Sorting the sheep from the goats

Transcription

1 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

2 It doesn t matter. refugee camp

3 .. or newest pediatric ER in Canada.

4 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.

5 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).

6 Pneumonia: epidemiology and diagnostic challenges Dr. M. Wright

7 There is nothing new about chest infections

8 There is nothing new about diseases of poverty

9 Changing mortality, New York

10 Pneumonia mortality USA

11 U5MR trends, rich countries

12 U5MR trends, poor countries

13 Where do they die?

14 What are the major causes of death?

15 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?

16 Progress towards MDG 4

17 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!

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

19 30 month male, January 2012 Tachypnea, cough, fever CXR: hyperinflated, collapsed LLL Diagnosed and treated as pneumonia

20 Same child, December 2012 Tachypnea, cough, fever CXR: hyperinflated, collapsed LLL Diagnosed and treated as asthma

21 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

22 WHO diagnostic criteria Diagnostic criteria: Age Respiratory rate 0-2 months > 60 breaths/minute 2-12 months > 50 breaths/minute months > 40 breaths/minute Severity criteria: Mild Tachypnea alone Moderate Tachypnea plus indrawing Severe Tachypnea plus lethargy

23 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 O 2 saturation

24 Dr Yang. The predictive value of history and clinical examination

25 General study design Four Indian centres: Lucknow, Kanpur and 2 in Bangalore Dedicated pediatrician and post-grad coordinator employed at each centre

26 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

27 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

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29 Data collection - history Age Cough Difficulty Breathing Lethargy Reduced feeding Fever Previous similar episodes Vaccinations

30 Data collection physical exam Weight Temperature Heart rate Respiratory rate Indrawing Auscultation Chest clear Crackles Wheeze Crackles and wheeze Bronchial breathing Responsiveness Alert Voice Pain Unconscious

31 The patients 524 patients 36% female Median age 11 months 53% admitted to hospital

32 Are WHO criteria accurate? Agreement between ER physician and pediatrician K=0.87 for wheezy diseases K=0.68 pneumonia

33 Can clinical measures predict diagnosis?

34 Can clinical measures predict disease severity? Better 96.1% Worse 2.3% Dead 1.6%

35 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

36 Clinical skills are valuable, but.. Observers must be well trained Measurements must be accurate

37 Dr Wensley Does technology improve predictive accuracy?

38 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.

39 Standardised CXR classification. WHO Study Classification Definition Classification Normal Normal No abnormalities detected End point consolidation Lobar changes Major patches Dense changes following lobar anatomical boundaries 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

40 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

41 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.

42 Pulse Oximetry Attach sensor to patient Press Start once waveform is good background colour is green

43 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

44 Upload data to REDCap Data uploaded from India field sites directly to REDCap server in Vancouver

45 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

46 Variation in CXR interpretation.

47 Can technology predict diagnosis?

48 Can technology predict disease severity?

49 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.

50 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

51 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.

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

53 It must be attached to a trained pair of ears.