Documentation of amniotic fluid embolism via lung histopathology. Fact or fiction?
OBJECTIVE
To evaluate pulmonary histopathology for confirming amniotic fluid embolism.


METHODS
The Capra hircus (goat) model with fresh, homologous amniotic fluid was used. Raw fluid (n = 8), fluid filtered through a 5-microns filter (n = 14) and meconium-stained fluid with 1-7% solid debris (n = 7) were injected. Three hours after embolization the animals were euthanized and specimens collected. Three to five areas of lung were sampled based on the most abnormal areas visually. Traditional and special stains were utilized. The study protocol was approved by the institutional review board and animal use and care committee. Statistical analysis was by chi 2 with Yates correction. Significance was defined as P < .05.


RESULTS
Amniotic fluid debris (fetal squames, mucin or foreign pigments) was found in 10 of 29 animals (34.5%). Debris was found in 7/7 (100%) of the meconium group, 2/8 (25%) of the raw fluid group and 1/14 of the filtered group (7%). The likelihood of finding debris in amniotic fluid embolism with meconium-stained fluid was greater than with raw (P < .017) or filtered amniotic fluid (P < .001).


CONCLUSIONS
In this animal model, histopathologic confirmation of amniotic fluid embolism was an unreliable marker of the event except in cases of amniotic fluid embolism involving meconium-stained fluid.
Hankins
Gary D V
GD
Department of Obstetrics and Gynecology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0587, USA.
Snyder
Russell
R
Dinh
Tung
T
Van Hook
James
J
Clark
Steven
S
Vandelan
Adrian
A
D000818:Animals; D003937:Diagnosis, Differential; D004195:Disease Models, Animal; D004619:Embolism, Amniotic Fluid / Q000175:diagnosis* / Q000473:pathology; D005188:False Negative Reactions; D005260:Female; D006041:Goats; D008168:Lung / Q000473:pathology*; D008470:Meconium / Q000737:chemistry*; D011247:Pregnancy; D012680:Sensitivity and Specificity