Thoracic-fluid conductivity in peripartum women with pulmonary edema

Objective: To measure the level of thoracic-fluid conductivity associated w ith pulmonary edema in peripartum women by noninvasive thoracic electrical bioimpedance. Methods: Between March 1994 and August 1996, 134 women were selected for th oracic electrical bioimpedance monitoring. Among them, 12 had pulmonary ede ma, 33 had severe preeclampsia, 17 had mild preeclampsia, and 72 were in un complicated early labor. Each subject's highest thoracic-fluid conductivity measurement was related to her clinical presentation. The Kruskal-Wallis o ne-way analysis of variance was used to compare groups' means. A receiver o perating characteristic curve was used to identify thoracic-fluid conductiv ity values associated with pulmonary edema. Results: Pulmonary edema was associated with severe preeclampsia in ten cas es, urosepsis in one case, and postoperative volume overload in one case. O ther than gestational age, there were no significant differences in materna l demographics between groups. Thoracic-fluid conductivity values in women with pulmonary edema (80.6 +/- 18.3 kohm(-1)) were significantly higher tha n those in women with severe preeclampsia (62.8 +/- 16.3 kohm(-1)), mild pr eeclampsia (53.3 +/- 11.2 kohm(-1)), or early labor (41.3 +/- 6.7 kohm(-1)) . Thoracic-fluid conductivity of at least 65 kohm(-1) best identified pulmo nary edema (sensitivity 83.3%; specificity 86.9%; positive predictive value 38.5%; negative predictive value 98.1%). Conclusion: Preeclampsia was associated with increased thoracic-fluid condu ctivity stratified between mild and severe disease. Thoracic-fluid conducti vity of at least 65 kohm(-1) was strongly associated with peripartum pulmon ary edema. Women with values above 65 kohm(-1) might be candidates for medi cal intervention even without overt clinical symptoms. (C) 1999 by The Amer ican College of Obstetricians and Gynecologists.