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KEY POINTS
Altered pulmonary physiology in pregnancy increases minute ventilation (via an increased tidal volume), producing a compensated respiratory alkalosis (PaCO2 28−32 mm Hg)
Intubation should be carried out by the most experienced operator available; upper airway edema and a reduced apnea time make for a difficult intubation.
Management of the critically ill pregnant patient is directed at optimizing maternal condition: do not avoid necessary drug therapy or radiological investigations.
Supine positioning in the pregnant patient may cause hypotension due to pressure of the uterus on the inferior vena cava; use a left lateral tilt position or manual displacement of the uterus to the left.
Obstetric delivery will not necessarily improve the maternal condition unless due to pregnancy-specific complications; delivery should be based on obstetric indications.
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Management of the critically ill pregnant patient is complicated by the altered physiology induced by pregnancy and the occurrence of relatively uncommon pregnancy-specific conditions. It is a situation with which few intensive care physicians gain significant expertise and there is a paucity of literature to guide management. The usual clinical approach may be altered by perceived limitations on investigations and therapy produced by the presence of a fetus.
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PHYSIOLOGIC CHANGES IN PREGNANCY
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The pregnant woman undergoes numerous physiologic changes to the cardiovascular, respiratory, and other systems, relevant to critical care management (Table 130-1).
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The upper airways develop edema and hyperemia mediated by hormonal changes, which may complicate endotracheal intubation. Lung volumes are altered with a 10% to 25% decrease in functional residual capacity (FRC), while total lung capacity decreases only minimally as the thoracic cage widens to compensate.1 Normal airway function does not appear to be affected by pregnancy, and forced expiratory volume in 1 second (FEV1) is not altered by the pregnant state. Lung compliance remains unchanged, but the enlarging uterus causes a reduced chest wall ...