What volume of lorazepam should a nurse administer for a weight-based dose of 0.05 mg/kg for a patient weighing 138 lbs, given that lorazepam is available at 2 mg/mL?

What volume of lorazepam should a nurse administer for a weight-based dose of 0.05 mg/kg for a patient weighing 138 lbs, given that lorazepam is available at 2 mg/mL?

• A. 1.2 mL
• B. 1.6 mL
• C. 2.0 mL
• D. 2.5 mL

Answer: (B)

To determine the correct volume of lorazepam to administer, the first step is to convert the patient's weight from pounds to kilograms, since the dosage is based on mg/kg. The conversion factor is approximately 1 kg = 2.2 lbs. For a patient weighing 138 lbs: \[ \text{Weight in kg} = \frac{138 \text{ lbs}}{2.2} \approx 62.73 \text{ kg} \] Next, calculate the total dosage required based on the weight-based dosing of 0.05 mg/kg: \[ \text{Dosage} = 0.05 \text{ mg/kg} \times 62.73 \text{ kg} \approx 3.14 \text{ mg} \] Now that we have the required dosage in mg, we need to convert this into the volume to be administered. Since lorazepam is available at a concentration of 2 mg/mL, we can use this concentration to find the volume: \[ \text{Volume (mL)} = \frac{\text{Dosage (mg)}}{\text{Concentration (mg/mL)}} \] Substituting the values: \[ \

To determine the correct volume of lorazepam to administer, the first step is to convert the patient's weight from pounds to kilograms, since the dosage is based on mg/kg. The conversion factor is approximately 1 kg = 2.2 lbs.

For a patient weighing 138 lbs:

[

\text{Weight in kg} = \frac{138 \text{ lbs}}{2.2} \approx 62.73 \text{ kg}

]

Next, calculate the total dosage required based on the weight-based dosing of 0.05 mg/kg:

[

\text{Dosage} = 0.05 \text{ mg/kg} \times 62.73 \text{ kg} \approx 3.14 \text{ mg}

]

Now that we have the required dosage in mg, we need to convert this into the volume to be administered. Since lorazepam is available at a concentration of 2 mg/mL, we can use this concentration to find the volume:

[

\text{Volume (mL)} = \frac{\text{Dosage (mg)}}{\text{Concentration (mg/mL)}}

]

Substituting the values:

[

\