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ASTHMA................i.............i.....i.....988
ACUTE BRONCHITIS ...i.....i......i...............991
PNEUMONIA.i...............i.......i.......i..... 992
TUBERCULOSIS.. . .................i............ 995
SARCOIDOSIS.....................i............997
CYSTIC FIBROSIS.. . ................i............ 997
CARBON MONOXIDE POISONING.. . ..i............ 999
A lung which is partialy destroyed or thrown out of function may suice or the respiration of a normal individual, but be unable to respond to the added demands of pregnancy, particulary in the latter months, when the enlarged restricts the mobiliy of the diaphragm.
-J. Whitridge Williams (1903)
As indicated by the above, it has long been appreciated that women in advanced pregnancy tolerate lung disease poorly. Nevertheless, pulmonary disorders are frequently encountered during pregnancy. Chronic asthma or an acute exacerbation is the most common and afects up to 8 percent of pregnant women. Moreover, asthma along with community-acquired pneumonia accounted for almost 10 percent of nonobstetrical antepartum hospitalizations in one managed care plan (Gazmararian, 2002). Pneumonia is also a frequent postpartum complication requiring readmission (Belfort, 2010). These and other pulmonary disorders are superimposed on several important pregnancy-induced changes of ventilatory physiology. For example, pregnant women, especially those in the last trimester, are susceptible to complications of severe acute pneumonitis as evidenced by the disparate number of maternal deaths during influenza pandemics.
The important and sometimes marked changes in the respira tory system induced by pregnancy are reviewed in Chapter 4 (p.
64), and values for associated tests can be found in the Appendix (p. 1260). Lung volumes and capacities that are measured directly to assess pulmonary pathophysiology may be signiicantly altered. In turn, these change gas concentrations and acid-base values in blood. Some of the physiological alterations induced by pregnancy were summarized by Wise and associates (2006): 1.
ital capaciy and inspiratory capaciy increase by approximately 20 percent by late pregnancy.
2.
Expiratory reserve volume decreases from 1300 mL to approximately 1100 mL.
3.
idal volume increases approximately 40 percent as a result of respiratory stimulation by progesterone.
4.