title: Three-hour interval drain clamping reduces postoperative bleeding in total knee arthroplasty: a prospective randomized controlled trial.
abstract: BACKGROUND
  Total knee arthroplasty (TKA) is a common procedure that has a risk of significant blood loss and blood transfusion, and carries a substantial risk for immunologic reactions and disease transmission. Drain clamping is a popular method that is applied to reduce blood loss after TKA. However, the clamping protocol remains controversial. Therefore, we established a new protocol, 3-h interval clamping, and compared the bleeding control efficacy of this protocol following TKA with the non-clamping technique.
  
  
  METHODS
  Between March and July 2008, we enrolled 100 patients (100 knees) who underwent uncomplicated TKA using a minimally invasive surgical technique. The patients were randomly assigned into two groups based on the draining protocol: non-clamping (group A) and 3-h interval clamping (group B). For group A, a vacuum drain was connected to a container and was run continuously during the first postoperative day, whereas the vacuum was stopped twice (for ~3 h each time) for group B. Demographic characteristics and clinical data were collected, including the levels of hemoglobin and hematocrit, the total blood loss volume, the number of patients who required a blood transfusion, and any complications that developed. The perioperative data were compared between the two groups.
  
  
  RESULTS
  The drainage blood volume in the interval-clamping group (group B) was significantly lower than that in the non-clamping group (group A) during the first 48 h following the procedure (p < 0.001 and p = 0.005 for first and second postoperative days, respectively). The mean fall in hemoglobin levels at 12 h in the interval-clamping group (2.8 ± 0.9 g/dL) was also lower than in the non-clamping group (3.2 ± 0.8 g/dL). In the 3-h interval clamping protocol, the number of patients requiring a transfusion was 2.2 times less than the number in the non-clamping protocol, but was not significantly different (odds ratio = 2.20, p = 0.24), and the significant predictor of blood transfusion was the preoperative hemoglobin level (odds ratio = 7.73, p < 0.001). No wound infection or clinical venous thromboembolisms were detected in our study.
  
  
  CONCLUSIONS
  The 3-h interval clamping is a newly developed protocol for reducing blood loss after TKA. The protocol lessens the decrease in postoperative hemoglobin levels. This protocol can be applied easily without increasing clinical thromboembolic events and wound complications.
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, 2 Prannok Street, Bangkoknoi district, Bangkok, Thailand.
authors.forename: Chaturong
authors.initials: C
authors.lastname: Pornrattanamaneewong
authors.forename: Rapeepat
authors.initials: R
authors.lastname: Narkbunnam
authors.forename: Pichet
authors.initials: P
authors.lastname: Siriwattanasakul
authors.forename: Keerati
authors.initials: K
authors.lastname: Chareancholvanich
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001803:Blood Transfusion / Q000706:statistics & numerical data; D003250:Constriction; D004322:Drainage / Q000379:methods; D005260:Female; D006488:Hemostasis, Surgical / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D019106:Postoperative Hemorrhage / Q000517:prevention & control*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome