Eleven of 38 ( 29 % ) and 16 of 27 ( 59 % ) patients ' chest tubes were , respectively , removed on the first and second postoperative days in Group S , but only two of 34 ( 6 % ) and ten of 32 ( 31 % ) patients , respectively , had their chest tubes removed in Group C ( two-tailed Fisher 's exact test , P = 0.02 and 0.005 for the first and the second postoperative days , respectively ) .