[Crisis event] Sudden supine hypotension syndrome during perianaesthesia

Focus on the sudden supine hypotension syndrome during perianaesthesia.
Contributions: Hangbo layout: Onion 1.
Occurrence and harm of sudden supine hypotension syndrome during perianaesthesia 1.
Syndrome of sudden supine hypotension during perianaesthesia The definition of symptoms Supine hypotensive syndrome (supine hypotensive syndrome, SHS) refers to the significant enlargement of the uterus in the third trimester of pregnancy.
When lying on the back, the heavy uterus presses against the spine and oppresses the inferior vena cava.
A series of manifestations caused by a sudden decrease in cardiac blood volume, leading to a rapid decrease in cardiac output, leading to insufficient supply of the heart and tissues
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The main manifestations: rapid drop in blood pressure, systolic blood pressure fell to 80mmHg or less decrease> 30mmHg, accompanied by rapid and weak pulse, shortness of breath, dizziness, lightheadedness, nausea, sweating and so on
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Peri-anaesthesia supine hypotension syndrome refers to supine hypotension syndrome that occurs within 1 to 2 days after the decision to undergo anesthesia for surgery to the end of anesthesia
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2.
The occurrence of sudden supine hypotension syndrome during perianaesthesia.
About 90% of women in the supine position during the third trimester of pregnancy will compress the inferior vena cava to varying degrees, and about 50% will have obvious supine hypotension syndrome symptoms
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The incidence of supine hypotension syndrome during cesarean section is 30%, and the incidence of hypotension during combined spinal-epidural anesthesia exceeds 40%
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Foreign studies have reported that in obstetric surgery, the incidence of supine hypotension syndrome after intraspinal anesthesia can be as high as 50%~80%
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Supine hypotension syndrome occurs in pregnant women in several situations as follows: ① During cesarean section, supine hypotension syndrome occurs most frequently after anesthesia and 10-20 minutes before the birth of the newborn, and intraspinal anesthesia is common.
See (epidural anesthesia, subarachnoid anesthesia, combined spinal-epidural anesthesia), but less common in general anesthesia
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Compared with epidural anesthesia, supine hypotension syndrome occurs earlier and has a higher probability in subarachnoid anesthesia
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Since the pelvic sigmoid colon occupies the left side, the uterus will have different degrees of dextrorotation in the third trimester of pregnancy.
The inferior vena cava located on the right side of the spine has the characteristics of thin blood vessel wall and large lumen, which is easily compressed by the uterus
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Pregnant women under non-anaesthesia can compensate for their pulse volume by increasing systemic resistance and accelerating heart rate, or through venous bypass, paraspinal veins, and atypical venous systems.
Anesthesia will weaken these compensatory mechanisms
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Studies have shown that timely monitoring and treatment of maternal hypotension is particularly important, and short-term hypotension will not increase maternal and fetal mortality
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②The supine position during ultrasound examination is a conventional position, and sometimes the uterus is pushed to the right for left-side abdominal exploration, which will aggravate the compression of the inferior vena cava and induce supine hypotension syndrome
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Supine hypotension syndrome can also occur when pregnant women in the third trimester of pregnancy lie supine for too long (rest or sleep)
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③In the case of multiple pregnancy, polyhydramnios, and giant babies, enlargement of the uterus will increase the pressure of the abdominal cavity, thereby compressing the inferior vena cava and blocking the blood return.
Patients with poor cardiopulmonary function and preeclampsia are more likely to suffer from supine hypotension syndrome
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3.
The manifestation of sudden supine hypotension syndrome during perianaesthesia.
Hypotensive shock-related symptoms of pregnant women in the third trimester of pregnancy after lying on the supine position: dizziness, chest tightness, nausea, vomiting, body cold sweat, rapid pulse, systolic blood pressure drop by 30mmHg or Drop below 80mmHg; hypotension can cause acute fetal distress: fetal heart rate increases, fetal movement increases, and then fetal heart rate is slow, and fetal movement decreases
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The symptoms of supine hypotension syndrome after anesthesia can be quickly improved or completely disappeared by changing the position and delivering the fetus.
This can be distinguished from the drop in blood pressure caused by other reasons after intraspinal anesthesia
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4.
The hazards of sudden supine hypotension syndrome during perianaesthesia Supine hypotension syndrome can cause fetus and neonatal asphyxia, endangering the life safety of mothers and neonates
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How to predict and prevent the occurrence of supine hypotension syndrome during the peri-anaesthesia period is a common problem faced by all anesthesiologists and obstetricians
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(1) Hazard to the fetus or newborn: When supine hypotension syndrome occurs during anesthesia, the pregnant woman's return heart blood volume decreases, the placental blood perfusion decreases, and the fetus suffers from fetal distress and neonatal asphyxia due to ischemia and hypoxia
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In the hypoxic state, in order to ensure the blood supply of vital organs, the heart and brain blood vessels will be expanded and other blood vessels will be contracted
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The contraction of the mesenteric blood vessels can lead to hypoxia in the gastrointestinal tract, increased bowel motility, and relaxation of the anal sphincter, which ultimately leads to meconium contamination of amniotic fluid
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When the aerobic metabolism of the fetus is inhibited, anaerobic glycolysis will be enhanced, and severe hypoxia for a long time will cause the accumulation of acidic metabolites, causing internal environmental disorders and acid-base balance disorders
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(2) Harm to the parturient: ① Placental abruption
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In supine hypotensive syndrome, increased intravenous pressure in the uterus leads to congestion or rupture of the decidual venous bed, and hematoma in the decidual layer can cause partial or complete separation of the placenta from the uterine wall.
The supine position occurs after anesthesia until the newborn is born.
High incidence of hypotension syndrome and placental abruption
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②Acute left-side heart failure: due to the wrong diagnosis of supine hypotension syndrome for pregnant and lying-in women after anesthesia, measures were not taken in time to relieve the uterine pressure on the inferior vena cava, and it was mistaken as drug-induced hypotension and spinal canal obstruction Insufficient return blood volume caused by the expansion of stagnant blood vessels, the application of boosting drugs and a large amount of rapid infusion leads to an increase in circulating blood volume and peripheral vasoconstriction.
The sharply increased return blood volume aggravates the pre-heart afterload, leading to acute pulmonary edema and left The occurrence of heart failure
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2.
Analysis of the causes of sudden supine hypotension syndrome during perianaesthesia? 1.
Patient factors ① Blood volume increase: blood volume increases at 6 weeks of gestation, and reaches a peak at 32 to 34 weeks of gestation
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②Dilution of blood: It is manifested by the decrease of hemoglobin concentration, hematocrit and blood viscosity, and the acceleration of red blood cell sedimentation rate
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Reason: The increased blood volume is the sum of plasma volume and blood cells.
The plasma volume first increases and is larger, while the red blood cell increases later and is smaller
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③Increase of interstitial fluid: blood dilution, decreased plasma albumin concentration and increased intracapillary venous pressure lead to increased interstitial fluid production, and increased plasma estrogen, aldosterone and deoxycorticosterone concentrations during pregnancy lead to sodium and water retention
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④ Increased cardiac output: the stroke volume and heart rate increase since the 10th week of gestation, and reach the highest peak at the 28th week of gestation
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⑤ Head and pelvis disproportion: When approaching the expected date of delivery, the access of the fetus in the normal fetal position to the pelvis will reduce the pressure on the inferior vena cava, while the abnormal fetal position (buttock, transverse, twin and huge fetal position) prevents the fetal head from entering the pelvis
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2.
Surgical factors ① Patients with elective cesarean section have not yet experienced paroxysmal uterine contractions.
The uterine blood flow is sufficient and the volume and weight are relatively large.
It also has a greater impact on the blood return of the lower limbs and pelvis, so it is prone to supine hypotension.
Syndrome; ②Most pregnant women undergoing emergency cesarean section have regular uterine contractions.
Paroxysmal uterine contractions can reduce uterine blood flow and relatively increase circulating blood volume; contraction of the uterus and lifting along the birth axis can reduce the impact on the inferior vena cava The compression of the parturients entering the labor process is hypertensive, the breathing deepens and the blood vessel tension increases, and the negative pressure of the intrathoracic vein is conducive to venous return
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3.
Anesthetic factors (1) Vasodilation: After intraspinal anesthesia, local anesthetics block the preganglionic fibers of the sympathetic ganglion to dilate the blood vessels within the block plane, resulting in a decrease in the return blood volume and a relatively insufficient blood volume
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(2) Muscle strength weakening: local anesthetics and muscle relaxants can weaken the muscle strength of the abdominal muscles and pelvic muscles, thereby weakening the supporting effect of the muscles and ligaments around the uterus on the uterus, and aggravating the compression of the inferior vena cava by the pregnant uterus
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(3) Local anesthetic liquid diffusion and high nerve block: In the third trimester of pregnancy, the epidural vena cava and the increase in intra-abdominal pressure can increase the pressure in the epidural space, and the sensitivity of the pregnancy itself to local anesthetics Increasing, regular doses of local anesthetics can cause high-level block, expand the blood vessels in the block plane and reduce the blood return to the heart.
The plane above T6 can also block the heart sympathetic nerve, which is manifested by decreased myocardial sympathetic tone, decreased contractility and heart rate Slow down, more likely to occur supine hypotension syndrome
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3.
Strategies to cope with sudden supine hypotension syndrome during perianaesthesia 1.
Recognition ①Supine hypotension syndrome is more common in pregnant women in the third trimester, and often occurs during ultrasound examination, prolonged supine position or cesarean section; ② Manifestations of blood pressure drop (systolic blood pressure drops below 80mmHg or blood pressure drop> 30mmHg), accompanied by fast and weak pulse, poor breathing, dizziness, chest tightness, nausea and sweating, etc.
; ③The above symptoms are rapid after changing the position and delivering the fetus Improvement or complete disappearance can be diagnosed as supine hypotension syndrome
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2.
Monitoring (1) Supine stress test: measure the blood pressure and heart rate of the mother in the left and supine position respectively.
If the heart rate of the mother in the supine position is measured twice in a row, the base value in the lateral position will increase more than 10 times.
/Min, or two consecutive measurements of the systolic blood pressure of the parturient in the supine position is more than 15mmHg lower than the basic value in the lateral position, or the parturient has symptoms such as dizziness, chest tightness, nausea, vomiting, cold sweats, and rapid pulse, which meets one of them It can be diagnosed
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The sensitivity of the supine stress test to predict supine hypotension syndrome after spinal anesthesia was 69% and the specificity was 92%
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(2) Research by Hanss et al.
proved that heart rate variability can reflect the balance of autonomic nerves.
The basic low-frequency and high-frequency ratio (LF/HF) was divided into two groups.
The results showed that the incidence of supine hypotension syndrome after spinal anesthesia in the high LF/HF group Obviously larger than the low LF/HF group
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(3) Older parturients (N35 years old), obesity (BMI>29~35), giant infants (weight>4000g) are all risk factors affecting supine hypotension syndrome after spinal anesthesia
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(4) Research by Young-Tae Jeon et al.
found that the incidence of hypotension was 41% when the mean arterial pressure was changed above 11mmHg caused by changes in body position before anesthesia
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3.
treatment before anesthesia, anesthesia after surgery or closely observe whether the early performance of pregnant women supine hypotensive syndrome: palpitations, shortness of breath, chest tightness, and so on
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In the left side position, the intra-abdominal pressure is significantly lower than the supine position.
After the anesthesia operation is completed, take the supine position, tilt the operating bed on the left side or elevate the right hip 15°~30°, and push the uterus to the left side of the abdominal cavity to facilitate amniotic fluid flow To the left, can reduce the incidence of supine hypotension syndrome after anesthesia
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Once the peri-anaesthesia maternal presents symptoms of hypotension syndrome in supine position, immediately take countermeasures and call for help: ①Keep the airway unobstructed, and inhale high-flow oxygen through the mask; ②Keep the left side lying or push the uterus to the left side, individually The uterus of pregnant and lying-in women will have left-handedness.
If the above measures are not effective, you should consider adjusting the operating bed: ③Remove vomit in time to prevent aspiration; ④Select appropriate vasoactive drugs according to the degree of blood pressure drop and heart rate increase to maintain Stable hemodynamics; ⑤ Shorten the operation time as much as possible, and be prepared to rescue the newborn
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4.
Thinking of Supine Hypotension Syndrome in Sudden Peri-anesthesia 1.
Adequate communication between doctors and patients before operation.
Ancient Greek Hippocrates once said: "There are two things in the world that can cure diseases, one is medicine, and the other is Language is more important than understanding the disease to understand the patient
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"It can be seen that good communication is an important prerequisite for ensuring a harmonious relationship between doctors and patients, and it is also the basis for improving the quality of medical services
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The medical model of "biology-psychology-society" also requires doctors to have good doctor-patient communication skills
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As one of the non-technical content of anesthesiologists, doctor-patient communication plays an important role in maintaining a good doctor-patient relationship, reducing doctor-patient conflicts, and reducing the incidence of medical disputes
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Anesthesiologists are a high-risk profession.
The related operations of anesthesia are all invasive.
Improper use of anesthetics will lead to fatal consequences.
There has always been a saying that “the anesthesiologist is the life guardian of patients during surgery”.
Reflects the importance of the work of anesthesiologists
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Faced with today's complex medical environment, anesthesiologists should pay more attention to improving doctor-patient communication skills, so as to reduce doctor-patient conflicts and medical disputes
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①Besides paying attention to the general situation of pregnant women before surgery, they should also ask about their preferences during pregnancy and whether they feel uncomfortable after changing their positions; ②Explain related matters such as surgical methods, anesthesia methods, and intraoperative cooperation, so as to reduce psychological pressure and prevent excessive tension, which is effective Nursing intervention can shorten the time of supine hypotension syndrome; ③For women with high-risk supine hypotension syndrome (uterine fibroids with pregnancy, giant infants, placenta previa, cephalopelvic disproportion, breech transverse position), before surgery Prepare first aid supplies
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2.
Routine oxygen inhalation and preventive fluid infusion Routine oxygen inhalation after anesthesia to increase the oxygen partial pressure of the mother and fetus, shorten the operation time as much as possible after the occurrence of supine hypotension syndrome, and prepare for the rescue of the newborn
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(1) Infusion site: In the third trimester of pregnancy, the uterus compresses the inferior vena cava, the lower limbs venous blood returns slowly, the intravascular pressure is higher than that of the upper limbs, and the intraspinal anesthesia will cause the lower limbs to dilate, while the upper limb veins are not compressed or anesthetized As a result of the block, the smooth flow of upper extremity infusion is beneficial to speed up the infusion and treatment.
Once supine hypotension syndrome occurs, the effective circulating blood volume can be supplemented in time, so the upper extremity vein should be selected for the infusion site
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(2) Liquid type: Appropriate infusion can reduce and prevent the occurrence of supine hypotension syndrome.
The effect of colloidal fluid and hypertonic crystalloid solution is better than that of isotonic crystalloid solution
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About 75% of the crystal fluid will be transferred to the interstitial space, and the expansion effect can only be maintained for 15 minutes; while the colloidal fluid stays in the blood vessel for a long time.
By increasing the intravascular colloidal osmotic pressure, it can effectively improve cardiac output and tissue hypoperfusion
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3.
Anesthesia method After intraspinal anesthesia and during surgery, the mother who is awake is helpful to find supine hypotension syndrome
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Compared with general anesthesia, intraspinal anesthesia is more used in cesarean section operations
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Intraspinal anesthesia includes continuous epidural anesthesia, subarachnoid anesthesia and combined spinal-epidural anesthesia
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Epidural stenosis at the end of pregnancy, the use of intraspinal anesthesia should reduce the amount of local anesthetics
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Continuous epidural block: give the test amount first and then give the drug in divided doses, monitor the block level to prevent extensive epidural block
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Subarachnoid block has the advantages of fast onset, good analgesic effect, and perfect muscle relaxation, but it is prone to supine hypotension syndrome
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5.
Sharing of typical cases of sudden supine hypotension syndrome during peri-anaesthesia 1.
1 case of severe supine hypotension syndrome Patient, female, 28 years old, weight 90kg, previously healthy, able to lie supine without discomfort before this operation
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Weight gain during pregnancy is 20kg
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Admission examination: whole body edema (+++), urine protein (+), abdominal circumference 118cm, uterine height 42cm, slightly larger than the gestational age, ECG: abnormal ST-segment T wave (inferior wall), abnormal ECG
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The preoperative diagnosis was: pregnant 38+5w G4P1 ROA waiting for labor
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Entering the operating room: blood pressure: 125/70mmHg, heart rate 105 beats/min, epidural puncture is performed at the L1-2 gap, the puncture is smooth, no cerebrospinal fluid is drawn back, 2% lidocaine 5ml is slowly pushed in, and the head is placed 4cm.
, Place the patient in the supine position.
After 5 minutes, the patient has no abnormalities.
Then, 10ml of 2% lidocaine is pushed through the epidural catheter again.
After 6 minutes, the patient feels dizzy and nauseous.
Blood pressure: 75/35mmHg, heart rate 114 beats/ Infusion, intravenous injection of ephedrine 20mg immediately, the effect was not good, then the patient developed restlessness, complained of general malaise, dyspnea, immediately pressurized oxygen with face mask, and intravenously pushed ephedrine 20mg again, but the patient was still irritable and had difficulty breathing Increased, cyanosis of the lips
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Blood pressure measurement: 56/25mmHg, heart rate 118 beats/min, auscultation of both lungs with clear breath sounds, no rales
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Urgently tilted the operating table to the left and moved the uterus, but then the blood pressure could not be measured, the heart rate was 128 beats/min, the patient was still irritable, the cyanosis further worsened, and the consciousness gradually disappeared.
He immediately gave a rapid intravenous infusion of dopamine 60mg and intravenous dexamethasone 10mg.
, Blood pressure quickly rose back to 120/60mmHg, and his consciousness quickly recovered.
This process took about 12 minutes
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At this time, the anesthesia plane is measured below T8
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Keep pushing the uterus, the operation ends smoothly, and the mother and child are safe
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2.
1 case of placental abruption caused by supine hypotension syndrome.
A 26-year-old patient was admitted to the hospital at 10 am due to menopause for 40+3 weeks, G1P0, LSA, breech position (mixed breech position)
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Admission examination: body temperature 37°C, pulse 80 beats/min, breathing 19 beats/min, blood pressure 110/70mmHg
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Obstetric examination: uterine height 33cm, abdominal circumference 100cm, breech presentation, fetal heart rate 136 beats/min
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At 2:30 pm on the day of admission, no uterine contractions, no rupture of membranes, fetal heart rate 144 beats/min, NST response type rating of 10, fetal estimated weight is about 3600g, considering mixed breech position, fetal estimated weight is larger for surgery Sign, cesarean section
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The patient entered the operating room at 3:30 in the afternoon, with a clear mind and good spirits, with a blood pressure of 115/70mmHg, a heart rate of 80 beats/min, continuous epidural puncture catheterization was smooth, and a supine position with a fetal heart rate of 140 beats/min.
At 3:45 pm, the test amount of local anesthetic 2% lidocaine plus 1:200,000 U adrenaline mixture 3ml was injected, 10 seconds after the injection, the patient was irritable, nausea, palpitation, and blood pressure continued to drop, 3:51:30 pm The blood pressure is as low as 60/30mmHg per second, the heart rate is as slow as 42 beats/min, and the level of acupuncture anesthesia does not appear.
The possibility of anesthesia accidents and allergies is ruled out, and supine hypotension syndrome is considered
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Adjust the operating bed to the left side and tilt 30°, move the uterus to the upper left with both hands, inhale oxygen with the mask, and intravenously inject 30mg of ephedrine.
No improvement, 60mg of ephedrine is added, and the fetal heart rate is 70~80 beats/min.
The surgeon immediately started the operation under local anesthesia.
The skin was cut at 3:58:30 in the afternoon, and the abdomen was opened at 4:1:20 in the afternoon.
Bloody amniotic fluid was visible when the uterus was cut.
The foot was breech first at 4:5:20 in the afternoon.
Lu gave birth to a baby boy weighing 3800g, rated 5 points by Apgar score at 1 minute, and scored 9 points at 10 minutes after rescue, and transferred to pediatric treatment
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After the fetus is delivered, bloody amniotic fluid gushes out, the color is red, the amount is about 1600ml, the uterine muscle is injected with oxytocin 20U, and the placenta is delivered quickly.
Checking the placenta shows 1/3 premature ablation, but no blood clot pressure, suggesting that the placental abruption time is very short (Within 10 minutes)
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After the fetus was delivered, the patient's blood pressure rose to 120/70mmHg after rehydration.
The estimated blood loss during the operation was about 1200ml, and the fluid was supplemented with 2000ml
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Postoperative diagnosis: ①40+3 weeks of intrauterine pregnancy, G1P0, LSA delivery; ②Beeches foot presentation; ③Placental abruption; ④Postpartum hemorrhage; ⑤Supine hypotension syndrome
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Symptomatic treatments such as fluid supplementation, blood supplementation, and anti-infection treatment are given after the operation
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The blood pressure was maintained at 110~120/60~70mmHg, the suture was removed on the 6th day, and the mother and son were discharged safely from the hospital on the 7th day
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