Sorting the sheep from the goats

How do we improve the diagnosis of pediatric respiratory diseases under low-resource conditions?

Pediatric Grand Rounds

February 27, 2015

It doesn’t matter…. refugee camp

….. or newest pediatric ER in Canada….

Tachypneic febrile children are the commonest clinical problem.

• What have they got?

– Asthma/pneumonia/bronchiolitis/bronchitis.

– Clinical need for clear diagnostic criteria.

• Which ones need to be admitted?

– Home/ward/ICU.

– Clinical need for accurate severity criteria.

Outline

• Dr Wright: – Global epidemiology of pneumonia and diagnostic

challenges wherever you are.

• Dr Yang: – Predicting diagnosis and disease severity if you

only have history and physical examination.

• Dr Wensley: – The clinical value of simple technology (chest

radiology, oximetry).

Pneumonia:

epidemiology and diagnostic challenges

Dr. M. Wright

There is nothing new about chest infections

There is nothing new about diseases of poverty

Changing mortality, New York

Pneumonia mortality USA

U5MR trends, rich countries

U5MR trends, poor countries

Where do they die?

What are the major causes of death?

Millenium Development Goals

• Universal agreement, in 2000, on eight health related goals

• Number 4:

Reduce U5MR by two thirds between 1990 and 2015

• Start point 12.4 million, end point 4.1 million in 2015

• How are we doing?

Progress towards MDG 4

The story so far…..

• U5MR is now below 8 million children per year for the first time ever

• Pneumonia has been the commonest cause of death for over 20 years

• 18 to 20% of deaths are due to pneumonia – most recent estimate 1.3 million per year

• Main country affected is India – 30 million cases per year with 350,000 pneumonia deaths

• Improving pneumonia outcome is important!

There is still the small matter of respiratory diagnostic confusion found everywhere

30 month male, January 2012 Tachypnea, cough, fever

• CXR: hyperinflated, collapsed LLL

• Diagnosed and treated as pneumonia

Same child, December 2012 Tachypnea, cough, fever

• CXR: hyperinflated, collapsed LLL

• Diagnosed and treated as asthma

WHO’s solution

• WHO introduced simplified criteria to guide antibiotic use by village health workers in the 1980s

• Assumed VHWs couldn’t use a stethoscope so auscultation was ignored

• Basically, significant tachypnea = pneumonia

• Greatly overdiagnose pneumonia and underdiagnose wheezy diseases (asthma, bronchiolitis)

• They are still the basis of pneumonia research 30 years later – long overdue for review

Age Respiratory rate

0-2 months > 60 breaths/minute

2-12 months > 50 breaths/minute

12- 59 months > 40 breaths/minute

WHO diagnostic criteria

• Diagnostic criteria:

• Severity criteria:

– Mild Tachypnea alone

– Moderate Tachypnea plus indrawing

– Severe Tachypnea plus lethargy

Current research from C and W divisions

• Respirology: – Multi-centre Indian study designed to update WHO criteria

– Sub-analysis of data to examine predictive value of chest radiographs

• Anesthesia: – Development and testing of a smart ‘phone app to allow

bedside measurement of O2 saturation

Dr Yang.

The predictive value of history and clinical examination

General study design • Four Indian centres: Lucknow, Kanpur and 2 in

Bangalore

• Dedicated pediatrician and post-grad coordinator employed at each centre

Inclusion criteria

• <5 years old

• Presenting to the ER with cough or difficulty breathing of less than 5 days duration

• Met WHO tachypnea criteria for pneumonia

Protocol

• Standardised 28 point data collection in ER including oximetry and CXR

• Reviewed at day 4 by pediatrician who assigned the ‘Gold standard’ reference diagnosis – Pneumonia

– Asthma

– Mixed

– Non-respiratory

• Disease severity groups at day 4 – Better

– Worse but alive

– Dead

Data collection - history

• Age

• Cough

• Difficulty Breathing

• Lethargy

• Reduced feeding

• Fever

• Previous similar episodes

• Vaccinations

Data collection – physical exam

•Weight

•Temperature

•Heart rate

•Respiratory rate

•Indrawing

Responsiveness

•Alert

•Voice

•Pain

•Unconscious

Auscultation

•Chest clear

•Crackles

•Wheeze

•Crackles and wheeze

•Bronchial breathing

The patients

• 524 patients

• 36% female

• Median age 11 months

• 53% admitted to hospital

Are WHO criteria accurate?

Agreement between ER physician and pediatrician

K=0.87 for wheezy diseases

K=0.68 pneumonia

Can clinical measures predict diagnosis?

Can clinical measures predict disease severity?

Better 96.1% Worse 2.3% Dead 1.6%

The accuracy of clinical predictors. Predicting Wheezy Diseases Sensitivity / specificity % • Wheeze on auscultation 82.2 / 87.8 • >2 previous episodes 43.0 / 85.4 • Wheeze and/ or >2 past episodes 85.9 / 76.1 Predicting Pneumonia • Crackles/ bronch breathing on auscultation 69.7 / 90.6 • Crackles and/or temp >38.6 deg C 78.5 / 70.2 Predicting Death or Deterioration • Conscious level alert to pain or unconscious 87.5 / 94.2 • Pulse >166/min and/or respiratory rate >66/min 80.0 / 78.9 • Conscious level P or U and/or weight >3 z 75.0 / 97.7

Clinical skills are valuable, but…..

• Observers must be well trained

• Measurements must be accurate

Dr Wensley

Does technology improve predictive accuracy?

1. Chest radiography

• Subanalysed the roughly 200 subjects in the 2 centres with digital X ray equipment.

• CXRs scored by modified WHO system.

• Film read by ER physician, pediatrician and two radiologists in Canada.

• CXR Scores compared to final diagnosis and disease severity.

Standardised CXR classification.

WHO

Classification

Study Classification Definition

Normal Normal No abnormalities detected

End point

consolidation

Lobar changes Dense changes following lobar

anatomical boundaries

Major patches Dense subsegmental patches

usually with air bronchogram

Other infiltrates Minor patches Fluffy subsegmental densities

Pleural effusion Pleural effusion Fluid collection between lungs

and chest wall

- Hyperinflation More than 6 anterior ribs

visible

2. Smart ‘phone oximeter

Dustin Dunsmuir, Mark Ansermino Departments of Anesthesiology, Pharmacology & Therapeutics and

Electrical and Computer Engineering The University of British Columbia, Vancouver, Canada

Smart ‘phone oximetry

• Smart ‘phone oximeter application developed by Dr Ansermino’s team.

• Smart ‘phone reading compared to standard Massimo oximeter.

• SaO2 values, at presentation, compared to final diagnosis and disease severity.

Pulse Oximetry

• Attach sensor to patient

• Press Start once waveform is good – background colour is green

Measure Respiratory Rate • Tap screen at each

breath

• Record 5 breaths

• Confirm lung animation timing with patient

Save data

• New version available with

animated baby

• Search for RRate on iTunes or

Google Play

Upload data to REDCap

• Data uploaded from India field sites directly to REDCap server in Vancouver

Technical measurements

Investigations Recorded details CXR score: • Normal ) • Hyperinflation ) • Minor patchy changes ) All yes/no • Major patchy changes ) • Lobar changes ) • Pleural fluid ) Oximetry % oxygen saturation

Variation in CXR interpretation.

Can technology predict diagnosis?

Can technology predict disease severity?

The limitations of technology (wherever you are)

• Oximetry does not predict diagnosis or disease severity.

• CXRs have some value predicting pneumonia but none for wheezy disease or severity.

• CXRs are of no value without quality control and staff training.

Added value of technology. Predicting Wheezy Diseases Sensitivity / specificity % • Wheeze on auscultation 82.2 / 87.8 • >2 previous episodes 43.0 / 85.4 • Wheeze and/ or >2 past episodes 85.9 / 76.1 • Oximetry/CXR finding No contribution Predicting Pneumonia • Crackles/ bronch breathing on auscultation 69.7 / 90.6 • Crackles and/or temp >38.6 deg C 78.5 / 70.2 • Major CXR changes 77.2 / 68.5 • Major CXR changes and/or crackles 82.9 / 70.2 Predicting Death or Deterioration • Conscious level P or U 87.5 / 94.2 • Pulse >166/min and/or respiratory rate >66/min 80.0 / 78.9 • Conscious level P or U and/or weight >3 z 75.0 / 97.7 • Oximetry/CXR findings No contribution

The situation isn’t hopeless.

• Most febrile tachypneic children can be managed with clinical skills alone.

• Short of a lung biopsy, you won’t be certain (wheezy disease +/- infection) in about 20% of cases.

• Chest radiographs, but not oximetry, have some added diagnostic value for pneumonia.

• Clinical skills are skills. Training, practice and updates are essential.

A stethoscope remains the most useful piece of technology but…..

It must be attached to a trained pair of ears.