Received September In vitro performance tests were made in order to Address correspondence and reprint requests to Dr. E-mail: bock bcm. These tests can provide important information yahoo. Adapting a milling machine, the wear test station was assembled with rotation controller, water lubri- cation, depth controller, and applied charge measure- ment system. The wear tests were divided into three steps. In the first step, all bearings were weighted in a precision scale with divisions of 0.
After that, each pair of male and female bearing was tested. Two types of pairs were tested, ceramic—polymeric pairs and ceramic—ceramic pairs. After the tests, the pairs were weighted again to measure the wear loss in mass. All pieces FIG. The new centrifugal blood pump is shown with a double tested had their contact surfaces polished and rough- pivot bearing system. Each test was performed under the following condi- pressure and flow 5.
Finally, two isolated normalized tests of hemolysis with human blood Hydrodynamic performance tests with mock were performed producing four values of normalized loop circuit index of hemolysis NIH , obtained from variation of A performance test circuit was assembled Fig. A wear test station was assembled with the The mock loop circuit was set with water solution purpose of measuring isolated wear rate.
The hanging flexible charge applied to the system Fig. The main idea reservoir was filled with 0. The pressure gauges were connected 0. The wear test station assembled in a vertical milling machine left with charge measurement system right.
Artif Organs, Vol. Simple mock loop circuit used during performance tests. The ultrasonic flow- and the blood temperature was controlled between meter transducer was located 0.
The mock polyvinyl chloride tubing, a flexible reservoir with circuit was set horizontal to the table for easy adjust- sampling port, an ultrasonic flowmeter with probe, a ment of pump afterload using a screw clamp. Any air pressure monitor with probes, a thermistor with ther- was removed from the circuit before the data acqui- mometer, and the blood pump Fig. Blood had the sition 6. With 0. A screw clamp was set around screw clamp open, the first point collected was the flexible tubing at the pump outlet side to produce the maximum flow for each pump speed.
Closing the required pressure conditions for left ventricle assist screw clamp, the pump afterload increases as the flow devices mm Hg. In each 6 h test, seven samples decreases, and the next points are collected each were collected T0, T1, T2, T3, T4, T5, and T6, and their 0. Values Blood was drawn from a human volunteer using a express the total loss of mass caused by wear in pairs large bore needle into a mL blood bag with and its total weight.
No negative pressure exceeded mm Hg FIG. Mock loop circuit used during hemolysis tests. Performance curves results in wear evaluation trials with ceramic— A diagram flow vs. Four pairs had the minimum with each pump curve superimposed in order to mass loss 0. Pivot bearing systems composed only of ceramic PFH releasing are known to have higher vibration during pumping PFH value was measured for each sample.
With applications instead of shock absorption experi- this PFH variation in time T0, T1, T2, T3, T4, T5, and enced in ceramic—polymeric pivot bearing systems T6 is possible to represent hemoglobin releasing in 3,6.
TABLE 1. Performance curves showing hydrodynamic characteristics for both pumps. After calculations, the preliminary hemolysis research. Characteristics of a blood pump combining the centrifugal and axial pump principles. Artif Organs ;— A comparative study between flow visualization and computational fluid The pair composed of alumina and UHMWPE was dynamic analysis for the sun medical centrifugal blood pump.
Baylor Gyro pump: a completely seal-less centrifugal pump aiming for long-term cir- The dual impeller centrifugal blood pump had culatory support.
The hydraulic char- 4. The ran- preoperative coagulopathy. Patients also were ex- domized blood product was added to the priming cluded if written informed consent had not been infusion, and calcium chloride was then added to obtained or was withdrawn. Participants were randomly assigned to receive Blood cardioplegia was used at a blood-to-car- either fresh whole blood or reconstituted blood dioplegia ratio of Blood flow on cardiopulmo- products for priming of the cardiopulmonary by- nary bypass was maintained at 2.
Those with single-ventricle lesions minute per square meter of body-surface area, with were stratified to ensure their equivalent distribu- an attempt to keep the venous oxygen saturation tion in the two study groups. Blood pressures were targeted to a mean arterial pressure of 40 to 60 mm Hg. During Administration. Nucleic acid testing was used to rewarming, an alpha-stat strategy i. All the patients underwent con- servative solution.
Units divided into components un- data collection derwent standard preparation. Packed red cells On the day of surgery, a preoperative illness-severi- were treated with a preservative solution Optisol, ty score was assigned to each patient.
Preoperative prothrombin time, partial- the time of circuit priming. A half unit of packed thromboplastin time, and fibrinogen levels were red cells was mixed with a half unit of fresh-frozen also obtained.
Blood samples for the measure- plasma to achieve a hematocrit of approximately 25 ment of lipopolysaccharide-binding protein, inter- percent. The other half unit of packed red cells was leukin-6 , interleukin-8, cardiac troponin I, activat- added to the circuit at the time of rewarming. All care providers, with the exception The degree of postoperative illness was deter- of the operating room perfusionist and circulat- mined at 24 hours to be either severe or nonsevere, n engl j med ;16 www.
The new england journal of medicine according to prospectively defined criteria. Total blood loss was assessed for 72 hours after statistical analysis the patient was admitted to the intensive care unit All data were analyzed on an intention-to-treat by measuring chest-tube drainage. Baseline Characteristics of the Patients. Independent-sample Mann—Whitney U tests unavailable. A total of patients underwent randomization and re- results ceived their assigned blood products for cardio- pulmonary bypass circuit priming.
Thus, the study. Thirty-four patients were excluded be- a total of patients were included in the inves- Table 2. Intraoperative and Postoperative Outcomes. The new england journal of medicine tigation, 96 in the fresh-whole-blood group and in the reconstituted-blood group. Demograph- The median age of the fresh whole blood was According to intention-to-treat analysis, Figure 1.
However, patients who received recon- od. Furthermore, among the patients who received stituted blood for priming had a shorter length of stay reconstituted blood, there was a trend toward a in the intensive care unit.
Correlational analyses to deter- mine the effect of the age of the blood on both chest-tube output and the requirement for packed red cells revealed no significant relationships.
This differ- 1. Throughout the hour study period there was a trend toward greater cumu- binding protein occurred in both groups Fig. At 48 and 72 hours, the levels of this protein in the fresh- whole-blood group became significantly greater than those in the reconstituted-blood group The notion has long been accepted that the use of In this prospective, randomized, double-blind fresh whole blood for circuit priming is critical for study, we demonstrated that the use of fresh whole optimal outcomes after surgery for congenital blood for cardiopulmonary-bypass circuit priming heart disease.
The appeal of this concept most like- in neonates and infants does not confer a signifi- ly stems from the fact that whole-blood priming cant clinical or biochemical advantage over priming guarantees the provision of all cellular and non- with a combination of packed red cells and fresh- cellular blood components. Moreover, it seems frozen plasma.
Perhaps more important, circuit intuitive that a manipulated or reconstituted prod- priming with fresh whole blood was associated uct should be less desirable than a natural, unma- with a significantly lengthier stay in the intensive nipulated product. Such beliefs have been support- care unit, greater perioperative fluid overload, and n engl j med ;16 www. The new england journal of medicine Figure 3.
For interleukin-6, 40 Fresh whole the normal range is 0 to 5. All laboratory values were elevated 10 Reconstituted blood postoperatively in both groups. Only the level of lipopoly- 0 saccharide-binding protein was statistically different be- tween the groups, reaching significantly lower levels in the reconstituted-blood group 48 and 72 hours after surgery.
These variables may be related to one another mechanistically. This prolongation, in turn, could increase the length of stay in the intensive care unit. Randomization 50 blood of the patients resulted in study groups that dif- Reconstituted fered substantively only in the type of blood prime blood 0 used for cardiopulmonary bypass. Reconstituted In contrast to fresh whole blood, all packed red 10 blood cells were preserved in the blood center by the ad- 5 dition of solutions that contain sodium chloride, adenine, dextrose, and mannitol.
Although the clin- 0 ical effects of these substances at the concentra- Preopera- 1 8 24 48 72 tive tions used are uncertain, it is known that manni- Hours tol is an antioxidant capable of scavenging oxygen free radicals, the levels of which increase with is- chemia—reperfusion during cardiopulmonary by- nitude of this decrease is explained by the use of pass.
Aside from this ini- throughout the body. The mag- the finding that the reconstituted-blood group did n engl j med ;16 www. More stringent donor- the use of reconstituted blood for bypass circuit eligibility criteria and more sensitive serologic and priming could be substantial.
Furthermore, from nucleic acid assays for viral detection have mini- the perspective of blood centers already grappling mized the risk associated with additional donor ex- with the need to maintain a blood-product supply posure transmission of HCV and HIV both occur that remains just ahead of demand,24 providing in less than 1 transfusion in 1 million Moreover, fresh whole blood reduces inventory control and this risk could be eliminated completely by the re- revenue because many units of platelets and fresh- constitution of blood from a single donor.
In con- frozen plasma are not obtained. The rate nates and infants does not confer a significant clin- of infections in patients undergoing cardiac sur- ical or biochemical advantage over priming with a gery is 23 per days, a rate 50 percent greater combination of packed red cells and fresh-frozen than that in the general population of patients in plasma.
On the contrary, the use of fresh whole the pediatric intensive care unit. In our opinion, these clinical hazards unit after surgery for congenital heart disease has outweigh the risk of the additional donor exposure also been associated with worsened cognitive func- associated with reconstituted-blood priming.
The tion. Since of Carter BloodCare, Dallas, for their tireless commitment to this approximately 19, operations for congenital study; and to the members of the data safety and monitoring board Gil Wernovsky, M.
States,23 with the majority requiring cardiopul- references 1. Anesth Analg ; 8. Mechanism of Factors associated with blood loss peutic strategies. Chest ; Blood ; ate analysis in children after open-heart sur- et al. Complement activation during cardio- Anesth Analg ; Coagulation defects in neonates during Ramamoorthy C. Association between age organ failure. J Thorac Cardiovasc Surg cardiopulmonary bypass. Ann Thorac Surg and blood loss in children undergoing open- ; Ann Thorac Surg ;
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