[Yao's Anesthesiology] Reading Notes day15 Perinatal Hemorrhage (1)

Perinatal hemorrhage (1) Patient, female, 41 years old, came to the hospital mainly because of "38 weeks of intrauterine pregnancy, painless vaginal bleeding"
.
The
patient had a painless vaginal bleeding at 28 weeks of pregnancy, and then spontaneously Remission
.

There have been three cesarean sections in the past
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Because of persistent vaginal bleeding, the obstetrician suggested immediate cesarean section
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The patient's vital signs are as follows: BP 90/36mmHg, HR 112 beats/min, RR 22 beats/min , SpO2 97% (no oxygen)
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Hematocrit: 25%
.

A.
Diseases and differential diagnosis 1.
What are the main causes of maternal death? 2.
Discussion of anesthesia-related maternal mortality
.

3.
According to the patient's condition , How to diagnose placenta previa? 4.
What types of placenta previa are divided into? How should it be treated? 5.
Which pregnant women are more prone to placenta previa? What are the related factors of placenta previa? 6.
How to diagnose placental abruption? 7.
What are the risk factors for placental abruption? A.
Diseases and differential diagnosis A1.
What are the main causes of maternal death? The main direct causes of death are: thrombosis, hypertension, premature birth, hemorrhage, amniotic fluid embolism and menstrual bleeding Sepsis of birth canal infection
.

Placental abruption and placenta previa account for 50% of maternal deaths due to hemorrhage and postpartum hemorrhage in 50%
.

A2.
Discussion of anesthesia-related maternal mortality
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Most deaths In 73% of cases that occurred during cesarean section under general anesthesia, airway problems (aspiration, failure of induction or intubation; hypoventilation or respiratory failure) were the cause
.

A3.
According to the patient's condition, how to diagnose placenta previa? People with placenta previa usually experience painless vaginal bleeding in the second and third trimesters
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Clinically, ultrasound is usually used to diagnose placenta previa
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A4.
What are the types of placenta previa? How should it be treated? There are three types of placenta previa: complete placenta previa, partial placenta previa and marginal placenta previa
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Complete placenta previa covers the entire internal os, partial placenta previa partially covers the internal os, and marginal placenta previa is located immediately adjacent to the internal os but does not cover the internal os
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If vaginal bleeding persists, or if the condition of the mother or the fetus is unstable, end the pregnancy as soon as possible
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Because of the position of the placenta, cesarean section should be preferred
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Because persistent vaginal bleeding may occur, the patient needs to have adequate venous access
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A series of laboratory tests, including complete blood counts, coagulation tests, and cross-matching, are also performed
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If the patient does not have coagulation disorders, regional block anesthesia is an option
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Current studies have demonstrated the relationship between placenta previa and placenta accreta
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If placenta accreta is suspected, general anesthesia should be administered
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A5.
Which pregnant women are more prone to placenta previa? What are the factors associated with placenta previa? Multiparous women, older women, women with a history of placenta previa, and women with a history of cesarean delivery are more likely to develop placenta previa
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A6.
How to diagnose placental abruption? Placental abruption usually presents with painful vaginal bleeding
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Typically, with uterine tenderness and contractions
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Because most bleeding is confined behind the placenta and not out of the vagina, it is often difficult to estimate the amount of vaginal bleeding
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Clinically, ultrasonography or MRI can be used to diagnose placental abruption
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A7.
What are the complications of placental abruption? Severe placental abruption is associated with anemia, coagulation abnormalities of varying degrees including disseminated intravascular coagulation, acute renal failure, postpartum hemorrhage, uterine atony, and Sheehan syndrome
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Placental abruption may also cause fetal distress or intrauterine stillbirth
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B.
Preoperative evaluation and preparation 1.
What is the significance of the changes in respiratory function of full-term pregnant women to anesthesiologists? 2.
What changes occur in the cardiovascular system of pregnant women during pregnancy? 3.
What laboratory results do you need before giving this patient anesthesia? 4.
What is supine hypotension syndrome? 5.
What is relative anemia during pregnancy? 6.
What invasive monitoring methods should be used in cases of severe bleeding? 7.
What anatomical changes during pregnancy may cause a difficult airway? 8.
What premedication will you give this patient? B.
Preoperative evaluation and preparation B1.
What is the significance of the changes in respiratory function of full-term pregnant women to anesthesiologists? During full-term pregnancy, maternal respiratory function may change as follows: • Congestion of the capillaries of the respiratory mucosa can lead to edema of the vocal cords, oropharynx, laryngopharynx, and trachea
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• The minute ventilation is increased by 45%, the tidal volume is increased by 45%, and the respiratory rate is unchanged, and the oxygen consumption can be increased by 30% to 40%.
7.
44•Functional residual capacity FRC decreased by 20% After rapid sequential induction, decreased FRC and increased oxygen consumption will rapidly develop hypoxemia in pregnant women
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Therefore, the patient should be inhaled with pure oxygen before induction, breathe with normal tidal volume for 3 to 5 minutes, or take four deep breaths, so as to achieve sufficient oxygen and denitrogenation, thus giving the maximum oxygen reserve to the patient before induction, as Endotracheal intubation buys more time and ensures patient safety
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Decreased FRC results in rapid changes in depth of anesthesia when using inhalation anesthesia
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Minimal alveolar gas concentration MAC decreases with inhaled general anesthesia during pregnancy
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B2.
What changes occur in the cardiovascular system of pregnant women during pregnancy? The following changes occur in the cardiovascular system of pregnant women during term pregnancy: • Blood volume increases by 45% • Plasma volume increases by 55% • Red blood cell (RBC) content increases by 30% • Cardiac output increases by 50% • Stroke volume increases by 25%• Heart rate increases by 25% • Pregnancy has little effect on systolic blood pressure • Diastolic blood pressure can drop by 20% in the second trimester, but returns to pre-pregnancy levels at term The change occurred after the fetus was delivered and was 80% higher than prenatally
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In addition, the following coagulation factors are increased in term pregnancy: coagulation factors I, VII, VIII, IX, X, and XII
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At the same time, fibrinogen also increased
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Factors II and V were unchanged, and factors XI and XIII were decreased
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Overall, the result was a 20% reduction in prothrombin time PT and partial thromboplastin time PTT
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Platelet counts do not change significantly at term, but thrombocytopenia below 100 occurs in about 1% of patients
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In general, most pregnant women experience a hypercoagulable state during pregnancy
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B3.
What laboratory results do you need before giving this patient anesthesia? Complete blood count (including platelets), blood type, and cross-matching
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In addition, coagulation function tests PT and PTT should also be performed
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Thromboelastography (TEG) can rapidly detect the relationship between coagulation factors and platelets, as well as the strength and stability of the blood clot
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In patients with preoperative thromboprophylaxis with LMWH, neuraxial anesthesia should not be administered until at least 10-12 hours after the last dose
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For patients receiving high-dose LMWH, neuraxial anesthesia should not be administered until at least 24 hours after the last dose
.

B4.
What is supine hypotension syndrome? Supine hypotension syndrome, also known as aorto-vena cava compression syndrome, is caused by the compression of the aorta and inferior vena cava by the pregnant uterus in the supine position
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Compression of the inferior vena cava can occur as early as 13-16 weeks of gestation
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At term pregnancy, 40% of pregnant women experienced a marked drop in femoral arterial pressure, consistent with their aortic compression
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Clinical symptoms include weakness, dizziness, nausea, vertigo, and syncope
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Aorto-vena cava compression syndrome leads to the following three mechanisms of uteroplacental hypoperfusion: (1) It reduces the venous return of pregnant women, which in turn leads to a decrease in arterial blood pressure
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② Direct compression of the internal iliac artery further reduces uterine arterial pressure
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③ Poor uterine venous return leads to decreased uterine perfusion pressure
.

B7.
What anatomical changes during pregnancy may cause a difficult airway? The risk of intubation failure after induction of general anesthesia in pregnant women is about 10 times that of patients with general anesthesia in general surgery
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Moreover, aspiration of gastric contents is generally the result of failed intubation
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The anatomical changes that lead to intubation failure during pregnancy are mainly tongue and laryngeal edema and capillary congestion, which further lead to increased airway mucosal fragility and susceptibility to bleeding
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Patients are prone to epistaxis, so nasal intubation is a relative contraindication
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In addition, breast hyperplasia and the resulting shortening of the distance between the chest and cheek can also make laryngoscope insertion difficult
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B8.
What premedication will you give this patient? For patients at high risk of aspiration, a nonparticulate oral antacid, such as sodium citrate, should be administered 30 minutes before induction of general anesthesia
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In addition, metoclopramide is given intravenously before surgery because it increases the tone of the lower esophageal sphincter and accelerates gastric emptying
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Immediately before surgery, sedatives or opioids are contraindicated because of their depressive effects on the neonate
.

Notes/Chen Lingjun Typesetting/Dingdang Maruko Ma May Day Happy Labor Day Salute to the laborers In the festival that belongs to the working people, pay tribute to everyone who works hard for life, pay tribute to everyone who works for others, and sincerely say: You have worked hard Yes, thank you!