1.
A multicenter randomized controlled trial to assess the feasibility of testing modified ultrafiltration as a blood conservation technology in cardiac surgery
Boodhwani M, Hamilton A, de Varennes B, Mesana T, Williams K, Wells GA, Nathan H, Dupuis JY, Babaev A, Wells P, et al
The Journal of Thoracic and Cardiovascular Surgery. 2010;139((3):):701-6.
Abstract
OBJECTIVES Modified ultrafiltration is a technique after cardiopulmonary bypass whereby blood withdrawn from the aortic cannula is passed across a semipermeable membrane to hemoconcentrate. Unblinded trials have suggested that modified ultrafiltration is efficacious for blood conservation. The objective of this trial was to assess the feasibility of a model testing modified ultrafiltration in which all members of the surgical team were blinded to the intervention. METHODS Patients (<65kg) undergoing procedures involving cardiopulmonary bypass were randomized to undergo either modified ultrafiltration (n=29) or sham (circulation without an interposed filter, n=36) for 15 minutes. The circuit was shielded from all members of the team except the perfusionist. A questionnaire was administered to determine the blinding success. RESULTS Modified ultrafiltration resulted in a removal of 1000+/-251mL of fluid and a reduction in the pump balance (1025+/-807 vs 1804+/-838; P < . 001) with an increase in hemoglobin immediately after intervention (increase of 7. 7+/-8. 8g/L in modified ultrafiltration vs 3. 8+/-5. 1g/L in sham; P=. 04). Introduction or increase in dose of vasopressors was more frequent in the modified ultrafiltration group (52% vs 28%; P=. 048). Differences in red cell transfusion rates between groups did not reach statistical significance (P=. 59). Blinding was successful for the anesthetist (blinding index 0. 13 [95% confidence interval, 0. 11-0. 38] and the intensivist (blinding index, 0. 09 [95% confidence interval, 0. 14-0. 31]) but not for the surgeon (blinding index, 0. 24 [95% confidence interval, 0. 05-0. 42]). The compliance rate for the transfusion protocol was greater than 90%. CONCLUSIONS Modified ultrafiltration was effective for hemoconcentration after cardiopulmonary bypass in patients of low body weight, but it is associated with an increased need for vasopressor support. The anesthetist and intensivist were successfully blinded to the intervention.
2.
Effect of hemoglobin levels in hemodialysis patients with asymptomatic cardiomyopathy
Foley RN, Parfrey PS, Morgan J, Barre PE, Campbell P, Cartier P, Coyle D, Fine A, Handa P, Kingma I, et al
Kidney International. 2000;58((3):):1325-35.
Abstract
BACKGROUND Hemoglobin levels below 10 g/dL lead to left ventricular (LV) hypertrophy, LV dilation, a lower quality of life, higher cardiac morbidity, and a higher mortality rate in end-stage renal disease. The benefits and risks of normalizing hemoglobin levels in hemodialysis patients without symptomatic cardiac disease are unknown. METHODS One hundred forty-six hemodialysis patients with either concentric LV hypertrophy or LV dilation were randomly assigned to receive doses of epoetin alpha designed to achieve hemoglobin levels of 10 or 13.5 g/dL. The study duration was 48 weeks. The primary outcomes were the change in LV mass index in those with concentric LV hypertrophy and the change in cavity volume index in those with LV dilation. RESULTS In patients with concentric LV hypertrophy, the changes in LV mass index were similar in the normal and low target hemoglobin groups. The changes in cavity volume index were similar in both targets in the LV dilation group. Treatment-received analysis of the concentric LV hypertrophy group showed no correlation between the change in mass index and a correlation between the change in LV volume index and mean hemoglobin level achieved (8 mL/m2 per 1 g/dL hemoglobin decrement, P = 0.009). Mean hemoglobin levels and the changes in LV mass and cavity volume index were not correlated in patients with LV dilation. Normalization of hemoglobin led to improvements in fatigue (P = 0.009), depression (P = 0.02), and relationships (P = 0.004). CONCLUSIONS Normalization of hemoglobin does not lead to regression of established concentric LV hypertrophy or LV dilation. It may, however, prevent the development of LV dilation, and it leads to improved quality of life.