Redsense Medical AB (publ.)
Hemodialysis 15 hours per week
During Hemodialysis the blood is cleared from waste products when our kidneys fail to do so. A typical dialysis session lasts 4-5 hours and is completed 3 times weekly. Throughout the world 2,5 million patients receive hemodialysis.
Each dialysis session the blood access site is punctured with two needles. The blood is pumped through an artificial kidney where the blood is cleared from waste products and then returned to the patient in a loop.
A serious complication
Venous needle dislodgement, VND, when the needle slips out and the returning blood is pumped onto the bed or chair instead of back to the patient’s blood-stream. As much as 400-500 ml of blood is lost every minute and if not detected immediately the consequences may be catastrophic and in some cases fatal.
The hemodialysis equipment used today is not equipped to detect VND reliably. The method of detection is limited to pressure measurement. When the needle is dislodged the pressure drop is too small to activate the system.
Measures for detection
VND can happen to anyone, and every attempt should be made to minimize the risk. Protection such as Redsense can be used to detect blood loss.
One in 720 treatments venous needle dislodgement and in 33% the patient outcomes are fatal. For most countries there are no comprehensive statistics and actual number is expected to be even higher. Prompt recognition of VND and response may prevent VND from developing into a disaster for everyone involved. Costs related to treatment of VND incidents include hospital care, medications and add up to hundreds of millions € annually. The use of Redsense may reduce the risk and save costs in healthcare.
Redsense consists of two parts; a sensor patch and an alarm unit which are coupled together. The sensor patch is one time use and employs fibre optic technology embedded in a patch. The sensor patch is placed directly over the venous needle insertion point like a plaster. The alarm unit is attached to the machine. The alarm unit is reusable and sends out light through the optical fibre and back. As much technology as possible has been incorporated in the alarm unit so the sensor patch is as costefficent as possible.
The technology is based on a sharp optical bend of the fibre optic cable at the tip located on the patch. When the sensor tip is dry the bend allows for some leakage of light. However when the bend comes in contact with liquid or blood, more light is emitted by the bend so that less light is returned to the alarm unit. Loss of light will vary depending on the refraction index of the fluid to which the tip is exposed; therefore the alarm unit can distinguish between blood and sweat, for example.
More potential applications
The technology can also be used in other medical contexts, such as monitoring of bleeding associated with surgery, burns, etc. These are individually at least the same size as the dialysis market, if not bigger, and there is a need for surveillance which has not yet been explored.
The next product in pipeline is the Redsense nurse call, which makes it possible to connect the Redsense alarm unit with the hospitals nurse call system.
Redsense is also designed in to allow for connection directly with the hemodialysis machines.
An alarm unit sends red light through an optical fibre which is embedded in a sensor patch. The sensor patch is placed over the venous needle insertion point where purified blood is pumped back to the patient. When blood comes in contact with the fibre bend at the tip of the sensor, light leakage from the fibre tip is increased. The alarm unit measures the returning level of light and will alarm audible and visibly if the light level decreases rapidly.