| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2002;73:739-743
© 2002 The Society of Thoracic Surgeons
a Department of Cardiothoracic Surgery, University of Tokyo, Tokyo, Japan
b Department of Public Health, University of Tokyo, Tokyo, Japan
Accepted for publication October 9, 2001.
* Address reprint requests to Dr Shibata, Department of Cardiothoracic Surgery, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-8655, Japan
e-mail: shibata-tho{at}h.u-tokyo.ac.jp
 |
Abstract |
|---|
 Top Abstract IntroductionMaterial and methodsResultsCommentReferences |
|---|
Methods. From July 1997 to December 2000, 148 thoracic aortic operations were performed in our department. Sixty-one cases involving patients who underwent elective thoracic aortic operation with deep hypothermic circulatory arrest were reviewed retrospectively.
Results. Seventeen patients did not meet the criteria for the blood conservation program and were excluded from the present study. Therefore, 44 patients were analyzed in this study. Overall, 50% of patients did not require operative homologous blood transfusion (HBT) and 43% did not require in-hospital HBT. Smaller amounts of autologous donation, greater blood loss, and a longer operation time were independent risk factors for HBT requirement. Among 16 patients who had made an autologous donation of 1,600 mL or greater, 75% did not require intraoperative HBT and 69% did not require in-hospital HBT. The overall perioperative mortality rate was 4.5%. As for postoperative complications, prolonged intubation and postoperative infection were significantly more frequent among patients who required in-hospital HBT.
Conclusions. Our combined blood conservation measures were effective in avoiding HBT during major thoracic aortic operations with deep hypothermic circulatory arrest and may have reduced postoperative complications. The amount of the autologous donation was a strong predictor for avoiding HBT.
|
Introduction |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Thoracic aortic operation is one of the most invasive procedures in cardiac surgery, and large amounts of blood transfusion are usually unavoidable [8]. Moreover, deep hypothermia is thought to be associated with an increased risk of hemorrhage [9]. However, the number of thoracic aortic operations is increasing, and operative outcomes are improving every year. To minimize transfusion-related complications, blood conservation techniques should be applied to thoracic aortic operations. In July 1997, we started a blood conservation program for thoracic aortic operations. In this study, we evaluated the effectiveness of our blood conservation program for thoracic aortic operations performed with deep hypothermic circulatory arrest (DHCA).
|
Material and methods |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Blood conservation program
To avoid homologous blood transfusion whenever possible, we used two different autologous transfusion methods: preoperative autologous donation and intraoperative autologous donation.
Preoperative autologous donation
Patients scheduled for elective operations were asked to enter the predonation program. The inclusion criteria for preoperative autologous donation were a hemoglobin value greater than 11 g/dL, an age of less than 75 years, no severe heart failure, no severe ischemic heart disease, and no active infectious disease. All donations were performed in the blood transfusion service of our hospital. The volume of each donation was 400 mL, and the donation was repeated once a week. The donated autologous blood was separated into packed red blood cells and plasma. The plasma was then frozen for later use as fresh-frozen plasma. If the anticipated storage period was more than 21 days, the red cell portion was also frozen. All patients were prescribed 200 mg/d oral iron supplement before their operation. Erythropoietin was used only when the hemoglobin value was less than 12 g/dL.
Intraoperative autologous donation
Patients were evaluated for the possibility of intraoperative donation according to their preoperative conditions. The inclusion criteria were stable hemodynamics and a hemoglobin value greater than 10 g/dL after the induction of anesthesia. In most cases, 400 mL of whole blood was collected from the central venous line by the anesthesiologist before the initiation of cardiopulmonary bypass (CPB) and simultaneously replaced with an equal volume of 6% hetastarch. It was stored at room temperature and reinfused after heparin protamine reversal.
Surgical procedures
The CPB was performed using a crystalloid priming solution and a membrane oxygenator. All patients underwent operations with DHCA, usually with retrograde cerebral perfusion for brain protection. The indications for DHCA were as follows:
After the initiation of CPB, patients were cooled down to 18°C. Retrograde cerebral perfusion was performed through the superior vena cava in patients who were operated on through a median sternotomy, as reported by Ueda and associates [10]. In patients who were operated on through a left thoracotomy, retrograde cerebral perfusion was performed by increasing the central venous pressure, as reported by Takamoto and associates [11]. At the end of the CPB, the blood remaining in the pump circuit was processed using an ultrafiltration device and reinfused. Intraoperative blood salvage was also performed using automatic blood collection and washing equipment, mainly before and after the CPB. Postoperative shed blood was not reinfused.
Aprotinin was used only for reoperations and procedures performed through a left thoracotomy. A dose of 2 x 106 kallikrein inhibitor units (KIU) of aprotinin was administered to the pump priming solution, and a constant infusion of 5 x 105 KIU per hour was maintained throughout CPB. Five grams of tranexamic acid was routinely administered after termination of CPB.
Indications of transfusion
During CPB, the hematocrit value was maintained in excess of 18% by adding blood if additional volume was required or, if the blood volume was sufficient, by removing excess fluid using an ultrafiltration device. If the hematocrit value was less than 25% postoperatively, the patient was given packed red blood cells to raise the hematocrit value. If the patient showed signs of unstable hemodynamics or evidence of organ dysfunction or acidosis, a blood transfusion was immediately performed to obtain a higher hematocrit value.
Definition of homologous blood transfusion
The HBT included homologous whole blood, red blood cells, fresh-frozen plasma, and platelets. Cryoprecipitates were not used, and biologic glues and albumin were not included in the HBT.
Clinical outcomes
Postoperative complications were also reviewed, which included stroke, prolonged intubation, infection, and renal failure. Prolonged intubation was defined as an intubation period longer than 24 hours after the operation. Postoperative infection was defined as systemic signs of infection plus a septic focus or bacteremia. Local infections without systemic signs were excluded. Renal failure was defined as renal dysfunction requiring hemodialysis. Perioperative mortality was defined as death occurring within 30 days after the operation.
Statistical analysis
All data were expressed as the mean ± the standard deviation. Continuous variables were analyzed using a Student’s t test, and categorical variables were analyzed using 
2 or Fisher’s exact test. Stepwise multivariate logistic regression analysis was used to determine the independent risk factors for HBT. A p value of less than 0.05 was considered to be significant.
|
Results |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
No complications associated with autologous donation were experienced. The mean amount of preoperative and intraoperative donation was 972 ± 329 mL and 321 ± 241 mL, respectively.
The diagnoses and operative procedures are shown in Table 1. Ten coronary artery bypass grafting and two aortic valve replacement were performed concomitantly. The mean operation time, CPB time, and DHCA time were 579 ± 198 minutes, 262 ± 94.3 minutes, and 69.1 ± 28.6 minutes, respectively. The mean blood loss was 991 ± 1,485 mL.
|
Risk factors for homologous blood transfusion
Overall, 50% of patients did not require operative HBT and 43% did not require in-hospital HBT. Significant univariate and multivariate variables associated with in-hospital HBT are shown in Tables 2–4.
Smaller amounts of autologous donation, greater blood loss, and longer operation time were independent risk factors for HBT requirement.
|
|
|
Clinical outcome
The overall perioperative mortality was 4.5%. Table 5
shows a comparison of postoperative complications and mortality between patients with and without in-hospital HBT. Prolonged intubation (> 24 hours) and postoperative infection were significantly more frequent in patients requiring in-hospital HBT.
|
|
Comment |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Several studies have revealed the efficacy of blood conservation techniques, such as preoperative and intraoperative autologous donation, intraoperative blood salvage, postoperative reinfusion of shed blood, and some pharmacologic agents, in reducing the need for HBT during cardiac operations. Further reductions in the need for HBT have been reported for combinations of these techniques. However, only one report has been made on the usefulness of blood conservation methods during thoracic aortic operations [12]. Moreover, no reports have been made on the efficacy of blood conservation measures in patients undergoing thoracic aortic operations with DHCA, who are believed to have the largest need for HBT.
The present study shows that major thoracic aortic operations with DHCA can be performed without HBT by using combined blood conservation measures. A sufficient amount of autologous blood is especially important, with the amount of the autologous donation being an independent predictor for avoiding HBT. Patients who donated 1,600 mL or more of autologous blood did not require intraoperative or in-hospital HBT in 75% and 69% of cases, respectively. These figures are significantly better than those of patients who donated smaller amounts of autologous blood. Some previous studies have reported that patients who donated three units of autologous blood preoperatively had a significantly lower need for HBT during cardiac operations [7, 13]. Our experience confirms these results. Consequently, an adequate donation schedule should be taken into account, as a short preoperative period is one of the main reasons for deferral. We believe that the first donation should be made at least 3 weeks before the operation to ensure completion of the predonation program.
We have not experienced any complications associated with this blood conservation program. None of the aneurysms were ruptured during the preoperative donation period. Theoretically, aneurysms might rupture during the donation periods; hyperdynamic responses to donation might predispose a patient to aneurysm rupture. Careful patient selection and follow-up are essential to prevent complications. Patients with very large aneurysms or symptoms should receive operations as quickly as possible and are not eligible for blood conservation programs. The patients’ medical status must be checked before and after the donation to strictly control blood pressure and to avoid anemia.
We did not retransfuse any shed blood after the operation. Although several studies have reported preferable results for the shed blood retransfusion after cardiac operations [4, 14], the efficacy of this procedure is still controversial [15]. Some studies have reported positive bacterial cultures obtained from samples of shed blood [16, 17] that could cause graft infection, leading to the patient’s death. We believe that meticulous hemostasis during the operation is the most important step in avoiding the need for HBT. None of the patients in this study required reexploration for postoperative bleeding.
Aprotinin has been widely used to reduce intraoperative and postoperative blood loss. However, Sundt and associates [18] reported a high incidence of thromboembolic complications when aprotinin was used in combination with DHCA. Therefore, aprotinin was used only in patients receiving a reoperation or undergoing a procedure through a left thoracotomy. Reoperation patients have an especially high risk of intraoperative and postoperative bleeding; in these cases, the benefits of aprotinin may outweigh its adverse effects. Aprotinin was used in patients undergoing a procedure through a left thoracotomy to prevent pulmonary hemorrhage.
We routinely administer tranexamic acid after CPB. Tranexamic acid is a synthetic antifibrinolytic drug that has been recently introduced for use in cardiac operations. Tranexamic acid acts by forming a reversible complex with plasminogen. Some studies have reported excellent effects on hemostasis comparable to those of aprotinin [19, 20]. 
-Aminocaproic acid is also reported to be effective, but this drug has not been approved in Japan.
Several reports have described adverse effects of HBT on postoperative recovery. Svensson and associates [12] reported that HBT was an independent risk factor for prolonged hospital stay after ascending aorta and aortic arch operations. Murphy and associates [21] reported that HBT was an independent risk factor for postoperative infection after coronary artery bypass grafting. In our study, some postoperative complications were more frequent among patients who required HBT during the perioperative period. Of course, the postoperative course is affected by various factors, and a direct cause and effect relationship cannot be inferred from our results. Although we believe that blood conservation measures have a beneficial effect on the postoperative outcome of thoracic aortic operations by reducing the need for HBT, further clinical investigation is required.
In conclusion, our combined blood conservation measures were effective in reducing the need for HBT in major thoracic aortic operations with DHCA and possibly in reducing postoperative complications. The amount of donated autologous blood is a strong predictor for avoiding HBT. Consequently, an appropriate autologous blood donation schedule is essential to ensure that sufficient autologous blood donation is made before operation.[13]
|
References |
|---|
|
TopAbstractIntroductionMaterial and methodsResultsCommentReferences |
|---|
Related Article
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
