Lipid Emulsion Rescue of Amniotic Fluid Embolism-Induced Cardiac Arrest: A Case Report
Windrik Lynch,MD, Russell K. McAllister, MD, Jack F. Lay, Jr, MBA, MD, and William C. Culp,Jr, MD
A&A Case Reports. 2016;XXX:00–00.
CASE REPORT
一名28岁的健康初产妇，体重76公斤，无吸烟史，在妊娠41周时阴道内使用米索前列醇引产。最初的实验室与系统检查均正常。六小时后，我们放置了一根导管于硬膜外，无相关并发症出现，经导管以10mL / h输注0.2％罗哌卡因持续镇痛。我们加用催产素增强宫缩，并放置宫内压导管监测宫内压。没过多久发生胎心率减慢，我们停用催产素以恢复胎心率。之后，我们发现导管穿刺部位出血。患者既往无凝血病病史，其他部位未见出血。我们对穿刺部位进行了检查，并加压包扎。1小时后，穿刺部位仍持续缓慢出血。我们进行了凝血相关检查，包括凝血酶原时间（PT）与国际标准化比例（INR），纤维蛋白原和D-二聚体。后来，胎心率减慢再次出现，阴道检查显示宫口完全扩张，宫颈管消失。我们使用真空辅助，将新生儿从阴道分娩出来，但造成了会阴三度裂伤。随即病人出现了产后出血，使用催产素、米索前列醇、卡前列素和甲基麦角新碱都无法控制出血。我们怀疑出血的病因是凝血病，凝血相关检查显示PT延长至22.6秒，INR为2.0（正常范围PT 为11-14秒和INR为0.8-1.1），提示可能出现了弥散性血管内凝血（DIC）。我们又额外放置了四根导管，预约了2个单位的红细胞（RBC），还使用了Bakri球囊导管填塞宫腔试图减缓阴道出血。我们对会阴撕裂伤进行了修复，尽管它并不是出血的主要来源。输血交叉试验完成后47min，患者突然出现呼吸困难和心绞痛，伴随意识改变，紧接着患者出现了低血压和心动过速。我们给予静脉输注10mg依托咪酯与100mg琥珀酰胆碱，并进行环状软骨加压和紧急气管插管。使用视频喉镜引导气管插管更容易。很快患者的股动脉和颈动脉不能触及脉搏，此时诊断考虑羊水栓塞（AFE）并发DIC及循环衰竭。我们立即实施高级生命支持（ACLS）和心肺复苏术（CPR），并放置了股静脉导管和桡动脉导管，还输注了6个单位红悬和4个单位新鲜冷冻血浆治疗阴道持续出血。有创动脉压力波形表明胸部按压提供了足够的外周灌注。床旁紧急经食管超声心动图（TEE）显示右心室三尖瓣中度反流，升主动脉的食道短轴视图没有明显的鞍状栓子，左心室经胃短轴切面显示左心室收缩功能严重受限，但左心室舒张末期容积正常。肝脏附近的下腔静脉发现血栓的可能，血栓直径小于1cm并且轻微的回声不规则。
A28-year-old otherwise healthy, nonsmoking, 76-kg primigravid woman presented at 41 weeks of gestation forvaginal misoprostol induction of labor. Initial examination and review of systems were unremarkable. After 6 hours,a labor epidural catheter was placed without complication,and a ropivacaine 0.2% epiduralanalgesic infusion wasinitiated at 10 mL/h. An oxytocin infusion was administered forlabor augmentation, and an intrauterine pressure catheter was placed. Occasional fetal heart decelerations occurred soon afterward, and the oxytoc ininfusion was stopped with the resolution of decelerations. Bleeding was then noted from the epidural catheter site. The patient had no history of coagulopathy, and there was no bleeding from any other site. The epidural catheter site was inspected, anda pressure dressing was applied. An hour later, the slow hemorrhage from the epidural catheter site had continuedand coagulation studies including prothrombin time (PT) with international normalized ratio (INR), fbrinogen, andd-dimer were performed. Late decelerations returned andvaginal examination showed complete dilationand complete effacement. The neonate was then vaginally delivered with vacuum assistance resulting in athird-degree perineallaceration. Thepatient developed postpartum hemorrhage that did not improve despite oxytocin, misoprostol, carboprost,and methylergonovine administration. The etiology of the hemorrhage was suspected to be coagulopathy.Coagulation studies showed an increased PT of 22.6 seconds and INR of 2.0 (normal range PT 11–14seconds and INR 0.8–1.1). Disseminated intravascular coagulation was suspected.Additional IV catheters were placed, 2 units of cross matched red blood cells (RBCs) were ordered for transfusion, and intrauterine tamponade witha Bakri balloon was performed to attempt to slow the vaginal hemorrhage. Aperineal laceration was repaired despite the fact that it was not considered to be the major source of hemorrhage.Forty-seven minutes after completion of transfusion of cross matched blood but before intensive care unit transfer, the patient suddenly reported dyspnea and angina and rapidly developed an altered mental status. The patient then became hypotensive and tachycardic.Tracheal intubation was performed emergently, facilitated by intravenous administration of 10mg etomidate and 100 mg succinylcholine when maintaining cricoid pressure. Thetracheal
tube was placed easily with a grade I laryngoscopic view.Shortly thereafter, pulses were absent onfemoral andcarotid artery examination. The presumed diagnosis was AFE presenting with disseminated intravascular coagulation and cardiovascular collapse.Advanced cardiac life support (ACLS) and cardiopulmonary resuscitation (CPR)were immediately initiated during which a femoral central venous catheter and radial arterial catheter were placed and 6 units of cross matched RBCs with 4 units of fresh frozen plasma were administered to treat ongoing vaginal hemorrhage.The arterial catheter waveform suggested adequate peripheral perfusion from chest compressions.Bedside rescue transesophageal echocardiography (TEE) revealed right heart strain with moderate tricuspid regurgitation, no obvious saddle embolus on midesophageal short-axis view ofthe ascending aorta, and severely depressed left ventricular systolic function with adequate left ventricular end-diastolic volume as seen onthe transgastric short-axis view of theleft ventricle. A fnding suspicious for a thrombus was seen in the inferior vena cava near the liver. This was a small,slightly echogenic irregularity within the inferior vena cavaless than 1cm in diameter.
尽管ACLS治疗时使用了多种药物，包括血管加压素、碳酸氢钠、氯化钙、阿托品和总共6mg的肾上腺素，但是患者的心律表现为心动过缓与心脏骤停相互交替并长达40分钟。尽管患者在硬膜外镇痛时输注的罗哌卡因完全在正常剂量范围内，并在整个分娩过程中提供了极有效的镇痛作用，局部麻醉药物全身急性毒性反应（LAST）也不能完全排除。检查输液状况看到罗哌卡因剩余剂量正常，也未出现输液泵故障。患者起初输注了8mL的0.2％罗哌卡因，共16mg。之后以10mL / h持续输注6小时，6小时内共输120mg。这远低于罗哌卡因（3mg / kg）的最大推荐剂量限度。此时我们给予患者1.5mL / kg大剂量20％脂肪乳弹丸注射。TEE清楚地显示，患者在30〜90秒内恢复了自主循环和窦性心律，左右心室功能也明显改善。几分钟后，患者的病情逐渐恶化再次出现心脏骤停，立即又开始CPR并第二次输注脂肪乳（1.5mL / kg）以0.25mL / kg / min。患者于30〜60秒内再次恢复窦性心律和自主循环。此外，患者的四肢也可以进行自主运动。
Despite several administrations of ACLS medications including vasopressin, sodium bicarbonate, calcium chloride,atropine, and a total of 6mg epinephrine, the patient’sheart rhythm fluctuated between profound bradycardia and asystole for a prolonged period of 40 minutes. Other diagnoses were considered such as local anesthetic systemictoxicity (LAST) despite the fact that her epidural analgesia infusion was well within the normal dosing range for ropivacaine and worked well providing effective analgesia throughout her labor. An inspection of theinfusion revealed the expected amount of ropivacaine left in the bottle andno evidence of pumpmal function. The patient receivedan initial 8-mLbolus of ropivacaine 0.2% totaling 16mg followed by an infusion of 10mL/h for 6 hours, totaling120mg over 6-hour period, well below the maximum recommended dose limit for ropivacaine (3 mg/kg). Asa lastresort, IV lipid 20% emulsion (1.5mL/kg) was administered as a bolus.Within 30 to 90 seconds, the patient had returnof spontaneous circulation, normal sinus rhythm, and dramatic improvement in left and right ventricular function,shown clearly by TEE. After several minutes, the patient’s condition slowly deteriorated once again toasystole, at which time CPR was once again started and a second lipid emulsion bolus (1.5mL/kg) was administeredand followed with an infusion at 0.25mL/kg/min. Within 30 to60 seconds, the patient again had a returnof spontaneous circulation with normal sinus rhythm. In addition, she also exhibited spontaneous movements of her extremities.
患者转入ICU时，意识已回复并能够遵循命令。转入ICU后停止输注脂肪乳。初始的凝血检查显示纤维蛋白原<60mg / dL和d-二聚体水平>20µg/mL（正常范围：纤维蛋白原150-400mg /mL和d-二聚体<0.5µg/mL）。因阴道持续出血，患者又加输了6个单位的红细胞、5个新鲜冷冻血浆、1个单位的血小板和2个单位的冷沉淀。发病初期，她需要肾上腺素和去甲肾上腺素升压以维持血压。直到后来凝血功能正常与血液动力学稳定性才停用升压药。患者整晚被镇静和机械通气，并且被密切监测。
She was transferred to the intensive care unit where she regained consciousness and was able to follow commands. Lipid emulsion infusion was discontinued shortly after arrival. Initial coagulation studies revealed fbrinogen levels <60mg/dL and d-dimer levels >20µg/mL (normalrange fbrinogen 150–400mg/mL and d-dimer <0.5 µg/mL).Because of ongoing vaginal hemorrhage, she required an additional 6 units of RBCs, 5 units of freshfrozen plasma, 1unit of platelets, and 2 units of cryoprecipitate. Initially, she required vasopressor support with epinephrine and norepinephrine until hemostasis and hemodynamic stability were achieved later thatevening. She was sedated and ventilated overnight and monitored closely.
患者双手出现了严重的再灌注损伤伴严重缺血性改变。此外，患者还出现了急性肾衰，并进行了4次透析治疗。第二天，停用镇静药，我们予以拔管因患者满足拔管条件。患者能够完全定向，并且没有任何明显的神经系统后遗症。患者因凝血障碍留置硬膜外导管，但在凝血功能检查正常后于住院第3天拔出导管。6个月后我们随访发现，除了与双手再灌注组织损伤相关的中度感觉缺失外，没有其他神经系统后遗症。出院后，患者完全能够进行日常生活和照顾新生儿。进一步的血液系统检查没有发现任何存在潜在凝血病或会导致循环衰竭的高凝状态的证据。
The patient developed profound reperfusion injuries inboth hands with severe ischemic changes. Inaddition, she experienced acute renal failure that required 4 sessions of dialysis. The next day, sedation was discontinued,and the patient was extubated after meeting all extubation criteria.The patient was fully oriented without any obvious neurologic sequelae. The epidural catheter had beenleft in placebecause of her coagulopathy but was removed on hospitalday 3 after normalization of coagulation studies. Follow-up at 6 months revealed no neurologic sequelae other than modest sensory-related defcits in bilateral hands related to reperfusion tissue injury. After discharge, the patient was able to fully participate in her activities of daily living and care for her newborn. Further hematologic investigation revealed no evidence of any underlying coagulopathicor hypercoagulopathic condition that may have providedalternative etiologies of the cardiovascular collapse.
脂肪乳发挥作用的可能机制：中和麻醉药的毒性；心脏的正性肌力作用；改善线粒体功能；内含前列环素前体物质亚麻酸，起到诱导血管舒张、降低肺动脉压力的作用。
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