Combined Assessment of Functional and Metabolic Performance of Human Donor Hearts: Possible Application in Donation After Circulatory Death.

BACKGROUND: Donation after circulatory death (DCD) represents an increasing source of organs. However, evaluating the suitability of DCD hearts for transplantation represents a challenge. Contractile function is the ultimate determinant of recovery. We developed a novel technique in an ex vivo rig for the measurement of contractility using intraventricular balloons. We compared this technique with the measurement of lactate metabolism, the current gold standard. METHODS: Human DCD (n = 6) and donation after brain death (n = 6) hearts were preserved by perfusion with a cold oxygenated crystalloid solution for 4 h, transferred to a blood perfusion rig at 37 °C where balloons were inserted into the left (LV) and right (RV) ventricles to measure developed pressure (DP = systolic minus diastolic). Perfusate lactate levels were measured for metabolic assessment. Concordance between LVDP and lactate was assessed during 4 h using cutoffs for LVDP of 70 mm Hg and for lactate of 10 mmol/L. RESULTS: Measurements of contractile function (LVDP) and metabolism (lactate levels) were deemed concordant in 7 hearts with either a high LVDP (mean 100 mm Hg) with low lactate (mean 6.7 mmol/L)) or a low LVDP (15 mm Hg) with high lactate (mean 17.3 mmol/). In the remaining 5 hearts, measurements were deemed discordant: 4 hearts had high LVDP (mean 124 mm Hg), despite high lactate levels 17.3 mmol/L) and 1 had low LVDP (54 mm Hg) but low lactate (6.9 mmol/L). CONCLUSIONS: The intraventricular balloon technique provides useful information regarding contractile recovery of donor hearts that if combined with lactate metabolism has potential application for the evaluation of DCD and marginal donation after brain death hearts before transplant.

Fractures of the femur and blood transfusions.

BACKGROUND: Blood loss estimation after trauma (i.e. physical injury) and early identification of potential sources of bleeding are important for planning of investigation and management of trauma. Long bone fractures have been reported to be associated with substantial volumes of blood loss requiring blood transfusion. The aim of this study was to assess rates and amounts of blood transfusion in the setting of isolated extra capsular femur fractures and to determine variables associated with the need for transfusion within the first 48 h of admission. METHODS: A retrospective cohort study was conducted of patients in The Alfred Trauma Registry with isolated extra capsular femur fractures over a 7-year period. We compared patients with a femoral shaft fracture (FSF) to patients with either distal femur or proximal femur fractures (i.e. extremity fracture). We collected data potentially associated with blood transfusion within 48 h as well as operation details and patient outcomes. RESULTS: There were 293 patients included, of which 121 had FSF and 172 extremity fracture. 105 (36%) patients received a blood transfusion during their admission. Admission haemoglobin (AOR 0.92; 95%CI 0.89-0.94, p < 0.01) was the only independently associated variable with blood transfusion within the first 48 h of hospital admission. CONCLUSION: Volume of blood transfused to patients with extra-capsular femoral fractures was low and usually in the post-operative period. FSF, compared to femoral extremity fractures, were not more likely to receive blood transfusion within the first 48 h of admission, and did not receive a higher volume of blood overall. In the setting of major trauma with haemorrhagic shock, alternate sources of bleeding should be sought.