【Crisis Resources】Sudden abnormal and extensive block during perianesthesia epidural anesthesia

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Sudden onset of abnormal and extensive block during perianesthesia epidural anesthesia

First, the occurrence and harm of sudden abnormal and extensive block during perianesthesia period of epidural anesthesia

Local anesthetics are injected into the epidural space to block the spinal nerves, causing temporary paralysis in the area of its innervation, called epidural block

The harm of abnormal widespread block under epidural anesthesia is mainly manifested in two ways

1.

(1) Effect on the patient's circulatory system: due to local anesthetics blocking the sympathetic nerve fibers in the thoracolumbar segment, vasodilation occurs, a series of hemodynamic changes occur, which are manifested as a decrease in

(2) Effect on the patient's respiratory system: The effect of spinal canal anesthesia on respiratory function depends on the level of the block plane, especially the range of motor nerve block is more important

(3) Effect on the patient's gastrointestinal tract: when the epidural anesthesia is abnormally and extensively blocked, due to sympathetic block, vagus excitability is enhanced, gastrointestinal peristalsis is hyperperistalsis, while the blood pressure drops and the visceral blood flow decreases, and the medulla oblongata vomiting center is stimulated by ischemia and hypoxia, and the patient is prone to nausea and vomiting, and in severe cases, it can lead to reflux aspiration and life-threatening

2.

Second, the perianesthesia period of epidural anesthesia sudden abnormal extensive block analysis

The epidural space is a potential cavity space, the cavity is full of fat, blood vessels and lymphatic vessels, and the volume they occupy is also different due to the objective environment, so the size of the epidural space volume is different in different people; When performing epidural anesthesia, the location of the catheter placement is different, and the local anesthetic site and spread range will also be significantly different

1.

(1) Infant patients, due to the small absolute value of the epidural space volume, the drug is easy to spread to the head side after giving a normal dose of local anesthetic, and it is easy to produce a blockade plane after administration
.

(2) Elderly patients, especially those with arteriosclerosis, due to tissue degeneration and intervertebral hole atresia, drug leakage is reduced after local anesthetics are given, and the hindrance of drug diffusion by tissues in the epidural space is reduced, and small doses of local anesthetics can also make the block plane wider
.

(3) In the third trimester of pregnancy, large masses in the abdominal cavity, a large amount of ascites, etc.
can lead to poor compression and return of the inferior vena cava, and the venous blood of the lower limbs, pelvic cavity and lower abdomen passes through the intravertebral and external veins and the superior vena cava, resulting in the expansion of the venous plexus of the epidural space, the gap is relatively small, and the drug
spreads easily.

(4) Critically ill, extreme failure, cachexia, internal environment disorders of patients, due to poor systemic condition, the compensatory capacity of various organ systems weakened, the tolerance to epidural anesthesia decreased, and normal doses or even small doses of local anesthesia may produce a wide range
of blockage for such patients.

2.
Abnormal subdural space extensive block The traditional concept is that the subdural space is a potential space between the dura meninges and the arachnoid membrane, and small doses of local anesthetics can be widely diffused into it, forming an abnormal high-plane block
.

Xie Suqin and other scholars refer to the research of many scholars, and believe that there is no anatomical subdural space, but there is a dural-arachnoid interface composed of flat nerve papillal cells and a large number of cell gaps between the dura and arachnoid membranes, which can expand to form a true subdural gap
under the action of external forces and other factors.

After the injection of local anesthetics, because the lower part of the subdural space is more resistant than the upper part, the drug is easy to spread rapidly to the cephalolateral side, but it takes a while to reach the spinal nerve root, so the clinical symptoms of high-plane block appear slowly
.

The occurrence of subdural space block is mostly related to anesthesia puncture procedures, and some patients may also have special triggers
.

(1) During the puncture operation, the dura meninges are injured and the subdural space is formed, resulting in widespread blockage
of the drug entering it during administration.

Epidural anesthesia is a blind probing operation, during anesthesia may be due to the operator's unskilled technology, unfamiliar with the anatomical structure, puncture too fast and too strong to lead to needle penetration too deep, puncture of the patient suddenly body movement, etc.
can lead to the needle tip directly puncturing the dura meninges into the subdural space; After the puncture enters the epidural cavity, the external dural puncture needle is rotated to 180° or more in order to adjust the direction of the catheter, and the rotation of the needle tip can also scratch the dura meninge, and then the drug enters the subdural space when the drug is injected; The tip of the epidural catheter is too hard, and the dura can also be damaged or punctured during catheterization and the catheter can be placed directly into the subdural space; Repeated gas injection tests during puncture can expand and separate the dura and arachnoid membranes, forming a true subdural gap
.

(2) The patient's own factors cause the drug to easily enter the subdural space
.

Patients who have undergone epidural puncture multiple times in the past are prone to narrowing of the adhesion of the epidural cavity, and it is easy to puncture the dura meninge; Spinal deformities, massive ascites, abdominal tumors, etc.
that cause puncture difficulties or multiple punctures, repeated punctures may puncture the dura meninge; Calcification of ligaments in the elderly, narrowing of the intervertebral space in children, difficulty in puncture operation, easy to puncture the dura meninge; Congenital dural thinning can also lead to easy puncture of the dura meninge
.

3.
Strategies for sudden abnormal and extensive block during perianesthesia epidural anesthesia

The occurrence of abnormal widespread blockade during epidural anesthesia has a strong interference with physiological functions and causes serious harm
to the body.

However, during clinical anesthesia, except for a small number of patients whose symptoms and signs suggest that abnormal generalized block may occur during epidural anesthesia, most abnormal generalized block often occurs unexpectedly and is difficult to prevent
effectively.

Abnormal planar diffusion caused by either epidural space block or subdural gap block results in impaired
respiratory and circulatory function.

The principle of management is to maintain the patient's circulatory and respiratory function stability and prevent the patient from causing damage
to important organs due to severe hypotension and hypoxia.

Immediate CPR is performed in patients with cardiac arrest due to abnormal broad-based blockade
.

1.
Pay attention to the preparation before anesthesia, avoid the occurrence of abnormal extensive blockade Before anesthesia, choose suitable instruments, discard inapplicable puncture needles and excellent epidural catheters; Proceed with caution during the puncture process, clarify the indications for entering the epidural cavity, avoid puncture too fast and too strong during the puncture process and repeatedly perform gas injection tests, and avoid rotating the puncture needle
after entering the epidural cavity.

Pay attention to the importance of observing the plane after injecting the test dose, the test amount should not exceed 3 to 5 ml, observe 5 to 10 minutes after administration, determine that there is no total spinal anesthesia, closely observe the small changes in the range of block and vital signs, if the plane spreads widely after giving a small amount of anesthesia, you should stop continuing to administer or cautiously give additional amounts
.

For patients who may have abnormal extensive blockade, vigilance should be raised, attention should be paid to replenishing blood volume before anesthesia, and circulatory breathing changes should be paid attention to after administration, so as to detect changes in the patient's vital signs early and intervene
early.

2.
Deal with abnormal widespread block quickly when it occurs

(1) Maintain circulatory stability: hypotension is often the first symptom of abnormal and extensive blockade of epidural anesthesia, mostly due to a decrease in the amount of blood returning to the heart, a decrease in the amount of cardiac output, and insufficient effective circulating blood volume
.

For mild blood pressure drops, 500 to 1000 ml of crystals or colloidal fluids can be quickly injected to replenish blood volume
.

If the blood pressure drops significantly, vasoconstrictor drugs
can be applied at the same time as rapid infusions.

Ephedrine is the most commonly used drug, because of its combination of α and β receptor excitatory effect, not only can raise blood pressure, but also can fight against the heart rate slowed down by broad-plane block, commonly used 5 to 10mg intravenously
.

If the blood pressure is severely reduced, dopamine can be pumped for maintenance and the dosage
can be adjusted according to the blood drug.

In addition to giving ephedrine, atropine 0.
3 to 0.
5 mg intravenously may be given to fight it
.

(2) Respiratory function maintenance: when abnormal extensive blockade patients due to intercostal muscle paralysis or even diaphragmatic nerve block, respiratory depression may occur, manifested as weak chest breathing, decreased tidal volume, severe cough weakness, unable to make a sound and cyanosis, should immediately mask oxygen
.

For patients with extreme dyspnea due to planar abnormalities, in addition to pressurized oxygenation, endotracheal intubation machine-controlled ventilation can be considered, which can not only effectively control the respiratory tract, but also avoid the risk of
reflux aspiration.

(3) Treatment of nausea and vomiting: hypotension caused by vomiting center excitement, vagus nerve excitation leads to increased gastrointestinal peristalsis are the triggers
of nausea and vomiting.

Once present, in addition to correcting hypotension, atropine may be considered to block vagus reflex and give drugs such as promethazine or haloperidol to antiemetic
.

In patients with hyperplanar block, sedation should be used to prevent reflux aspiration
.

3.
When abnormal extensive blockade occurs in other treatments, awake patients will have chest tightness, breath holding, speech weakness and even no words due to excessive flatness, decreased blood pressure and respiratory depression, and various uncomfortable feelings will inevitably lead to nervous fear and irritability
.

For such patients, they should be comforted by words in time, telling the patient that the discomfort will be reduced after treatment, so that the patient can cooperate with the treatment
.

If necessary, a small amount of sedative is given to relieve nervousness
.

After the patient's vital signs remain stable, the operation can be continued, and the operation can be closely observed during the operation and followed up
in time after the operation.

4.
Typical cases of sudden abnormal and extensive blockade during perianesthesia period of epidural anesthesia

Case 1, patient, female, 24 years old, weight 74 kg, ASAI.
grade, G1P0, 39 weeks gestation, admitted to hospital with a proposed lower uterine caesarean
section.

Choose continuous epidural anesthesia, take L2 to 3 gaps, the puncture is smooth, the breakthrough is obvious, the negative pressure is positive, 3 cm upwards, pate, no blood and cerebrospinal fluid
withdrawn.

Test volume 1.
73% lidocaine carbonate 5 ml, 5 minutes after anesthesia plane at T12-L2, no spinal anesthesia, given 1.
73% lidocaine carbonate 7 ml, 10 minutes later anesthesia plane up to T8, surgery begins
.

The surgery went smoothly and the vital signs were stable
.

When the appendages are explored before closure, the patient has a feeling of discomfort with traction, so 0.
25% bupivacaine is given 8 ml (postoperative analgesic load).


After 10 minutes, the patient complains of dyspnea, dizziness
.

At this time, the blood pressure is 125/78mmHg, SpO2 97%, the immediate nasal catheter oxygen SpO2 is 98%, the dyspnea is not improved, and the resuscitation drugs
such as tracheal intubation are urgently prepared.

After the operation, the patient complained of double nose obstruction, difficult speech, inability to move both upper limbs, and the test plane reached T4
.

Since the blood pressure stabilized at 120 to 130/70 to 80 mmHg, SpO2 >95%, and the end-respiratory carbon dioxide (PETCO2) monitoring waveform rules, it continued to be closely observed without further treatment
.

After 30 minutes, the plane is bounded by the midline, the right side reaches T10, and the left side is still T4, the patient has improved breathing, speaks strongly, has a clear right nose, obstructs the left nose, moves the right upper limb, and cannot move
the left upper limb.

After 1 h, right plane T10, left plane T4, deoxySpO2 >97%, blood pressure 129/84 mmHg, sent back to the ward
.

Postoperative follow-up, no specialty
.

Analysis and discussion: epidural anesthesia abnormal extensive blockade, usually delayed occurrence, mostly 20 to 30 minutes after the first dose, often have chest tightness, dyspnea, speaking weakness and irritability and other prodromal symptoms, and then develop to severe insufficiency of ventilation, or even respiratory arrest, blood pressure may drop sharply or no major changes, spinal nerve block often up to 12 to 15 nodes, still segmental
.

Abnormally extensive spinal nerve blocks include extensive blocks in the epidural space and extensive subdural space
blocks.

In this case, in pregnant women, there is poor inferior vena cava return, extradural space venous plexus outburst, and an decrease in the effective volume of the epidural, so the possibility of extensive blockade of the epidural space is greater, and the extensive blockade of the subdural space is mostly without the inducement of
the reduction of the effective volume of the epidural.

The main preventive measure in such cases is to reduce the amount of local anesthesia
used accordingly.

In this case, 0.
25% bupivacaine 8ml was added, which is
suspected of being too useful.

During the operation, the condition should be closely observed, monitoring should be strengthened, and abnormalities
should be detected early.

Once a broad block occurs, the first priority is to strengthen respiratory management, prepare for endotracheal intubation, and closely monitor blood pressure changes
.

If blood pressure drops significantly, volume should be rapidly expanded and vasoactive agents
used as appropriate.

As long as breathing and circulation are properly managed, the prognosis is good
.

Nasal congestion in this case may be caused
by sympathetic nerve blockade and nasal mucosal congestion.

Case 2, patient, female, 35 years old, due to "full term pregnancy to be delivered", intends to perform a caesarean section under continuous epidural
anesthesia.

Preoperative blood pressure was checked for 133/76mmHg, heart rate 75 beats per minute, laboratory tests of blood routine, coagulation function are within the normal range, electrolyte, liver and kidney function is normal
.

L1-2 gap is selected for epidural puncture, the puncture process is smooth, an epidural catheter is placed on the side of the head, the catheter depth is 4cm, and 1% lidocaine 3ml is injected as a test dose
after redrawing the bloodless and cerebrospinal fluid.

The absence of signs of total spinal anesthesia and local anesthesia toxicity were observed, and the anesthesia level was measured by acupuncture 5 minutes later
.

There is no cerebrospinal fluid reflux in the redraw syringe again, because the patient is more nervous, the anesthesiologist believes that the patient is too nervous, the pain distinction is not clear, did not attract attention, 5 minutes later again added 1% lidocaine + 0.
375% bupicaine mixture 5ml
.

Immediately the patient complained of panic, chest tightness and shortness of breath, immediately measure blood pressure 66/43mmHg, heart rate 59 times / min, SpO2 98%, after intravenous administration of ephedrine 1Omg, the patient's symptoms did not improve significantly, measured blood pressure 72/48mmHg, heart rate 58 times / min, SpO2 85%, at this time the patient nausea and vomiting, obvious irritability, pale, shortness of breath, can only nod or shake his head to answer the
anesthesiologist's question.

Immediately measure the plane to the T2 level, give ephedrine 20mg again, while the mask is pressurized with oxygen, rapid infusion of hydroxyethyl starch 500ml, review blood pressure 91/55mmHg, heart rate 68 times / min, SpO2 up to 99%, instruct the surgeon to immediately start surgery to end the pregnancy
.

1 minute after delivery of the fetus Apgar score 9 points, the operation lasted 45 minutes, after the end of the anesthesia block plane is still in T2, the lower extremities are painless, can not move
.

Surgery to check the blood pressure 95/60mmHg, heart rate 70 times / min, sent to the anesthesia resuscitation room for continued observation, about 1 hour after the end of surgery, the plane gradually dropped to T8, blood pressure 100/60mmHg, heart rate 70 times / min, SpO2 99%, vital signs stable, sent back to the obstetric ward
.

Repeated retractions of the syringe during this process do not see cerebrospinal fluid reflux
.

The patient who was followed up on the second day after surgery had good movement of both lower limbs without special discomfort
.

Postmortem analysis considered that the patient had vertebral venous plexus due to intravena cava compression in pregnancy, the volume of the spinal canal was reduced, and the volume after administration was relatively excessive, resulting in abnormal widespread blockade
.

Notes/Hang Bo

Typesetting/Meat

END