Table 4.

Pleural fluid biochemistry (and blood/pleural fluid ratios), and pre-thoracentesis ultrasonographic findings.

	Non-Expandable Lung n =12	Expandable Lung n =31	p-Value
Biochemistry
Pleural fluid protein, g/L	34.6 (11.5)	40.7 (10.9)	0.22
Pleural fluid albumin, g/L	17.1 (9.5)	23.1 (6.2)	0.058
Plasma albumin, g/L	31.0 (8.1)	28.5 (4.4)	0.30
Albumin gradient, g/L	10.8 (2.3)	6.3 (5.8)	0.080
Pleural fluid LDH, U/L	360 (284–1724)	165 (121–225)	0.007
Serum LDH, U/L	189 (180–190)	200 (170–270)	0.16
LDH gradient, U/L	7.3 (8.6)	1.2 (1.3)	0.015
Pre-thoracentesis ultrasound
Pleural fluid swirling, n (%)	3 (25%)	18 (58%)	0.052
Pleural fluid septations, n (%)	6 (50%)	3 (10%)	0.004
Pleural thickening, n (%)	10 (83%)	20 (65%)	0.23
Pleural nodules, n (%)	3 (25%)	8 (26%)	0.96
Atelectasis/consolidation, n (%)	7 (58%)	16 (52%)	0.21
Lung sliding, n (%)	2 (18%)	20 (65%)	0.008
Post-thoracentesis ultrasound
Apposition of pleural lines, n (%)	1 (9%)	22 (73%)	<0.001
US assessed full drainage, n (%)	2 (18%)	19 (63%)	0.010

Data are presented as mean (SD) or median (IQR). LDH; Lactate Dehydrogenase. Gradient (blood concentration minus pleural fluid concentration).