Avoid giving LRS/D5 0.3 NaCl in cases of CNS infection. Why?

Question

Avoid giving LRS/D5 0.3 NaCl in cases of CNS infection. Why?

Answer 1

Be aware that Demerol is compatible with 5% dextrose and lactated Ringer's solution, dextrose-saline solution combinations, and 2.5%, 5%, or 10% dextrose in water.

Binds to, and depresses opiate receptors in spinal cord and CNS, altering perception of and response to pain

Use cautiously in:

head trauma; increased intracranial pressure (ICP); severe renal, hepatic, or pulmonary disease; hypothyroidism; adrenal insufficiency; extensive burns; alcoholism

undiagnosed abdominal pain or prostatic hyperplasia

elderly or debilitated patients

pregnant patients (not recommended before labor)

labor (drug may cause respiratory depression in neonate)

breastfeeding patients

children

Answer 2

Wow.  I'm not sure what that first post was all about...

In general, during CNS infections, you worry about cerebral edema--therefore, you try to avoid giving hypotonic fluids, and even isotonic fluids you have to be careful about.  Lactated Ringers is isotonic, and 0.3% saline (?) would be hypotonic, although 0.3% is a weird number.  0.9% is isotonic, and hypotonic fluids are usually made to half of that or 0.45%

The key point is that with cerebral edema, you want to use hypertonic or saltier fluids to, in a sense, "suck" the water out of the brain to reduce swelling.  Hypotonic solutions, and to some extent, isotonic solutions will put _more_ water into the brain, potentially worsening the swelling.