A patient intravenously infusing injection Mannitol. After infusion, which parameter should assess by the nur… - KGMU 2023

KGMU 2023

Medical Surgical Nursing

Medium

Appeared in: KGMU 2023

Explanation

Mannitol is a potent osmotic diuretic that works by drawing water into the renal tubules, leading to a rapid increase in urine production.
Monitoring urine output is the most direct and immediate method to assess the therapeutic effectiveness of the drug.
It is also a critical safety measure. A lack of urine output indicates potential renal failure and retention of the drug, which can cause a dangerous expansion of extracellular fluid volume, leading to pulmonary edema and heart failure.
The primary goal is to ensure that the rate of diuresis is adequate to remove the drug and excess fluid from the body.

Option B: While daily weight is a key indicator of fluid balance, it reflects changes over a longer period (e.g., 24 hours) and is not suitable for the immediate, hour-by-hour evaluation needed after administering a rapid-acting diuretic like Mannitol.
Option C: Blood pressure is a secondary assessment. It can change due to fluid shifts caused by Mannitol (either decrease from dehydration or increase from fluid overload), but it does not directly measure the drug's primary diuretic action.
Option D: Assessing respiration is important to monitor for the complication of pulmonary edema, but it is not the primary assessment of the drug's effectiveness. Monitoring urine output is the action that helps prevent this complication in the first place.

Visual 1: Flowchart: Illustrating the mechanism of action of Mannitol. It should show Mannitol entering the glomerulus, creating high osmotic pressure in the tubule, preventing water reabsorption, and leading to increased urine output. A separate branch should show the consequence of no urine output: Mannitol retention, fluid shift into the vascular space, and pulmonary edema.
Visual 2: Diagram: A cross-section of a kidney nephron highlighting the proximal tubule and loop of Henle, showing how the osmotic force of Mannitol in the filtrate pulls water from surrounding tissues into the tubule.

Clinical Relevance

Nursing practice connection: Safe nursing care depends on performing Nursing assessment following administration of an osmotic diuretic (Mannitol) in the correct sequence, documenting the action clearly, and monitoring for the expected response.
Failure to monitor urine output after Mannitol administration can lead to missed signs of renal failure, resulting in life-threatening fluid overload, pulmonary edema, and congestive heart failure.
Nurses must use an in-line filter for IV Mannitol administration because the solution can crystallize, especially at cooler temperatures, which could cause a venous occlusion or embolism.
What if? If the patient's urine output is less than 30-50 mL/hour after Mannitol infusion, the nurse must immediately notify the physician. This is a critical sign that the drug is not being excreted and may indicate developing renal failure or an inadequate therapeutic response.

How to Approach the Question

First, identify the drug mentioned in the question: Mannitol.
Recall the pharmacological class and primary mechanism of action of Mannitol. It is an osmotic diuretic.
Understand the therapeutic goal of a diuretic: to increase urine output to remove excess fluid.
Connect the drug's action to the most direct nursing assessment. To know if a diuretic is working, you must measure the amount of urine it produces.
Evaluate the other options. Weight, blood pressure, and respiration are all important assessments for a patient receiving IV fluids, but they are secondary to or consequences of the primary effect measured by urine output.

Concept Tested & Keywords

Concept Tested: Nursing assessment following administration of an osmotic diuretic (Mannitol).
Stem keywords: Mannitol, intravenously, infusion, assess
Lead-in keywords: which parameter

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