redsense innovation

Seeing red

In 2004 the Swedish county hospital of Halmstad had witnessed venous needle dislodgement on a number of occasions. A few key people from the hemodialysis department discovered that these incidents were by no means unique, and that existing alarm systems were renowned for not working. They got in touch with Innovation Team, a consultant company specialised in realising medical device innovations.

The versatile Redsense blood loss detector can be used in any location, whether it be in clinic, nocturnal, or at home. Anyone, anywhere, using any type of machine can take advantage of the Redsense alarm’s continuous VND (venous needle dislodgement) monitoring. Working in conjunction with existing safety precautions, such as secure taping of the needles, and tubing; Redsense provides added protection needed for peace of mind. Busy acute, and nocturnal clinics benefit from the additional venous needle monitoring that Redsense provides The unobtrusive unit lets personnel know that the patient’s venous needle is intact. The alarm unit’s constant green monitoring light shines as a beacon that all is well, and it is conveniently mounted on the machine’s IV pole so it is easy to see. At night, when the overhead lights are turned off to allow nocturnal patients to sleep, the staff can breathe easy knowing that Redsense is on duty, keeping an eye on the needle. At home, patients and their family benefit from Redsense alarm security. It is impossible for someone to monitor the venous needle site 24-7. But for the Redsense alarm, continuous monitoring is what it does, and it does it well. In any situation, if blood is detected at the venous needle site, Redsense alerts everyone around that their immediate attention is needed to turn off the machine, and respond appropriately. Anytime day or night, Redsense is monitoring, and always on the lookout for blood.
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The Alarm Unit sends light through the optical fiber, to the tip of the sensor and back again. The sensor patch is placed directly over the puncture hole where the venous needle returns purified blood to the patient from the dialysis machine.

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Light leaks from the fiber end. The leakage of light increases if blood comes into contact with the fiber end.
Redsense will alarm on contact with blood onto the fiber optic end at the tip of the sensor.

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The Alarm Unit measures the returning level of light. If the level of light is suddenly reduced, the Alarm Unit sounds the alarm immediately.

Venous Needle Dislodgement - A safety problem

redsense bloodloss article

Dr. Sandroni published in 2009 that 0.0003% of VND incidents are fatal and 0.0008% are serious1. The Department of Veteran Affairs presented similar data in 2008, showing 0.0016% of VND´s are serious.17 VND incident rates, from RPA in 2007 show 0.1282% incident rate and data from Dr. Ahlmén in 2008 show 0.1736%.2, 3

1 Sandroni, S, Shockerman, T, Hayes-Light, K, Catastrophic Hemorrhage from Venous Needle Dislodgment during Hemodialysis, Journal of the  American Society of Nephrology, volume 9, November 2008, Abstract issue.
2 RPA Renal Physicians Association, Health and Safety Survey to improve patients safety in end stage renal disease (2007)
3 Ahlmén J, Gydell KH, Hadimeri H, Hernandez I, Rogland B, Strömbom U, (2008) A new safety device for hemodialysis, Hemodialysis International 12 (2), Page 264-267.


Globally this would mean that:

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EDTNA/ERCA questionnaire recordings of 283 VND incidents indicate that 23% of VND's are serious and severe needing resuscitation to save patients lives and 5% either died or suffer from long term sequelae.


Hemodialysis 15 hours per week

During Hemodialysis 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.


Blood access

During 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 before being returned to the patient in a loop.


A serious complication

Venous needle dislodgement, VND, is when the needle slips out and the returning blood is pumped onto the bed or chair instead of back to the patient's bloodstream. 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.


Equipment limitation

The hemodialysis equipment used today are not equipped to detect VND reliably. The method of detection is limited to pressure measurements. When the venous needle is dislodged the pressure drop is often too small to activate the system.


Measures for detection

VND can happen to anyone. Every attempt should be made to minimize the risk, and protection such as Redsense can be used to detect blood loss.


1. How to connect

1 Attach the Alarm Unit to dialysis machine’s IV pole / drip stand.  (fig 1)
2 Connect the AC adapter to a wall outlet and to the black-colored connector on the Alarm Unit. (fig 2)
3 Connect the optical extension fiber to the alarm unit. Turn the coupling roughly a 1/3 turn to lock it. Check that the coupling is looked.
3. Open and check that the sensor patch. (fig 3).
4 Activate the alarm unit by pushing the on/off button and check that the indicator lights are on and that the alarm signal can be heard by the staff in the clinic or observing person at home.
5 To stop testing the indicator lights and the alarm signal, push the on/off button again. The green indicator lights starts to flash together with a intermittent signal.
6 Connect the fiber from the sensor patch to the optical extension fiber. Open the connector on the end of the optical extension fiber by holding in the locking button, inserting the sensor patch fiber from the sensor patch until it stops/resists, then releasing the lock button. When the green indicator lights is solid, and the intermittent signal is turned off the monitoring function is working correctly.

Make sure the area around the needle is dry.


Apply the sensor patch to the skin over the needle with the absorbent part of the sticker centered directly over the insertion point. Be sure that the self-adhesive part of the patch does NOT cover the wings. (fig. 4)

9 Secure the needles in place as usual using tape or similar material and according to the existing policy and procedure. Dressing material may be applied directly over the surface of the sensor patch. (fig. 5)
10 Redsense is now monitoring the venous needle blood access indicated by the steady green light on the display.
11 For more detailed information about how to use the Redsense alarm system, please download Instructions for use / Alarm Unit, Fiber optic extension & Sensor patch below.

redsense reliability

Let Redsense help keep an eye on your venous needles

Redsense is designed to react on blood loss immediately, enabling nurses and doctors to focus on other tangible problems of hemodialysis.
 Redsense is designed to alarm when blood reaches the sensor, so the dialysis caregiver or observing person at home, can apply appropriate action when a venous needle dislodges.