The mean PrRPl/B was 0.65 and 0.67 ( 95 % CI = 0.60-0 .69 and 0.62-0 .72 ) on the first postoperative day , and it remarkably dropped down to 0.39 and 0.33 ( 95 % CI = 0.33-0 .45 and 0.27-0 .39 ) on the second day in Groups S and C , respectively , and remained below 0.5 on the third day ( repeated-measures of ANOVA design , post hoc ` within-group ' comparison of the first postoperative day versus second and third days ; P < 0.002 ) .