Critical care case study - Acute kidney injury: Nursing

Nurse Greta works in the intensive care unit, or ICU, and is caring for Reggie, a 47-year-old diagnosed with acute kidney injury, or AKI. Nurse Greta goes through the steps of the Clinical Judgment Measurement Model to make clinical decisions about Reggie’s care by recognizing and analyzing cues, prioritizing hypotheses, generating solutions, taking action, and evaluating outcomes.

First, Nurse Greta recognizes important cues, including Reggie’s vital signs which are temperature 98.9 F, or 37.1 C, heart rate 100 beats per minute, respirations 26 breaths per minute, blood pressure 154/78 mmHg, and oxygen saturation 92 percent on 2 liters of oxygen per nasal cannula. Upon assessment, Nurse Greta notes Reggie’s urine output from his indwelling catheter was 25 milliliters in the last hour and has a dark amber color. He also has a 2+ pitting edema in his bilateral lower extremities and crackles upon auscultation to his lung bases.

Next, Nurse Greta analyzes these cues. She reviews the electronic health record, or EHR, and notes Reggie’s admitting diagnosis was glomerulonephritis, and his most recent labs show a BUN of 31 mg/dL, creatinine of 2.6 mg/dL, and estimated glomerular filtration rate, or eGFR, of 65 milliliters per minute. Additionally, his potassium is 5.8 mEq/L; his urinalysis shows protein and blood; and his arterial blood gas results indicate metabolic acidosis.

Nurse Greta knows AKI is a sudden decline in kidney function that occurs over hours or days and can be reversible if identified and treated promptly. She knows it can occur following glomerulonephritis, which is an inflammation of the network of capillaries in the kidneys that filter blood, called the glomeruli. This can cause intrarenal AKI, where part of the kidney itself, like the glomeruli, is damaged.

When glomeruli are damaged, their permeability increases, allowing large molecules and cells, like protein and blood, to pass through into the urine, resulting in proteinuria and hematuria. Additionally, glomeruli are unable to maintain a normal GFR. This can lead to hypervolemia, edema, weight gain, hypertension, and pulmonary crackles.

As GFR decreases, waste products like creatinine and urea accumulate in the blood, leading to azotemia, a condition where there are high levels of nitrogen-containing substances in the blood, which can manifest as anorexia, nausea, vomiting, weakness, and altered mental status.

Serum electrolyte balance is also disrupted, leading to the possibility of arrhythmias related to hyperkalemia. These kidneys are also unable to excrete hydrogen ions and reabsorb bicarbonate, resulting in metabolic acidosis.