title: Tourniquets do not increase the total blood loss or re-amputation risk in transtibial amputations.
abstract: OBJECTIVE
  To investigate the total blood loss (TBL) and the safety with respect to the re-amputation rate after transtibial amputation (TTA) conducted with and without a tourniquet.
  
  
  METHODS
  The study was a single-centre retrospective cohort study of patients with a primary TTA admitted between January 2013 and April 2015. All patients with a primary TTA were assessed for inclusion if the amputation was performed because of arteriosclerosis or diabetic complications. All patients underwent a standardized TTA procedure that was performed approximately 10 cm below the knee joint and performed with sagittal flaps. The pneumatic tourniquet, when used, was inflated around the femur to a pressure of 100 mmHg above the systolic blood pressure. The number of blood transfusions within the first four postoperative days was recorded. The intraoperative blood loss (OBL), which is defined as the volume of blood lost during surgery, was determined from the suction volume and by the weight difference of the surgical dressings. The trigger for a blood transfusion was set at a decrease in the Hgb level < 9.67 g/dL (6 mmol/L). Transfusions were performed with pooled red blood cells containing 245 mL per portion, which equals 55 g/L of haemoglobin. The TBL during the first four postoperative days was calculated based on the haemoglobin level and the estimated blood volume. The re-amputation rate was evaluated within 30 d.
  
  
  RESULTS
  Seventy-four out of 86 consecutive patients who underwent TTA within the two-year study period were included in the analysis. Of these, 38 were operated on using a tourniquet and 36 were operated on without using a tourniquet. There were no significant preoperative differences between the groups. The patients in both groups had a postoperative decrease in their Hgb level compared with preoperative baseline values. The patients operated on using a tourniquet received approximately three millilitres less blood transfusion per kilogram body weight compared with patients operated on without a tourniquet. The duration of surgery was shorter and the OBL was less for the tourniquet group than the non-tourniquet group, whereas no significant difference was observed for the TBL. The TBL median was 859 mL (IQR: 383-1315) in the non-tourniquet groupvs737 mL (IQR: 331-1218) in the tourniquet group (P= 0.754). Within the 30-d follow-up period, 9 patients in the tourniquet group and 11 in the non-tourniquet group underwent a re-amputation at the trans-femoral level. The use of a tourniquet showed no statistically significant association with the 30-d re-amputation at the femur level in the multiple logistic regression model (P= 0.78). The only variable with a significant association with re-amputation was age (OR = 1.07;P= 0.02).
  
  
  CONCLUSIONS
  The results indicate that tourniquets do not cause severe vascular damage with an increased postoperative bleeding or failure rate as the result.
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Wied
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Tengberg
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Gitte
authors.initials: G
authors.lastname: Holm
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kallemose
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Nicolai B
authors.initials: NB
authors.lastname: Foss
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Troelsen
authors.affiliation: Christian Wied, Peter T Tengberg, Gitte Holm, Thomas Kallemose, Anders Troelsen, Morten T Kristensen, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, 2650 Hvidovre, Denmark.
authors.forename: Morten T
authors.initials: MT
authors.lastname: Kristensen
keywords: Intraoperative blood loss; Lower extremity amputation; Pneumatic tourniquet; Re-amputation; Total blood loss; Transtibial amputation