Assessment of changes in body water by bioimpedance in acutely ill surgical patients.
OBJECTIVE
To evaluate the relationship between changes in body bioelectrical impedance (BI) at 0.5, 50 and kHz and the changes in body weight, as an index of total body water changes, in acutely ill surgical patients during the rapid infusion of isotonic saline solution.


METHODS
Prospective clinical study.


METHODS
Multidisciplinary surgical ICU in a university hospital.


METHODS
Twelve male patients treated for acute surgical illness (multiple trauma n = 5, major surgery n = 7).


METHODS
stable cardiovascular parameters, normal cardiac function, signs of hypovolemia (CVP < or = 5 mmHg, urine output < 1 ml/kg x h).


METHODS
After baseline measurements, a 60 min fluid challenge test was performed with normal saline solution, 0.25 ml/kg/min [corrected].


RESULTS
Body weight (platform digital scale), total body impedance (four-surface electrode technique; measurements at 0.5, 50 and 100 kHz) and urine output. Fluid retention induced a progressive decrease in BI at 0.5, 50 and 100 kHz, but the changes were significant for BI 0.5 and BI 100 only, from 40 min after the beginning of the fluid therapy onwards. There was a significant negative correlation between changes in water retention and BI 0.5, with individual correlation coefficients ranging from -0.72 to 0.95 (p < 0.01-0.0001). The slopes of the regression lines indicated that for each kg of water change, there was a mean decrease in BI of 18 ohm, but a substantial inter-individual variability was noted.


CONCLUSIONS
BI measured at low frequency can represent a valuable index of acute changes in body water in a group of surgical patients but not in a given individual.
Chioléro
R L
RL
Department of Anaesthesiology, University Hospital, Lausanne, Switzerland.
Gay
L J
LJ
Cotting
J
J
Gurtner
C
C
Schutz
Y
Y
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001834:Body Water / Q000737:chemistry*; D001835:Body Weight; D016638:Critical Illness; D017097:Electric Impedance; D006785:Hospitals, University; D006801:Humans; D007262:Infusions, Intravenous; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D011446:Prospective Studies; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D013557:Switzerland / Q000453:epidemiology; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D015430:Weight Gain
D012965:Sodium Chloride; D012964:Sodium