The physician orders Zithromax 500 mg IVPB every 24 hours.

The medication is supplied in 500 mg/250 mL to infuse over 90 minutes.

Calculate the flow rate in milliliters per hour.

(ROUND TO WHOLE NUMBER: LABEL CORRECTLY TO RECEIVE CREDIT)

The aortic valve is best auscultated at the second intercostal space (ICS) along the right sternal border. This anatomical landmark corresponds to the superficial projection of the aorta and is where the sounds of aortic valve closure and blood flow through the aorta are most clearly transmitted to the chest wall. Optimal sound transmission is achieved by minimizing intervening tissue. Pulmonic rationale:

The pulmonic valve is best auscultated at the third intercostal space (ICS) along the left sternal border, also known as Erb's point. While the pulmonic area is typically at the second ICS left sternal border, Erb's point provides a broader area for detecting murmurs related to both the pulmonic and aortic valves. This location provides good sound transmission for the pulmonary artery. Tricuspid rationale:

The tricuspid valve is best auscultated at the fourth intercostal space (ICS) along the left sternal border. This location overlies the right ventricle and the tricuspid valve, allowing for clear detection of its closure sounds and any associated murmurs. The proximity of the valve to the chest wall at this point facilitates optimal auscultation. Mitral rationale:

The mitral valve is best auscultated at the fifth intercostal space (ICS) at the midclavicular line (MCL). This location is also known as the apex of the heart, where the left ventricle's impulse is strongest. Sounds produced by the mitral valve, particularly during its closure, are best heard here due to the direct anatomical projection and maximal cardiac impulse. .

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.