Comparison of methods to quantitate spontaneous pneumothorax - A study from a tertiary care hospital

Background Pneumothorax can present as a respiratory emergency and has varied etiology. However, literature available on assessment and management of primary spontaneous pneumothorax (PSP) based on radiological quantitation is scarce. This study was undertaken to compare two different methods of quantitating pneumothorax size with that recommended in American Thoracic Society (ATS) guideline on chest radiogram with respect to possible change in management practices. Patients and methods A prospective cohort of adults presenting with spontaneous pneumothorax (SP) over 3 years to Emergency and Pulmonology Department, St John’s Medical College Hospital, Bangalore, was included. Demographic characteristics and clinical presentation were compiled. Management of SP was based on ATS guidelines. PSP size on chest radiogram was requantitated in the included patients using Light’s index and Collin’s method and was compared with that proposed by the ATS guideline. Results Seventy-six participants with SP were studied; their mean age was 43.7 years, with a preponderance of male patients (84.2%). Twenty-four (31.6%) patients had PSP and 52 (68.4%) patients had secondary spontaneous pneumothorax. In PSP, there was poor agreement between various methods of estimating size of pneumothorax on chest radiogram (Kappa statistic=0.23; ICC of 0.263). Three (12.5%) of the 24 incidences of PSP, which were treated conservatively as per ATS guidelines, would have required invasive intervention if Light’s index or the Collin’s formula were taken into consideration. Conclusion There was poor agreement of radiological pneumothorax size estimation by Collin’s, Light’s, and that proposed in the ATS guidelines. Thus, a unified, standardized method of radiological assessment of PSP is required.