ISSN:
1741-0444
Keywords:
Impedance spectroscopy
;
Clinical monitoring
;
Dielectric constant
;
Cell membrane
;
Extracellular fluid
;
Surgery
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract A study is conducted to determine whether the extracellular fluid (ECF) volume fraction and equivalent dielectric constant of the cell membrane εm, derived from the dielectric properties of the human body can track the progression of surgical tissue injury. Frequency-dependent dielectric constants and electrical conductivities of body segments are obtained at surgical (trunk) and non-surgical sites (arm and leg) from five patients who have undergone oesophageal resections, before and at the end of surgery and on the day after the operation. The ECF volume fraction and the equivalent εm of body segments are estimated by fitting the dielectric data for body segments to the cell suspension model incorporating fat tissue, and their time-course changes are compared between body segments. By the day after the operation, the estimated ECF volume fraction has increased in all body segments compared with that before surgery, by 0.13 in the arm, 0.16 in the trunk and 0.14 in the leg (p〈0.05), indicating postoperative fluid accumulation in the extracellular space. In contrast, the estimated equivalent εm shows a different time course between body segments on the day after the operation, characterised by a higher change ratio of εm of the trunk (1.34±0.66, p〈0.05), from that of the arm (0.66±0.34) and leg (0.61±0.11). The results suggest that the equivalent εm of a body segment at a surgical site can track pathophysiological cell changes following surgical tissue injury.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02345006
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