ARDS: how are we doing? Martin Hughes September 2010

MAIN ARTICLE Acute respiratory distress syndrome: an audit of incidence and outcome in Scottish intensive care units M. Hughes,1 F. N. MacKirdy,2 J. Ross,2 J. Norrie3 and I. S. Grant4 on behalf of the Scottish Intensive Care Society 1 Intensive Care Unit, Royal Infirmary, Castle St, Glasgow, UK 2 Scottish Intensive Care Society Audit Group, Anaesthetic Department, Victoria Infirmary, Langside Avenue, Glasgow,UK 3 Robertson Centre For Biostatistics, University of Glasgow, University Avenue, Glasgow, UK 4 Consultant, Intensive Care Unit, Western General Hospital, Crewe Road South, Edinburgh, UK

Methods Ward Watcher computer in each of 23 ICUs Midnight entry of PaO 2 /FiO 2 (nursing staff) Additional data Chest x-ray enquiry Alternative diagnoses excluded Diagnosis based on American European consensus Underlying diagnosis

Methods 2 Daily data collection PaO 2 /FiO 2 Indices of organ dysfunction Ventilation modes and parameters Infection and antibiotics Specific therapies e.g. NO, prone position, steroids Feeding, fluid use and fluid balance

Incidence 8.1% of ICU admissions 26.1% of occupied bed days 16.5/100,000/year

Results ICU mortality SMR (Hospital mortality APACHE II Mean age LOS mean LOS median 19.3%53.1% (43% %) %60.9%) ( ) ( ) Whole populationARDS (n=375)

Ventilatory parameters day 1 Murray 2.41/2.56 PaO 2 /FiO 2 118mmHg Mean Peak Paw 31.0 cmH 2 O Mean PEEP 7.5 cmH 2 O Mean TV 642ml (9.2ml per kg)

Univariate analysis - ICU death Age: Odds Ratio (OR) 1.15 (1.08, 1.23) for each 5 year increase Admission source: ICU/HDU/ward doubled OR compared with theatre Days in hospital before ICU: OR 1.04 (1.01, 1.07) for each day

Univariate analysis - ICU death APACHE II: OR 1.09 (1.05, 1.12) for each 1 unit increase SAPS II: OR 1.06 (1.04, 1.08) for each 1 unit increase ICU stay strongly negatively predictive: stay < 5 days 89% mortality

Univariate analysis - ICU death: Admission variables SBP < 90mmHg: OR 2.53 (1.55, 4.14) Cardiac dysrythmia: OR 2.42 (1.20, 4.90) ARF: OR 3.93 (2.24, 6.91) Immunosuppression: OR 3.24 (1.17, 8.99)

Organ failures Median max 2 Survivors median max 2 (IQR 1-3) Non Survivors median max 3 (IQR 2-4) At death: 21% 1 OF, 28% 2 OF, 29% 3 OF, 17 %4 OF, 6% 5 OF.

Multivariate analysis: significant factors Age: 5 years OR 1.13 (1.04, 1.23) SAPS II: 1 unit OR 1.05 (1.03, 1.07) SBP < 90: OR 2.51 (1.38, 4.54) Days in ICU: 1 day OR 0.95 (0.93, 0.97) Days in hospital before ICU: 1 day OR 1.05 (1.01, 1.08)

Significant negatives Direct or indirect lung injury GCS Very severe cardiac illness Severe respiratory disease Hepatic encephalopathy, cirrhosis Admission time HR > 150, GI bleed

Why the poor mortality? Other studies were series in single centres Note France 32% vs 60% Small amount of trauma Ventilatory or other management Severity of illness

What should we do? Repeat some of the study: prospective observational cohort study Mortality Underlying diagnosis and severity Organ dysfunction and support Ward watcher data Ventilatory parameters Fluid balance

Problems Funding Additional work in each unit: ventilation, fluids, diagnosis, organ dysfunction Data validation

Questions Would it be useful? Is it worth the additional work? Is there a way to simplify it? Is there anything else which would improve it?