Noninvasive CSF Turbidimeter / NIRS

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I’m a neurosurgery resident in Turkey. We are working on a system that will measure CSF density and content in real time.

We want to measure turbidity of the otherwise clear CSF that flows through the closed yet transparent line. So that we can see if the cell count/protein content of the fluid is increasing. CSF is normally a clear fluid but with blood it can go bright red, to pink, to yellow. And with infection it can become yellowish green and turbid with particulates.

Classically, its qualities are assessed with its protein and glucose content as well as lymphocyte and erythrocyte. Afterward the CSF sample is cultured and that gives us the spesific organism.

We want an early warning device that tells us the CSF is changing color or increasing in turbidity.

This is the device we’re using for the CSF drainage: http://www.medtronic.me/content/dam/medtronic-com/products/neurological/critical-care/mns-duetqrg.pdf

The challenge is that we can’t modify the drainage device itself, it has to get noninvasive measurements. The tubing could go through any measurement device, but CSF cannot touch anything nonsterile. So I can’t use regular turbidimeters that are used for pools…

Using NIRS or raman spectrometer, would it be possible to measure turbidity or cell count accurately? I intend to modify an arduino board for logging.

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Hi,

You can measure turbidity using a device described here, or at least take a look at their reference for their turbidimeter. They use a white LED and an LDR. For colour you can use a TCS34725 I2C module.

You may be able to get even more information with a laser and camera.
By shining the laser through the CSF (and drain tube) and into the camera, the beam is diffracted by an angle that depends on the particle size, so a clearly defined luminous disc of a particular size will appear around the laser dot, as seen by the camera. This is the same disc around car headlights at night in the mist.