Preoperative fluid retention increases blood loss during major open abdominal surgery

Abstract

Background: Quantification of renal fluid conservation is possible by urine analysis, and the results can indicate dehydration. The present report sought to determine whether this fluid retention correlates with fluid requirements during major abdominal surgeries that have estimated operating times ≥ 2 h.

Methods: Urine colour, specific weight, osmolality and creatinine concentration were used to calculate a composite "fluid retention index" (FRI) in 97 patients prior to major abdominal surgery. Goal-directed fluid volume optimization, with hydroxyethyl starch supplemented with a background administration of crystalloid fluid, was used.

Results: The median preoperative FRI was 3.0. Fluid retention, considered as present when FRI ≥ 3.5, was found in 37% of the patients. Fluid retention was followed by a significantly larger blood loss (+ 125%; 450 vs. 200 ml), higher haemorrhage rate (+ 41%; 123 vs. 87 ml/h) and greater need for both colloid (+ 43%; 1.43 vs. 1.00 l) and crystalloid (+ 18%; 1.28 vs. 1.08 l) fluids. Despite the larger blood loss, the total fluid balance was more positive after surgery in the dehydrated patients (+ 26%; 1.91 vs. 1.51 l; P < 0.02).

Conclusions: Preoperative fluid retention, as detected in a urine sample, was associated with a greater blood loss and a more positive fluid balance during major abdominal surgery.

Trial registration: ClinicalTrials.gov, NCT01458678.

Keywords: Abdominal; Blood loss; Dehydration; Surgery; Urine specimen collection.

Conflict of interest statement

Ethics approval and consent to participate

The study was performed at the University Hospital in Linköping between November 2011 and December 2014. Permission was obtained from the Regional Ethical Review Board in Linköping (2011/101–31) on March 30, 2011, and all patients who participated in the study provided written informed consent. The study was registered at Clinical Trials (NCT01458678).

Consent for publication

Not applicable.

Competing interests

The authors have no competing interests to declare.

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Figures

Fig. 1

Fluid retention index (FRI) versus fluid balance parameters (a, b). The regression lines refer to the gynaecological and urological operations only (r = 0.58 and 0.54, respectively)

Fig. 2

Fluid retention index (FRI) versus the surgical blood loss in all patients (a; note the log scale) and the rate of the haemorrhage in gynaecological and urological patients (b; r = 0.38) and GI surgeries (c; no significant linear relationship)