Critical thinking is the foundation for successful nursing practice. The ability to respond to problems using the nursing process effectively is critical thinking.

Prioritizing, Delegation, Decision-Making, and Triage is the foundation for questions and your ability to reason, not memorize. Know the legalities and the scope of practice for Registered Nurses, Vocational/Practical Licensed Nurses, and unlicensed Assisted Persons (Nursing Assistants, Orderlies, etc.)

SITUATION

A 17-year-old female model comes to your emergency department (ED) complaining of generalized cramps and numbness in her fingers. Medical history is noncontributory. When questioned, she tells you that she has been on a high-protein diet for "about 6 weeks." An I.V. line is started and blood is drawn for laboratory studies. Her serum calcium level is 5.5 mg/dl.

I.     In assessing this patient for hypocalcemia, Chvostek's sign is elicited by:

II.   Trousseau's sign can be elicited in the hypocalcemic patient by:

SITUATION

A 71-year-old woman is transported to the ED because of fatigue and a change in mental status. On physical examination, her temperature is 96.8 degrees F. (36 degrees C.) rectally. Her BP is 110/74 mm Hg; pulse, 48 beats/minute; respirations, 12 breaths/minute; periorbital edema is present, and a yellowish skin pigmentation is noted. Her daughter relates a history of "thyroid problem" and noncompliance with medical therapy. The diagnosis of myxedema is made.

III.  The patient admitted with hypothyroid crisis (myxedema coma) would most likely have which of the following electrolyte abnormalities?

IV.  Which of the following acid-base imbalances is most likely to occur in this patient?

SITUATION

A 64-year-old man is admitted to the ED with altered mental status, jaundice, and increased abdominal girth. Medical history is significant for cirrhosis. An I.V. line is established and blood is drawn for laboratory studies. Liver enzyme levels (serum glutamic axaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), bilirubin) are elevated. The diagnosis of hepatic encephalopathy is made.

V.    The patient with hepatic failure should be monitored for which one of the following?

ANSWERS AND RATIONALE

I.        Correct answer -- C

A decrease in ionized calcium causes an increase in neuromuscular excitability. Tapping over a branch of the facial nerve and observing for twitching of the upper lip on the ipsilateral (same) side as stimulation is considered a positive Chvostek's sign. Inflating a BP cuff on the upper arm or having the patient hyperventilate will both produce carpopedal spasm and are part of the diagnostic tests used to elicit Trousseau's sign.

II.       Correct answer -- A

Trousseau's sign is elicited by applying a BP cuff to the patient's arm, inflating to the patient's systolic pressure, and observing for carpopedal spasm. Another method for producing this phenomenon is hyperventilation, in which the alkalotic state decreases serum calcium levels.

III.      Correct answer -- A

Patients with myxedema coma suffer from hyponatremia. This usually is a result of inappropriate secretion of antidiuretic hormone (ADH). Also, the myxedematous state results from the interstitial accumulation of a mucopolysaccharide substance that attracts water and produces water retention. Therefore, the hyponatremia is caused by dilution. Hypoglycemia is also seen in myxedema coma, owing to the hypometabolic state.

IV.     Correct answer -- A

Respiratory acidosis and CO₂ narcosis are a result of lowered thyroxine (T₄) and Tri-iodothyronine (T₃) levels. These hormones increase metabolic functions, such as respiration. Thus, a decrease in T₃ and T₄ levels depresses respiratory function, thereby causing hypoventilation. In addition, metabolic acidosis may develop as hypoxia increases serum lactate levels.

V.      Correct answer -- C

In hepatic failure, hypokalemia occurs as a result of elevated aldosterone levels; aldosterone causes a loss of potassium. A decreased plasma protein level results from hypoalbuminemia. Calcium levels are decreased in hepatic failure because of inadequate storage of Vitamin D. The patient with hepatic failure should be monitored for free water excess because of a plasma hyponatremia.