Sorting the sheep from the goatsmed-fom-pediatrics.sites.olt.ubc.ca/files/2013/11/How-Do...(wheezy...
Transcript of Sorting the sheep from the goatsmed-fom-pediatrics.sites.olt.ubc.ca/files/2013/11/How-Do...(wheezy...
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.