Table 4.

Pleural Effusion-Serum Electrolyte Gradient in Patients With HF-Associated Pleural Effusion

	Chloride (mEq/L)			Sodium (mEq/L)			Potassium (mEq/L)
	Serum	PlF	PlF-serum gradient	Serum	PlF	PlF-serum gradient	Serum	PlF	PlF-serum gradient
Patient no.
1	97	106	9	131	133	2	5.4	5.2	−0.2
2	102	116	14	143	145	2	3.4	3.3	−0.1
3	105	111	6	138	138	0	5	4.7	−0.3
4	106	113	7	144	145	1	4.1	4	−0.1
5	103	110	7	137	138	1	3.9	3.8	−0.1
6	114	118	4	139	141	2	4.2	4.3	0.1
7	95	101	6	128	132	4	5.7	5.7	0
8	96	101	5	135	135	0	4	4.1	0.1
9	106	114	8	139	141	2	3.9	3.8	−0.1
10	100	107	7	139	138	−1	4.5	3.7	−0.8
11	97	108	11	137	137	0	4.3	3.9	−0.4
12	111	115	4	144	144	0	4.2	4.1	−0.1
13	106	113	7	143	143	0	3.6	3.8	0.2
14	104	113	9	140	141	1	4.2	4.4	0.2
15	110	117	7	146	145	−1	4.2	4	−0.2
Mean±SD	104±5.7	111±5.3	7.4±2.6	139±4.9	140±4.3	0.9±1.4	4.3±0.6	4.2±0.6	−0.1±0.3

HF, heart failure; PlF, pleural fluid.