Critical care case study - Diabetic ketoacidosis: Nursing

Nurse Ji Yun works in the emergency department and is caring for Osborn, a 47-year-old patient with a history of type 1 diabetes mellitus, who was diagnosed with diabetic ketoacidosis, or DKA. Nurse Ji Yun goes through the steps of the Clinical Judgment Measurement Model to make clinical decisions about Osborn’s care by recognizing and analyzing cues, prioritizing hypotheses, generating solutions, taking action, and evaluating outcomes.

First, Nurse Ji Yun recognizes important cues, including Osborn’s vital signs which are temperature 99.4 F, or 37.5 C, heart rate 118 beats per minute, respirations 28 breaths per minute, blood pressure 90/56 mmHg, and oxygen saturation 91 percent on 2 liters of oxygen per nasal cannula. Upon assessment, Nurse Ji Yun notes Osborn’s breathing is deep and labored, and his breath has a sweet odor. He’s slightly lethargic and is oriented to person and place, but not time. Nurse Ji Yun notes that Osborn’s current blood glucose level is 400 mg/dL, or 22.2 mmol/L.

Next, Nurse Ji Yun analyzes these cues. He reviews the electronic health record, or EHR, and sees that Osborn recently recovered from pneumonia and his urine is positive for ketones. Also, arterial blood gas results show a pH of 7.2 and a bicarbonate of 15 mEq/L, indicating metabolic acidosis.

Nurse Ji Yun knows diabetic ketoacidosis is a life-threatening complication of type 1 diabetes mellitus caused by an insulin deficiency, where glucose can’t be taken up into cells and used for energy.

He also knows that infections, like pneumonia, can precipitate diabetic ketoacidosis by increasing stress hormones that contribute to elevated glucose and reduced insulin utilization. As glucose levels rise, the kidneys reach the maximum amount of glucose they can reabsorb, so extra glucose spills into the urine, resulting in glycosuria. Additionally, since glucose is osmotically active, glycosuria is accompanied by a large amount of water in the urine, resulting in polyuria. Glucose also pulls water out of cells and into the bloodstream, expanding the blood volume and leaving the cells dehydrated.

As an alternative energy source, fat is converted into glucose by metabolizing fatty acids, resulting in ketones. This results in a build-up of acidic ketones within the blood, giving rise to metabolic acidosis.

To compensate, the respiratory rate increases to blow off excess carbon dioxide and increase the pH, resulting in deep, rapid breathing, called Kussmaul respirations. Additionally, as ketone by-products are exhaled, they cause the breath to have a fruity smell. Eventually, diabetic ketoacidosis can severely alter level of consciousness, interfering with airway patency and ultimately resulting in cerebral edema and coma.

Nurse Ji Yun recognizes that Osborn needs prompt management of diabetic ketoacidosis.

Now, using the information he's gathered, Nurse Ji Yun chooses a priority hypothesis of impaired glucose regulation. Then, he generates solutions to address Osborn’s impaired glucose regulation, including pharmacologic and non-pharmacologic interventions; and he establishes the expected outcome that after intervening, Osborn’s blood glucose will improve within 15 minutes.

Then, Nurse Ji Yun takes action to implement these solutions. First, he speaks with the emergency provider to report his assessment findings and obtain orders. Nurse Ji Yun notes orders for a bolus of isotonic fluids and subsequent maintenance IV fluids, as well as a bolus of regular IV insulin, followed by a continuous insulin infusion. There are also orders to monitor Osborn’s urine output and serum potassium; and to increase oxygen as needed to ensure his oxygen saturation remains above 94%.