Why D5w Is Bad For Patients With Brain Injury?

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Can someone explain why D5W is bad for patients with brain injury? Pharmacist in my hospital told me that. I thought D5W is hypertonic because of the sugar, therefore it should be drawing fluids from the brain - supposedly a beneficial thing for patients with brain swelling.

Originally Posted by konkan

Can someone explain why D5W is bad for patients with brain injury? Pharmacist in my hospital told me that. I thought D5W is hypertonic because of the sugar, therefore it should be drawing fluids from the brain - supposedly a beneficial thing for patients with brain swelling.

D5W is isotonic initially...then the sugar is metabolized, and it becomes hypotonic (just water)...which will flush out of the vasculature and into the cells...and worsen the cerebral edema.

Originally Posted by konkan

Can someone explain why D5W is bad for patients with brain injury? Pharmacist in my hospital told me that. I thought D5W is hypertonic because of the sugar, therefore it should be drawing fluids from the brain - supposedly a beneficial thing for patients with brain swelling.

1.) Straight D5W is slightly hypoosmotic (something like ~270 milliosmoles), and if you remember a&p lectures, h2o goes from low to high concentration.
With head traumas, your main goal is to decrease ICP; you want less fluid in your head, so you mix whatever drug in NS. Since it's isoosmotic/slightly hyperosmotic, the ICP should decrease since free water will be moving towards the body/circ system, as opposed to staying in your noggin. For an increased response, they can hang 3% NaCl, or in special ICU cases, a bolus of 23.4% NaCl.

2.) On a less important note, tight glycemic control generally equals better outcome, and making everything in NS makes it easier for RNs to titrate the insulin drip...just make sure they're getting glucose via diet or something.