Table 3.

Single-factor chi-square analysis of operational variables (N = 167)

Factors	Classification	Number	Percent	Mean ± SD	F value	P value
Hidden blood loss (△Hb) (g/L)	△Hb < 10	30	18.00	19.30 ± 6.56	2.729	0.031
	10 ≤ △Hb < 20	56	33.50	20.77 ± 8.23
	20 ≤ △Hb < 30	43	25.70	17.84 ± 4.54
	30 ≤ △Hb < 40	32	19.20	18.94 ± 5.55
	40 ≤ △Hb	6	3.60	12.83 ± 3.66
Surgery begins	< 14:00 P.M.	53	31.70	18.86 ± 6.60	0.525	0.470
	≥ 14:00 P.M.	114	68.30	19.66 ± 6.75
Op-duration T (h)	T < 2	24	13.50	17.92 ± 3.96	4.524	0.002
	2 ≤ T < 3	97	55.90	18.38 ± 5.49
	3 ≤ T < 4	35	25.20	23.00 ± 9.78
	4 ≤ T < 5	3	1.40	15.33 ± 2.08
	5 ≤ T	8	4.00	16.00 ± 3.21
Transfusion	No	152	91.00	18.82 ± 6.15	2.682	0.071
	Yes	15	9.00	22.07 ± 10.25
Urine tube	No	33	19.80	17.70 ± 6.46	1.882	0.172
	Yes	134	80.20	19.46 ± 6.67
Drainage	No	147	88.00	19.09 ± 6.56	8.345	0.894
	Yes	20	12.00	19.30 ± 7.36
Tourniquet	No	2	1.20	12.50 ± 3.54	2.021	0.157
	Yes	165	98.80	19.19 ± 6.63