Comprehensive Respiratory System Disorders Q 68

---

If a client continues to hypoventilate, the nurse will continually assess for a complication of:

  

     A. Respiratory acidosis

     B. Respiratory alkalosis

     C. Metabolic acidosis

     D. Metabolic alkalosis

    

    

Correct Answer: A. Respiratory acidosis

---

Respiratory acidosis represents an increase in the acid component, carbon dioxide, and an increase in the hydrogen ion concentration (decreased pH) of the arterial blood. The respiratory centers in the pons and medulla control alveolar ventilation. Chemoreceptors for PCO2, PO2, and pH regulate ventilation. Central chemoreceptors in the medulla are sensitive to changes in the pH level. A decreased pH level influences the mechanics of ventilation and maintains proper levels of carbon dioxide and oxygen. When ventilation is disrupted, arterial PCO2 increases and an acid-base disorder develops.

---

Option B: In almost every scenario, respiratory alkalosis is induced by a process involving hyperventilation. These include central causes, hypoxemic causes, pulmonary causes, and iatrogenic causes. Central sources are a head injury, stroke, hyperthyroidism, anxiety-hyperventilation, pain, fear, stress, drugs, medications such as salicylates, and various toxins. Hypoxic stimulation leads to hyperventilation in an attempt to correct hypoxia at the expense of a CO2 loss.

Option C: Hydrogen ion concentration is determined by acid ingestion, acid production, acid excretion, and renal and GI bicarbonate losses. Buffers such as bicarbonate minimize significant pH alterations. Further classification of metabolic acidosis is based on the presence or absence of an anion gap, or concentration of unmeasured serum anions.

Option D: In general, the causes can be narrowed down to an intracellular shift of hydrogen ions, gastrointestinal (GI) loss of hydrogen ions, excessive renal hydrogen ion loss, retention or addition of bicarbonate ions, or volume contraction around a constant amount of extracellular bicarbonate known as contraction alkalosis. All of which leads to the net result of increased levels of bicarbonate in the blood.

---