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A Woman in Labor with Hypotension and Dyspnea After Epidural Placement 

A Woman in Labor with Hypotension and Dyspnea After Epidural Placement
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A Woman in Labor with Hypotension and Dyspnea After Epidural Placement
Author(s):

Janet Waters

DOI:
10.1093/med/9780190609917.003.0022
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A 32-year-old female with history of significant obesity presented at 40 weeks’ gestation in labor. Blood pressure was 130/80, and pulse was 85. Epidural anesthesia was planned prior to vaginal delivery. Placement was challenging. A test dose of 3 mL of 1.5% lidocaine + epinephrine was given, immediately followed by 10 ml of 0.25% Bupivacaine. About three minutes later, the patient complained of inability to feel or move her legs. She then developed shortness of breath followed by marked hypotension, with systolic blood pressure of 60 and heart rate of 40.

What do you do now?

Epidural and Spinal Anesthesia

Total spinal block is a rare but serious complication of epidural anesthesia. It occurs when large doses of local anesthetic intended for the epidural space are inadvertently injected into the subarachnoid space. This can produce anesthesia involving the entire spinal cord, nerve roots, and brainstem. When this occurs, patients develop weakness of the lower and sometimes upper extremities. Cranial nerve findings, including pupillary dilatation, may occur. Respiratory insufficiency ensues, followed by cardiovascular collapse with profound hypotension and bradycardia. Instant recognition and supportive treatment is needed to prevent maternal and fetal demise. Patients may be placed in reverse Trendelenburg to prevent further caudal spread of the anesthetic agent. Intubation and positive pressure ventilation can be done to manage respiratory insufficiency. Hypotension may be managed with vasopressors such as epinephrine, norepinephrine, ephedrine, or phenylephrine. Bradycardia can be treated with atropine or glycopyrrolate. Urgent delivery by elective caesarean section may be indicated if fetal bradycardia ensues.

The primary factor that leads to a total spinal block is the failure to wait an adequate time following a test dose. A test dose is a small amount of local anesthetic with epinephrine. This test dose is intended to assess whether an epidural catheter has inadvertently been placed either in a vein or into the intrathecal space. If it has been placed into a vein, then the patient will experience tachycardia from the epinephrine and light-headedness from local anesthetic neurotoxicity. If the catheter is placed into the intrathecal space, the patient will develop lower-extremity paralysis; however, because of the small dose, the block doesn’t spread beyond the umbilicus. Following a test dose, three to five minutes should pass prior to larger doses of local anesthetic. If this time is not given, then a total spinal block can result upon further dosing. Given full and immediate support, most patients with a total spinal block have complete recovery with no further sequelae.

Other Complications of Epidural and Spinal Anesthesia

Epidural Hematoma

Epidural hematoma occurs in one out of 200,000 spinal anesthetics and one in 150,000 epidurals. Predisposing risk factors include spinal cord and nerve root tumors, coagulopathy, and inherited and iatrogenic clotting dysfunction. Women with significantly decreased platelet counts due to HELLP are at risk for this complication. Use of antiplatelet agents or anticoagulants can also sharply increase the risk of developing an epidural hematoma. Neuraxial anesthesia must be delayed until the effects of these drugs have subsided (Table 22.1).

Table 22.1 Anticoagulants and Waiting Period Prior to Neuraxial Procedure

Medication

Prior to Neuroaxial Procedure

Fondipaparinux (Arixtra)

72 hours

Clopidogrel (Plavix)

48 h

Abciximab (Reopro)

48 h

Enoxaparin (Lovenox) high dose

24 h

Enoxaparin (Lovenox) low dose

12 h

Eptifibatide (Integrelin)

8 h

Tirofiban (Aggrastat)

8 h

Unfractionated heparin, high dose IV continuous

When PTT < 40s

Unfractionated heparin, low dose

No time restrictions

Signs and symptoms of epidural hematoma include unusual back pain, numbness or weakness in the legs, and bowel and bladder dysfunction. Urgent MRI may be used to confirm the diagnosis. Emergency surgical decompression should be undertaken as soon as possible to reduce the risk of permanent injury. Diagnosis can be confounded by prolonged labor where a normal neurological exam is obscured by the presence of epidural anesthesia.

Spinal Cord Injury

Direct spinal cord injury can occur when neuraxial anesthesia is injected into the spinal cord instead of the epidural or subarachnoid space—in 80% of patients, the spinal cord and conus medullaris end at the level of the first lumbar vertebra, and in 20% of patients at the level of the second lumbar vertebra. Placement of the neuraxial block below the L2 level reduces the risk of injury. When this does not occur, direct injury to the spinal cord, conus medullaris, or nerve roots may occur. Patients will complain of pain or paresthesias in the lower extremities when a needle or catheter hits the spinal cord or conus.

Epidural Abscess

Epidural abscess is uncommon and occurs in 1:500,000 neuraxial blocks in the obstetrical population. Onset of symptoms may occur several days after the procedure. Skin flora are the most common infectious agents, with Staphylococcus aureus being the most common bacteria. Failure to adhere to aseptic conditions while placing a neuraxial block can increase risk of development. Prolonged use of epidural catheters beyond three days can also raise the incidence of epidural abscess. Immunocompromised patients are also at risk. Patients will present with fever, headache, back pain, leg weakness, and bowel and bladder dysfunction. Urgent MRI with gadolinium may confirm the diagnosis. Aggressive treatment with antibiotics is necessary. In cases of cord compression, surgical decompression may be necessary.

Meningitis

Meningeal infection is a rare complication of epidural and spinal anesthesia. It occurs in 1:39,000 cases. Microbial contamination from the mouth or the nose of the individual performing the block is the most frequent source. Streptococcus viridans is the most common agent. Use of face masks and sterile gloves reduces the risk of transmitting infectious agents. Clinical manifestations include headache, fever, neck pain and stiffness, and confusion. Seizures may also occur. Diagnosis is made by lumbar puncture, and treatment is with appropriate antimicrobial therapy.

Intravascular Injection of Local Anesthetic

This complication can occur during epidural anesthesia placement when a large amount of local agent is inadvertently injected into the vascular system. Toxicity to cardiovascular and nervous system ensues. Bupivacaine is the most toxic, followed by ropivacaine, levobupivacaine, lidocaine, and chloroprocaine. Patients may complain of a metallic taste in the mouth, perioral paresthesias, double vision, and tinnitus. Agitation and confusion may occur, followed in some patients by seizures. Cardiac collapse may occur, with hypotension, arrhythmia, and cardiac arrest. Lipid emulsion is the treatment of choice. A 20% intralipid should be given as a 1.5 mL/kg IV bolus over 60 seconds, followed by a 0.25 mL/kg IV (400 ml) infusion over 30–40 minutes. The infusion of lipid may be continued until cardiovascular status stabilizes. Continuation of cardiopulmonary resuscitation is necessary during lipid infusion. Some advocate the use cardiopulmonary bypass if available. Recovery may take up to two hours. As discussed above, the use of a test dose is mandatory in order to avoid this complication.

Dural Puncture Headache

Dural puncture headache is the most common complication of obstetrical anesthesia. It can occur after spinal anesthesia, which is typically used for elective caesarean section. It most commonly occurs when epidural anesthesia is administered for labor pain management and the dura is inadvertently punctured. The larger needle that is used for epidural placement allows greater CSF leakage a smaller spinal needle does. Dural puncture headache results from this CSF leak through the punctured dura. This results in a low-pressure headache. Onset is usually within 24–48 hours of the procedure but can occur up to five days after delivery. Patients experience a diffuse headache upon standing, which improves within 15 minutes after lying flat. Traction on the meninges and meningeal vessels upon standing is felt to be the source of the postural symptoms. Some patients complain of neck stiffness, or tinnitus with an echoing effect. Severe cases may result in 6th nerve palsies with diplopia.

Treatment may be initiated with bed rest and hydration. If the symptoms do not improve after 24–48 hours of conservative management, then an epidural blood patch may be done by the anesthesiology team. This is performed by placing 15–20 ml of autologous blood into the epidural space. The blood serves as a “patch” over the dural hole. The volume of blood may restore central nervous system (CNS) pressure. Patients often experience immediate relief. Success rate is 70–97%. In some patients, a second patch is needed. In patients whose headaches are not postural, other possible diagnoses must be considered and appropriate workup initiated.

Key Points to Remember

  • Total spinal block may be prevented by assuring three to five minutes have passed after giving the test dose of local anesthetic and epinephrine prior to administering full dose of the anesthetic agent.

  • Administering neuraxial block below the L2 lumbar level reduces the risk of spinal cord and cauda equina injury.

  • Postdural headache is the most common neurological complication of neuraxial block. The hallmark is a headache that improves when the patient is supine. Persisting symptoms may be treated with an epidural blood patch.

References

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