NACE Physiological Adaptation 4 — Questions and Answers
Question 1: A patient with chronic kidney disease has a serum potassium of 6.2 mEq/L. Which ECG change should the nurse anticipate first?
- Widened QRS complex
- Peaked T waves (Correct answer)
- Flattened P waves
- Prolonged PR interval
Correct answer: Peaked T waves
Peaked T waves are the earliest ECG manifestation of hyperkalemia, preceding widened QRS and other changes.
Question 2: A patient post-thyroidectomy develops tingling around the mouth and carpopedal spasms. Which lab value should the nurse check immediately?
- Serum sodium
- Serum calcium (Correct answer)
- Serum potassium
- Serum magnesium
Correct answer: Serum calcium
Hypocalcemia due to inadvertent parathyroid removal causes tetany symptoms including perioral tingling and carpopedal spasms.
Question 3: Which compensatory mechanism occurs in a patient with metabolic acidosis?
- Increased renal bicarbonate excretion
- Decreased respiratory rate
- Kussmaul respirations to blow off CO2 (Correct answer)
- Increased aldosterone secretion
Correct answer: Kussmaul respirations to blow off CO2
Kussmaul respirations (deep, rapid breathing) are the respiratory compensation for metabolic acidosis, eliminating CO2 to raise pH.
Question 4: A patient in hypovolemic shock has a BP of 80/50 mmHg and HR of 128 bpm. Which physiological response explains the tachycardia?
- Parasympathetic stimulation of the SA node
- Baroreceptor-mediated sympathetic activation (Correct answer)
- Increased vagal tone from hypoxia
- Direct effect of lactic acid on cardiac muscle
Correct answer: Baroreceptor-mediated sympathetic activation
Decreased arterial pressure reduces baroreceptor stretch, triggering sympathetic nervous system activation that increases heart rate.
Question 5: A patient with SIADH has a serum sodium of 118 mEq/L. Which symptom is most concerning?
- Dry mucous membranes
- Pitting edema in lower extremities
- Seizures and altered consciousness (Correct answer)
- Increased urine output
Correct answer: Seizures and altered consciousness
Severe hyponatremia causes cerebral edema, leading to seizures and altered consciousness, which are life-threatening neurological complications.
Question 6: A patient with a pulmonary embolism has sudden onset of hypoxia despite oxygen therapy. Which physiological mechanism best explains this finding?
- Increased pulmonary capillary permeability
- Ventilation-perfusion mismatch (Correct answer)
- Decreased alveolar surfactant production
- Left ventricular failure causing pulmonary edema
Correct answer: Ventilation-perfusion mismatch
PE causes ventilation-perfusion (V/Q) mismatch because alveoli are ventilated but perfusion is blocked by the clot, preventing gas exchange.
Question 7: Which finding indicates that a patient with diabetic ketoacidosis (DKA) is responding to treatment?
- Serum glucose decreasing from 450 to 280 mg/dL with continued ketonuria
- Arterial pH rising from 7.10 to 7.32 with decreasing serum ketones (Correct answer)
- Urine output increasing from 20 mL/hr to 60 mL/hr with persistent Kussmaul breathing
- Blood pressure normalizing with persistent abdominal pain
Correct answer: Arterial pH rising from 7.10 to 7.32 with decreasing serum ketones
Resolution of acidosis (rising pH) and decreasing ketones indicate that insulin therapy is correcting the underlying metabolic derangement in DKA.
NACE Physiological Adaptation 4
A patient with chronic kidney disease has a serum potassium of 6.2 mEq/L.
Which ECG change should the nurse anticipate first?