Thoracic-fluid conductivity in peripartum women with pulmonary edema

Abstract

Objective: To measure the level of thoracic-fluid conductivity associated with pulmonary edema in peripartum women by noninvasive thoracic electrical bioimpedance. Methods: Between March 1994 and August 1996, 134 women were selected for thoracic electrical bioimpedance monitoring. Among them, 12 had pulmonary edema, 33 had severe preeclampsia, 17 had mild preeclampsia, and 72 were in uncomplicated early labor. Each subject’s highest thoracic-fluid conductivity measurement was related to her clinical presentation. The Kruskal-Wallis one-way analysis of variance was used to compare groups’ means. A receiver operating characteristic curve was used to identify thoracic-fluid conductivity values associated with pulmonary edema. Results: Pulmonary edema was associated with severe preeclampsia in ten cases, urosepsis in one case, and postoperative volume overload in one case. Other than gestational age, there were no significant differences in maternal demographics between groups. Thoracic-fluid conductivity values in women with pulmonary edema (80.6 ± 18.3 kohm −1) were significantly higher than those in women with severe preeclampsia (62.8 ± 16.3 kohm −1), mild preeclampsia (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 pulmonary 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 conductivity stratified between mild and severe disease. Thoracic-fluid conductivity of at least 65 kohm −1 was strongly associated with peripartum pulmonary edema. Women with values above 65 kohm −1 might be candidates for medical intervention even without overt clinical symptoms.