Bioimpedance spectroscopy for the differential diagnosis of hyponatremia

Figures & data

Table 1. Clinical, laboratory, echocardiographic, and bioimpedance measurements of all patients.

	Mean ± sd	Min–max
Clinical date
Age (years)	65.16 ± 11.02	40–89
BMI (kg/m^2)	29.82 ± 5.60	18–44.7
SBP (mmHg)	116.14 ± 17.94	90–161
DBP (mmHg)	69.59 ± 10.60	50–91
Laboratory date
Hb (g/dL)	10.85 ± 1.60	7–14.7
WBC (/mm^3)	8.45 ± 2.92	2.2–14.9
Platelets (/mm^3)	226.3 ± 125.5	21–794
Na (mEq/L)	126.2 ± 6	110–135
K (mEq/L)	4.2 ± 0.9	2.6–6.9
Cl (mEq/L)	93.9 ± 8.6	77–110
Urea (mg/dL)	49.8 ± 30.3	6–115
Creatinine (mg/dL)	2.54 ± 1.64	0.5–7
Serum Osmolality (mosm/kg)	283.6 ± 25.9	236–363
Urine Osmolality (mosm/kg)	277.4 ± 123.4	140–685
Echocardiographic measurements
LVEDD (cm)	5.15 ± 0.61	4–6.5
LVESD (cm)	3.40 ± 0.72	2.3–5.1
EF (%)	49.9 ± 13.6	18–65
LA (cm)	4.27 ± 0.55	3–5.9
Aortic diameter (cm)	2.69 ± 0.54	1.9–3.8
Septum thickness (cm)	1.23 ± 0.23	0.9–2.3
PWT (cm)	1.15 ± 0.15	0.9–1.8
SPAP (mmHg)	38.13 ± 11.02	22–69
Bioimpedance measurements
OH (L)	1.22 ± 4.23	−15.6 to 18.3
TBW (L)	33.11 ± 8.33	22.5–66.2
ECW (L)	16.42 ± 4.08	10.2–33.2
ICW (L)	16.70 ± 5.92	10.6–49.3
FTI (kg m^2)	17.23 ± 6.60	5.2–35.1
LTM (kg)	29.93 ± 10.19	13.2–59
ATM (kg)	43.14 ± 14.40	12.2–75.1

Notes: SBP, systolic blood pressure; DBP, diastolic blood pressure; BUN, blood urea nitrogen; LVEDD, left ventricular end diastolic diameter; LVESD, left ventricular end systolic diameter; EF, ejection fraction; LA, left atrium diameter; PWT, posterior wall thickness; SPAP, systolic pulmonary arterial pressure; OH, overhydration; TBW, total body water; ECW, extracellular water; FTI, fat tissue index; LTM, lean tissue mass; ATM, adipose tissue mass.

Table 2. Laboratory and echocardiographic measurements of hypervolemic and hypovolemic groups.

	Hypervolemi (mean ± Sd)	Hypovolemi (mean ± Sd)	p
Laboratory date
Hb (g/dL)	10.60 ± 1.59	11.35 ± 1.55	0.095
WBC (/mm^3)	8.75 ± 2.94	7.86 ± 2.88	0.284
Platelets (/mm^3)	240.08 ± 135.86	198.74 ± 99.09	0.451
Na (mEq/L)	126.03 ± 5.93	126.50 ± 6.17	0.784
K (mEq/L)	4.37 ± 0.94	3.92 ± 0.74	0.08
Cl (mEq/L)	93.43 ± 7.59	94.88 ± 10.70	0.630
Urea (mg/dL)	50.21 ± 27.83	49.05 ± 35.59	0.623
Creatinine (mg/dL)	2.86 ± 1.76	1.92 ± 1.18	0.054
Echocardiographic measurements
LVEDD (cm)	5.06 ± 0.56	5.31 ± 0.68	0.230
LVESD (cm)	3.30 ± 0.63	3.56 ± 0.87	0.283
EF (%)	51.78 ± 12.16	46.21 ± 15.83	0.246
LA (cm)	4.26 ± 0.53	4.29 ± 0.62	0.834
Aortic diameter (cm)	2.61 ± 0.50	2.84 ± 0.60	0.231
Septum thickness (cm)	1.28 ± 0.26	1.15 ± 0.11	0.081
PWT (cm)	1.17 ± 0.18	1.13 ± 0.08	0.528

Notes: LVEDD, left ventricular end diastolic diameter; LVESD, left ventricular end systolic diameter; EF, ejection fraction; LA, left atrium diameter; PWT, posterior wall thickness.

Figure 1. Accuracy of bioimpedance measurement for the differential diagnosis of hyponatremia.