[Crisis event] Sudden amniotic fluid embolism during perianaesthesia

1.
Occurrence of sudden amniotic fluid embolism during peri-anesthesia A syndrome with a series of severe symptoms
.

More than 70% of cases of amniotic fluid embolism occur during childbirth and within 48 hours after childbirth, and there are also rare cases such as induced abortion, abortion, and amniocentesis
.

Reports of its first clinical symptoms vary, and the early clinical manifestations are usually hypotension, hypoxemia, and disseminated intravascular coagulation
.

Typically, bleeding is the most common clinical presentation
.

2.
High-risk factors: The incidence of amniotic fluid embolism in the world is 2~8/100 000, but the mortality rate is very high, accounting for 5%~15% of the total deaths of pregnant women in developed countries, and it is the primary factor of maternal mortality
.

The high-risk factors of amniotic fluid embolism include: 1.
Advanced maternal age (age > 35 years)
.

② placental abnormalities
.

③ cesarean section or vaginal forceps delivery
.

④ placenta previa
.

⑤ Preeclampsia
.

⑥ excessive amniotic fluid
.

⑦ cervical tear
.

⑧ uterine rupture
.

3.
Diagnosis: Benson's criteria are widely used in clinical diagnosis of amniotic fluid embolism: the puerpera has one or more of the following manifestations within 48 hours after delivery: ① The puerpera has acute hypotension or cardiac arrest
.

② maternal acute hypoxia, manifested as dyspnea, cyanosis or respiratory arrest
.

③ Maternal coagulation disorders, laboratory data indicate intravascular fibrinolysis, or unexplained severe bleeding
.

④ Maternal coma or eclampsia
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⑤ The above symptoms lack other meaningful explanations
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The typical clinical course of amniotic fluid embolism can be divided into three stages: acute pulmonary hypertension and cardiac and pulmonary failure stage (shock stage), coagulation dysfunction stage (bleeding stage), acute renal failure stage, and finally lead to multiple organ failure, mainly It is the failure of important organs such as the brain and liver in a short period of time
.

However, due to individual differences in patients, the symptoms of patients may appear in sequence, out of sequence or at the same time
.

Very atypical cases of amniotic fluid embolism may present only as obstructed labor, or sudden unexplained intrauterine hemorrhage and shock after delivery
.

Some patients are often misdiagnosed as anesthesia accidents, eclampsia, heart disease, anaphylactic shock, and postpartum hemorrhage
.

Amniotic fluid embolism is an unpredictable and extremely dangerous complication of obstetrics with low morbidity and high mortality
.

In the event of amniotic fluid embolism, the puerperae may undergo hysterectomy, or even hemiplegia, vegetative state and even death
.

Babies may suffocate, cerebral palsy or even die
.

At the same time, if the patient's family cannot be fully communicated in a timely manner, it may escalate into a medical disturbance, resulting in extremely adverse social impact
.

Therefore, as a medical worker, we should be vigilant.
When pregnant women are highly suspected of amniotic fluid embolism before and after labor, they should immediately rescue them
.

2.
Analysis of the causes of sudden amniotic fluid embolism during the peri-anesthesia period The pathogenesis of sudden amniotic fluid embolism during the peri-anesthesia period is unclear.
The traditional view is that the amniotic fluid enters the maternal blood circulation through the existence of a breach and causes pulmonary embolism, which in turn causes a series of clinical symptoms
.

The specific ways for amniotic fluid to enter the mother are: (1) During labor, cervical dilation may cause the internal cervical vein to be torn, or when the cervix is ​​surgically dilated and the fetal membranes are stripped, the internal monitor is placed to cause damage to the internal cervical vein, rupture of the vein wall, Opening is an important way for the amniotic fluid to enter the mother; (2) there are abundant venous sinuses at or near the placenta attachment, if the placenta attachment or its vicinity ruptures, the amniotic fluid may enter the maternal uterine veins through this fissure; (3) around the fetal membranes Blood vessels, such as the rupture of the fetal membranes, the opening of the decidual sinuses under the fetal membranes, and the strong uterine contractions may also squeeze the amniotic fluid into the blood sinuses and enter the maternal circulation; one
.

However, it is currently believed that the release of endogenous mediators after the amniotic fluid components enter the mother is the main cause of a series of clinical symptoms
.

As an antigen, fetal components strongly stimulate the body's response, such as antigen-antibody reaction, release immune substances and prostaglandins, leukotrienes, histamine, bradykinin, cytokines, etc.
, resulting in anaphylactic shock-like reactions
.

At the same time, a large amount of procoagulant substances in amniotic fluid are mainly thromboplastin and fibrinolysis-activating enzyme, which cause a strong coagulation reaction, a large amount of platelets and coagulation factors and hyperfibrinolysis, resulting in consumptive coagulation disorders and severe bleeding
.

3.
Coping strategies for sudden amniotic fluid embolism during peri-anesthesia period The success rate of treatment for patients with sudden amniotic fluid embolism during peri-anesthesia period is related to the time of onset, so when the patient is suspected of amniotic fluid embolism during childbirth or cesarean section, the diagnosis should be made Emergency preparedness and measures, diagnosis while treating, pay attention to multidisciplinary cooperation
.

The first aid principles for amniotic fluid embolism include: maintaining airway patency, maintaining oxygen supply, actively rescuing circulatory failure, and correcting coagulation dysfunction
.

Specific measures are as follows: 1.
Strengthen monitoring to maintain hemodynamic stability
.

Once amniotic fluid embolism is highly suspected, immediate pulmonary artery intubation for hemodynamic monitoring with pulmonary artery floating catheter is helpful for early diagnosis and avoids hemodynamic disturbance caused by blind infusion
.

2.
High-concentration oxygen supply to correct hypoxia
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Immediate positive end-expiratory pressure oxygen to improve alveolar capillary hypoxia when there is dyspnea
.

Immediate tracheal intubation at the time of loss of consciousness is beneficial to prevent the occurrence of pulmonary edema, thereby reducing the burden on the heart
.

3.
Actively correct circulatory failure and ensure the blood supply of important organs
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Actively add enough fluids, vasoactive drugs dopamine, norepinephrine to maintain blood pressure, dobutamine, milrinone to maintain cardiac contractility
.

The ideal state is to maintain systolic blood pressure>90mmHg, arterial partial pressure of oxygen>60mmHg, urine output>0.
5ml/(kg*h)
.

4.
Prevention and treatment of disseminated intravascular coagulation
.

Component transfusion is the first choice for correction of disseminated intravascular coagulation
.

Disseminated intravascular coagulation is usually accompanied by massive bleeding, and preferential transfusion of packed red blood cells can maintain oxygen delivery to tissue cells and correct tissue hypoxia
.

Fibrinogen, platelet suspension, fresh frozen plasma, cryoprecipitate and recombinant activated factor VIIa are used to supplement coagulation factors and have a certain effect on reducing the amount of bleeding
.

Cryoprecipitation can not only supplement a variety of coagulation factors, but also supplement fibrinogen and fibronectin, which can remove the amniotic fluid components in the maternal blood
.

In addition, blood purification and plasma exchange are possible to remove harmful components in the blood
.

5.
Obstetric treatment
.

Amniotic fluid embolism occurs before the delivery of the fetus.
Regardless of the mode of delivery, the delivery should be terminated quickly and the resuscitation of neonatal asphyxia should be prepared
.

Uterine treatment: ① hysterectomy
.

In critical condition, it is very dangerous
.

The general condition should be actively improved, the surgical trauma and bleeding should be reduced, the suture should be tight, the bleeding should be completely stopped, thrombin should be placed on the wound surface, the stump bleeding should be prevented during hysterectomy, and the abdominal cavity should be drained
.

②Conditions permit, keep the uterus
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The uterine cavity was packed with sterile gauze containing thrombin after delivery, and the uterine artery or the internal iliac artery was ligated
.

③Uterine suture is more suitable for bleeding during cesarean section
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④Interventional therapy, percutaneous bilateral internal iliac artery embolization (critically ill patients), bilateral uterine artery embolization (generally good patients)
.

6.
Correct pulmonary hypertension
.

Oxygen supply can only solve the partial pressure of alveolar oxygen, and pulmonary hypertension must be relieved as soon as possible in order to fundamentally improve hypoxia
.

Available prostacyclin, aminophylline, papaverine hydrochloride, atropine, phentolamine to relieve pulmonary vascular and bronchial spasm
.

Inhaled nitric oxide has recently been reported to successfully relieve amniotic fluid embolism-induced pulmonary hypertension
.

7.
Anti-allergic should be
.

Early use of high-dose adrenal corticosteroids for anti-allergic treatment, such as dexamethasone, hydrocortisone,
etc.

8.
Prevention and treatment of multiple organ dysfunction syndrome
.

Amniotic fluid embolism is prone to shock, and the shock caused by it is more complicated, and it is related to various factors such as allergic, pulmonary, cardiogenic, and disseminated intravascular coagulation, so it must be comprehensively considered when dealing with it
.

After shock occurs, myocardial hypoxia, energy synthesis disorder, and the influence of acidosis can lead to weak myocardial contraction, reduced cardiac output, and even heart failure.
Therefore, during the treatment process, the pulse should be strictly monitored and attention should be paid to whether there are any lung bottoms.
Moist rales, if conditions permit, central venous pressure monitoring should be performed
.

If the pulse rate is more than 140 beats/min, or there are moist rales at the bottom of both lungs, or the central venous pressure rises above 12cmH2O, fast digitalis preparation can be given, usually 0.
4mg of Maohuan C and 20ml of 25% glucose solution After 4 to 6 hours, 0.
2 mg of arabinoside C can be given as appropriate to prevent and treat heart failure
.

Sufficient blood volume supplementation can restore blood pressure to normal, improve blood flow in the renal cortex, and prevent infection
.

9.
Other measures
.

Extracorporeal circulation, hemodialysis, extracorporeal membrane oxygenation, intra-aortic balloon counterpulsation, nitric oxide therapy, application of auxiliary artificial heart, application of recombinant activated factor VIIa, treatment of refractory hypoxemia and inhalation of prostacyclin to improve the prognosis of patients with amniotic fluid embolism
.

4.
Thoughts on sudden amniotic fluid embolism during the peri-anesthesia period The social awareness of medicine is seriously insufficient, and amniotic fluid embolism, a rare obstetric complication, is not known to patients and their families
.

Therefore, the government should popularize medical knowledge in the community, community health service stations should do a good job of publicity in the community, so that pregnant and lying-in women can understand basic medical knowledge, and at the same time, training institutions and maternity schools should be set up, so that every prospective father and mother can learn pregnancy And childbirth knowledge, understand childbirth risks
.

Do a good job of propaganda and education for pregnant women when they are admitted to the hospital, emphasizing the related risks
.

In the event of amniotic fluid embolism, the anesthesiologist should cooperate with the obstetrician to do rescue work
.

In the event of cardiac and respiratory arrest, immediate cardiopulmonary resuscitation and primary life support should be performed; tracheal intubation should be performed to facilitate tracheal management; central venous puncture and arterial puncture should be performed to facilitate massive infusion and blood transfusion and invasive central venous and arterial pressure.
Monitoring and blood gas analysis
.

Generally, patients with amniotic fluid embolism are more seriously ill and consume a lot of manpower, material and financial resources, so the early prevention of amniotic fluid embolism is very important
.

Specific measures include: (1) Do not interfere too much with the vaginal delivery process, use oxytocin strictly, and be alert to the occurrence of amniotic fluid embolism for those who apply oxytocin after premature rupture of membranes or artificial rupture of membranes
.

② When gynecologists do vaginal and cervical examinations to pregnant women, the movements should be gentle to avoid damage to the birth canal
.

③ Artificial rupture of membranes should be performed during the interval between contractions
.

④ It is strictly forbidden to violently press the abdominal cavity of pregnant women to force the delivery of the fetus
.

⑤ Strictly grasp the indications of cesarean section, and try to absorb the amniotic fluid after rupture of the membrane to prevent it from entering the uterine blood sinus
.

⑥ When the uterine contractions are too strong or tonic, the uterine smooth muscle relaxant magnesium sulfate should be used to inhibit uterine contractions
.

In the event of a dispute over maternal or infant adverse conditions, the matter should be handled in accordance with the law.
Both the doctor and the patient should distinguish between rights and responsibilities, and the medical incident should be placed within the framework of the matter, and a fair evaluation should be given to the doctor and patient according to the law
.

Patients and medical staff should fully understand the relevant laws, reporting systems and relevant handling procedures for dealing with doctor-patient conflicts, clarify the methods of handling responsibilities and faults, and the compensation and punishment measures for conflicts
.

Case Sharing Case 1, mother, 25 years old, 1 pregnancy, 0 birth, 38 weeks gestation, breech presentation, umbilical cord around the neck for 2 weeks
.

Preoperative examination results were normal
.

The uterus was incised during the operation and the baby was successfully taken out.
About 5 minutes after the delivery of the placenta, the puerpera suddenly felt blurred vision, chest tightness, suffocation, irritability, blood pressure 70/45mmHg, heart rate 30 beats/min, poor uterine contraction, and the appearance of uterine seromuscular layer.
Flaky congestion, a lot of non-clotting in the vagina
.

Auxiliary examination: ①The chest X-ray film was taken at the bedside, showing diffuse punctate infiltrates in both lungs, distributed around the hilum
.

②Laboratory examination: 3P test is positive, platelets < 100X109/L, and progressive decline, plasma fibrin <1.
5g/L, prothrombin time, partial thromboplastin time and thrombin time are all greater than normal values, consider For amniotic fluid embolism
.

Immediate rescue after diagnosis of amniotic fluid embolism: ① Open other venous channels and perform blood coagulation tests
.

②Supply oxygen.
Immediately perform general anesthesia and tracheal intubation to give oxygen with positive pressure, and the oxygen flow is 5~10L/min.
③Relieve pulmonary hypertension, use according to the condition: a.
Add 10% glucose injection 20mL 60mg of Poppy Cheng slowly intravenously
.

b.
Atropine 1mg added to 10% glucose injection 10mL subcutaneously
.

c.
Aminophylline 250mg is added to 20ml of 10% glucose injection, and it is slowly injected intravenously
.

d.
Anti-allergic, use methylprednisolone 180mg, add 5% glucose solution for intravenous drip
.

e.
Prevention and treatment of disseminated intravascular coagulation, rapid blood transfusion and a large amount of supplementation of coagulation factors, plasma, fibrinogen and albumin
.

f.
Obstetric treatment: While actively taking the above treatment measures, due to the large ecchymosis on the surface of the uterus and the oozing blood from the needle eye, the ligation of the uterine artery was ineffective, and finally a total hysterectomy was performed
.

10 days after the operation, the patient was discharged
.

Case 2, a puerpera, 26 years old, 2 births 0, labored at 38 weeks of gestation, due to regular uterine contractions after membrane rupture, the puerpera developed cough, wheezing, bruising, coma, blood pressure dropped immediately and could not be measured, and immediately sent to the operating room Perform emergency cesarean section
.

Immediately in the operating room, general anesthesia tracheal intubation was performed with positive pressure, oxygen flow 5-10L/min, other venous channels were opened, and coagulation function tests were performed
.

The uterus is cut open to remove the baby
.

There was no response when the baby was taken out, and the Apgar score was 1 in 1 minute.
Cardiopulmonary resuscitation was performed immediately, but the rescue was abandoned due to severe asphyxia
.

Maternal consideration of amniotic fluid embolism, immediate anti-allergy, application of methylprednisolone 180mg, intravenous infusion of 5% glucose solution, rapid blood transfusion and a large amount of coagulation factors, plasma, fibrinogen and albumin
.

While actively taking the above-mentioned treatment measures, ligation of the uterine artery was performed
.

Postoperative bleeding was controlled, and the total amount of bleeding was 1000ml.
Due to the low blood pressure of the puerperae before anesthesia, the puerpera developed right lower extremity hemiplegia after surgery
.

 Notes / Ruofen Typesetting / Meatloaf