Questions and Answers

Hemosep (29)

1. In trauma can Hemosep process large volumes in a short time?

Large volumes can be utilised by the filling of the collection bag and each single collection bag being processed via a queue system or by having several machines in operation at one time.

2. How does the device “Maintain All Cell Species” ?

The key filtration technique is via the membrane. This filters the plasma and locks the waste fluid inside the membrane. It has been designed to only allow the very small species through it and therefore all cells can be maintained to the benefit of the patient. Due to this process cell species recovery is attained and this includes the proteins and clotting factors. The filter membrane is the control membrane of the system and the unique pore size for this important element of the device has been selected to ensure that no cellular components of the blood product can pass into the super absorber during use. The unique pore size is small enough to permit efficient fluid transport into the super absorber, but is too restrictively small to permit the passage of even the smallest intact cells, i.e. the platelets.

3. How is leukocyte activation managed?

Leukocyte activation is not a real problem post-CPB. The leukocyte dynamics associated with CPB result in a high leukocyte population, but these are largely in an inactivated state. If clinicians are concerned about the leukocyte population of the concentrate, they may choose to leukocyte filter the material. Some clinical groups leukocyte filter all blood products as a matter of course. The view of many clinicians is that this should not be necessary.

4. What procedures are available to QA the reinfusate?

Measure PCV, do a full blood count if this is felt necessary. There are no other methods for this.

5. How many Hemosep bags will I need?

Each Hemosep concentration bag has a capacity of 1 litre (4 units). The average blood transfused into a patient following surgery is 2.7 units so each bag has the capacity to over achieve on the average units of blood needed. As with any device, the protocol for development has to fit in with the average need and requirements. The device has been tested, developed and manufactured in this way for that requirement. One of its aims was to make it as simple and compact as possible so it would be able to be used in theatre and not get in the way or become cumbersome toward any process that may be being followed.

6. What trials and safety tests have been undertaken?

Full clinical trials have taken place in Turkey. Following publication of the initial data, validation sources were used such as NHSBT. Full CE approval was granted for the medical device following initial assessments and positive trial outcomes showing no adverse responses to the filtration process. Additional indications for use are being sought for the CE certification for use in paediatrics. In addition to this, further developments to increase filtration options and properties are in full development.

7. What is planned by way of launch and availability?

The launch of the product is already underway in various worldwide markets, which includes all western European areas, registration in Canada and FDA approval for the USA. Availability in the short term will be via the direct supply through Advancis Surgical based in the U.K, where we have a large and capable team managing administration, customer service, logistics and support. Moving forward, applications have been made into the NHSSC, Scottish procurement and Welsh procurement for inclusion of the device. Future supply will be included on the NHSSC to ensure all sites can receive comprehensive delivery and service in a manner they are accustomed to with other product categories. Comprehensive training will be provided directly to clinicians by way of initial interaction and future on-going training if required. Full stock levels are currently accessible via Advancis Surgical with provisions in place for increased demand in the initial term

8. Assessment of platelet activation and overall quality

This is yet to be investigated fully but there is no reason to assume that platelet function will be impacted by the use of the technology. There is no high sheer during the process and surface contact is minimal. Small platelets and platelet fragments are removed by the system, resulting in a loss of around 30% of platelet numbers. These studies are underway, however our clinical studies suggest that there is a reduction in the need for platelets post-surgery.

9. Can Hemosep recycle the clotting properties as these are below the pore size?

Proteins involved in the clotting cascade will be removed by the device as these are less than the pore size. However, there are residual clotting factors in the concentrate in proportion to the amount of plasma left in the mix. This is not the case with other devices which also generally remove platelets.

10. Does the bag filter out the anti coagulant?

The level of anti coagulant in the concentrate for transfusion is fairly low and has no apparent impact upon observed effects of transfusion in clinical trials however the ACT (activated clotting time) is reduced.

11. Why does it not return the whole blood instead of concentrate ?

The device returns a concentrated blood product consisting of all cell species plus a varying amount of plasma. The Hemosep device is capable of high concentration rates. We have produced PCVs of over 75%, but this takes more time. The selected PCV reflects that of competitive devices and meets the level commonly required by clinicians.

12. Does Hemosep retain Vitamin K or is this diluted away?

All plasma borne elements will be diluted in proportion to the volume of plasma removed.

13. Will Hemosep remove any damaged RBC, WBC cells as with the Cell Saver

The Hemosep device will remove fragmented cells and fragments below the pore size.

14. What was the type of cardiac surgery on which the trials were conducted?

Trial of the Hemosep device was conducted on CABG (Coronary Artery Bypass Graft) patients.

15. What is the effect of the activated platelet levels?

There is no suggestion at the present time that platelets are activated by the process.

16. Can the device recycle the waste product from the competitor cell salvage devices?

The Hemosep device can be used in conjunction with other cell salvage devices. In high trauma situations, where the return of the patients’ blood has to be processed within a few minutes, the excess fluid can then be transfused into the Hemosep bag and run through the filtration process to save and utilise cell species from the waste fluid.

17. Will the Hemosep device aid in the reduction of post-operative bleeding?

Post-operative bleeding is a major factor in any major surgery, there are several factors surrounding the cause of this. One factor is the reduction in clotting factors associated with the current practice of only giving a patient back the red blood cells therefore reducing the clotting agents in the blood and the Hemosep device. The Hemosep device recycles the blood in all cell species, retaining the residual clotting factors in the concentrate; this in turn will aid in the reduction of post-operative bleeding and potential help in the reduction of surgery.

18. SHOT compliance.

SHOT manages and records data surrounding adverse effects of incorrect blood types being given; it also recommends processes to ensure the wrong blood type does not get transfused into the wrong patient. In the Hemosep system each blood collection bag includes an area to formally write down the patient’s details. In line with SHOT guidelines correct patient identification is crucial to prevent wrong blood (IBCT) incidents. The bedside check is an essential step to ensure that the correct blood component is given to the patient and to detect errors that may have occurred earlier in the transfusion process. This situation assumes that the processed blood is being done whilst the patient is transferred away from theatre. However, if the device is located close to the CPB machine, the blood can be directly pumped into the concentration bag, valve closed, processed on the shaker, collection bag valve opened to release blood into the blood collection bag, hung up and then directly transfused back to the patient ensuring continued connection to the overall circuit.

19. What is the anti-coagulant content of the post filtered blood?

There is some residual anti coagulant, but the volume of blood transfused is relatively small and the systemic impact of this is very low. It is possible to remove anti coagulant by re-suspending the cells in saline after initial processing but this adds to the processing time. Current clinical studies have demonstrated that the presence of some anti coagulant in the processed blood does not impact on the patient. This is evident in a reduced blood loss in Hemosep treated patients compared to control.

20. What other areas the device can be used in?

Advancis Surgical will be developing additions to the device for use in the Orthopaedic, Paediatric and Neonatal practices.

21. How does Hemosep compare in price to other methods of cell salvage?

The Hemosep device recycles all the cell species, therefore reducing the need for additional blood components to be added. In overall costs this makes using Hemosep one of the most cost efficient methods on the market.

22. I currently have a contract, how can I justify the added cost ?

Due to the way Hemosep recycles the cell species, it saves money by reducing the need to add platelets to a patient (the cost of platelets are £209.30 per bag with an average 1.2 bags being used per patient transfusion). Hemosep can save around £150 per patient, making it economical even if current cell salvage techniques are still in place.

23. What is the overall quality of blood returned to the patient post CPB?

The blood product returned after concentration is very similar to that of the pre-surgical blood.

24. Can you expand on haemoglobins levels?

If plasma free haemoglobin is being referred to, then there is no issue. We have not detected any significant levels of haemolysis with this device.

25. If we are using a saline heparin mix to prevent clotting in the blood reservoir would we then need to administer any protamine to offset this or would the device filter enough of the heparin out to warrant no use, in relation to a procedure that will have no protamine administered as part of the normal clinical practice?

The Hemosep device will remove the majority of the heparin solution on processing of 1 litre of blood there is no need to administer any protamine to offset this due to the overall systemic levels residing in the patient after transfusion. If however several bags are transfused back to the patient it is advisable to monitor the levels using the A.C.T. and administer protamine if necessary.

26. If the device filters the blood at a unique size would this not then filter out the elements we want to remove in obstetric applications also?

Hemosep will remove the amniotic fluid there is however considerable contamination residing in the fluid to which further research is needed to fully establish what contaminants can and cannot be removed.

27. What are the benefits of returning the white blood cells (WBC)?

The WBC are in a non-activated state therefore classed as fresh WBC’s, these are essential to fighting infections in the body and should therefore aid in the overall recovery period.

28. In which surgical procedure is Hemosep best suited?

Hemosep is best suited to elective producers where a steady blood loss occurs; in cases of massive trauma many centres will adopt the practice of returning the whole blood to the patient in order to give the blood back as quickly as possible. Standard cell saver devices can be used to accomplish this, however in the case of massive trauma there is little evidence to suggest there is any clinical benefit to the patient.

29. How much Heparin is left in the processed blood?

The levels of heparin left in the processed blood are negligible, when transfused back to the patient the systemic levels are within the same scope as levels needing to be achieved when heparin is administered, it is therefore not necessary to increase the protamine levels, in cases where several bags of blood are transfused back to the patient it is advised to monitor the A.C.T. and take appropriate action.

Any disadvantages/risks regarding:

A)     white cell activation,

There is no evidence that the system activates white cells. Indeed there is some evidence that markers of IR are reduced in the blood concentrate. However, activated white cells that are present in the blood being processed will be concentrated in the final product. These are unlikely to be in numbers that constitute a clinical risk, however if there is a concern with these cells, the deployment of Leukocyte filtration will effectively remove these.

B)      retention of plasma free Hb,

The process is not haemolytic and therefore does not produce plasma free haemoglobin. Any plasma free haemoglobin in the pre-processed blood product will be removed in proportion to the amount of plasma extracted by the concentration process.

C)      cell haemolysis products,

 The process has not been shown to cause haemolysis.

D)     damage to platelets,

No evidence of platelet damage or activation..

E)      residual anticoagulant etc

There will be some residual anticoagulant in the blood product, but this will not be at a level that is of clinical significance, particularly for open heart surgery where anticoagulant reversal will be calculated on the total systemic load.     

2.  What is the benefit of removing the plasma (and clotting factors?) –

 No benefit in removing clotting factors, indeed there is evidence that some clotting factors are concentrated by the system. The main advantage in terms of clotting etc is around the retention of platelet populations.

3. Why not just give back unprocessed whole blood –

This blood product will be haemodiluted through either systemic haemodilution with circuit priming or anticoagulation with saline drip etc. There are some very high volume circumstances whereby delivery of whole blood has an advantage in terms of volume loading, but not generally the case.

•         How long it takes to process – 15 – 20 MINUTES

•         What are the benefits – Patient receives their own blood, reducing the need for platlets, and aids recovery & helps reduce the risk of post operative bleeding also.