Cesarean Section
Christopher F. James
CASE SUMMARY
A 36-year-old woman, gravida 2, para 1,001, with a 34-week intrauterine pregnancy presented with a complete placenta previa, minimal bleeding, and occasional contractions. Over the next 24 hours, contractions continued despite tocolysis, along with intermittent bleeding and decreased serum hemoglobin levels from 10.2 g per dL at admission to 9.0 g per dL. A cesarean section was scheduled and the patient was taken to the operating room. A combined spinal epidural (CSE) anesthetic was administered, utilizing 12 mg of bupivacaine with dextrose plus 150 µg of intrathecal morphine. She was then placed in the left lateral tilt position. Shortly thereafter the patient complained of nausea and her blood pressure decreased acutely from 120/70 to 85/40 mmHg. Ten milligrams of intravenous ephedrine were administered immediately, with resolution of the nausea and restoration of blood pressure. A viable male infant weighing 2,440 g, with Apgar scores of 7 at 1 minute and 9 at 5 minutes, was delivered without incident, but the placenta was fragmented. The remainder of the procedure was uneventful until skin closure when the patient developed heavy vaginal bleeding despite increased doses of oxytocin and intramuscular prostaglandin F2α (Hemabate; Upjohn, Kalamazoo, MI). She underwent immediate surgical reexploration, and an emergency hysterectomy was performed. The intraoperative course was eventful for a marked fluid resuscitation, which included 4 units of packed red blood cells. Approximately 90 minutes later, the patient experienced some abdominal discomfort. The spinal block had receded to approximately the T6-7 dermatome level. She was given 50 µg of intravenous fentanyl, and the epidural catheter was dosed with lidocaine 2% with epinephrine, with resolution of the discomfort. Her postoperative period was significant for low grade, disseminated intravascular coagulation, requiring more blood products until her hemoglobin and coagulation studies normalized. The epidural catheter was removed 24 hours later. The patient was discharged from the hospital 3 days after her procedure in good condition.
What Is the Historic Perspective on Cesarean Section?
Although cesarean section has been sporadically alluded to in ancient times, the accuracy concerning the onset of the procedure remains in question. Roman law, as far back as the eighth century BC, established that abdominal delivery be performed in a dying or dead woman in an attempt to save the life of the baby or, more commonly, to allow for separate burial for mother and child.1 It was not until the 19th century that cesarean deliveries were attempted, not for the sole purpose of saving the fetus, but also to save the mother, although the mortality rate approached 100%, and cesarean section was therefore reserved for rare circumstances. The most common causes of maternal mortality from cesarean section in those early days were from hemorrhage and sepsis. Various surgical techniques for abdominal deliveries were subsequently devised to minimize the complications; however, the most common uterine incision today—the low transverse incision—was not reported until the 1920s and was not accepted in common practice until the 1950s. With the evolving and improved surgical and anesthetic techniques in the 20th century, along with greater supportive care including blood banking, fluid resuscitation, and antibiotics, maternal mortality following cesarean section markedly decreased, but still remains higher than the mortality rate with vaginal delivery. In the most recent report on Confidential Enquiries into Maternal Deaths in the United Kingdom during the period 2000 to 2002, the relative risk of maternal mortality was 3.7 for cesarean sections versus vaginal deliveries2 (see Table 48.1).
Two of the most striking changes in obstetric anesthesia practice over the last half century is the increasing incidence of cesarean section deliveries and the marked
decrease in general anesthesia for cesarean deliveries. The incidence of cesarean section was approximately 5% in the 1950 to as late as the 1970s, and then markedly increased to more than 20% in the mid-1980s and early 1990s.3 The incidence of cesarean deliveries in the United States has increased to 29.1% in 2004, a 6% increase from the previous year.3 Although lower, this same trend is also present in other developed countries such as the United Kingdom, which had a rate of 12.5% in 1990 and jumped to 18.3% in 1999, and in Canada with an incidence of 18% during 1994 to 1995, increasing to 22.1% during 2000 to 2001.4,5
decrease in general anesthesia for cesarean deliveries. The incidence of cesarean section was approximately 5% in the 1950 to as late as the 1970s, and then markedly increased to more than 20% in the mid-1980s and early 1990s.3 The incidence of cesarean deliveries in the United States has increased to 29.1% in 2004, a 6% increase from the previous year.3 Although lower, this same trend is also present in other developed countries such as the United Kingdom, which had a rate of 12.5% in 1990 and jumped to 18.3% in 1999, and in Canada with an incidence of 18% during 1994 to 1995, increasing to 22.1% during 2000 to 2001.4,5
TABLE 48.1 Vaginal versus Cesarean Delivery Case Fatality Rates per 100,000 in the United Kingdom: Years 2000-2002 | ||||||||||||||||||||||||||||||||||||||
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What Factors Have Contributed to the Increased Rate of Cesarean Sections?
The increased cesarean section rate is attributed to both an increased incidence of primary and repeat cesarean sections. Dystocia is the most common cause for the rising primary cesarean section and is followed by malpresentation, antepartum bleeding, hypertension, and preterm gestation. The primary cesarean section rate rose from 19.7% of all cesarean deliveries in 1994 to 28.3% in 2001, an increase of 44% in 7 years and 8% in 2004 from the previous year.3,6 Other contributing factors to the increased primary cesarean section rate are physician preferences and patient choice. Either can dictate whether an elective primary cesarean delivery can be performed, as opposed to relying solely on patient characteristics or intrapartum factors.7 In the past, elective primary cesarean section in an uncomplicated patient was considered unacceptable.7 Despite the rising primary cesarean section rate, a history of repeat cesarean section is the most common cause for cesarean delivery. This trend is due to the declining rate of vaginal birth delivery after cesarean section (VBAC) that peaked to more than 28% in the mid-1990s and has decreased to a low of 10.6% in 2003,3 attributed mainly to more recent data suggesting an even greater threat of uterine rupture with induction, especially with prostaglandins.
What Types of Anesthesia Are Used for Cesarean Section?
In an older survey in the United States, general anesthesia was the most common form of anesthesia for cesarean delivery in 1981, and, by 1992, epidural anesthesia surpassed general anesthesia mainly because of the rise of epidural anesthesia for labor.8 With the improvement of spinal needles in the last 10 to 15 years, spinal anesthesia has become the most common anesthetic technique for cesarean delivery.9 The decline in the use of general anesthesia for cesarean section can be attributed to a greater maternal mortality when compared to regional anesthesia and the increased use of neuraxial analgesia for laboring patients (approximately 20% in the 1980s to 90% or greater in some institutions in 2006), which can usually be converted to surgical anesthesia for cesarean delivery.10,11 In a major tertiary center in the United States, the incidence of cesarean section under general anesthesia decreased from 7.2% in 1990 to 3.6% in 1995, a significant decline from the 35% to 45% incidence in the 1981 survey.8,12
The American Society of Anesthesiologists (ASA) committee on professional liability has been conducting a study of insurance company closed malpractice claims against anesthesiologists since 1985. Despite the limitations of such analysis—that is retrospective review, unknown denominator, lag time between review and actual event, and claims not necessarily denoting a complication—there is valuable information that can be gleaned from this report. Twelve percent of the claims involved obstetric anesthesia (792 obstetric cases from a total of 6,449), whereas obstetric cases make up only approximately 10% of all surgical cases.13,14 Most of the obstetric claims involved cesarean sections.
Complications with cesarean sections will include those associated with regional and general anesthesia, and specific obstetric situations.
▪ REGIONAL ANESTHESIA
Regional anesthesia options for cesarean section include spinal, epidural, or CSE anesthesia. Other options such
as local anesthesia or infiltration block are seldom used now. These techniques are utilized mainly in extraneous circumstances, such as unavailability of anesthesia for emergent situations and in morbidly obese patients, where regional and general anesthesia may be quite difficult. The problem with local anesthesia includes the inadequacy of pain relief during an abdominal procedure and the possibility of local anesthetic toxicity due to the large amount of drug that is usually required to provide analgesia.
as local anesthesia or infiltration block are seldom used now. These techniques are utilized mainly in extraneous circumstances, such as unavailability of anesthesia for emergent situations and in morbidly obese patients, where regional and general anesthesia may be quite difficult. The problem with local anesthesia includes the inadequacy of pain relief during an abdominal procedure and the possibility of local anesthetic toxicity due to the large amount of drug that is usually required to provide analgesia.
▪ SPINAL ANESTHESIA
The anesthetic of choice for cesarean section today is spinal anesthesia. The advantages of spinal anesthesia include the rapid onset of the block, diminishing the time from entry to the operating room to incision as compared with epidural anesthesia, which translates to added efficiency, an important factor in today’s hospital environment.15 Other advantages include the greater density of the block, allowing for more muscle relaxation during the procedure, which is obviously preferred among surgeons, along with fewer requirements for systemic supplementation due to pain, the simpler nature of the spinal technique compared with epidural anesthesia, and fewer overall complications.15 The two neuraxial complications that can lead to maternal mortality include local anesthetic toxicity and a total spinal. Both of these complications are a result of epidural anesthesia (see Table 48.2). With spinal anesthesia, the local anesthetic dose is small, and there is relatively no appreciable systemic absorption from the cerebrospinal fluid (CSF). On the other hand, the greater dose (fivefold or more) required with an epidural anesthetic, along with the vascular absorption in the epidural space, or even a direct vascular injection, especially with the engorged epidural veins in the pregnant patient, render an epidural more prone to local anesthetic toxicity. Moreover, it is this large dose of local anesthetic, resulting from an epidural attempt which accidentally is injected intrathecally, that leads to a total spinal anesthetic versus, at worst, a high spinal with a spinal local anesthetic dose.
TABLE 48.2 Complications of Neuraxial Blocks for Cesarean Section | ||||||||||||||||||||||||||||||||||||
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What Are the Complications Related to Spinal Anesthesia in the Parturient?
▪ POSTDURAL PUNCTURE HEADACHE
A longtime concern with spinal anesthesia has been the incidence of postdural puncture headache (PDPH), especially in the obstetric population. With the improved technology of present day spinal needles—mainly, the pencil-point needles such as the Whitacre, Sprotte, and Gertie Marx, as opposed to the older diamond-point or cutting spinal needles such as the Quincke needle and the smaller gauge needles—the incidence of PDPH has markedly declined to <1% in the obstetric patients, and therefore has contributed to the popularity of spinal anesthesia for cesarean section. PDPH has both medical and legal implications. In the ASA Closed Claims Study, headache was the fourth leading claim in the 1990s (third in the 1970s and 1980s), consisting of 14% of all obstetric anesthesia claims and only surpassed by maternal death, newborn brain damage, and maternal nerve injury14 (see Table 48.3). PDPH invokes a significant morbidity for postpartum patients because they cannot remain upright or ambulate because of the severity and postural nature of the headache, along with its associated symptoms that include nausea and vomiting, photophobia, and, more rarely, visual and auditory symptoms such as diplopia, tinnitus, and decreased hearing due to cranial nerve (CN) involvement (CN VI and VIII). There also have been scant reports of intracranial subdural hematomas following dural puncture with neuraxial anesthesia.16 Therefore, it is imperative for anesthesiologists to strive for a low headache incidence and treat and carefully follow any PDPH.
▪ HYPOTENSION
The most common side effect of neuraxial anesthesia for cesarean section is hypotension. Hypotension is a result of the extent of the sympathetic block from local anesthetics that contributes to both arterial and venodilatation. The incidence of hypotension with spinal anesthesia is greater than epidural anesthesia due primarily to the more rapid onset of the block and can approach an incidence of 70% or greater, despite preblock and postblock measures such as intravenous fluids, uterine displacement, and the use of vasopressors (Table 48.2). Uterine displacement should be performed for all cesarean sections in an attempt to avoid the supine hypotensive syndrome. Various intravenous crystalloid fluids, with
or without colloid solutions or colloid solutions alone, have been used to pretreat patients before neuraxial block; however, no technique can eliminate hypotension. Although pretreatment with colloid solutions may show a decreased incidence of hypotension versus crystalloids in cesarean sections, the increased costs and possible side effects, along with the lack of documented improved outcome has precluded the use of colloids in routine cases. Other studies have even questioned the efficacy of pretreatment with intravenous fluids versus no bolus administration before spinal anesthesia for cesarean section, finding no statistical difference in the incidence of hypotension.17,18,19 Moreover, even with documented increases in blood volume and cardiac output after the infusion of 1,500 mL of crystalloid, there was no significant reduction in the incidence of hypotension.20
or without colloid solutions or colloid solutions alone, have been used to pretreat patients before neuraxial block; however, no technique can eliminate hypotension. Although pretreatment with colloid solutions may show a decreased incidence of hypotension versus crystalloids in cesarean sections, the increased costs and possible side effects, along with the lack of documented improved outcome has precluded the use of colloids in routine cases. Other studies have even questioned the efficacy of pretreatment with intravenous fluids versus no bolus administration before spinal anesthesia for cesarean section, finding no statistical difference in the incidence of hypotension.17,18,19 Moreover, even with documented increases in blood volume and cardiac output after the infusion of 1,500 mL of crystalloid, there was no significant reduction in the incidence of hypotension.20
TABLE 48.3 American Society of Anesthesiologists (ASA) Closed claims Study: Obstetric Claims, Maternal, 1990s | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Ephedrine, a mixed α-adrenergic and β-adrenergic agonist, has been the vasopressor of choice for the obstetric patient secondary to having the least effect on uterine blood flow, as opposed to the pure α-adrenergic agonists, such as phenylephrine. However, phenylephrine in small doses has been shown to be as safe and effective as ephedrine and may also produce less fetal acidosis.21 Phenylephrine in bolus doses of 50 to 100 µg can be administered when there is minimal response to ephedrine or in cases of maternal tachycardia that can be worsened by ephedrine. The greater incidence occurs in nonlaboring patients versus laboring patients. Unfortunately, with neuraxial blocks, especially to the extent that is required, that is T4 level, for adequate surgical anesthesia for abdominal cases, the cardiac accelerators fibers to the heart (T1 to T4) are also blocked. This results in bradycardia, along with hypotension, in contrast to the typical tachycardic response with an intact sympathetic system, further contributing to a decrease in cardiac output. The fetal and neonatal effects of maternal hypotension are dependent on the extent and duration of the hypotension. Prolonged and severe hypotension can lead to fetal acidosis, fetal bradycardia, and increased time to sustained respirations in neonates. Alternatively, transient maternal hypotension is usually well tolerated, except in situations where there may already be compromised to the uteroplacental unit or in chronic conditions such as diabetes, chronic hypertension, and collagen vascular diseases.
What Are the Complications Associated with Epidural Anesthesia?
With the increasing use of epidural analgesia for the laboring patient, epidural anesthesia for cesarean section has increased over the last three decades. Since the early 1970s, epidurals for labor have been extended for use in cesarean sections.22 However, because of the resurgence of spinal anesthesia in obstetrics with the availability of pencil-point needles, de novo epidural anesthesia for elective cesarean sections have markedly decreased. The disadvantages of epidural anesthesia versus spinal anesthesia for operative procedures include the slower onset of the block, less dense block, and the greater potential for local anesthetic toxicity through an accidental intravascular injection or total spinal block with an accidental intrathecal injection due to the larger dose and volume of local anesthetic required with epidurals. Despite these factors, there are advantages to epidural anesthesia, which include its flexibility, that is, increasing the duration of the block by further dosing the epidural catheter if the surgery is prolonged. Prolonged cesarean sections are considered a risk for morbidly obese patients and patients with prior multiple cesarean sections or other abdominal surgeries because they are
susceptible to technical surgical difficulties, including the possibility of a cesarean hysterectomy. Moreover, with epidural anesthesia, the epidural catheter can also be used for postoperative analgesia. There is also a hemodynamic advantage over spinal anesthesia, namely a decreased incidence and degree of hypotension secondary to the slower onset of the epidural block as opposed to the faster onset of the spinal block. Obstetric situations that may make epidural anesthesia more amenable than spinal anesthesia include specific cardiac lesions such as mitral and aortic stenosis and severe preeclampsia.
susceptible to technical surgical difficulties, including the possibility of a cesarean hysterectomy. Moreover, with epidural anesthesia, the epidural catheter can also be used for postoperative analgesia. There is also a hemodynamic advantage over spinal anesthesia, namely a decreased incidence and degree of hypotension secondary to the slower onset of the epidural block as opposed to the faster onset of the spinal block. Obstetric situations that may make epidural anesthesia more amenable than spinal anesthesia include specific cardiac lesions such as mitral and aortic stenosis and severe preeclampsia.
The most common complication with epidural anesthesia is hypotension but, as stated in the preceding text, the incidence and severity is less than with spinal anesthesia due to the nature of the block (Table 48.2). Although in theory, PDPH should not occur with epidural anesthesia, if the dura matter is penetrated with a typical 17-or 18-gauge epidural needle, the incidence of PDPH may be as high as 50% to 80%. The incidence of accidental dural puncture with an epidural needle has been reported from 0.2% to 3%, depending on the experience of the provider. Moreover, the direction of the bevel of spinal needles (diamond-point) and epidural needles contribute to the incidence of PDPH. Studies using spinal and epidural needles have demonstrated a decreased incidence of spinal headaches when the bevel of the needle is oriented parallel to the longitudinal axis of the vertebral column, despite the fact that not all dural fibers are longitudinal.23,24
▪ BACKACHE
Backache is a common problem in the general population and is obviously exacerbated in pregnancy, secondary to hormonal changes, that is, relaxin which loosens ligaments, and the exaggerated lumbar lordosis from the gravid uterus. The incidence of back pain in pregnant patients is approximately 40% to 50%, with or without regional anesthesia. Unfortunately, in the ASA Closed Claims analysis, back pain made up approximately 10% of the obstetric anesthesia claims (Table 48.3). Although it would appear that the larger needle and the larger volume of fluid that are used in epidural anesthesia may render backaches more common following epidural anesthesia than with spinal anesthesia, backaches after any type of neuraxial blocks are transient and do not have long term or serious sequelae. Moreover, some patients with back pain during pregnancy may also have a radiculopathy, and even sciatica, that needs to be ascertained and documented before performing a neuraxial block.
What Are the Neurologic Complications Associated with Neuraxial Blocks?
Neurologic complications can be divided into minor and major neurologic sequelae. Unfortunately, in obstetrics, neuraxial blocks are commonly blamed for neurologic complications; however, most problems are obstetric related, that is, pregnancy and the labor and delivery process. In a recent survey from Sweden, the incidence of severe neurologic complications after neuraxial blocks was 1 in 25,000 following epidural blocks in the obstetric patient versus 1 in 3,600 in all other nonobstetric patients.25 Minor neurologic sequelae include headache (which has been addressed) and backache.
▪ NEUROLOGIC DEFICITS
A main concern following neuraxial anesthesia are neurologic deficits. Once again, neuraxial blocks are commonly blamed for postpartum neurologic injuries; however, there are nerve injuries that are common to the obstetric patient. Palsies of the femoral nerve, lumbosacral trunk, and more rarely, obturator nerve can occur with compression of the fetal head at the sacral ala or in the pelvis. Moreover, during surgery, retraction can also lead to femoral nerve palsy. Also, not commonly associated with cesarean section per se, severe hip flexion during attempted vaginal delivery can result in femoral nerve compression. These cases may still require a cesarean section if the vaginal delivery attempt failed. Although lateral femoral cutaneous nerve and common peroneal nerve palsies usually occur when the patient is in stirrups and not during a cesarean section, the lateral femoral cutaneous nerve can be compressed by the belt used to secure the patient on the operating room table. Despite the rarity and potential cause of any neurologic deficit, diagnostic testing and treatment may be indicated.
▪ TRANSIENT NEUROLOGIC SYMPTOMS
Spinal hyperbaric lidocaine is used for short cases and has been associated with a higher incidence of transient neurologic symptoms (TNSs) than other local anesthetics. Symptoms of TNS include pain in the lower extremities and buttocks, and lasts anywhere from <1 day to as long as 10 days, but with no evidence of neurologic pathology.26 Besides the local anesthetic, the incidence of TNS was also felt to be due to certain positioning, mainly the lithotomy position. However, it has been reported in the supine position as well, again with a higher incidence with hyperbaric lidocaine versus hyperbaric bupivacaine.27 However, the incidence among the obstetric patient, especially for cesarean section, appears lower than for the general surgical population.28 Despite the lower incidence among obstetric patients, the use of hyperbaric lidocaine in obstetrics has been questioned.29
▪ CAUDA EQUINA SYNDROME
A more severe and possible permanent neurologic deficit is the cauda equina syndrome, consisting of back pain, perineal anesthesia, lower extremity sensory and motor
deficits, bladder, and bowel dysfunction. Cauda equina syndrome was reported following accidental spinal administration in the early 1980s with the old formulation of 2-chloroprocaine containing the antioxidant, sodium bisulfite. More recently, in the early 1990s, the combination of a continuous spinal anesthetic with microcatheters (28 and 32 gauge) and hyperbaric lidocaine 5% also resulted in a few cases of cauda equina syndrome, which led the U.S. Food and Drug Administration (FDA) to withdraw the microcatheters in 1992. The main cause was postulated to be from pooling of a highly concentrated local anesthetic at the conus of the spinal cord. Fortunately, since the mid-1980s, no obstetric cases of cauda equina syndrome following neuraxial blocks have been reported.
deficits, bladder, and bowel dysfunction. Cauda equina syndrome was reported following accidental spinal administration in the early 1980s with the old formulation of 2-chloroprocaine containing the antioxidant, sodium bisulfite. More recently, in the early 1990s, the combination of a continuous spinal anesthetic with microcatheters (28 and 32 gauge) and hyperbaric lidocaine 5% also resulted in a few cases of cauda equina syndrome, which led the U.S. Food and Drug Administration (FDA) to withdraw the microcatheters in 1992. The main cause was postulated to be from pooling of a highly concentrated local anesthetic at the conus of the spinal cord. Fortunately, since the mid-1980s, no obstetric cases of cauda equina syndrome following neuraxial blocks have been reported.
▪ PROLONGED NEUROLOGIC BLOCK
Another occasional scenario following neuraxial anesthesia is a prolonged block. The vast majority of cases simply involve a prolonged duration of the local anesthetic, that is, a slow regression of the block, especially in situations where a cesarean section was preceded by a failed protracted labor and a block that not only required multiple bolus doses, but also if it was lateralized more to one side. However, despite this more common scenario, a differential diagnosis of a prolonged block includes neurotoxicity of the local anesthetic, wrong drug administered, trauma from either the neuraxial needle or positioning, preexisting neurologic disease, and space-occupying lesions such as an epidural hematoma or abscess (see Section “Spinal Epidural Hematoma”). Although rare, there have been case reports of sciatic neuropathy when placing a wedge under the right hip for left uterine displacement, consequently causing a left-sided sciatic neuropathy from compression.
▪ SPINAL EPIDURAL HEMATOMA
The incidence of epidural hematoma in the obstetric patient is rare. The estimated incidence of epidural hematoma in the general surgical population is 1 in 150,000 after an epidural anesthetic and 1 in 220,000 after a spinal anesthetic.30 In the obstetric patient, a recent review reported only a few cases of epidural hematoma after epidural anesthesia, with no cases after spinal anesthesia.31 Moreover, most of these obstetric cases had an identifiable coagulation deficiency. In a retrospective study of more than 500,000 obstetric cases from the United Kingdom, there was only 1 case of an epidural hematoma, and in a prospective multicenter series of more than 100,000 obstetric cases, no cases of epidural hematoma were reported.32,33 Also, in a recent survey from Sweden that differentiated between obstetric and general surgical patient, the incidence of spinal hematoma following epidural anesthesia was 1 in 200,000 in the obstetric population versus 1 in 3,600 in female orthopedic patients.25 Obviously, neuraxial anesthesia in patients with severe clotting disorders, and in those on certain anticoagulants is discouraged.
Historically, a neuraxial block in patients with platelet counts <100,000 was discouraged. However, the more recent consensus is that a platelet count above 75,000 may be acceptable under certain clinical conditions, barring any clinical signs of bleeding, history of easy bruising or bleeding. An isolated low platelet count, which may be present in up to 8% of all healthy obstetric patients with no other stigmata, has no predictive value for anesthetic-related sequelae. On the other hand, if the platelet count is normal but has acutely fallen, such as in severe preeclampsia or hemolysis, elevated liver enzymes, and a low platelet count (HELLP) syndrome, a neuraxial block may not be indicated, and therefore decisions on neuraxial anesthesia should be individualized, depending on the particular situation. Unfortunately, there are more obstetric patients that are being placed on low molecular weight heparin (LMWH) that creates a greater concern for neuraxial anesthesia. Neuraxial anesthesia should be delayed for at least 10 to 12 hours after a LMWH dose used for thromboprophylaxis and at least 24 hours for larger, treatment doses of LMWH based on the most recent consensus statement from the American Society for Regional Anesthesia and Pain Medicine.34 Signs and presenting symptoms of a spinal epidural hematoma include new onset numbness, weakness, bowel, and bladder dysfunction, as well as radicular back pain, keeping in mind that severe back pain is not essential for the diagnosis. These symptoms can occur within 12 hours of the neuraxial procedure, which can make the diagnosis difficult in cases with a prolonged block. Any suspicion should lead to prompt diagnosis through magnetic resonance imaging to perform an emergency, decompressive laminectomy to evacuate the hematoma, preferably within 6 hours of any symptoms to avoid permanent neurologic damage.
▪ SPINAL INFECTIONS
Spinal infections include meningitis and spinal epidural abscess. Fortunately, both meningitis and epidural abscess are rare complications following neuraxial anesthesia in the obstetric patient. Epidural abscess occurs more commonly through a hematogenous spread from a remote infectious site and rarely following neuraxial anesthesia. Moreover, most of the epidural abscess cases occur in unhealthy patients, such as immunocompromised patients, diabetics, and those with heavy alcohol usage. The onset of symptoms of an epidural abscess is more insidious and may not manifest until 4 days to 1 week and a half in the postpartum period, in contrast to the more rapid onset of symptoms from an epidural hematoma. Symptoms include severe lower back pain, fever, and leukocytosis, followed by sensory and motor loss of the lower extremities. As stated previously, once neurologic symptoms have occurred, time is of the essence and magnetic resonance imaging, neurosurgical consultation, and emergency decompressive laminectomy should be performed. On rare situations, antibiotic therapy has been used without the need for surgery.
TABLE 48.4 Anesthesia Complications for Cesarean Sections: 1999-2002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Unlike patients with a spinal epidural abscess, most cases of meningitis following spinal, epidural, or CSE anesthesia occur in otherwise healthy subjects. Despite sporadic case reports, anecdotal cases of meningitis after neuraxial blocks, and more recent reports following CSEs, large surveys totaling more than 680,000 cases have failed to show any cases of meningitis.35 In a recent observational study of cesarean deliveries where 93% of the more than 34,000 cases were performed under neuraxial anesthesia (spinal, epidural and CSE), no cases of meningitis or epidural abscess were reported36 (see Table 48.4). Spinal and CSE anesthesia appear to have a higher incidence than epidural anesthesia as the dura is penetrated. Symptoms usually present within 1 to 3 days, postpartum and include headache, fever, and neck stiffness.34 A controversial issue is the performance of a neuraxial block in the presence of an infection. A small animal study demonstrated that a lumbar puncture in the presence of an untreated bacteremia resulted in some cases of meningitis; however, if pretreated with a bacteriasensitive antibiotic, it did not result in any cases of meningitis.37 A common situation in obstetrics is the use of a neuraxial block in a patient with treated or untreated chorioamnionitis, which has failed to show any association with a central nervous system (CNS) infection. Obviously, if the diagnosis of chorioamnionitis is made, it would seem prudent to treat it before performing a neuraxial block or surgical procedure. Situations where a neuraxial block is contraindicated include patients with clinical signs of septicemia, localized infection at the sight of injection, and in severely immunosuppressed patients.
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