Pediatric airway dimensions-A summary and presentation of existing data

BACKGROUND

Age-related pediatric airway dimension reference values for cricoid, tracheal, and bronchial diameters as well as tracheal and bronchial lengths are essential for distinguishing normal from pathological airway findings and for manufacturing and selecting appropriately sized airway equipment.

AIM

The aim of this work was to summarize and present existing pediatric airway dimension data for the larynx, trachea, and main stem bronchi from fetus to adolescence.

METHODS

A systematic literature search was carried out using PubMed, Scopus, Embase, and Google Scholar. Publications containing original data on pediatric airway dimensions as mean or median in tabular form and spanning narrow age groups of 1 or 2 years were included in our study. Original data such as diameters, lengths, and cross-sectional areas of trachea, cricoid, left and right main bronchi in fetuses and children were collected and presented as figures.

RESULTS

Pediatric airway dimension data were gathered and compiled from 15 studies fulfilling the inclusion criteria. Data were obtained from different measurement methods such as autopsy, chest X-ray, computed tomography, magnetic resonance imaging, rigid and flexible bronchoscopy as well as ultrasound examinations. There was considerable variation among age-related data due to biologic heterogeneity, different presentation of data, different definitions, and various measurement techniques.

CONCLUSION

This investigation revealed heterogeneous data on pediatric airway dimensions, making it impossible to compile them into standard reference values for airway dimensions. New studies with structured and standardized measurements and data presentation in large populations of children are required to provide more valid pediatric airway dimension data.

Airway dimensions from fetal life to adolescence-A literature overview

BACKGROUND

Data on airway dimensions in pediatric patients are important for proper selection of pediatric airway equipment such as endotracheal tubes, double-lumen tubes, bronchial blockers, or stents. The aim of the present work was to provide a synopsis of the available data on pediatric airway dimensions.

METHODS

A systematic literature search was carried out in the PubMed database, Scopus, Embase, Web of Science, Prisma, and Google Scholar and secondarily completed by a reference search. Based on inclusion and exclusion criteria, a final selection of 109 studies with data on pediatric airway dimensions published from 1923 to 2018 were further analyzed.

RESULTS

Six different airway measurement methods were identified. They included anatomical examinations, chest X-ray, computed tomography, magnetic resonance tomography, bronchoscopy, and ultrasound. Anatomical studies were more abundant compared to other methods. Data provided were very heterogeneously presented and powered. In addition, due to different study conditions, they are hardly comparable. Among all, anatomical and computer tomography studies are thought to provide the most reliable data. Ultrasound is an upcoming technique to estimate airway parameters of fetus and premature infants. There was, in general, a lack of comprehensive studies providing a complete range of airway dimensions in larger groups of patients from birth to adolescence.

CONCLUSIONS

This work revealed a large heterogeneity of studies providing data on pediatric airway dimensions, making it impossible to compare, or assemble them to normograms for clinical use. Comprehensive studies in large population of children are needed to provide full range nomograms on pediatric airway dimensions.

Assessment of airway compression on chest radiographs in children with pulmonary tuberculosis

BACKGROUND

Because small, pliable paediatric airways are easily compressed by enlarged lymph nodes, detection of radiographic airway compression might be an objective criterion for diagnosing pulmonary tuberculosis.

OBJECTIVE

To investigate the frequency and inter-observer agreement of airway compression on chest radiographs in children with pulmonary tuberculosis compared to those with a different lower respiratory tract infection.

MATERIALS AND METHODS

Chest radiographs of children with suspected pulmonary tuberculosis were read by two readers according to a standardised format and a third reader when there was disagreement. Radiographs of children with proven pulmonary tuberculosis were compared to those with a different lower respiratory tract infection. We evaluated frequency and location of radiographic airway compression. Findings were correlated with human immunodeficiency virus (HIV) status and age. We assessed inter-observer agreement using kappa statistics.

RESULTS

We reviewed radiographs of 505 children (median age 25.9 months, interquartile range [IQR] 14.3-62.2). Radiographic airway compression occurred in 54/188 (28.7%) children with proven pulmonary tuberculosis and in 24/317 (7.6%) children with other types of lower respiratory tract infection (odds ratio [OR] 4.9; 95% confidence interval [CI] 2.9-8.3). A higher frequency of radiographic airway compression occurred in infants (22/101, or 21.8%) compared to older children (56/404, or 13.9%; OR 1.7; 95% CI 1.0-3.0). We found no association between airway compression and HIV infection. Inter-observer agreement ranged from none to fair (kappa of 0.0-0.4).

CONCLUSION

There is a strong association between airway compression on chest radiographs and confirmed pulmonary tuberculosis. However this finding's clinical use as an objective criterion for diagnosis of pulmonary tuberculosis in children is limited by poor inter-observer agreement.