The nurse is percussing the lungs of a patient.
The nurse knows that percussion over normal adult lungs will reveal:

Step 1 is convert grams to milligrams. 1 g = 1000 mg.

Step 2 is calculate how many milliliters will the nurse administer. 800 mg ÷ (1000 mg ÷ 2.5 mL) = 800 mg ÷ 400 mg/mL = 2 mL.

Choice A rationale

Partially withdrawing and redirecting the needle after aspirating blood significantly increases the risk of tissue trauma, pain, and the formation of a hematoma at the injection site. Furthermore, there is a risk of inadvertently injecting medication into a blood vessel or the interstitial tissue, which could lead to complications such as nerve damage or localized irritation.

Choice B rationale

Aspirating blood indicates the needle tip has entered a blood vessel. Administering medication intravenously when an intramuscular injection is intended can have serious systemic consequences, including rapid absorption and potential adverse drug reactions or toxicity. Therefore, the safest action is to withdraw the needle, discard the contaminated medication, and prepare a new dose to ensure proper drug delivery.

Choice C rationale

Administering the drug despite aspirating blood significantly increases the risk of injecting the medication directly into a blood vessel (intravascular injection) rather than the muscle. This can lead to rapid systemic absorption, potentially causing adverse effects or toxicity, and may also result in a larger, more painful hematoma and delayed drug action.

Choice D rationale

Continuing to administer the drug after aspirating blood, regardless of the injection speed, is dangerous because it confirms the needle's placement within a blood vessel. Intravascular administration of an IM medication can lead to immediate systemic effects, allergic reactions, or drug overdose, bypassing the intended slower absorption rate of muscle tissue, and increasing risk of complications.