Advice

The technology

The technology

Hemosep (Brightwake) is an ultrafiltration and haemoconcentration system for concentrating residual bypass blood during or after surgery. Haemoconcentration is the process of reducing the amount of plasma in the blood relative to the amount of red blood cells. It is usually done to offset haemodilution (the increase of plasma in the blood relative to red blood cells), which can be caused by administering essential fluids during surgery.

Hemosep consists of 4 main components:

  • Hemosep bag and tubing (containing a filter membrane and super-absorption material in a pad, for concentrating the blood)

  • Hemosep shaker unit

  • 1 litre blood collection bag for concentrated blood

  • intraoperative pump with suction tool and blood reservoir.

The Hemosep bag is single-use and comes in adult and paediatric sizes. Adult Hemosep bags have a maximum optimum capacity of 500 ml; paediatric Hemosep bags have an optimum capacity of 200 ml but can hold up to 250 ml if needed. More than 1 Hemosep bag may be needed per surgery, depending on the type of surgery and degree of blood loss.

Hemosep has 2 uses. It can be used to ultrafilter residual, haemodiluted blood after a bypass by connecting the Hemosep bag directly to the cardiopulmonary bypass system. It can also be used during surgery: blood is taken from the surgical site and passed into the reservoir using a heparin-infused suction tool, where it is filtered and pumped into the Hemosep bag.

However Hemosep is used, once in the bag blood is ultrafiltered using a membrane-controlled super-absorber plasma removal process. The filter membrane in the bag prevents movement of blood cells from the bag to the super-absorber pad while allowing free movement of plasma into the pad. The filtration can be helped by placing the Hemosep bag on the orbital shaker unit, which agitates the blood and encourages movement of cells across the membrane surface. The result is that concentrated blood is held within the bag while plasma is stored as a gel matrix within the super-absorber pad.

Once the concentrated blood reaches a packed cell volume of over 35%, it can be transferred to the collection bag for autotransfusion. Packed cell volume is calculated by centrifuging a small sample of the blood product and measuring the proportion of concentrated red blood cells.

The manufacturer recommends the use of a leukocyte reduction filter when reinfusing the blood.

Innovations

Concentrated blood collected using Hemosep contains not only red blood cells, as with other centrifugation cell salvage devices, but also platelets, white blood cells and clotting residuals. In this way Hemosep is designed to avoid the need for centrifugation and other blood preparation steps. It can therefore be used without the need for highly trained technical staff.

Plasma collected using Hemosep in stored in a gel, which is easier and safer to dispose of than large amounts of fluid associated with centrifugation methods.

Current NHS pathway

Cell salvage is routinely done during major surgery in the NHS when the patient is at risk of moderate blood loss. Haemodilution during surgery can cause impaired coagulation and this can increase the risk of bleeding, the need for subsequent transfusions, and morbidity.

One method is to re-transfuse salvaged, heparinised blood (such as from a bypass machine) directly back into the patient. Another is centrifugation cell salvage, which involves taking blood from the surgical site and mixing it with anticoagulants in a collection reservoir. The reservoir filters the blood before it is centrifuged to separate the red blood cells from other blood products. These are then washed with saline solution while still in the centrifuge, displacing any remaining blood products. The concentrated blood is then pumped into a bag ready for reinfusion.

Allogenic blood transfusions may also be used during and after high blood loss surgeries, but these are reliant on the availability of donor blood.

Hemosep would be used as an alternative to current cell salvage methods for autologous blood transfusion, and could be used instead of allogenic blood transfusions.

NICE's guideline on blood transfusions advises the use of intraoperative cell salvage with tranexamic acid for patients who are expected to lose a high volume of blood. NICE interventional procedures guidance on radical prostatectomy or radical cystectomy states that cell salvage during surgery may cause the reinfusion of malignant cells, and guidance on intraoperative blood cell salvage in obstetrics states that it may cause amniotic fluid embolism and haemolytic disease in the mother in future pregnancies. Safety guidelines produced in 2009 by the Association of Anaesthetists of Great Britain and Ireland (AAGBI) recommend cell salvage because it is cost effective compared with red blood cell transfusions, but state that it should not be used in the presence of bowel content unless there is a catastrophic haemorrhage.

NICE is aware of the following CE-marked devices that appear to fulfil a similar function to Hemosep:

  • Hemobag (Global Blood Resources).

Population, setting and intended user

Hemosep would be used in a tertiary care setting during and after routine cardiac and trauma surgery in which the patient had moderate to high blood loss. It can be used in both adults and children. It would most likely be used by a clinical perfusion scientist, perfusionist, blood conservation co-ordinator or anaesthetist. Around 1 hour's training is needed to use Hemosep; the manufacturer provides this at no extra cost. The device comes with a training manual and quick reference guide.

Costs

Technology costs

The manufacturer estimates the average cost per treatment to be £240 (Advancis Surgical, 'The true cost of cell salvage compared to Hemosep'). Table 1 shows the cost of Hemosep and the associated consumables.

Table 1: Device and consumables costs

Description

Cost

Additional information

Hemosep orbital shaker unit

£3,500

Reusable

Shaker unit maintenance (annual)

£500

Reusable

Reservoir attachment, IV pole and fittings

£375

Reusable

Adult or child kit (1 Hemosep bag and 1 collection bag)

£80

Single-use, purchased individually

Suction kit

£143

Single-use

1-to-3 adapter

£25

Optional; connects the blood collection reservoir to up to 3 Hemosep bags

Costs of standard care

Using the Dideco Electa Cell Salvage device as an example, the average total cost of cell salvage (including consumables) is £296.72 per transfusion, based on a costing statement from the NICE guideline on blood transfusion. This does not include the cost of the device itself. The same costing statement estimates that allogenic blood transfusion costs £170.14 for the first unit of red blood cells and £162.01 per subsequent unit. However, this does not include transfusion of any other blood, or blood components, so is likely to be an underestimate for surgery in practice.

Resource consequences

Because cell salvage devices are commonly provided to the NHS at no charge, Hemosep would cost more than current cell salvage methods. This could be offset if Hemosep reduced the need for allogenic blood transfusions because of the cost of additional blood components needed per transfusion.

A national comparative audit of blood transfusions (PDF) from 2011 states that, on average, 2 units of red blood cells are used per transfusion episode. Based on cost estimates from this and the NICE costing statement, Hemosep could save around £332.15 per transfusion compared with use of donor red blood cells. These savings may be greater if additional blood components are transfused.

When compared on a cost per transfusion basis with cell salvage methods, Hemosep could save around an estimated £56.72 per transfusion. This is mainly because of a reduced need for additional blood components and specialist staff. Hemosep could also provide a viable option for patients who cannot have donor blood transfusions.

There are likely to be few practical issues because Hemosep needs minimal staff training and no additional technical staff.

Hemosep is currently used routinely in 1 NHS trust.

Regulatory information

Both adult and paediatric Hemosep bags were CE marked as class IIb devices, the intraoperative suction kit (including the pump) was CE marked as a class IIa device and the Hemosep shaker unit was CE marked as a class I device, all in August 2012.

A search of the Medicines and Healthcare Products Regulatory Agency website revealed that no manufacturer field safety notices or medical device alerts have been issued for this technology.