Table 2.

Differences between patients having a Fluid Retention Index (FRI) of >4.0 on admission to hospital as evidence of strong renal water conservation before the surgery.

	FRI ≤ 4.0 (N = 857)	FRI > 4.0 (N = 64)	Odds ratio or difference (95% CI)	P-value
FRI (mean score)	2.1 ± 0.9	4.7 ± 0.5	2.58 (2.35–2.81)	<0.001
Age (yr)	61.3 ± 11.9	52.6 ± 12.6	8.92 (5.85–12.0)	<0.001
Females (%)	48	34	0.58 (0.34–0.98)	0.049
ASA I, II, III*	78/20/2	80/16/4	–	0.12
Infused ringer
Volume (mL)	1,974 ± 708	2,320 ± 848	345 (161–529)	<0.001
>3 L (%)	5.7	14.3	2.75 (1.28–5.89)	0.007
Infused Voluven (mL)
Incidence (%)	93%	94%	–	0.85
Volume (mL)	551 ± 177	717 ± 250	151 (75–228)	0.001
Urine (mL)	380 (200–600)	200 (118–500)	100 (50–170)	0.003
Urine flow (mL/min)	1.6 (0.9–2.5)	0.9 (0.6–1.7)	0.70 (0.23–1.21)	<0.001
Baseline (mmHg)	92 ± 12	89 ± 10	3.4 (0.4–6.4)	0.03
Surgery/baseline (ratio)	0.95 ± 0.14	1.01 ± 0.17	0.062 (0.39–1.05)	0.002
Blood loss
Volume (mL)	80 (50–120)	100 (30–170)	42 (10–73)	0.01
>500 mL (%)	1	5	4.86 (1.28–18.43)	0.04
Extubation time (min)	27 (18–40)	30 (21–50)	5 (1–10)	0.001
P-glucose (mmol/L)
Baseline	5.0 ± 0.6	5.1 ± 0.5	–	0.47
Postoperative	6.6 ± 1.8	5.8 ± 1.6	0.88 (0.33–1.43)	0.006
P-creatinine (μmol/L)
Baseline	65.6 ± 13.7	63.5 ± 14.2	–	0.21
Change (%)	+0.7 ± 16.0	−4.4 ± 16.0	3.42 (0.61–6.24)	0.017
Paralytic ileus (days)	1.5 ± 1.3	2.4 ± 2.3	0.81 (0.46–1.16)	0.001
Food intolerance (days)	2.4 ± 2.3	3.9 ± 3.2	1.52 (0.70–2.35)	0.011
Infection (%)
Respiratory	21	19	0.87 (0.46–1.67)	0.72
Wound	10	17	1.99 (1.00–3.96)	0.046
Fever	17	28	1.89 (1.07–3.35)	0.03

The statistical test was one-way ANOVA or the Mann–Whitney’s U test depending on data distribution. Categorical data were evaluated by the chi-square test. Bonferroni correction of the p-values to account for multiple testing was applied.

FRI, Fluid Retention Index; MAP, mean arterial pressure; ASA, American Society of Anesthesiologists (scale for physical health).

^*The inclusion of ASA class III is a protocol violation.