One liter of normal saline is to infuse over 8 hours. At what rate will the nurse set the infusion pump?

Step 1: Identify the dosage required and the concentration available.

• Required dosage: 40 mg
• Available concentration: 20 mg/mL

Step 2: Calculate the volume to be administered.

• Volume to be administered = Required dosage ÷ Available concentration
• Volume to be administered = 40 mg ÷ 20 mg/mL

Step 3: Perform the division.

• Volume to be administered = 40 ÷ 20
• Volume to be administered = 2 mL

Step 4: Round the answer to the nearest whole number (if necessary).

• Volume to be administered = 2 mL (no rounding needed)

The nurse should administer 2 mL.

Choice A Reason: 0.8 mEq/L

The therapeutic range for lithium is typically between 0.6 and 1.2 mEq/L. A level of 0.8 mEq/L falls within this range and is considered normal. Therefore, it is unlikely that a client with this lithium level would present with symptoms such as mental confusion, frequent urination, and coarse tremors. These symptoms are more indicative of lithium toxicity, which occurs at higher levels.

Choice B Reason: 2.3 mEq/L

A lithium level of 2.3 mEq/L is significantly above the therapeutic range and indicates lithium toxicity. Symptoms of lithium toxicity include mental confusion, frequent urination, and coarse tremors, which match the client’s presentation. Severe toxicity can occur at levels above 2.0 mEq/L and can be life-threatening if not treated promptly. Therefore, this is the most likely lithium level for the client described.

Choice C Reason: 1.8 mEq/L

A lithium level of 1.8 mEq/L is above the therapeutic range but below the level typically associated with severe toxicity. While some symptoms of toxicity might appear at this level, they are generally less severe than those described in the scenario. The client’s symptoms suggest a more severe level of toxicity, making this choice less likely.

Choice D Reason: 1.2 mEq/L

A lithium level of 1.2 mEq/L is at the upper limit of the therapeutic range. While it is possible for some mild side effects to occur at this level, the severe symptoms described (mental confusion, frequent urination, and coarse tremors) are more indicative of a higher, toxic level of lithium. Therefore, this choice is also less likely.