A doctor calls the nurse to obtain the daily laboratory results of a client who is receiving parenteral nutrition. Which is the most important laboratory result for the nurse to present to the doctor?

Appeared in: DHS 2018 shift 1st

Explanation

Parenteral Nutrition (PN) formulas are highly individualized and prescribed daily based on the patient's current metabolic needs.
Serum electrolyte levels, including sodium, potassium, magnesium, calcium, and phosphate, are the most critical values needed to safely tailor the daily PN solution.
Daily monitoring is essential to prevent severe complications like refeeding syndrome, which involves dangerous shifts in phosphate, potassium, and magnesium.
Maintaining electrolyte homeostasis is crucial for vital cellular functions, especially with the high glucose and amino acid load administered in PN.

Option A: The White Blood Cell (WBC) count is used to monitor for infection, a known risk with central venous catheters used for PN. However, it does not provide information needed to adjust the nutritional components of the PN formula.
Option C: Arterial Blood Gas (ABG) levels assess a patient's acid-base balance and oxygenation status. This is not a routine daily lab for PN management unless the patient has a pre-existing or developing respiratory or severe metabolic disorder.
Option D: Haemoglobin and haematocrit levels are used to monitor for anemia and assess long-term nutritional status. While important, they do not change rapidly enough to require daily adjustment of the PN formula and are typically checked weekly.

Clinical Relevance

Nursing practice connection: Use the key finding related to Laboratory Monitoring for Parenteral Nutrition to guide bedside assessment, documentation, and the next nursing action.
The nurse's primary responsibility is to ensure timely collection and prompt reporting of critical lab values to the prescriber, which is essential for patient safety in PN therapy.
Failure to monitor and report electrolyte abnormalities can lead to life-threatening cardiac arrhythmias, seizures, and respiratory failure.
What if? The patient also has acute kidney injury. In this scenario, monitoring serum electrolytes (especially potassium and phosphorus) and fluid balance (via daily weights) becomes even more critical, as the kidneys' ability to regulate these substances is impaired, increasing the risk of severe imbalances.

How to Approach the Question

First, identify the question type as a clinical scenario requiring prioritization.
Analyze the keywords in the stem: 'parenteral nutrition,' 'daily laboratory results,' and 'most important.'
Focus on the core task implied by the keywords: The doctor needs information to formulate the daily PN solution.
Evaluate each lab test based on its relevance to this specific daily task. Ask yourself, 'Which of these values directly influences the chemical composition of the PN bag every 24 hours?'
Eliminate options that are monitored for other reasons (WBC for infection), less frequently (weekly H&H), or only in specific situations (ABGs for acid-base crisis).
Conclude that serum electrolyte levels are the key variable for daily PN prescription, making them the most important result to report for this purpose.

Concept Tested & Keywords

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E6 Nursing Fundamentals Taylor p. 783-785

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 79-81

Practise the full DHS 2018 shift 1st

Attempt every question from this paper in a timed mock, then review the full solution for each one.