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Dehydration and fluid volume kinetics before major open abdominal surgery
Author(s) -
HAHN R. G.,
BAHLMANN H.,
NILSSON L.
Publication year - 2014
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.12416
Subject(s) - medicine , dehydration , urine osmolality , anesthesia , urine , abdominal surgery , nausea , renal function , vomiting , creatinine , plasma osmolality , urology , surgery , biochemistry , chemistry , vasopressin
Assessment of dehydration in the preoperative setting is of potential clinical value. The present study uses urine analysis and plasma volume kinetics, which have both been validated against induced changes in body water in volunteers, to study the incidence and severity of dehydration before open abdominal surgery begins. Methods Thirty patients (mean age 64 years) had their urine analysed before major elective open abdominal surgery for colour, specific weight, osmolality and creatinine. The results were scored and the mean taken to represent a ‘dehydration index’. Thereafter, the patients received an infusion of 5 ml/kg of R inger's acetate intravenously for over 15 min. Blood was sampled for 70 min and the blood haemoglobin concentration used to estimate the plasma volume kinetics. Results Distribution of fluid occurred more slowly ( P < 0.01) and the elimination half‐life was twice as long (median 40 min, not significant) in the 11 patients (37%) diagnosed to be moderately dehydrated as compared with euhydrated patients. The dehydration index indicated that the fluid deficit in these patients corresponded to 2.5% of the body weight, whereas the deficit in the others was 1%. In contrast, the 11 patients who later developed postoperative nausea and vomiting had a very short elimination half‐life, only 9 min (median, P < 0.01). These patients were usually euhydrated but had microalbuminuria ( P < 0.03) and higher natriuresis ( P < 0.01). Conclusions The degree of dehydration before major surgery was modest as evidenced both by urine sampling and volume kinetic analysis.