Lung function and postural changes during pregnancy
Aarhus University Hospital, Aarhus, Central Jutland, Denmark Respiratory Medicine
(Impact Factor: 3.09).
12/1989; 83(6):467-70. DOI: 10.1016/S0954-6111(89)80127-1
The aim of this study was to determine the effects of postural changes on lung function in pregnant women during the first, second, third trimester and post partum. A significant decrease in FRC, PEF and FEV1 was observed as a result of the postural changes. Arterial oxygenation, MVV and DLCO remained largely the same.
Available from: Gerald Stanley Zavorsky
- "In each study, two to four diffusion tests were performed per session. DL CO decreased by 10–15% in the second and third trimester in both singleton and twin pregnancies compared to the first trimester and post-partum (Gazioglu et al., 1970; McAuliffe et al., 2002; Norregaard et al., 1989). Greater resistance to diffusion through the alveolar membrane (DM) and not a decrease in pulmonary capillary blood volume (Vc) accounted for the decrease in DL CO (Gazioglu et al., 1970). "
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ABSTRACT: This paper reviews the scientific evidence for the safety of carbon monoxide (CO) and nitric oxide (NO) inhalation to measure pulmonary diffusing capacity (DL(CO) and DL(NO)) in pregnant women and their fetuses. In eight earlier studies, 650 pregnant women had DL(CO) measurements performed at various times during pregnancy, with a minimum of two to four tests per session. Both pregnant subjects that were healthy and those with medical complications were tested. No study reported adverse maternal, fetal, or neonatal outcomes from the CO inhalation in association with measuring DL(CO). Eleven pregnant women, chiefly with pulmonary hypertension, and 1105 pre-term neonates, mostly with respiratory failure, were administered various dosages of NO (5-80ppm for 4 weeks continuously in pregnant women, and 1-20ppm for 15min to 3 weeks for the neonates). NO treatment was found to be an effective therapy for pregnant women with pulmonary hypertension. In neonates with respiratory failure and pulmonary hypertension, NO therapy improved oxygenation and survival and has been associated with only minor, transient adverse effects. In conclusion, maternal carboxyhemoglobin ([Hb(CO)]) levels can safely increase to 5% per testing session when the dose-exposure limit is 0.3% CO inhalation for <or=3min, and for NO, 80ppm for <or=3min. The risk of late fetal or neonatal death from increased Hb(CO) from diffusion testing is considerably less than the risk of death from all causes reported by the Centers for Disease Control, and is therefore considered "minimal risk".
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ABSTRACT: In conclusion, it is important to appreciate the anatomic and physiologic adaptations in pregnancy in order to accurately diagnose and treat cardiopulmonary disease states in the gravid woman. Without knowing what constitutes normalcy in pregnancy, inappropriate diagnosis and interventions may occur. Furthermore, this knowledge is fundamental for understanding how disease states affect pregnancy and how pregnancy affects disease.
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