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Respiratory Changes in pregnancy
Respiratory Changes in pregnancy ( 5 Questions)
A nurse is teaching a pregnant client about the respiratory changes that occur during pregnancy.
The nurse should explain that the increased oxygen consumption is due to:.
Increased metabolic rate and fetal oxygen demand are not the main causes of increased oxygen consumption during pregnancy. The maternal rate of oxygen consumption rises progressively during pregnancy, reaching a peak of 20% above nonpregnant levels . The fetal oxygen demand is only a small fraction of this increase .
Increased progesterone levels and sensitivity to carbon dioxide. Progesterone is a hormone that increases during pregnancy and acts as a trigger of the primary respiratory center by increasing the sensitivity of the respiratory center to carbon dioxide . This leads to an increase in ventilation and oxygen consumption during pregnancy
Elevation of the diaphragm and increased chest wall compliance are mechanical effects of pregnancy that reduce the lung volumes and capacities, such as functional residual capacity and expiratory reserve volume . These changes do not affect the oxygen consumption directly.
Increased tidal volume and respiratory rate are the consequences of increased oxygen consumption during pregnancy, not the causes. Tidal volume increases by 40% and respiratory rate increases by 15% during pregnancy . These changes result in an increase in minute ventilation by 50% .
Increased progesterone levels and sensitivity to carbon dioxide. Progesterone is a hormone that increases during pregnancy and acts as a trigger of the primary respiratory center by increasing the sensitivity of the respiratory center to carbon dioxide . This leads to an increase in ventilation and oxygen consumption during pregnancy .
Choice A is wrong because increased metabolic rate and fetal oxygen demand are not the main causes of increased oxygen consumption during pregnancy. The maternal rate of oxygen consumption rises progressively during pregnancy, reaching a peak of 20% above nonpregnant levels . The fetal oxygen demand is only a small fraction of this increase .
Choice C is wrong because elevation of the diaphragm and increased chest wall compliance are mechanical effects of pregnancy that reduce the lung volumes and capacities, such as functional residual capacity and expiratory reserve volume .
These changes do not affect the oxygen consumption directly.
Choice D is wrong because increased tidal volume and respiratory rate are the consequences of increased oxygen consumption during pregnancy, not the causes. Tidal volume increases by 40% and respiratory rate increases by 15% during pregnancy . These changes result in an increase in minute ventilation by 50% .