Identify the correct way to mix NPH insulin with regular insulin?

Central Institute of Psychiatry - 9 July 2022

Fundamental of Nursing

Easy

Appeared in: Central Institute of Psychiatry - 9 July 2022

Explanation

The correct procedure for mixing insulins is guided by the mnemonic 'clear before cloudy'.
Regular insulin is a clear, short-acting insulin, while NPH is a cloudy, intermediate-acting insulin.
To prevent contamination, the clear (Regular) insulin must be drawn into the syringe first.
Contaminating the Regular insulin vial with NPH would alter its rapid onset of action, leading to unpredictable blood glucose levels.

Option A: This statement describes the overall task but does not provide the specific, correct instruction on how to perform it safely. It is too general to be the best answer.
Option B: This is incorrect and unsafe. Drawing the cloudy (NPH) insulin first can contaminate the clear (Regular) insulin vial, altering its short-acting properties and making its effect unpredictable.
Option D: This option is incorrect because it includes an incorrect procedure ('Take NPH first'). When one of the choices is incorrect, an 'all of the above' option cannot be right.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Procedure for mixing NPH and Regular insulin as background academic context rather than a clinical decision trigger.
Correct insulin mixing technique is a critical patient safety skill. Errors can lead to either hypoglycemia (if the short-acting insulin is unexpectedly potent) or hyperglycemia (if its action is blunted).
Nurses must provide clear, repeated education and use the teach-back method to ensure patients and caregivers can demonstrate this procedure correctly before performing it independently.
What if a patient accidentally draws NPH insulin first and injects it into the Regular insulin vial? The entire vial of Regular insulin is now contaminated and must be discarded. Using it would lead to unpredictable glycemic control. The patient should start over with new vials.

How to Approach the Question

First, identify the question type. This is a process-based question asking for the correct step in a specific nursing procedure.
Recall the key safety principle or mnemonic associated with mixing NPH and Regular insulin. The universally taught rule is 'clear before cloudy'.
Identify which insulin corresponds to 'clear' (Regular insulin) and which corresponds to 'cloudy' (NPH insulin).
Apply the rule: The clear insulin must be drawn into the syringe before the cloudy one.
Evaluate the options based on this rule. 'Take regular insulin first' directly matches the correct procedural step.
Eliminate the other options. 'Take NPH first' is the opposite of the rule. 'Mix...' is too general. 'All of the above' is incorrect because one option is wrong.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 2 p. 212-214