Does the suction drain diameter matter? Bleeding analysis after total knee replacement comparing different suction drain gauges☆

OBJECTIVES To evaluate bleeding and the estimated blood loss in patients who underwent total knee replacement (TKR) with different closed suction drains (3.2-mm and 4.8-mm gauge). METHODS This was a randomized controlled trial with 22 patients who underwent TKR and were divided into two groups: Group I, with 11 patients in whom the 3.2-mm suction drain was used, and Group II, with 11 patients in whom the 4.8-mm suction drain was used. The hematocrit was measured after 24, 48 and 72 h after surgery in order to calculate the estimated blood loss. The drained volume was measured 3, 6, 12, 24, and 48 h after TKR, and thereafter both groups were compared. RESULTS Regarding the hematocrit, there were no differences between groups in measured periods (24, 48, and 72 h after surgery). The total bleeding measured at the suction drains within 48 h was higher in Group II, with a statistically significant difference (p = 0.005); in the first 24 h, there was major bleeding in Group II (mean 893 mL), with a significant difference (p = 0.004). Between 24 and 48 h, there was no statistically significant difference in both groups (p = 0.710). The total estimated bleeding was higher in Group I, with mean of 463 mL, versus 409 mL in Group II, with no statistical significance (p = 0.394). CONCLUSIONS Bleeding was higher in the group that used the 4.8 mm gauge suction drain, with no differences in hematocrit and estimated blood loss.