A nurse in the cardiovascular intensive care unit is caring for a client with acute decomp… — NCLEX-RN

A nurse in the cardiovascular intensive care unit is caring for a client with acute decompensated heart failure. The client weighs $209\text{ lbs}$ .

The client is receiving a continuous intravenous infusion of dobutamine. The standard hospital mixture contains $500\text{ mg}$ of dobutamine in $250\text{ mL}$ of $5\%$ dextrose in water (D5W). The infusion pump is currently running at $17.1\text{ mL/hr}$ .

The provider's order reads: 'Titrate dobutamine by $1.5\text{ mcg/kg/min}$ every $15\text{ minutes}$ to achieve a cardiac index $\geq 2.2\text{ L/min/m}^2$ .'

The latest hemodynamic assessment reveals a cardiac index of $1.8\text{ L/min/m}^2$ . The nurse prepares to perform the next titration step according to the protocol.

At what value in $\text{mL/hr}$ will the nurse program the infusion pump for the new dose? (Round the final answer to the nearest tenth.)

Answer: 21.4 mL/hr

Answer

The new infusion pump rate should be set to

21.4\text{ mL/hr}

To arrive at the correct value, the nurse must first convert the weight to kilograms (

95\text{ kg}

) and determine the solution's concentration (

2,000\text{ mcg/mL}

). The low cardiac index dictates an upward titration. The required dose increase (

1.5\text{ mcg/kg/min}

) is multiplied by weight (

95\text{ kg}

) and time (

60\text{ minutes}

) to find the hourly dose increase (

8,550\text{ mcg/hr}

). Dividing this by the concentration (

2,000\text{ mcg/mL}

) yields the rate increase of

4.275\text{ mL/hr}

. Adding this to the current baseline rate of

17.1\text{ mL/hr}

equals

21.375\text{ mL/hr}

, which correctly rounds to

21.4\text{ mL/hr}

Step-by-Step Solution

Convert the client's weight from pounds to kilograms.

209\text{ lbs} \div 2.2\text{ lbs/kg} = 95\text{ kg}

The medication dosing protocol is based on metric weight (kilograms).

Calculate the exact concentration of the dobutamine infusion in

\text{mcg/mL}

500\text{ mg} = 500,000\text{ mcg}

. Then,

500,000\text{ mcg} \div 250\text{ mL} = 2,000\text{ mcg/mL}

Titration orders are in micrograms (mcg), so the medication concentration must match this unit to calculate volume.

Determine the necessary clinical intervention based on the current cardiac index.

The current cardiac index is

1.8\text{ L/min/m}^2

, which is less than the goal of

2.2\text{ L/min/m}^2

. The dose must be increased by the ordered

1.5\text{ mcg/kg/min}

Nurses must independently assess parameters to decide the direction of the titration before performing the math.

Calculate the total dose increase in

\text{mcg/min}

for this specific client.

1.5\text{ mcg/kg/min} \times 95\text{ kg} = 142.5\text{ mcg/min}

This isolates the exact amount of extra drug the client needs every minute.

Convert the per-minute dose increase to a per-hour dose increase.

142.5\text{ mcg/min} \times 60\text{ minutes/hour} = 8,550\text{ mcg/hr}

IV infusion pumps are programmed in hourly rates (

\text{mL/hr}

), so the dose must reflect an hourly timeframe.

Calculate the volumetric rate increase (

\text{mL/hr}

) required to deliver the extra

8,550\text{ mcg/hr}

8,550\text{ mcg/hr} \div 2,000\text{ mcg/mL} = 4.275\text{ mL/hr}

This translates the needed extra medication into the actual fluid volume the pump will deliver.

Add the rate increase to the current running rate and apply rounding rules.

17.1\text{ mL/hr} + 4.275\text{ mL/hr} = 21.375\text{ mL/hr}

. Rounded to the nearest tenth, this is

21.4\text{ mL/hr}

The final step combines the current baseline therapy with the newly calculated upward adjustment.

Key Concept

Weight-Based Continuous Infusion Titration and Hemodynamic Interpretation

Estimated Time:3m 0s

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