Status epilepticus treated by barbiturate anaesthesia with continuous monitoring of cerebral function

The Origin of the Burst-Suppression Paradigm in Treatment of Status Epilepticus

After electroencephalography (EEG) was introduced in hospitals, early literature recognized burst-suppression pattern (BSP) as a distinctive EEG pattern characterized by intermittent high-power oscillations alternating with isoelectric periods in coma and epileptic encephalopathies of childhood or the pattern could be induced by general anesthesia and hypothermia. The term was introduced by Swank and Watson in 1949 but was initially described by Derbyshire et al. in 1936 in their study about the anesthetic effects of tribromoethanol. Once the EEG/BSP pattern emerged in the literature as therapeutic goal in refractory status epilepticus, researchers began exploring whether the depth of EEG suppression correlated with improved seizure control and clinical outcomes. We can conclude that, from a historical perspective, the evidence to suppress the brain to a BSP when treating status epilepticus is inconclusive.

Guidelines for the evaluation and management of status epilepticus

Status epilepticus (SE) treatment strategies vary substantially from one institution to another due to the lack of data to support one treatment over another. To provide guidance for the acute treatment of SE in critically ill patients, the Neurocritical Care Society organized a writing committee to evaluate the literature and develop an evidence-based and expert consensus practice guideline. Literature searches were conducted using PubMed and studies meeting the criteria established by the writing committee were evaluated. Recommendations were developed based on the literature using standardized assessment methods from the American Heart Association and Grading of Recommendations Assessment, Development, and Evaluation systems, as well as expert opinion when sufficient data were lacking.

Propofol and barbiturates for the anesthesia of refractory convulsive status epilepticus: pros and cons

OBJECTIVE

To discuss mainly the use of propofol and barbiturates in the anesthesia of refractory status epilepticus (RSE).

METHODS

Review of literature.

RESULTS

There are no prospective, randomized works comparing the effects of anesthetics in the treatment of RSE. Recently, the use of propofol has increased in the treatment of RSE. Propofol terminates both clinical and electric seizures quickly, but the maintenance of burst-suppression EEG pattern requires repetitive titration of doses. Relapses of seizures have occurred in 19-33% of patients, especially when tapering of dose. The advantages of barbiturates are lower frequency of short-term treatment failures, breakthrough seizures and changes to a different anesthetic agent. On the other hand, prolonged recovery leads to prolonged duration of mechanical ventilation, intensive care and hospital stay.

DISCUSSION

The use of propofol, barbiturates or midazolam in the anesthesia of RSE can be justified. When using propofol, the duration of high doses should be limited to 48 hours and the risk of propofol infusion syndrome should be kept in mind. High doses of barbiturates terminate effectively seizures but recovery from anesthesia prolongs ventilator treatment and intensive care.

[Refractory status epilepticus: diagnosis, therapy, course, and prognosis]

Status epilepticus (SE) is a frequent neurological emergency with an annual incidence of 10-20/100,000 individuals. The overall mortality is about 10-20%. Patients present with long-lasting fits or series of epileptic seizures or extended stupor and coma. Furthermore, patients with SE can suffer from a number of systemic complications possibly also due to side effects of the medical treatment. In the beginning, standardized treatment algorithms can successfully stop most SE. A minority of SE cases prove however to be refractory against the initial treatment and require intensified pharmacologic intervention with nonsedating anticonvulsive drugs or anesthetics. In some partial SE, nonpharmacological approaches (e.g., epilepsy surgery) have been used successfully. This paper reviews scientific evidence of the diagnostic approach, therapeutic options, and course of refractory SE, including nonpharmacological treatment.

Neurologic outcomes of pediatric epileptic patients with pentobarbital coma

Status epilepticus is a life-threatening condition requiring emergent medical attention. Although initial therapies with antiepileptic drugs generally terminate seizures within 30 to 60 minutes, patients with refractory status epilepticus require additional intervention. High-dose pentobarbital has been the most commonly prescribed agent for the management of refractory status epilepticus in children. The objective of this research was to evaluate the association between the response of pentobarbital coma and neurologic outcomes in refractory status epilepticus. Twenty-three subjects were treated with pentobarbital coma for at least 48 hours. Medical records were reviewed to collect patient demographic information, responses to treatment, and neurologic outcomes. Among the 23 patients reviewed, 12 patients were controlled with pentobarbital (responders), six were unresponsive to pentobarbital (nonresponders), and five patients relapsed after discontinuation or during tapering of pentobarbital (relapser). The mortality rate among the relapser and nonresponder groups combined was 90.9%, but no deaths occurred among the responder group (P < 0.001). The survival rate was greater among toddlers compared with neonates or older children. Failure of seizure control after pentobarbital coma was associated with a poor prognosis. The potential for serious complications of pentobarbital therapy among neonates highlights the need for careful dosing in this age group.

Prolonged thiopentone infusion for neurosurgical emergencies: usefulness of therapeutic drug monitoring

Serial serum thiopentone concentrations were measured during and following completion of an intravenous infusion of thiopentone in 20 patients with neurosurgical emergencies. The concentration data from a further 55 patients who had had some such measurements were reviewed retrospectively. The patients received an infusion for longer than 24 hours at a rate adjusted to maintain EEG burst suppression. The data were interpreted in terms of thiopentone pharmacokinetics and used to produce statistical models relating to clinical outcomes. In these patients, the one-month mortality rate following commencement of thiopentone treatment was 20%; the mean durations of pupillary and motor unresponsiveness following cessation of an infusion were 22 and 91 hours, respectively. Predictors of a prolonged duration of motor unresponsiveness included a prolonged duration of pupillary unresponsiveness, a low thiopentone clearance and a high maximum serum concentration of thiopentone. From pooled logistic regression, median effective serum thiopentone concentrations (EC50) were found to be 50 mg x l(-1) for recovery of pupillary responsiveness and 12 mg x l(-1) for the recovery of motor responsiveness. Because prolonged high-dose thiopentone leads to prolonged residual serum concentrations, it is difficult to distinguish the residual pharmacological effects of thiopentone from the clinical condition. This study suggests that, based on EC50 values for responses, monitoring of post-infusion serum thiopentone concentrations may help determine whether a patient's clinical state is due to residual thiopentone pharmacological effects.

Status epilepticus

Status epilepticus is a medical emergency that requires rapid and vigorous treatment to prevent neuronal damage and systemic complications. Failure to diagnose and treat status epilepticus accurately and effectively results in significant morbidity and mortality. Cerebral metabolic decompensation occurs after approximately 30 min of uncontrolled convulsive activity, and the window for treatment is therefore limited. Therapy should proceed simultaneously on four fronts: termination of seizures; prevention of seizure recurrence once status is controlled; management of precipitating causes of status epilepticus; management of the complications. This article reviews current opinions about the classification, aetiology and pathophysiology of adult generalised convulsive status epilepticus and details practical management strategies for treatment of this life-threatening condition.

Efficacy of five days' barbiturate anesthesia in the treatment of intractable epilepsies in children

PURPOSE

To analyze the efficacy of barbiturate anesthesia in the treatment of intractable epilepsies in childhood.

METHODS

Anesthesia for 4-5 days with thiopentone sodium was used to treat children with intractable epilepsy in the Department of Pediatrics, Oulu, Finland, from November 1980 through December 1995. The number of epileptic seizures, the number and dosage of antiepileptic drugs (AEDs), and psychomotor development before and after anesthesia were compared.

RESULTS

Fifty-four children with intractable epilepsy were treated with barbiturate anesthesia. Twenty-four children had infantile spasms; 22, Lennox-Gastaut syndrome; seven, complex partial epilepsy; and one, myoclonic epilepsy. Twenty-four (44.4%) children had complications during the anesthesia. The seizures recurred in 53 of the 54 patients in a median time of 12 days after the anesthesia. In 42 (78%) children, the seizure frequency returned to a level equal to or higher than that before the anesthesia in a median time of 211 days. The number of AEDs was significantly greater after than before the anesthesia (6.33 vs. 4.8; p < 0.001). Seventeen (32.5%) children were treated surgically after the anesthesia.

CONCLUSIONS

Although the seizures are eliminated or the seizure frequency decreases for a short period after the barbiturate anesthesia, the anesthesia does not change the long-term outcome and is therefore inefficient in the treatment of childhood intractable epilepsies.

Pharmacodynamics and pharmacokinetics of thiopental

Thiopental is an ultra short-acting barbiturate which remains the standard against which other induction agents are judged; it is also indicated for the therapy of brain hypoxic-ischaemia injuries and status epilepticus. Aspects of drug distribution that govern the onset and end of drug effect have been intensively studied to determine which parameters (in patient characteristics, diseases and administration modalities) influence effective dose and concentrations in individual patients. Thiopental has been used as a reference for pharmacokinetic and/or pharmacodynamic models in the study of rapid and short acting effect drugs. In anaesthesiology the pharmacokinetics of thiopental are described as linear; when doses and duration of treatment increase, nonlinear pharmacokinetics occur because of the saturation and/or the induction of the metabolism.

Treatment of refractory status epilepticus with propofol: clinical and pharmacokinetic findings

PURPOSE

We compared propofol with high-dose barbiturates in the treatment of refractory status epilepticus (RSE) and propose a protocol for the administration of propofol in RSE in adults, correlating propofol's effect with plasma levels.

METHODS

Sixteen patients with RSE were included; 8 were treated primarily with high-dose barbiturates and 8 were treated primarily with propofol.

RESULTS

Both groups of patients had multiple medical problems and a subsequent high mortality. A smaller but not statistically significant fraction of patients had their seizures controlled with propofol (63%) than with high-dose barbiturate therapy (82%). The time from initiation of high-dose barbiturate therapy to attainment of control of RSE was longer (123 min) than the time to attainment of seizure control in the group receiving propofol (2.6 min, p = 0.002). Plasma concentrations of propofol associated with control of SE were 14 microM +/- 4 (2.5 microg/ml). Recurrent seizures were common when propofol infusions were suddenly discontinued but not when the infusions were gradually tapered.

CONCLUSIONS

If used appropriately, propofol infusions can effectively and quickly terminate many but not all episodes of RSE. Propofol is a promising agent for use in treating RSE, but more studies are required to determine its true value in comparison with other agents.

Successful treatment of amoxapine-induced refractory status epilepticus with propofol (diprivan)

Tonic-clonic seizure activity is a recognized complication of amoxapine overdose. Refractory drug-induced status epilepticus is associated with significant morbidity and mortality. Standard regimens for controlling status epilepticus may be ineffective for aborting drug-induced seizures. The authors report the case of a 30-year-old woman who presented with an amoxapine overdose that deteriorated into status epilepticus refractory to conventional therapy. Propofol given by intravenous bolus and maintenance infusion successfully halted the patient's seizure activity. This case suggests that propofol may be effective as an anticonvulsant in refractory drug-induced status epilepticus.

Failure to recognize status epilepticus in a paralysed patient

Paralysis induced by neuromuscular blocking agents facilitates ventilation of seriously ill patients but may preclude clinical recognition of seizures. We describe the occurrence of severe cognitive impairment in a 14-year-old girl in whom status epilepticus was recognized only when pancuronium was withdrawn after 14 hours of paralysis. This patient emphasizes a potential danger of paralysis from drugs in patients with acute cerebral dysfunction.

Displacement of thiopental from human serum albumin by associated drugs

Displacement of thiopental from its binding sites to 4% human serum albumin solution was studied in vitro. Experimental conditions were selected to reproduce a physiological situation. Associations were studied according to the therapeutic conditions of use of the substances (drug and protein concentrations). The unbound fraction of thiopental was obtained by equilibrium dialysis at 37 degrees C and pH 7.4. Eleven drugs were associated with thiopental in 50 combinations of drugs and molar ratios. Bromhexine, citocoline, dextromoramide, dexamethasone, and methotrimeprazine had no effect on thiopental binding. The unbound fraction of thiopental significantly increased with cefamandole, cefazolin, diazepam, desmethyldiazepam, furosemide, and fentanyl. At usual therapeutic drug concentrations, the unbound fraction increase was < 5%. Higher values, however still < 10%, were found with associated drugs that were added at maximal concentrations observed in therapy. The displacement of thiopental from its albumin binding by drugs that are normally associated with the treatment of intracranial hypertension does not modify the pharmacokinetic parameters or pharmacological effect of thiopental.

Status epilepticus: clinical experience with two special devices for continuous cerebral monitoring

Continuous cerebral monitoring (CCM) was performed on 34 patients in status epilepticus (SE), using changes in amplitude detected by the cerebral function monitor (CFM) and changes in frequency detected by compressed spectral array (CSA). The EEG was used intermittently to help identify seizure patterns obtained with these methods. Seventeen patients in clinically manifest SE also had non-convulsive seizures. In 17 patients, SE was refractory to conventional anticonvulsants, requiring treatment with pentobarbital or paraldehyde. In these patients, CCM provided dynamic electroencephalographic monitoring of burst-suppression and prompt detection of breakthrough seizures. Patients in SE should undergo CCM to differentiate between non-convulsive seizures and post-ictal state both of which may produce prolonged unresponsiveness following clinical seizures. CCM after data reduction with the two special devices used is a viable and practical alternative to continuous conventional EEG monitoring during SE. However, in order to evaluate the sensitivity and specificity of these methods, it will be necessary to design a study in which both the EEG and the devices using data reduction be used continuously and concurrently.

Medical management of recurrent seizures in dogs and cats

The problem of recurrent seizures is a common and challenging one in veterinary medical practice. The pathophysiology and pharmacologic suppression of focal seizure activity have been studied extensively in basic research settings, yet little is known of the genesis, modulation, and termination of generalized seizures, the most common form of seizures noted to occur in companion animals. Knowledge concerning the pharmacokinetic fate of anticonvulsant drugs currently used in veterinary medicine is adequate, though prospective clinical studies of the efficacy of these drugs in the treatment of various types of seizures are lacking. This study will review the available literature regarding the pharmacology, use, and side effects of anticonvulsant drugs currently available for control of recurrent seizures in companion animals. Alternative anticonvulsant drugs will also be described.

Pentobarbital and EEG burst suppression in treatment of status epilepticus refractory to benzodiazepines and phenytoin

Seven patients with complex partial or secondarily generalized tonic-clonic status epilepticus (SE) refractory to benzodiazepines (BZDs) and phenytoin (PHT) were treated with pentobarbital (PTB) coma with an EEG burst suppression (BSP) pattern. PTB administered by continuous intravenous (i.v.) infusion pump at a loading dose of 6-8 mg/kg in 40-60 min was usually sufficient to produce BSP activity and seizure control. PTB was continued 0-24 h at 1-4 mg/kg/h, adjusted to maintain blood pressure (BP) and BSP. Infusion rate was decreased if systolic BP (SBP) was less than 90 mm Hg. Normal saline fluid challenge was occasionally used to elevate BP, but in no case was it necessary to discontinue PTB infusion or use pressors. Other antiepileptic drugs (AEDs) were maintained at therapeutic levels for chronic seizure protection. Seizures were stopped in all cases. Four patients attained premorbid neurologic status, two patients briefly survived in vegetative states with recurring seizures after PTB withdrawal, and one patient died of asystole after receiving PTB for 7 h. Patients who had poor outcomes had prolonged seizures (16 h to 3 weeks) before institution of PTB anesthesia, and all had significant underlying central nervous system (CNS) pathology. PTB-induced BSP appears to be safe and effective for refractory SE if it is started soon after failure of a BZD and PHT. Ultimate prognosis depends on SE etiology.

Can barbiturate anaesthesia cure infantile spasms?

Five patients with infantile spasms and hypsarrhythmia and one with Lennox-Gastaut syndrome were treated with brief thiopentone anaesthesia as the primary treatment of infantile spasms. Thiopentone (30 mg/kg) was given intravenously and burst suppression was reached in EEG in three patients by this dose. The results were disappointing. In three patients a transient beneficial effect on spasms and hypsarrhythmia was seen, but all patients relapsed. Three other patients had anaesthesia for surgery. The spasms ceased and hypsarrhythmia disappeared dramatically, and the effect was permanent. The possible mechanisms of the therapeutic effect are discussed. It seems advisable to give anaesthesia and surgery prior to steroid treatment in any case where the both are needed.

Prolonged electrocerebral silent barbiturate coma in intractable seizure disorders

Barbiturate coma (BC) is a known modality for terminating resistant convulsive status epilepticus. It is usually applied until seizure activity ends. We recently adopted a modified protocol of prolonged, electrocerebral silent BC to treat patients with chronic seizure activity resistant to multiple regimens of antiepileptic drugs. Four patients, aged 4 months to 10 years, with long-standing intractable generalized seizures were treated. Seizure frequency ranged from one to two to numerous times per day. Following BC, one patient has been seizure free during 8 months of follow-up, and another has had only two seizures in 18 months. A 4-month-old infant was seizure-free for 2 weeks after BC and then died from underlying CNS disease. A 10-year-old girl died during BC from shock and hyperpyrexia. The results obtained in our patients indicate that prolonged electrocerebral silent BC may exert a beneficial long-term effect in treatment of intractable seizure disorders. This procedure might also be beneficial in other forms of epilepsy.

Status epilepticus and alcohol abuse: an analysis of 82 status epilepticus admissions

In 1979-80, 82 cases of grand mal status epilepticus (71 patients, 39 male and 32 female) were admitted to the Casualty Department of Meilahti University Hospital in Helsinki, Finland. The cause of the underlying epilepsy was symptomatic in 43 cases (52.4%) and idiopathic in 19 cases (23.2%). In 6 cases (7.3%), there was a history of alcohol withdrawal seizures, and in 14 cases (17.1%) there was no earlier history of convulsions. Status epilepticus was associated with an acute or progressive cerebral disorder in 14 episodes. These comprised 6 bouts of status with brain tumour, 4 with acute stroke and 4 with brain injury. Alcohol abuse preceded the status in 29 episodes (35.4%), 23 of which occurred in men (53.5% of the male cases). Excessive use of alcohol was the only obvious precipitating factor for status in 16 cases, and in 6 cases the status presented as a prolonged alcohol withdrawal seizure. A change or irregularity of anticonvulsive drug therapy could be documented in 14 cases and an acute infection outside the central nervous system in 7 cases. Intravenous diazepam, used as the only therapy for status epilepticus, was effective in 58 of 78 episodes. In 7 cases of prolonged status, a thiopental sodium anaesthesia proved effective. The total mortality was 4.2%, including 2 deaths from concomitant extracerebral disorders and one late death from brain metastasis.

The cerebral function analysing monitor. Initial clinical experience, application and further development

The cerebral function analysing monitor is a development of the cerebral function monitor. It produces a more detailed analysis of the electroencephalogram (EEG) amplitude and analyses the frequency of the waveforms into standard beta, alpha, theta and delta bands. It can analyse the EEG from two input channels, produce traces of the standard EEG, and compute visual, auditory, somato sensory and brain stem evoked potentials.

Status epilepticus: a plan for management

Status epilepticus of the generalized tonic-clonic form is a serious, life-threatening neurological emergency. Management must be swift and effective to protect the brain from anoxic damage and serious neurological sequelae. Most cases are due to withdrawal or non-compliance with anticonvulsant medication in known epileptics. Diazepam, phenytoin and phenobartital are effective in stopping these episodes. Other drugs may be effective in certain individuals, but most appear to work with `hit or miss' effectiveness. Barbiturate anesthesia is an effective method of ending status epilepticus episodes when the primary agents have failed, and this step should be undertaken early in the management of resistant cases.

Treatment of status epilepticus with thiopentone sodium anaesthesia in a child

A 4-month-old infant was admitted to the Pediatric Intensive Care Unit with Pneumococcal meningitis. A few hours after admission he developed intractable convulsions that could not be stopped with phenytoin, phenobarbitone and a continuous drip of diazepam. Thiopentone sodium anaesthesia was induced for 24 h terminating the status epilepticus. The clinical course, correlary EEG findings, treatment protocol and blood levels of the drugs given are described in detail.

Plasma and cerebrospinal fluid barbiturate levels during prolonged continuous thiopentone infusion

During an infusion of thiopentone to control status epilepticus secondary to hypoxic brain damage, thiopentone and pentobarbitone levels were measured in the serum and cerebrospinal fluid (CSF). Pentobarbitone was found to be present in the serum between 7.8 and 11.1% of the thiopentone levels. There was a prompt response in serum levels of thiopentone to changes in the infusion rate. The CSF thiopentone varied between 15 and 40% of the serum levels. The CSF anticonvulsant threshold for thiopentone for this patient was between 5 and 15 mg/litre.

Status epilepticus or what?

This case report describes a man who had two grand mal seizures, each one followed by a lengthy period of unconsciousness during which he was extremely restless, with violent uncoordinated movements. This was probably a form of status epilepticus conforming to a diagnosis of grand mal seizure, followed by a complex partial seizure, but was similar to what has been described as post epileptic mania or delirium. A brief historical perspective is included together with a resumé of the differential diagnosis of adult onset epilepsy.