Pediatric Lung Ultrasound (PLUS) In Diagnosis of Community Acquired Pneumonia (CAP) Dr Neetu Talwar Senior Consultant, Pediatric Pulmonology Fortis Memorial Research Institute, Gurugram
Study To compare the accuracy of PLUS with CXR in hospitalized, pediatric patients of community acquired pneumonia (CAP)
Background
CAP Leading cause of morbidity & mortality worldwide Key to Success in Management Focus is upon early detection & Rx
Why PLUS? Pediatric Lung Ultrasound (PLUS) recently evolved from conventional role in diagnosing pulmonary edema & fluid status in PICU to a revolutionary role of imaging pulmonary parenchyma, both in & out of ICU
What about CXR? Chest Radiography (CXR) facilitates in diagnosis of, both pneumonia as well as related complications
However CXR has limitations.. o Ionizing radiation Especially - multiple CXRs Increased risk of cancer o High degree of intra-& interobserver variations o Hence Overestimation Increased use of unnecessary antibiotics o Lack of findings does not r/o diagnosis, esp when strong clinical suspicion
Limitations o Time delay ordered & when actually done o Transport o Expensive o May miss the diagnosis: Retro cardiac lesions Juxta diaphragmatic Early stage Lesions < 1 cm o False positive
What about CT Chest? Considered as gold standard tool in lung imaging, but.. Greater Limitations: o Higher exposure to ionizing radiation o Limited availability o Cost issues o Difficult patient cooperation, hence need for anesthesia or sedation o Lack of portability o Time Delay
Again Why PLUS? Several Advantages o No Radiation o Simple o Reliable o Available as point of care ultrasound (POCUS) o Accurate o Clinician based o Learning curve is faster o Lesser cost o Saves time / Quick to perform Advantage of being available at Bedside
Yes, PLUS! o Portable o Diagnostic in: Specific areas which may be missed by CXR (radio occult conditions) Sub cm lesions o Repeatable, FU easy o Reduces need for repeat CXR o Immediate report o Hence. Improved care o More use in resource - limited set up
Materials and Methods Study Area Study Type Study Population Dept of Pediatrics, Fortis Memorial Research Institute (FMRI), Gurugram Prospective observational study:1 yr All hospitalized, clinically suspected cases of CAP [as per British Thoracic Society (BTS) guidelines]; age of 3 mths to 18 yrs; meeting inclusion criteria
o Informed Written Consent o Ethics Clearance taken o No conflict of interest o No Funding
Sample Size o Accuracy of point of care lung ultrasound found in other similar articles was found to range between 60-90%. o Therefore, assuming (p)=80% as accuracy with 10% margin of error, minimum required sample size at 5% level of significance was 62 pts o Our Sample size was 100 (n)
Inclusion Criteria o Clinical suspicion of CAP as per BTS o Age: 3 mths to 18 yrs o Willing to participate o Mild / uncomplicated clinical course o Imaging &PLUS within 6 hrs of each other & within 24 hrs of hospitalization
Exclusion Criteria o Age:< 3 mths or > 18 yrs o K/C/O congenital lung disease o Known C/O chronic / complex condition o Chronic Resp condition o Known C/O malignancy o Hemodynamically unstable o CXR done from outside or not within 6 hrs of PLUS o Mechanical ventilation o Congenital heart disease o Immunocompromised pt o Bronchial Asthma
Phillips IU22 Clips / Images Recorded
Lung Ultrasound o Simple & portable ultrasound machine o Curvilinear (3.5-5 megahertz) & linear probes (high resolution; 7.5-10 megahertz) Each hemi thorax divided: 1 Anterior superior 2 Anterior inferior 3 Lateral superior 4 Lateral inferior 5 Posterior superior 6 Posterior inferior
Zones
Lung Ultrasound Definitions Consolidation Nonaerated lung Lobar Consolidation - lobe or a segment affected Peripheral Consolidation - focal area of nonaerated lung, typically abutting pleural surface
Air bronchogram Punctate or branching echogenicities within areas of lung consolidation Static No motion within bronchi Dynamic - move within the bronchi Mass o Focal solid lesion o Doesn t appear to be arising from lung parenchyma Doppler o +/- of color Doppler flow within an area of consolidation or mass
(N) Lung o Pleural Line o Sliding Sign o A Lines o Seashore Sign M Mode
Longitudinal Scan o Pleural line - regular echogenic line - moves continuously during respiration o Lung Sliding Sign - Pleural motion
Transverse Scan A lines o Pleura-lung interface o Parallel curvilinear o Regular intervals from pleura o Normal aeration pattern
M-mode cursor over pleural line; 2 patterns: o Motionless portion of chest above pleural line - horizontal waves, o Sliding below pleural line - granular pattern, sand Seashore Sign
o Absence of A lines o Hypoechogenic area; poorly defined borders o Compact underlying comet tail artifacts B o Air Bronchograms o Fluid bronchograms o Hepatization of lung o Shred Sign Pneumonia
B Lines o Vertical comet-tail Artifacts - pleural line o Erase A lines o Move with lung sliding o Presence is due to fluidrich subpleural interlobular septae, surrounded by air
Hepatization Air content further decreases (lung consolidations), acoustic window becomes completely open, & lung - directly visualized like solid parenchyma (liver/ spleen)
Air bronchograms
Shred Sign Deeper border of consolidated lung tissue that makes contact with aerated lung tissue is irregular & shredded
INTERPRETATION CODE-SHEET OF LUNG ULTRASOUND LUNG ULTRASOUND REPORT FORM PATIENT IDENTIFICATION NUMBER: DATE OF ULTRASOUND: OVERALL IMPRESSION FOR BOTH LUNGS: READER: IMPRESSION: IMPRESSION RIGHT LUNG LEFT LUNG Normal Yes / No Yes/No Pneumonia Yes/No Yes/No Pleural effusion Yes/No Yes/No Pneumothorax Yes/No Yes/No Others Yes/No Yes/No
Impression Lung Anterior Superior Anterior Inferior Lateral Superior Lateral Inferior Posterior Superior Posterior Inferior PLEURAL SPACE Normal Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Pneumothorax Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Effusion Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No LUNG Normal Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Interstitial Disease Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Consolidation Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No If Yes Solid Solid Solid Solid Solid Solid Cavitory Cavitory Cavitory Cavitory Cavitory Cavitory Air Bronchogram Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Static Static Static Static Static Static Dynamic Dynamic Dynamic Dynamic Dynamic Dynamic Mass Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No Doppler (Perfused) Yes/No Yes/No Yes/No Yes/No Yes/No Yes/No
X-ray chest X-ray chest taken in PA view; results interpreted by 3 trained radiologists. Radiologists were blinded to patients history & examination findings
PATIENT IDENTIFICATION NUMBER: CHEST X-RAY REPORT FORM READER: DATE OF CHEST X-RAY: IMPRESSION: Overall impression for Both Lungs IMPRESSION RIGHT LUNG LEFT LUNG Normal Yes / No Yes/No Lobar Consolidation Yes/No Yes/No Patchy Consolidation Yes/No Yes/No Pneumothorax Yes/No Yes/No Atelectasis Yes/No Yes/No
Statistical Analysis o Descriptive statistics analyzed with SPSS version 17.0 software o Continuous variables presented as mean ± SD o Categorical variables expressed as frequencies & percentages o The Pearson's chi-square test or the chi-square test of association used to determine if there was a relationship between two categorical variables o p < 0.05 was considered statistically significant
Formula used n = =1.96*1.96*0.8*0.2 0.1*0.1 =61.46 o o o o Where p is observed accuracy of point of care PLUS in diagnosis of CAP in children q = 1 p d is the margin of error is the ordinate of standard normal distribution at α% level of significance
Results o Total of 112 hospitalized children (CAP) o 100 patients met selection criteria & recruited o 56 (56%) were boys o Mean age + SD of children in yrs was 4.31 ± 4.41 o Radiological diagnosis of pneumonia - 58 (58%) patients o Lung ultrasound was abnormal in 86 (86%) patients
In CXR positive pts, PLUS positive in all (58/ 58) (100%) Whereas, in radiologically (N) pts, but clinically diagnosed CAP, lung ultrasound was abnormal in 28/42 (66.67%) patients Thus, lung ultrasound (LUS) has a high sensitivity (100%) with specificity of 33.3% (for diagnosing radiologically proven cases of CAP) PPV was 67.4%, NPV was 100% & Accuracy was 72%
o Difference in diagnosis of CAP by chest radiology & PLUS, showed the chi square statistic of 19.4444, with a p value of 0.00001 (highly significant) o Comparison of lung Ultrasound & x ray diagnosis, showed the number of observed agreements to be 72. No of agreements expected by chance was 55.8. Cohen s kappa coefficient (k) was 0.367, with SE of kappa = 0.079. 95% confidence interval: From 0.213 to 0.521. o Strength of agreement is considered to be 'fair
Conclusion PLUS is a highly sensitive test in diagnosing CAP It can be used as a first use diagnostic modality in suspected cases of CAP, thus replacing CXR Significantly reduce radiation exposure in this vulnerable pt grp Towards A Radiation Free Pulmonology Practice
Acknowledgements - Team Pediatric Team Radiology team Statistician Parul LUS technician Staff Patients
Thank You