Final answer:
During pregnancy, the respiratory parameters that are increased include tidal volume and oxygen consumption. These changes accommodate the increased oxygen demands of the fetus and the mother's body. Other parameters like airway resistance or PaCO2 do not necessarily increase, and functional residual capacity typically decreases.
Step-by-step explanation:
Respiratory Parameters Increased During Pregnancy
During pregnancy, several respiratory parameters are altered as a result of hormonal and mechanical changes. Two notable changes that occur include an increase in tidal volume and oxygen consumption. Tidal volume, which is the amount of air that is inhaled or exhaled in a single breath at rest, increases because pregnant women require more oxygen to meet both their own metabolic demands and those of the growing fetus. Consequently, respiratory minute volume — the total volume of gas inhaled or exhaled from the lungs per minute — also increases significantly. Likewise, oxygen consumption rises to supply increased oxygen to the fetus and meet the heightened metabolic demands of the mother's body.
While tidal volume and oxygen consumption are increasing, this does not mean that other parameters such as airway resistance or PaCO2 (partial pressure of carbon dioxide in arterial blood) increase; in fact, PaCO2 often decreases slightly in pregnancy to compensate for the increase in minute ventilation. Plasma bicarbonate levels may also be affected due to compensatory mechanisms for the respiratory alkalosis induced by hyperventilation. The functional residual capacity, on the other hand, can decrease during pregnancy due to the upward pressure of the growing uterus on the diaphragm.