Accidental total spinal block: a complication of an epidural test dose

Total spinal anaesthesia following obstetric neuraxial blockade: a narrative review

BACKGROUND

Total spinal anaesthesia (TSA) is an emergency caused by high neuraxial blockade. It is a recognised complication of all neuraxial techniques in obstetric anaesthesia. Its incidence and outcomes have not been evaluated. There is compelling evidence that TSA continues to be a problem in contemporary practice, having the capacity to cause significant morbidity and mortality if not recognised early and promptly treated. This review based on a literature search aims to clarify the epidemiology of TSA, summarise its pathophysiology, and identify risk factors and effective treatments.

METHODS

We performed a literature search using PubMed, Web of Science and Google Scholar databases using specified search terms for materials published using search terms. For each case, the type of block, the difficulty of the procedure, the dose of local anaesthetic, positivity of aspiration before and after the event, maternal outcome, Apgar score, onset of symptoms, cardiorespiratory and neurological manifestations, cardiorespiratory support employed, admission to an intensive care unit, cardiac arrest events and duration of mechanical ventilation were extracted.

RESULTS

A total of 605 cases were identified, of which 51 were sufficiently detailed for analysis. Although TSA is described after all neuraxial techniques, spinal after epidural was a particular concern in recent reports. Respiratory distress was universal but apnoea was not. The onset of apnoea was variable, ranging from 1 to 180 min. Hypotension was not invariable and occurred in approximately half of cases. Multiple fatalities and neurological injuries were reported, often in under-resourced areas when providers were not skilled in airway management or when recognition and intervention were delayed. In the most recent reports good outcomes were achieved when effective treatments were rapidly provided.

CONCLUSIONS

The available literature confirms that TSA remains an active clinical problem and that with prompt recognition and treatment good outcomes can be achieved. This requires anticipation and preparedness in all clinical areas where neuraxial techniques are performed.

Obstetric Anesthesia and Heart Disease: Practical Clinical Considerations

Maternal morbidity and mortality as a result of cardiac disease is increasing in the United States. Safe management of pregnancy in women with heart disease requires appropriate anesthetic, cardiac, and obstetric care. The anesthesiologist should risk stratify pregnant patients based upon cardiac disease etiology and severity in order to determine the appropriate type of hospital and location within the hospital for delivery and anesthetic management. Increased intrapartum hemodynamic monitoring may be necessary and neuraxial analgesia and anesthesia is typically appropriate. The anesthesiologist should anticipate obstetric and cardiac emergencies such as emergency cesarean delivery, postpartum hemorrhage, and peripartum arrhythmias. This clinical review answers practical questions for the obstetric anesthesiologist and the nonsubspecialist anesthesiologist who regularly practices obstetric anesthesiology.

Epidural test dose in obstetric patients: should we still use it?

PURPOSE OF REVIEW

As the application of a test dose after epidural catheter insertion in obstetrics has recurrently been associated with serious adverse events affecting both maternal and foetal outcomes, the question whether to test or not remains a controversial issue.

RECENT FINDINGS

Present guidelines do not provide clear recommendations in this regard and several recent surveys indicate a heterogeneity in clinical routine.

SUMMARY

Physiological alterations during pregnancy and labour restrict the use and also the validity of traditional test agents. Epinephrine is not appropriate to detect a vascular insertion in labour and the application of a local anaesthetic test dose may lead to dose-dependent fatal consequences should the catheter be intrathecal, due to an increased sensitivity in parturients. Given the current practice of opioid-amended-low-concentration epidurals, the waiving of a test dose results at worst in a failed epidural, a stark contrast to the potentially severe to fatal complications of a 'traditional' test dose. Hence, an originally preventive measure providing potentially more harm than the consequences of the situation aimed to prevent, should not be recommended. A simple fractionated administration of the initial analgesic dose seems reasonable though.

Epidural electrical stimulation test versus local anesthetic test dose for thoracic epidural catheter placement: a prospective observational study

PURPOSE

This study examined the concordance between epidural electrical stimulation test (EEST) and local anesthetic (LA) test dose to indicate correct thoracic epidural catheter position. The relationship between the test results and epidural postoperative analgesia was also assessed.

METHODS

This prospective observational cohort study was done in patients receiving thoracic epidural analgesia for abdominal surgery. After insertion, the epidural catheter was tested using a nerve stimulator to elicit a motor response. The LA test dose was then administered, and sensory block to ice and pinprick was assessed. The primary outcome was the presence/absence of motor response to EEST and sensory block to test dose. Concordance of responses was assessed using kappa statistics, and their predictive power of postoperative epidural analgesia was evaluated.

RESULTS

Sixty-eight thoracic epidural catheters were inserted, of which 62 were used perioperatively. The kappa agreement between EEST and LA test dose responses was moderate at 0.42 (95% confidence interval [CI], 0.18 to 0.67). Positive responses to EEST and LA test dose were observed in 62 (100%) and 50 (81%) patients, respectively, while 52 patients (84%) showed adequate analgesia postoperatively. The sensitivity (95% CI) of EEST and LA test dose to predict adequate postoperative epidural analgesia was 1 (0.93 to 1) and 0.79 (0.65 to 0.89), respectively, and the positive predictive values (95% CI) of EEST and LA test dose were 0.84 (0.75 to 0.93) and 0.82 (0.71 to 0.92), respectively.

CONCLUSION

Following thoracic epidural catheter insertion, the responses to the EEST and LA test dose showed "moderate" agreement. The EEST has a higher sensitivity than the LA test dose to predict adequate epidural analgesia following abdominal surgery, however, both tests have a comparable positive predictive value.

An inadvertent subarachnoid injection reversed by cerebrospinal fluid lavage for the treatment of chronic low back pain: A case report

RATIONALE

We present a case of high spinal anesthesia after inadvertent injection of local anesthetics and corticosteroids into the subarachnoid space during attempted epidural injection. Cerebrospinal fluid (CSF) lavage is a suitable method for treatment.

PATIENT CONCERNS

A 45-year-old woman presented with posterior thigh, leg, and ankle pain for >6 months and was treated with epidural injection. Five minutes after the third time of epidural injection, the patient complained loss of sensation and muscle strength in the lower extremities and abdominal area.

DIAGNOSES

A high spinal anesthesia was confirmed by the patient loss of sensation and muscle strength in the lower extremities and abdominal area.

INTERVENTIONS

CSF lavage was performed for treatment.

OUTCOMES

After CSF lavage, the patient gradually returns to normal sensory and motor functions of lower limbs. On the fourth day, the patient sensed her physical function restoring gradually and was discharged uneventfully. At 4-month follow-up, the patient could have normal activities without obvious subsequent complications and any pain.

LESSONS

We conclude that CSF lavage could be a helpful maneuver to clear lidocaine and betamethasone and avoid potential nerve damage caused by an unintentional intrathecal injection during an epidural injection for the treatment of chronic low back pain.

A prospective randomized trial of lidocaine 30 mg versus 45 mg for epidural test dose for intrathecal injection in the obstetric population

BACKGROUND

The epidural test dose, used to identify unintended intrathecal placement, should reliably produce a spinal block without posing a threat to the patient. Most anesthesiologists administer a dose of local anesthetic, commonly lidocaine 45 mg. Pregnant patients are more sensitive to local anesthetics; high and total spinal anesthesia have been reported in the pregnant population with this dose. We hypothesized that lidocaine 30 mg was as effective as lidocaine 45 mg in creating rapid objective evidence of a sensory or motor block.

METHODS

In this prospective, randomized, double-blind trial, patients scheduled for cesarean delivery were assigned to 1 of 4 groups: lidocaine 30 mg in the spinal or epidural space, or lidocaine 45 mg by the same routes. A blinded observer assessed the degree of sensory and motor block. The ability to identify intrathecal injection of each dose was compared. Sensory block above T6 dermatome and hypotension were recorded as side effects.

RESULTS

Intrathecal administration of lidocaine 30 mg produced rapid subjective and objective signs of neuroblockade within 3 minutes (100%, 95% confidence interval CI, 85%-100% for each). Lidocaine 45 mg produced similar results. All patients in both groups described their legs as warm or heavy after 3 minutes and had a motor block by 5 minutes. On the basis of an intrathecal catheter rate of 1:380, the observed negative predictive value for intrathecal placement if the patient described no sensory changes at 3 minutes was 100% (95% CI, 99.95%-100%) for 30 mg and 100% (95% CI, 99.93%-100%) for 45 mg. We did not identify a decrease in the rate of side effects with the lower dose.

CONCLUSIONS

Our results suggest that there is unlikely to be a large difference in the ability of these doses to detect unintentional intrathecal catheter placement. While the negative predictive value for intrathecal injection is very high for both doses, the 95% CI for the sensitivity of either dose is too wide to demonstrate clinical safety to identify all intrathecal catheters. A much larger study is warranted to assess whether there is a lower sensitivity with the 30-mg dose, or a propensity toward high cephalad motor block levels with the 45-mg dose.

Aphonia induced by conversion disorder during a Cesarean section

Aphonia induced by conversion disorder during surgery is a rare event. We report a woman 28 years of age who was undergoing a Cesarean section under epidural anesthesia. The patient sustained aphonia without detected neurologic deficits. Emergency consultations of a psychiatrist and neurologist were carried out in the operating room postoperatively. After a thorough medical and neurologic work-up, the consultative psychiatrist and the neurologist unanimously made the diagnosis of conversion disorder. Thirty-six hours after the operation, the patient's voice started to return. We venture on sharing the findings of this case with our fellow anesthesiologists in order to highlight discussion and illuminate the differential diagnosis. We have reviewed the literature and excluded an organic lesion as the culprit of the event.

Aphonia and quadriplegia---a rare complication following epidural labor analgesia

We report an obstetric patient who developed unusual neurological complications after an epidural injection of a local anesthetic and a narcotic in a seemingly faultless manner. Ten minutes after receiving a loading dose, the patient developed aphonia, quadriplegia, and facial palsy while retaining normal consciousness and stable hemodynamics. The episode spontaneously resolved 40 minutes later. We wish to draw attention to anesthesiologists of the possibility that even in the presence of a negative aspiration test or without noticeable dural puncture, the injected drugs may enter the intrathecal or subdural space instead of pooling entirely in the epidural compartment. Once an unexpected high block and unusual symptoms or signs are noted, a prompt differential diagnosis must be made and treatment initiated as soon as possible.

Innovative approaches to neuraxial blockade in children: the introduction of epidural nerve root stimulation and ultrasound guidance for epidural catheter placement

Continuous epidural blockade remains the cornerstone of pediatric regional anesthesia. However, the risk of catastrophic trauma to the spinal cord when inserting direct thoracic and high lumbar epidural needles in anesthetized or heavily sedated pediatric patients is a concern. To reduce this risk, research has focused on low lumbar or caudal blocks (ie, avoiding the spinal cord) and threading catheters from distal puncture sites in a cephalad direction. However, with conventional epidural techniques, including loss-of-resistance for localization of the needle, optimal catheter tip placement is difficult to assess because considerable distances are required during threading. Novel approaches include electrical epidural stimulation for physiological confirmation and segmental localization of epidural catheters, and ultrasound guidance for assessing related neuroanatomy and real-time observation of the needle puncture and, potentially, catheter advancement. The present article provides a brief and focused review of these two advances, and outlines recent clinical experiences relevant to pediatric epidural anesthesia.

The Epidural Test Dose: A Review

This review systematically examines the literature on the ability of the classical epidural test dose and other strategies to detect intravascular, intrathecal, or subdural epidural needle/catheter misplacement. For detection of simulated intravascular misplacements, a sensitivity (S) and a positive predictive value (PPV) > or =80 demonstrated by at least two randomized controlled trials coming from two different centers were determined for the following tests and patient populations: Nonpregnant adult patients = increase in systolic blood pressure (SBP) > or =15 mm Hg (S = 80-100 and 93-100; PPV = 80-100 and 83-100) or either an increase in SBP > or =15 mm Hg or an increase in heart rate > or =10 bpm after the injection of 10 (S = 100; PPV = 83-100) or 15 microg of epinephrine (S = 100; PPV = 83-100); pregnant patients = sedation, drowsiness, or dizziness within 5 min after the injection of 100 microg of fentanyl (S = 92-100; PPV = 91-95); and children = increase in SBP > or =15 mm Hg after the injection of 0.5 microg/kg of epinephrine (S = 81-100; PPV = 100). Conversely, more studies are required to determine the best strategies to detect intrathecal and subdural epidural needle/catheter misplacements in these three patient populations.

Total spinal anaesthesia as a complication of local anaesthetic test-dose administration through an epidural catheter

We describe a case of total spinal anaesthesia, which occurred after a 3-ml lignocaine (20 mg ml(-1)) test dose was administered through an epidural catheter in a 79-year-old patient scheduled for gastrectomy under combined general and epidural anaesthesia. The surgery was postponed, and the patient required admission to the intensive therapy unit. Spinal MRI from the total spinal cord did not reveal any pathology. During the next 24 h the patient recovered and after 11 days was successfully operated on under general anaesthesia. No late complications followed. We presume that during placement, the epidural catheter had migrated to the spinal canal as a result of technical difficulties. Although controversial, we consider that administering a standard test dose of local anaesthetic via an epidural catheter is recommended, especially in high-risk patients and when epidural space identification or catheter placement poses technical difficulties. A test dose of local anaesthetic does not fully prevent complications.

Assessing bupivacaine 10mg/fentanyl 20μg as an intrathecal test dose

After ethics committee approval and verbal consent, women undergoing elective caesarean section given spinal anaesthesia with hyperbaric 0.5% bupivacaine 10 mg (2 mL) plus fentanyl 20 microg (spinal group, n = 20) and women requesting epidural analgesia in labour given the same drugs and doses epidurally, either in the same concentration (epidural small volume group, n = 10) or as 10 mL of 0.1% bupivacaine plus fentanyl 20 microg (epidural large volume group, n = 12) were recruited. The temperature of the great toes, sensory block on the outer ankle (S1 dermatome), motor block at the ankle and haemodynamic changes were recorded every 2 min for 10 min. There was a significant rise in foot temperature only in the spinal group. At four minutes a combination of warm toes and motor or sensory block, usually both, were seen only in the spinal groups. Haemodynamic changes were non-specific. We conclude that bupivacaine 10 mg with fentanyl 20 microg is a reliable agent to detect intrathecal placement by 4 min by which time a combination of motor and sensory block at the ankle and toe warming should be present.

A case of extensive block with the combined spinal-epidural technique during labour

The increasing use of combined spinal-epidural analgesia in obstetric practice has arisen from a desire to achieve a rapid onset of analgesia while reducing the intensity of the motor block. Although the procedure has an excellent safety profile, as with any technique there are potential problems. Difficulty in assessing the position of the epidural catheter after establishment of the spinal blockade may lead to an abnormally extensive block when a full-strength local anaesthetic solution is used. We present a case in which the use of 0.5% bupivacaine to top-up the epidural component of a combined spinal-epidural resulted in a total spinal block. The possible causes of this complication are discussed.

Cardiopulmonary arrest in pregnancy: successful resuscitation of mother and infant following immediate caesarean section in labour ward

Our patient experienced cardiopulmonary arrest secondary to profound hypotension and was unable to be resuscitated with external cardiac massage and assisted ventilation. This case demonstrates the need for continued vigilance by medical and nursing staff when epidural anaesthesia is being established. Resuscitation equipment should be available in the labour ward as cardiopulmonary resuscitation and immediate Caesarean section can be lifesaving in the event of a cardiopulmonary arrest.

[Dangers and complications in pain therapy with epidural and intrathecal catheters.]

Pain therapy with epidural or intrathecal catheters is an invasive method. These techniques have specific indications in both acute and chronic pain therapy. However, complications can occur. Thus, the potential complications and the therapy necessary must be known.Drugs: Complications resulting from acute local anesthetic intoxication's are rare. High plasma levels during chronic therapy may lead to confusion. Respiratory depression can occur in opioid naive patients up to 12 (-24) h after injection. Adequate monitoring is a prerequisite for this therapy. After application of clonidine, hypotension is frequent in hypertonic and hypovolemic patients. Epidural or intrathecalcatheter placement can result in therapeutic failure, trauma by punction and inability to place the catheter. During chronic therapy, technical problems can occur, e.g., dislocation, occlusion. To exclude intrathecal and intravascular placement, application of a test dosage of a local anesthetic with adrenaline is recommended.Neurological complications can result in nerve root deficit or "simple" post-spinal headache, but cauda equina syndromes, paralyses, intracranial bleeding, sinus thrombosis and central neurological deficits have been reported. Skininfection at the insertion site of the catheter has been observed with an incidence of 1.9 to 7.7%. A spinal infection with neurological deficit is rare. Spinal infections are often associated with other diseases. Spinalhematomas are rare. Coagulation disorders and anticoagulants can lead to bleeding. Intravenous heparin should be avoided, because this is frequently associated with spinal bleeding. Therapy with cumarines is a contraindication for insertion of spinal catheters.Monitoring: During treatment with spinal catheters, adequate monitoring increases safety for the patients. Efficacy of the injections, puncture site and the neurological status should be documented daily. Neurological deficits must be diagnosed without losing time and adequate therapy must be initiated.

Combined spinal-epidural-general anesthesia

Each one of the three kinds of anesthesia (spinal, epidural, general) has its advantages and disadvantages. A new concept of combined spinal-epidural-general anesthesia (CSEGA) is illustrated with the objective of producing a new kind of anesthesia. The aim is to draw out the good from each compartment. CSEGA can be based on muscle relaxation and anesthesia on its spinal part with the epidural augmentation. The endotracheal intubation can be kept in place with a very small dose of an inhalational anesthetic. There is no need for muscle relaxant drugs, i.v. opioids or benzodiazepines, for postoperative analgesia serves the epidural catheter. Very small doses of local anesthetic drugs injected into the spinal or epidural compartments, could be all that is needed for operations on any part of the body, including thorax and head. CSEGA is a new concept in anesthesia. The mixing of regional anesthesia with general anesthesia affords the anesthesiologist the opportunity to lower the local anesthetic doses, avoid using many kinds of intravenous drugs (muscle relaxants, opioids, benzodiazepines, etc.) and to approach a kind of anesthesia that is closer to the ideal.

Cesarean section in a pregnant patient with an anterior mediastinal mass and failed supradiaphragmatic irradiation

Nodular sclerosing Hodgkin's disease stages IA and IIA are the most common presentation of this disease during pregnancy. Patients presenting with late Hodgkin's disease with failed irradiation for cesarean section present a unique challenge. When this presentation occurs, a voluntary interruption of pregnancy is recommended. Upper body irradiation during the second trimester of pregnancy is recommended as well. We report a case involving a pregnant patient at 34 weeks' gestation presenting for cesarean section with a symptomatic anterior mediastinal mass occupying over 50% of the thoracic diameter. The anesthetic management was performed using continuous spinal.