When fluids are administered subcutaneously, which precaution should be observed?

When administering fluids subcutaneously, it is crucial to avoid hypertonic or irritating solutions. This is because subcutaneous administration involves injecting fluids into the tissue beneath the skin, where they can be gradually absorbed. Hypertonic solutions have a higher osmolarity than the surrounding tissues, which can cause irritation, discomfort, and potential tissue damage at the injection site. Additionally, irritating solutions can lead to local inflammation, necrosis, or even an adverse tissue reaction, making it essential to select fluid types that are safe for subcutaneous use. Isotonic solutions, in contrast, are generally safe as they have the same osmotic pressure as body fluids, and thus are suitable for subcutaneous administration.

Precautions like avoiding rapid infusion and intravenous administration serve different purposes and are not specific to the rationale behind choosing fluid types for subcutaneous administration.