Approximately 20% of cardiac surgery patients need allogenic blood during the perioperative period
[5]. In order to reduce allogeneic blood transfusion, preoperative autologous blood donation has been widely used in countries outside China
[6-10] and satisfactory outcomes have been acquired. To the best of our knowledge, similar results have not been reported in swine model experiment because preoperative autologous blood donation is hard to perform and difficult to manage. The problem of hemodilution exists during the cardiopulmonary bypass surgery
[11-13]. Blood loss caused by open heart surgery and mechanical destruction of blood by extracorporeal circulation unit can lead to anaemia and hypoxemia. Blood transfusion is much more necessary to cardiac surgery in animals because animal experiment conditions are poorer than clinical surgery, which would lead to more blood loss.
In the present study, each swine, weighing 27-50 kg, lost approximately 600 mL blood during the perioperative period, thus they would suffer from severe anaemia, which greatly influences the success rate of surgery if blood transfusion was not given. No literature has been retrieved regarding blood type detection or crossmatch prior to blood transfusion in swine as well as adverse effects after blood transfusion. It is difficult to determine whether the animal death was caused by failed surgery or was related to allogeneic blood transfusion.
During the swine surgery in which much blood would be lost, such as liver and heart transplantation, swine blood is mostly harvested from slaughterhouse 1-2 days prior to surgery, but heparin (100-200 mg) or sodium citrate must be added to prevent hemagglutination. Evidence exists that blood can be also provided by donor swine[14]. Precisely, following jugular vein cannula, swine were transfused with a small amount of saline solution. A total of 1 000-1 500 mL swine blood was collected into a sodium citrate pre-added blood-collecting bottle which was connected to the jugular venous duct. After thorough bloodletting, swine often die, and blood type detection and crossmatch are generally not determined prior to bloodletting. Because experimental swine costs much, thus blood collection from experimental swine would increase experimental cost. The present adopted preoperative autologous blood donation using the leap-frog technique, which meets the need of blood use in surgery and also allows the survival of swine, leading to low scientific research costs.
In the present study, the extracorporeal circulation time was (110.94±11.68) minutes. To save blood use, all collected blood was transfused back, which retrieve some red cells to some extent. There was one swine presenting with hemoglobinuria after blood transfusion in each group. The possible cause for the autologous blood donation group is that the mechanical destruction of blood caused by the use of extracorporeal circulation unit increases free hemoglobin, and the possible cause for the allogeneic blood transfusion group is the potential hemolytic reaction caused by allogeneic blood transfusion in addition to increased free hemoglobin. Results from this study demonstrate that Hb concentration was slightly, but not significantly, higher in the autologous blood donation group than in the allogeneic blood transfusion group; however, at 1 day after the surgery, the Hb concentration was significantly higher in the autologous blood donation group than in the allogeneic blood transfusion group (P < 0.01). This occurs because autologous blood transfusion does not need blood type detection and crossmatch, has no rejection, and is conductive to recovery of animals. Evidence exists that preoperative autologous blood donation can lower Hb concentration and Hct level prior to and during surgery compared with control group, but when discharge, Hb concentration and Hct level are higher in the preoperative autologous blood donation group than in the control group[8].
Modern blood transfusion medicine has become a new subject and blood transfusion has an irreplaceable role in treatment. Xiao et al[15] tried allogeneic blood transfusion in animal experiments, but some problems exist in allogeneic blood transfusion among large- and middle-sized animals in terms of blood matching to prevent transfusion reaction and control blood transfusion-caused transmissible diseases. Allogeneic blood transfusion easily leads to bacterial infection owing to immunosuppression[9]. Allogeneic blood transfusion for surgical operations in animals has not been widely used. One autologous blood donation and transfusion in surgical operation of miniature pigs can greatly enhance the survival rate of pigs after surgery and it is safe and feasible[16]. In recent years, we try to retrieve the blood lost and back transfused into animals after screening to save the animals suffering from hemorrhea during the surgery. The method can markedly boost the survival rate of animals, but it is restrained in animal experiments owing to strict sterile operation procedure, complicated operation of blood collection, and high cost.
In the present study, blood loss is calculated according to the blood left in the suction bottle, gauze, dressing, extracorporeal circulation unit, and blood sample
[17-18], approximately 600 mL per pig. One preoperative autologous blood donation cannot satisfy the surgery and more blood lost during one blood collection would cause the hemorrhagic shock of experimental animals. Considering no other surgical wounds during blood collection, 20% systematic blood was collected at 9 days prior to cardiac bypass surgery. During blood collection, a compound solution of sodium lactate solution and hydroxyethyl starch was added to supplement with the lost blood. At 2 days prior to surgery, the collected blood was back transfused into the animals and 30% systematic blood was further collected. Swine vital signs are not markedly influenced because some autologous blood is back transfused. For patients undergoing autologous blood donation using the leap-frog technique, erythropoietin is suggested to accelerate erythropoiesis
[19-20]. In the present study, erythropoietin was not used, but four eggs per day were added. Results from this study demonstrated that swine survival rate was significantly higher in the autologous blood donation group than in the allogeneic blood transfusion group (87.5% versus 62.5%,
P < 0.01). In the autologous blood donation group, one swine died from anaemia and hypoxemia 2 hours after surgery because much blood was lost prior to extracorporeal circulation and all autologous blood pre-donated prior to surgery was added to prevent too high dilution. In the allogeneic blood transfusion group, three swine died, two because of unable to improve hypoxemia during chest closure and one because of hypoxia caused by nontimely incubation. These findings suggest that the preoperative autologous blood donation is feasible for experiments among large-sized animals. Further complementary studies involving larger animal numbers are warranted.
