When administering heparin subcutaneously, the nurse will follow which procedure?

Correct Answer: D

Rationale: The correct answer is D because when administering heparin subcutaneously, using a - to -inch 25- to 28-gauge needle is appropriate to ensure proper delivery into the subcutaneous tissue. This needle size is suitable for subcutaneous injections and helps prevent complications such as leakage or irritation. As for the other choices: A: Aspirating the syringe before injecting the medication is not necessary for subcutaneous injections as it is commonly done for intramuscular injections to ensure proper needle placement. B: Massaging the site after injection is not recommended as it can cause bruising or discomfort. C: Applying heat to the injection site is not a standard procedure for subcutaneous injections and may not provide any benefit in this context.

Correct Answer: A

Rationale: Microsomal oxidation is primarily mediated by cytochrome P450 enzymes located in the endoplasmic reticulum of hepatocytes. Lipid-soluble drugs can easily penetrate cell membranes to reach the microsomes where cytochrome P450 enzymes are located, making microsomal oxidation most prominent for lipid-soluble drugs. Water-soluble drugs have limited access to microsomes, reducing the likelihood of undergoing significant microsomal oxidation. Low molecular weight drugs are generally more likely to be lipid-soluble and undergo microsomal oxidation, while high molecular weight drugs may be too large to efficiently access microsomes for this metabolic pathway. Therefore, the correct choice is A: Lipid soluble.

Correct Answer: A

Rationale: The correct answer is A. Chemical antagonism refers to the interaction between two drugs where they combine to form an inactive compound. This results in a decrease in the overall pharmacological effect of the drugs. In contrast, options B, C, and D are incorrect because they describe scenarios where the combination of drugs leads to a more active, more water-soluble, or more fat-soluble compound, which would typically result in enhanced pharmacological effects rather than antagonism.

Correct Answer: B

Rationale: The correct answer is B: Low potency. Tetracaine is a potent local anesthetic with high potency. It has a slow onset, long duration, and high toxicity. Low potency would imply weaker anesthetic effects, which is not true for tetracaine. Other choices are incorrect as tetracaine is known for its strong anesthetic properties.

Correct Answer: B

Rationale: The correct answer is B: Secretions. Atropine is used to reduce respiratory secretions before inhaling anesthetics as it helps prevent airway obstruction and aspiration. It does not affect muscle tone or nausea/vomiting. Choice A is incorrect because atropine can actually increase muscle tone. Choice C is incorrect because atropine does not directly address nausea and vomiting. Overall, the main purpose of using atropine in this context is to decrease secretions, making option B the correct answer.