TABLE 2.

Diagnostic accuracy of ultrasound (US) in pleural chest syndromes: evidence from systematic reviews

	Number of studies	Population, unit of analysis	US features, comparator	Reference standard	Prevalence and number	Sensitivity	Specificity
Pneumothorax
Wilkerson 2010 [25]	4 studies No meta-analysis	Blunt trauma, By patient (3 studies) By hemithorax (1 study)	Not stated CXR	Chest CT or release of air	21.5–30.1% of 497 patients 11.5% of 218 hemithoraces	US: 86–98% CXR: 28–75%	US: 97–100% CXR: 100%
Ding 2011 [24]	20 studies	Trauma, post-lung biopsy, critically ill By hemithorax#	Absent lung sliding, absent comets, lung point CXR	Chest CT or clinical findings and release of air	13.2% of 7569 hemithoraces	US: 88% CXR: 52%	US: 99% CXR: 100%
Alrajhi 2012 [27]	8 studies	Trauma, iatrogenic By patient#	Absent lung sliding, absent comets CXR	Chest CT or release of air	Not stated (unable to calculate) 1048 patients	US: 90.9% CXR: 50.2%	US: 98.2% CXR: 99.4%
Alrajab 2013 [28]	13 studies	Trauma, post-lung biopsy, critically ill By hemithorax	Not defined CXR	Chest CT	22.5% of 3028 hemithoraces	US: 78.6% CXR: 39.8%	US: 98.4% CXR: 99.3%
Ebrahimi 2014 [29]	28 studies	Trauma, iatrogenic, critically ill By patient#	Not stated CXR	Chest CT	20% of 5314 patients	US: 87% CXR: 46%	US: 99% CXR: 100%
Pleural effusion
Grimberg 2010 [30]	4 studies	Trauma, heart failure, ICU patients with ARDS By patient	Not stated CXR	CT or drainage	27.6% of 924 patients	US: 92–96% CXR: 24–100%	US: 88–100% CXR: 85–100%
Yousefifard 2016 [31]	12 studies	Trauma, heart failure, critically ill, surgical patients By patient	Not stated CXR	CT, US, CXR	41.5% of 1554 patients	US: 94% CXR: 51%	US: 98% CXR: 91%

CXR: chest radiography; CT: computed tomography; ICU: intensive care unit; ARDS: acute respiratory distress syndrome. ^#: Included and pooled studies reporting the alternative unit of analysis, by either doubling the number of patients or halving the number of hemithoraces in those studies.