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Amniotic fluid embolism during caesarean section
International Journal of Obstetric Anesthesia (2004) 13, 271–274 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijoa.2004.03.002
CASE REPORT
Amniotic fluid embolism during caesarean section G. Tramoni, S. Valentin, M. O. Robert, M. V. Sergeant, P. Branche, S. Duperret, H. J. Clement, F. Lopez, C. Boisson, P. Audra, R. C. Rudigoz, J. P. Viale Dpartement d’anesthsie ranimation, Service d’obsttrique and Fdration de Biochimie, Hpital de la Croix Rousse, and Service d’obsttrique, Hpital Edouard Herriot, Pavillon K, Lyon, France SUMMARY. Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. A high index of clinical suspicion is necessary to make an early diagnosis to reduce morbidity and mortality. We report a non-fatal case of amniotic fluid embolism occurring during a caesarean section, with special emphasis on the mode of development and diagnosis. The initial presentation of this syndrome was a coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of amniotic fluid embolism was supported by the observation of amniotic fluid in the central venous blood as well as in the broncho-alveolar fluid. 2004 Elsevier Ltd. All rights reserved. Keywords: Amniotic fluid embolism; Caesarean section; Broncho-alveolar fluid
section with coagulopathy. The diagnosis of AFE was supported by the observation of amniotic cells in the central venous blood as well as in the broncho-alveolar fluid.
INTRODUCTION Amniotic fluid embolism (AFE) occurs rarely but is one of the leading causes of maternal mortality. It was first described in 1926 and became an established clinical entity in 1941.1,2 The classical description is sudden onset of dyspnoea, cyanosis and hypotension out of proportion to the blood loss, followed quickly by cardiorespiratory arrest. In addition to haemodynamic collapse and pulmonary injury, 40% of patients surviving the initial haemodynamic insult may develop a disorder of coagulation ranging from minor disturbances in platelet count to disseminated intravascular coagulation (DIC).3–10 Because initial characteristic signs may be mistaken and therefore make diagnosis difficult, a high index of suspicion for this condition is required as early management is the key point for a favourable outcome. We report on a non-fatal case of AFE occurring during a caesarean
CASE REPORT A 28-year-old primigravida was admitted for delivery at 40 weeks and 3 days’ gestation after a normal pregnancy. She was otherwise healthy, she had not been taking any medication and had no known allergy. The labour was spontaneous with a blood pressure of 120/60 mmHg on admission and no temperature elevation was noted. Her coagulation profile was also normal and an epidural catheter was inserted for analgesia. After a test dose with 1% lidocaine 3 mL, analgesia was provided by a mixture of bupivacaine 0.1% and sufentanil 0.5 lg/mL. After a 10-mL bolus, a continuous infusion at 10 mL/h was started. In order to augment labour, oxytocin was administered at a rate of 1.5-6 mL/h (Syntocinon 0.1 unit/mL). During labour, some episodes of hypertension were recorded but considered to be the result of agitation, as there was neither pain nor clinical signs of eclampsia. Because a temperature of 38C was noted, amoxycillin (1 g i.v. three times a day) was started. A reduction in fetal heart rate variability was noted. Four hours after epidural catheter insertion, the membranes were ruptured artificially, revealing
Accepted March 2004 G. Tramoni, S. Valentin, M. O. Robert, S. Duperret, P. Branche, H. J. Clement, F. Lopez, J. P. Viale, Dpartement d’anesthsie ranimation, Hpital de la Croix Rousse, Lyon, France; M. V. Sergeant, R. C. Rudigoz, Service d’obsttrique, Hpital de la Croix Rousse, Lyon, France; C. Boisson, Fdration de Biochimie, Hpital de la Croix Rousse, Lyon, France; P. Audra, Hpital Edouard Herriot, Service d’obsttrique, Pavillon K, Lyon, France. Correspondence to: Dr. Grard Tramoni, Dpartement d’anesthsie ranimation, Hpital de la Croix Rousse, 103 grande rue de la Croix Rousse, 69317 LYON cedex 04, France. Tel.: +33 4 72 07 24 40; Fax: +33 4 72 07 19 85. E-mail: [email protected] 271
272 International Journal of Obstetric Anesthesia meconium-stained amniotic fluid. Vaginal examination showed the cervix to be dilated 5 cm. A temporal fetal oxygen sensor was inserted registering a fetal oxygen saturation of 37-40%. Four hours later, vaginal examination showed the cervix to be only 8 cm dilated and a lower segment caesarean section was performed under epidural anaesthesia because of low fetal oxygen saturation and reduced fetal heart rate variability. During this period, maternal heart rate, blood pressure and pulse oximetry were within normal range. A live male infant weighing 3610 g was delivered. Apgar scores were 10 at 1, 5 and 10 min. The amniotic fluid was grossly stained and the umbilical artery pH was 7.23. Immediately following delivery of the placenta, a profuse post-partum haemorrhage was observed with uterine atony. Medical and obstetric management was started immediately and blood sampled at this time disclosed DIC (Table 1). The trachea was intubated and assisted mechanical ventilation with an inspired oxygen concentration of 100% was instituted. Resuscitation included infusion of colloid Hydroxy Ethyl Amidon (HEA) 1.5 L, Ringer’s lactate 4 L and 4% albumin 1 L. Transfusion of 10 units of packed red blood cells, 1 unit of platelet concentrates, 11 units of fresh frozen plasma and 3 g of fibrinogen were given. An intrauterine examination was performed. Two infusions of oxytocin (Syntocinon 10 units) were administered, one intravenously and one into the myometrium. Uterine massage was continuous. Because uterine atony did not respond to oxytocin, a prostaglandin continuous intravenous infusion (Sulprostone, Nalador 500 lg) was started. As the haemorrhage persisted the hypogastric arteries were surgically ligated and a second intravenous infusion of prostaglandin was given. Five units of prostaglandin (Misoprostol, Cytotec 200 lg) were given rectally with another prostaglandin intravenous infusion. Despite the surgical ligation, the haemorrhage continued and a B-Lynch surgical suture was placed. After a short improvement,
further profuse haemorrhage resumed and total hysterectomy was necessary. At that time, the total volume administered was 13 L. At the end of surgery, after one hour of monitoring in the recovery room, the patient was transferred to the intensive care unit (ICU). Upon admission in the ICU her blood pressure was 70/40 mmHg, she remained tachycardic, and a norepinephrine infusion was instituted (0.4 lgkg-1min-1). Auscultation of the chest was normal. Blood analysis revealed a microangiopathic anaemia with a haemoglobin concentration of 4.2 g/dL, thrombocytopenia (82 · 109/ L); coagulation results were consistent with a severe DIC (Table 1). In addition, lactic acidosis was noted (lactic acid: 6.5 mmol/L; normal range 0.6-2.2 mmol/ L), as well as a profound hypoalbuminaemia (plasma albumin 19.8 g/L). Arterial blood gas values under assisted mechanical ventilation with a 40% inspired oxygen concentration were pH 7.33, PaCO2 5.03 kPa (37.7 mmHg), PaO2 18.0 kPa (135 mmHg). Liver function tests were normal and the creatine phosphokinase level was 353 units/L. The chest X-ray was normal and the electrocardiogram showed only a sinus tachycardia. Central venous blood and broncho-alveolar fluid were sampled and sent for cytologic analysis. The latter showed amniotic material after direct examination with Nil blue stain and Wright stain and epithelial cells were demonstrated (Fig. 1). Finally, echocardiography ruled out any left ventricular dysfunction or pulmonary hypertension, as previously noted in AFE.11,12 During the first day, clinical examination and laboratory data showed some improvement in the coagulopathy. Catecholamine use was tapered and the trachea was extubated 6 h after admission. Neurological examination was normal without sedation. Despite this improvement, acute renal failure occurred, and continuous veno-venous haemodialysis was necessary. During the second day post partum, a decrease in blood pressure associated with abdominal distension prompted a second operation for haemostasis. Intra-abdominal bleeding from the surgical
Table 1. Laboratory results one month prior to delivery and in the immediate postpartum period Time in relation to delivery PT (%) ACT (s) Fibrinogen (g/L) Platelets (·109/L) D-dimers (ng/mL) F II (%) F V (%) F VII (%) F VIII (%) F X (%) Hb (g/dL) Bilirubin (lmol/L) FDP (mg/L) Haptoglobin (g/L)
1 month before
0
+7 h
+14 h
+24 h
+48 h
Normal range
118 33 7.1 188 12.1 -
50 126,4 1.9 47 7.5 640 -
64 53,2 1.9 83 4000 49 4.2 40 -
53 60 1.6 43 37 40 82 51 9.1 20 0.3
88 43,3 4.0 45 61 66 93 152 72 9.0 <10 -
95 38,8 11.5 76 9.6 -
70-120 26-40 2-4.5 150-500 0-500 60-120 60-120 60-120 60-200 60-120 11.5-14.5 <20 0-10 >0.7
PT: prothrombin time; ACT: activated cephalin time; FDP: fibrin degradation products; Hb: haemoglobin.
Amniotic fluid embolism during caesarean section 273
Fig. 1 Fetal squamous cell in the broncho-alveolar fluid (Wright stain).
site was noted and 3 L of intraperitoneal blood were removed. An additional transfusion was started including units of platelets and fresh frozen plasma. On the third day, the patient was noted to be somewhat confused. Over the following days this developed into loss of temporal and spatial orientation, aggression and episodes of fear. Magnetic resonance imaging (MRI) of the brain performed one week later was normal. Despite these neurologic symptoms, the patient’s condition gradually improved and she was discharged from the ICU on the seventh day post partum. The final diagnosis was AFE leading to profuse post-partum haemorrhage, DIC and acute renal failure.
DISCUSSION Amniotic fluid embolism is a rare event, ranging from one in 8000 to one in 80 000 deliveries.4 As a consequence, no single institution has sufficient experience to assess risk factors, determine the pathophysiology and clinical course, or evaluate management strategies. Data registers have been developed to study amniotic fluid embolism and the potential of maternal mortality.13–15 The AFE syndrome was first described by Meyer in 1926.1 It became an established clinical entity in 1941 after Steiner and Luschbaugh published a maternal mortality case series that included eight women who had squamous cells and mucin, presumably of fetal origin, within their pulmonary vasculature.2 The classic description is sudden onset of dyspnoea, cyanosis and hypotension out of proportion to the blood loss, followed quickly by cardiorespiratory arrest.4 This initial episode is usually followed in survivors by disseminated intravascular coagulation (DIC). In our case report, two distinctive features should be noted, namely the intensity of the coagulopathy disorder and the presence of neurological signs, while pulmonary and circulatory impairment were rapidly treated.
The clinical coagulation disorder was the first sign in the course of the caesarean section. Indeed, the biological signs of DIC occurring during AFE are difficult to ascribe to the AFE itself. The massive haemorrhage and the transfusion needed for management could induce the same coagulation factor deficit. This unusual presentation has been studied in an abstract published by Porter et al., some years ago.5 They isolated eight clinical cases where acute coagulopathy developed without antecedent hypotension, hypoxia or evidence of any other events or disease processes including placental abruption. Five patients were delivered by caesarean section. Acute haemorrhage occurred post partum in seven patients and intrapartum in one patient. Uterine atony was noted in five of eight patients. Six of eight patients exsanguinated despite appropriate medical management. Porter et al., concluded that isolated fatal DIC is a forme fruste of AFE, with a mortality rate similar to that observed in the more classic form. Recent studies confirmed the association of AFE and DIC.6–9 The pathophysiology of this coagulopathic disorder remains controversial. As discussed in the review on AFE by Davies et al., the experimental data suggest that amniotic fluid has a direct factor X activating property and thromboplastin-like effect.7 A tissue factor found in the amniotic fluid could account for the activation of the coagulation pathway.16 Encephalopathy is not commonly encountered in AFE. Indeed, if neurologic syndromes are present in the course of AFE, they usually develop after severe prolonged hypotension or even cardiac arrest. In our observation, late occurrence of neurologic disorientation could be the consequence of micro-emboli of amniotic material. A normal MRI would not rule out this putative mechanism. In all circumstances, the diagnosis of AFE is difficult to establish on the basis of clinical and laboratory findings. The usual clinical criteria are as follows: acute hypotension or cardiac arrest, acute hypoxia, coagulopathy, absence of other explanations for the manifestation observed, onset during labour within 30 min of delivery or surgical abortion.13 The other diagnoses to consider in a patient presenting with the above signs are haemorrhagic shock, placental abruption, sepsis, pulmonary thromboembolism, aspiration of gastric contents and eclampsia. A pathognomonic marker of AFE is still lacking. The finding of fetal squamous cells or other amniotic fluid material in the maternal pulmonary circulation is neither specific nor sensitive for the diagnosis of AFE. Indeed, squamous cells have been retrieved from the pulmonary vasculature of patients being monitored for conditions other than AFE.17 Moreover, the differentiation between maternal and fetal elements retrieved from the maternal circulation is problematic.18 Various stains such as Wright stain may provide greater sensitivity for
274 International Journal of Obstetric Anesthesia detecting fetal debris other than routine hematoxylineosin staining; however, data concerning the accuracy of these methods are lacking. The detection of fetal hair or mucin in central venous or pulmonary artery blood can support the diagnosis of AFE, but cannot be considered pathognomonic, as small amounts can enter the maternal circulation in the absence of AFE.19 Finding fetal squamous cells in the broncho-alveolar lavage may support the diagnosis of AFE, especially if the patient developed pulmonary oedema.20 In our patient, the diagnosis of AFE was supported by the detection of squamous cells in the central venous blood and rapidly confirmed in broncho-alveolar fluid. Because there are fewer types of cells in broncho-alveolar fluid than in venous blood, fetal squamous cells could be found more easily. More studies are needed in order to assess the value of finding squamous cells both in central venous blood and in broncho-alveolar fluid. Recently, two studies attempted to develop simple, non-invasive, sensitive tests for diagnosing amniotic emboli using fetal material detection in the peripheral maternal blood. However, the respective value of a monoclonal antibody that recognizes characteristic components of meconium and amniotic fluid or of a plasma level of zinc coproporphyrin as a characteristic component of meconium still remains to be confirmed.21 In conclusion, we report on a case of AFE in a 28-year-old woman. The initial presentation of this syndrome was coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of AFE was supported by the observation of squamous cells in central venous blood as well as in broncho-alveolar fluid. REFERENCES 1. Meyer J. Embolia pulmonar amnio caseosa. Brasil Medico 1926; 2: 301.
2. Steiner P, Luschbaugh C. Maternal pulmonary emboli by amniotic fluid. JAMA 1941; 117: 1245. 3. Clark S L. Amniotic fluid embolism. Clin Perinatol 1986; 13: 801–811. 4. Morgan M. Amniotic fluid embolism. Anaesthesia 1979; 34: 20–32. 5. Porter T, Clark S, Dildy G, Hankins G. Isolated disseminated intravascular coagulation and amniotic fluid embolism. Am J Obstet Gynecol 1996; 174: 486. 6. Awad I T, Shorten G D. Amniotic fluid embolism and isolated coagulopathy: atypical presentation of amniotic fluid embolism. Eur J Anaesthesiol 2001; 18: 410–413. 7. Davies S. Amniotic fluid embolus: a review of the literature. Can J Anaesth 2001; 48: 88–98. 8. Letsky E A. Disseminated intravascular coagulation. Best Pract Res Clin Obstet Gynaecol 2001; 15: 623–644. 9. Bastien J L, Graves J R, Bailey S. Atypical presentation of amniotic fluid embolism. Anesth Analg 1998; 87: 124–126. 10. Locksmith G J. Amniotic fluid embolism. Obstet Gynecol Clin North Am 1999; 26: 435–444. 11. Girard P, Mal H, Laine J F, et al. Left heart failure in amniotic fluid embolism. Anesthesiology 1986; 64: 262–265. 12. Vanmaele L, Noppen M, Vincken W, De Catte L, Huyghens L. Transient left heart failure in amniotic fluid embolism. Intensive Care Med 1990; 16: 269–271. 13. Clark S L, Hankins G D, Dudley D A, Dildy G A, Porter T F. Amniotic fluid embolism: analysis of the national registry. Am J Obstet Gynecol 1995; 172: 1158–1169. 14. Cooper G M, Lewis G, Neilson J. Confidential enquiries into maternal deaths, 1997–1999. Br J Anaesth 2002; 89: 369–372. 15. Tuffnell D J, Johnson H. Amniotic fluid embolism: the UK register. Hosp Med 2000; 61: 532–534. 16. Lockwood C J, Bach R, Guha A, et al. Amniotic fluid contains tissue factor, a potent initiator of coagulation. Am J Obstet Gynecol 1991; 165: 1335–1341. 17. Hankins G D, Snyder R, Dinh T, et al. Documentation of amniotic fluid embolism via lung histopathology. Fact or fiction? J Reprod Med 2002; 47: 1021–1024. 18. Clark S L, Pavlova Z, Greenspoon J, Horenstein J, Phelan J P. Squamous cells in the maternal pulmonary circulation. Am J Obstet Gynecol 1986; 154: 104–106. 19. Fava S, Galizia A C. Amniotic fluid embolism. Br J Obstet Gynaecol 1993; 100: 1049–1050. 20. Blanc P L, Guibaud S, Bedock B, Robert D. Diagnosis of amniotic embolism by broncho-alveolar lavage. Presse Med 1987; 16: 479–480. 21. Kobayashi H, Ohi H, Terao T. A simple, noninvasive, sensitive method for diagnosis of amniotic fluid embolism by monoclonal antibody TKH-2 that recognizes NeuAc alpha 2-6GalNAc. Am J Obstet Gynecol 1993; 168: 848–853.
CASE REPORT
Amniotic fluid embolism during caesarean section G. Tramoni, S. Valentin, M. O. Robert, M. V. Sergeant, P. Branche, S. Duperret, H. J. Clement, F. Lopez, C. Boisson, P. Audra, R. C. Rudigoz, J. P. Viale Dpartement d’anesthsie ranimation, Service d’obsttrique and Fdration de Biochimie, Hpital de la Croix Rousse, and Service d’obsttrique, Hpital Edouard Herriot, Pavillon K, Lyon, France SUMMARY. Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. A high index of clinical suspicion is necessary to make an early diagnosis to reduce morbidity and mortality. We report a non-fatal case of amniotic fluid embolism occurring during a caesarean section, with special emphasis on the mode of development and diagnosis. The initial presentation of this syndrome was a coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of amniotic fluid embolism was supported by the observation of amniotic fluid in the central venous blood as well as in the broncho-alveolar fluid. 2004 Elsevier Ltd. All rights reserved. Keywords: Amniotic fluid embolism; Caesarean section; Broncho-alveolar fluid
section with coagulopathy. The diagnosis of AFE was supported by the observation of amniotic cells in the central venous blood as well as in the broncho-alveolar fluid.
INTRODUCTION Amniotic fluid embolism (AFE) occurs rarely but is one of the leading causes of maternal mortality. It was first described in 1926 and became an established clinical entity in 1941.1,2 The classical description is sudden onset of dyspnoea, cyanosis and hypotension out of proportion to the blood loss, followed quickly by cardiorespiratory arrest. In addition to haemodynamic collapse and pulmonary injury, 40% of patients surviving the initial haemodynamic insult may develop a disorder of coagulation ranging from minor disturbances in platelet count to disseminated intravascular coagulation (DIC).3–10 Because initial characteristic signs may be mistaken and therefore make diagnosis difficult, a high index of suspicion for this condition is required as early management is the key point for a favourable outcome. We report on a non-fatal case of AFE occurring during a caesarean
CASE REPORT A 28-year-old primigravida was admitted for delivery at 40 weeks and 3 days’ gestation after a normal pregnancy. She was otherwise healthy, she had not been taking any medication and had no known allergy. The labour was spontaneous with a blood pressure of 120/60 mmHg on admission and no temperature elevation was noted. Her coagulation profile was also normal and an epidural catheter was inserted for analgesia. After a test dose with 1% lidocaine 3 mL, analgesia was provided by a mixture of bupivacaine 0.1% and sufentanil 0.5 lg/mL. After a 10-mL bolus, a continuous infusion at 10 mL/h was started. In order to augment labour, oxytocin was administered at a rate of 1.5-6 mL/h (Syntocinon 0.1 unit/mL). During labour, some episodes of hypertension were recorded but considered to be the result of agitation, as there was neither pain nor clinical signs of eclampsia. Because a temperature of 38C was noted, amoxycillin (1 g i.v. three times a day) was started. A reduction in fetal heart rate variability was noted. Four hours after epidural catheter insertion, the membranes were ruptured artificially, revealing
Accepted March 2004 G. Tramoni, S. Valentin, M. O. Robert, S. Duperret, P. Branche, H. J. Clement, F. Lopez, J. P. Viale, Dpartement d’anesthsie ranimation, Hpital de la Croix Rousse, Lyon, France; M. V. Sergeant, R. C. Rudigoz, Service d’obsttrique, Hpital de la Croix Rousse, Lyon, France; C. Boisson, Fdration de Biochimie, Hpital de la Croix Rousse, Lyon, France; P. Audra, Hpital Edouard Herriot, Service d’obsttrique, Pavillon K, Lyon, France. Correspondence to: Dr. Grard Tramoni, Dpartement d’anesthsie ranimation, Hpital de la Croix Rousse, 103 grande rue de la Croix Rousse, 69317 LYON cedex 04, France. Tel.: +33 4 72 07 24 40; Fax: +33 4 72 07 19 85. E-mail: [email protected] 271
272 International Journal of Obstetric Anesthesia meconium-stained amniotic fluid. Vaginal examination showed the cervix to be dilated 5 cm. A temporal fetal oxygen sensor was inserted registering a fetal oxygen saturation of 37-40%. Four hours later, vaginal examination showed the cervix to be only 8 cm dilated and a lower segment caesarean section was performed under epidural anaesthesia because of low fetal oxygen saturation and reduced fetal heart rate variability. During this period, maternal heart rate, blood pressure and pulse oximetry were within normal range. A live male infant weighing 3610 g was delivered. Apgar scores were 10 at 1, 5 and 10 min. The amniotic fluid was grossly stained and the umbilical artery pH was 7.23. Immediately following delivery of the placenta, a profuse post-partum haemorrhage was observed with uterine atony. Medical and obstetric management was started immediately and blood sampled at this time disclosed DIC (Table 1). The trachea was intubated and assisted mechanical ventilation with an inspired oxygen concentration of 100% was instituted. Resuscitation included infusion of colloid Hydroxy Ethyl Amidon (HEA) 1.5 L, Ringer’s lactate 4 L and 4% albumin 1 L. Transfusion of 10 units of packed red blood cells, 1 unit of platelet concentrates, 11 units of fresh frozen plasma and 3 g of fibrinogen were given. An intrauterine examination was performed. Two infusions of oxytocin (Syntocinon 10 units) were administered, one intravenously and one into the myometrium. Uterine massage was continuous. Because uterine atony did not respond to oxytocin, a prostaglandin continuous intravenous infusion (Sulprostone, Nalador 500 lg) was started. As the haemorrhage persisted the hypogastric arteries were surgically ligated and a second intravenous infusion of prostaglandin was given. Five units of prostaglandin (Misoprostol, Cytotec 200 lg) were given rectally with another prostaglandin intravenous infusion. Despite the surgical ligation, the haemorrhage continued and a B-Lynch surgical suture was placed. After a short improvement,
further profuse haemorrhage resumed and total hysterectomy was necessary. At that time, the total volume administered was 13 L. At the end of surgery, after one hour of monitoring in the recovery room, the patient was transferred to the intensive care unit (ICU). Upon admission in the ICU her blood pressure was 70/40 mmHg, she remained tachycardic, and a norepinephrine infusion was instituted (0.4 lgkg-1min-1). Auscultation of the chest was normal. Blood analysis revealed a microangiopathic anaemia with a haemoglobin concentration of 4.2 g/dL, thrombocytopenia (82 · 109/ L); coagulation results were consistent with a severe DIC (Table 1). In addition, lactic acidosis was noted (lactic acid: 6.5 mmol/L; normal range 0.6-2.2 mmol/ L), as well as a profound hypoalbuminaemia (plasma albumin 19.8 g/L). Arterial blood gas values under assisted mechanical ventilation with a 40% inspired oxygen concentration were pH 7.33, PaCO2 5.03 kPa (37.7 mmHg), PaO2 18.0 kPa (135 mmHg). Liver function tests were normal and the creatine phosphokinase level was 353 units/L. The chest X-ray was normal and the electrocardiogram showed only a sinus tachycardia. Central venous blood and broncho-alveolar fluid were sampled and sent for cytologic analysis. The latter showed amniotic material after direct examination with Nil blue stain and Wright stain and epithelial cells were demonstrated (Fig. 1). Finally, echocardiography ruled out any left ventricular dysfunction or pulmonary hypertension, as previously noted in AFE.11,12 During the first day, clinical examination and laboratory data showed some improvement in the coagulopathy. Catecholamine use was tapered and the trachea was extubated 6 h after admission. Neurological examination was normal without sedation. Despite this improvement, acute renal failure occurred, and continuous veno-venous haemodialysis was necessary. During the second day post partum, a decrease in blood pressure associated with abdominal distension prompted a second operation for haemostasis. Intra-abdominal bleeding from the surgical
Table 1. Laboratory results one month prior to delivery and in the immediate postpartum period Time in relation to delivery PT (%) ACT (s) Fibrinogen (g/L) Platelets (·109/L) D-dimers (ng/mL) F II (%) F V (%) F VII (%) F VIII (%) F X (%) Hb (g/dL) Bilirubin (lmol/L) FDP (mg/L) Haptoglobin (g/L)
1 month before
0
+7 h
+14 h
+24 h
+48 h
Normal range
118 33 7.1 188 12.1 -
50 126,4 1.9 47 7.5 640 -
64 53,2 1.9 83 4000 49 4.2 40 -
53 60 1.6 43 37 40 82 51 9.1 20 0.3
88 43,3 4.0 45 61 66 93 152 72 9.0 <10 -
95 38,8 11.5 76 9.6 -
70-120 26-40 2-4.5 150-500 0-500 60-120 60-120 60-120 60-200 60-120 11.5-14.5 <20 0-10 >0.7
PT: prothrombin time; ACT: activated cephalin time; FDP: fibrin degradation products; Hb: haemoglobin.
Amniotic fluid embolism during caesarean section 273
Fig. 1 Fetal squamous cell in the broncho-alveolar fluid (Wright stain).
site was noted and 3 L of intraperitoneal blood were removed. An additional transfusion was started including units of platelets and fresh frozen plasma. On the third day, the patient was noted to be somewhat confused. Over the following days this developed into loss of temporal and spatial orientation, aggression and episodes of fear. Magnetic resonance imaging (MRI) of the brain performed one week later was normal. Despite these neurologic symptoms, the patient’s condition gradually improved and she was discharged from the ICU on the seventh day post partum. The final diagnosis was AFE leading to profuse post-partum haemorrhage, DIC and acute renal failure.
DISCUSSION Amniotic fluid embolism is a rare event, ranging from one in 8000 to one in 80 000 deliveries.4 As a consequence, no single institution has sufficient experience to assess risk factors, determine the pathophysiology and clinical course, or evaluate management strategies. Data registers have been developed to study amniotic fluid embolism and the potential of maternal mortality.13–15 The AFE syndrome was first described by Meyer in 1926.1 It became an established clinical entity in 1941 after Steiner and Luschbaugh published a maternal mortality case series that included eight women who had squamous cells and mucin, presumably of fetal origin, within their pulmonary vasculature.2 The classic description is sudden onset of dyspnoea, cyanosis and hypotension out of proportion to the blood loss, followed quickly by cardiorespiratory arrest.4 This initial episode is usually followed in survivors by disseminated intravascular coagulation (DIC). In our case report, two distinctive features should be noted, namely the intensity of the coagulopathy disorder and the presence of neurological signs, while pulmonary and circulatory impairment were rapidly treated.
The clinical coagulation disorder was the first sign in the course of the caesarean section. Indeed, the biological signs of DIC occurring during AFE are difficult to ascribe to the AFE itself. The massive haemorrhage and the transfusion needed for management could induce the same coagulation factor deficit. This unusual presentation has been studied in an abstract published by Porter et al., some years ago.5 They isolated eight clinical cases where acute coagulopathy developed without antecedent hypotension, hypoxia or evidence of any other events or disease processes including placental abruption. Five patients were delivered by caesarean section. Acute haemorrhage occurred post partum in seven patients and intrapartum in one patient. Uterine atony was noted in five of eight patients. Six of eight patients exsanguinated despite appropriate medical management. Porter et al., concluded that isolated fatal DIC is a forme fruste of AFE, with a mortality rate similar to that observed in the more classic form. Recent studies confirmed the association of AFE and DIC.6–9 The pathophysiology of this coagulopathic disorder remains controversial. As discussed in the review on AFE by Davies et al., the experimental data suggest that amniotic fluid has a direct factor X activating property and thromboplastin-like effect.7 A tissue factor found in the amniotic fluid could account for the activation of the coagulation pathway.16 Encephalopathy is not commonly encountered in AFE. Indeed, if neurologic syndromes are present in the course of AFE, they usually develop after severe prolonged hypotension or even cardiac arrest. In our observation, late occurrence of neurologic disorientation could be the consequence of micro-emboli of amniotic material. A normal MRI would not rule out this putative mechanism. In all circumstances, the diagnosis of AFE is difficult to establish on the basis of clinical and laboratory findings. The usual clinical criteria are as follows: acute hypotension or cardiac arrest, acute hypoxia, coagulopathy, absence of other explanations for the manifestation observed, onset during labour within 30 min of delivery or surgical abortion.13 The other diagnoses to consider in a patient presenting with the above signs are haemorrhagic shock, placental abruption, sepsis, pulmonary thromboembolism, aspiration of gastric contents and eclampsia. A pathognomonic marker of AFE is still lacking. The finding of fetal squamous cells or other amniotic fluid material in the maternal pulmonary circulation is neither specific nor sensitive for the diagnosis of AFE. Indeed, squamous cells have been retrieved from the pulmonary vasculature of patients being monitored for conditions other than AFE.17 Moreover, the differentiation between maternal and fetal elements retrieved from the maternal circulation is problematic.18 Various stains such as Wright stain may provide greater sensitivity for
274 International Journal of Obstetric Anesthesia detecting fetal debris other than routine hematoxylineosin staining; however, data concerning the accuracy of these methods are lacking. The detection of fetal hair or mucin in central venous or pulmonary artery blood can support the diagnosis of AFE, but cannot be considered pathognomonic, as small amounts can enter the maternal circulation in the absence of AFE.19 Finding fetal squamous cells in the broncho-alveolar lavage may support the diagnosis of AFE, especially if the patient developed pulmonary oedema.20 In our patient, the diagnosis of AFE was supported by the detection of squamous cells in the central venous blood and rapidly confirmed in broncho-alveolar fluid. Because there are fewer types of cells in broncho-alveolar fluid than in venous blood, fetal squamous cells could be found more easily. More studies are needed in order to assess the value of finding squamous cells both in central venous blood and in broncho-alveolar fluid. Recently, two studies attempted to develop simple, non-invasive, sensitive tests for diagnosing amniotic emboli using fetal material detection in the peripheral maternal blood. However, the respective value of a monoclonal antibody that recognizes characteristic components of meconium and amniotic fluid or of a plasma level of zinc coproporphyrin as a characteristic component of meconium still remains to be confirmed.21 In conclusion, we report on a case of AFE in a 28-year-old woman. The initial presentation of this syndrome was coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of AFE was supported by the observation of squamous cells in central venous blood as well as in broncho-alveolar fluid. REFERENCES 1. Meyer J. Embolia pulmonar amnio caseosa. Brasil Medico 1926; 2: 301.
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