Ventrics and cm water. What does it mean?


I'm new to the ICU and lately I've had a lot of neuro pts with ventrics set to 5 or 10 cm H2O or whatever the order is. Yesterday my charge nurse kind of started quizzing me on what it all

means. My pt had her set to 5cm H2O and her ICPs had been about 5 all day. Is there a correlation between where the drainage is set (in terms of cm H2O) and ICP. I feel like he was making it sound as if there was. Also can someone explain the indications for raising/lowering the drain. Thanks so much in advance!


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So, you've a ventricular drain that allows drainage of CSF. You've also a drainage bag apparatus that is on a ruler thingy with a laser level.

The gradations on the ruler are cm's. When you shoot the laser at the tragus of the ear, or right at the ear canal, you level the drainage bag with the source of CSF coming out of the drain: the ventricles of the brain.

When you level at the ear, you're at 0 cm H2O. If you raise the apparatus to 7 cm's above this point, in order for CSF to come out of the drain, the pressure inside the brain must be greater than 7 cm H2O. It will drain until the pressure is 7 and then stop.

So what you're doing is setting the ICP manually by raising or lowering the drainage apparatus.

In your case, the physician wants the pressure to be 5, so you raise the apparatus 5 CMS above the ventricles and CSF will drain to maintain that ICP