Which of the following statement(s) is/are true concerning the response to a decrease in functional residual capacity percent (FRC)?

b. Respiratory alkalosis may occur

c. Decreasing compliance is a common occurrence

Pulmonary arterial spasm in response to local hypoxia autoregulates pulmonary blood flow and maintains adequate gas exchange during alveolar collapse—up to a point. However, when the loss in ventilation exceeds the decrease in perfusion, a ventilation-perfusion mismatch occurs, which results in incomplete oxygenation of blood perfusing that area of the lung. The resultant hypoxemia stimulates an increased rate and depth of breathing which may serve to reexpand the person’s inflated area of lung. If it does not, hypoxemia will continue but increased ventilation in other areas of the lung will result in excess CO2 excretion, hypocapnea and respiratory alkalosis. The blood gas picture, hypoxemia with respiratory alklalosis, is the most common abnormality of gas exchange in surgical patients and it is a hallmark of ventilation-perfusion imbalance. Oxygenation of blood in the poorly ventilated area of lung can be improved by increasing concentration of oxygen in the inspired gas. The use of supplemental oxygen, however, treats the symptom rather than the basic cause and may actually make the problem worse by adding to absorption atelectasis, depriving the poorly ventilated area of nitrogen to hold alveoli open. This may result in total alveolar collapse. In this circumstance, blood perfusing the nonventilated area will mix with blood from other areas of the lung, resulting in hypoxemia that does not improve significantly in response of administration of oxygen. Aside from the effects on gas exchange, loss of alveolar space results in changes in the volumepressure relationships in the lung. A decrease in functional residual capacity always results in a shift in the volume-pressure relationship toward a condition of decreasing compliance.