The Analysis of Amniotic Fluid Embolism Cases Confirmed by the Forensic Autopsy

Foreword: Although the amniotic fluid embolism (AFE) has extremely low probability, it is actually an item of obstetric complication which is very difficult to prevent or process, and cause inevitable fast death. It occurs frequently in the peripartum period. The clinical manifestations of such cases may be sudden collapse, hypotension, cardiopulmonary failure, or massive hemorrhage. Till now, there was not effective method or test to predict it to occur. The forensic autopsy seems the best and only method to confirm the diagnosis of AFE. The report of forensic autopsy is also the best evidence which the judge determines the medical malpractice or not. The author attempts to more thorough understand the AFE by study the cases that confirmed by the forensic autopsy. We try to discuss the cases of AFE from the two different viewpoints of clinician and forensic pathologist. We hope this article will become a reference for them in the future.

Materials and methods: Forty seven cases were collected from the database of Institute of Forensic Medicine, Ministry of Justice from Jan 1, 1999 to Dec 31, 2007. All cases were AFE as cause of death and confirmed by the forensic autopsy. An addition case of AFE who was met by the author in 2009, altogether 48 cases was analyzed. We analyze and discuss the age, nationality, native place, medical history, obstetric history, gestational age of the cases. The fetus condition, delivery method, indication of labor, the place to happen, the death place of mother, the gross and microscopic findings of autopsy, and the differential diagnosis of death were also included.

Results: The most cases fall in the range of 30 to 35 years old women with 39 or 40 gestational weeks. Primiparas are more than multiparas. The delivery methods are 27 cases by vaginal delivery, 17 cases by schedule cesarean section and four cases by emergency operation. The fetuses are 21 boys and 17 girls, two pairs of male and female twins, one pair of two female twins, and unrecorded in 10 fetuses. The locations of AFE occurrence are 27 cases in clinic, 19 cases in hospital, and two cases in medical center. The declaration of death was done for 30 cases in medical center, 18 in hospital, but none was done in clinic. The AFE occurs before childbirth in 17 cases, within 30 minutes in 11 cases with fetal mortality rate 18.18% and more than a half hour in six cases with fetal mortality rate as high as 83.33%. The numbers of cases that AFE occurred postpartum is 31, within two hours in 19, and more than two hours in 12. Twenty seven victims had survival interval less than six hours. There are 10 cases having associated autopsied findings in addition to AFE: cervical laceration, hepatic laceration, brain herniation, pulmonary embolism, internal bleeding, placenta accreta, and myocarditis. The other 34 cases have no other significant finding. One case has only blood examination due to family unwilling to receive autopsy. In the other 45 autopsy, there is just one case which has no evidence of AFE in gross finding and the microscopic review. In the two cases above, AFE was still the final diagnosis that was made by the forensic pathologist depending on the clinical manifestations recorded on the medical charts.

Discussion: From clinician''s viewpoint, about one fourth such cases won’t have the evidence of fetal or amniotic materials in maternal lungs. But some pathologists insist that the AFE diagnosis must have fetal or amniotic fluid components in histopathological examination of lung sections. However, AFE should be considered but not confirmed when we just find out some fetal cells or amniotic fluid components in blood samples from pulmonary arteries or right ventricle. Due to clinician and forensic pathologist having the different standpoints, so even in the definite AFE was made after forensic autopsy performed, there would be different opinion between the clinician and forensic pathologist. If detail information of clinical manifestations and autopsied findings in such cases were collected, it should be helpful to make accurate diagnosis of AFE.

Conclusion: Equivocal conclusion will lead to the inexhaustible argument! It also will possibly let the public prosecutor or judge''s volition become the sole criterion to determine right and wrong! This article does not give any comment about the quality of investigation report by forensic pathologist. We just hope the standard criteria or procedure to confirm AFE will be established soon after this discussion, regardless in clinic or forensic medicine.