity

Pulmonary oedema

↓ Surfactant

dysfunction ↓

Collapse

Loss of Hypoxic Pulmonary

Vasoconstriction

Hypoxic respiratory

failure + =

Acute Inflammation

ARDS: a worthy syndrome?

ARDS for Physicians

What is ARDS? Why should I care?

Should I change what I do?

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?

Can ARDS be prevented?

• Identifying a pre-ARDS population – Where are they?

• Time to intervene • Identifying at risk populations

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

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

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

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

Can ARDS be prevented?

• Identifying a pre-ARDS population – Where are they?

• Time to intervene • Identifying at risk populations

– Epidemiology – Biomarkers

• Personalised medicine

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

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

VALI - Mechanical Ventilation

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

Influence of body mass index on outcome of mechanically ventilated patients

Anzueto et al. Thorax 2011;66:66-73

Mind the 2nd translational gap!

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

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

• 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

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

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

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

ARDS for Physicians

What is ARDS? Why should I care?

Should I change what I do?

ARF & diffuse pulmonary infiltrates

Pneumonia likely

First line antibiotic regimen

Echocardiogram Pulmonary artery catheter

Cardiac cause Pulmonary embolism

treatment failure

yes no

CT thorax Bronchoscopy and BAL

?Open lung biopsy?

Diagnosis

What’s the diagnosis?

Pneumonia

Bacterial Milliary Tb

Viral H1N1, HSV, CMV, SARS, Hantavirus

Fungal PCP

Other Strongaloidiasis

P. Vascular PE, Sickle lung, VO dz

Diffuse alveolar haemorrhage

Malignancy BA Carcinoma, Lymphangitis

Acute leukaemia, lymphoma

Cryptogenic

Acute Interstitial Pneum

Cryptogenic Organising Pneum

Acute eosinophilic pneum

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

Management of ARDS

Summary • ARDS is like an iceberg • Prediction Scoring - LIPS Biomarkers, phenotyping

• Capture Education, cohesive practice and audit IT/ automated surveillance - “sniffer”

• Interventions Treat the disease! Avoid iatrogenic injury - process Drugs (don’t hold your breath)