On the third postoperative day , daily drainage remained @ ml in @ ( @ % ) patients , among whom , @ ( @ % ) would have their chest tubes removed on the PrRPl/B value in Group C. However , drains could not be removed due to the high protein content of draining fluid despite the acceptable volume of daily drainage in only three ( @ % ) of @ cases in Group S ( McNemar 's paired proportions test , P = @ ) .