Abstract: A blood pump is disclosed. The blood pump apparatus is arranged to provide pulsatile flow, and comprises a flexible inner cylindrical duct providing a blood flow region, and an outer cylindrical duct arranged to surround the inner cylindrical duct and arranged to accommodate a pumping fluid. In the pump the inner cylindrical duct is described as comprising a blood inlet for receiving blood into the region, a blood outlet for passing blood out from the blood flow region and a passageway therebetween. There is also described the feature of the inner duct comprising a non return valve at the blood inlet and a non return valve at the blood outlet, the outer cylindrical duct having a fluid port for a pumping fluid, and a pump device arranged to cyclically deliver and withdraw pumping fluid to the fluid port thereby cyclically compressing and expanding the flexible inner cylindrical duct urging blood through the blood flow region and delivering a pulsating blood flow through the blood outlet.

Abstract: A sensing device is provided. The device comprises a gas permeable member, a sensing member and optical means. The gas permeable member is arranged to receive gas from a substance to be tested. The sensing member is located adjacent to the gas permeable member and comprises a sensing substance. A property of the sensing substance is modified when it is brought into contact with the gas received by the gas permeable member. The optical means comprises a light source which is arranged to irradiate the sensing substance together with a first sensor which is configured to detect a change in the aforementioned property of the sensing substance.