Which anesthetic should be used in the treatment of refractory status epilepticus?

Anesthesia-Associated Periodic Discharges

PURPOSE

Anesthetic agents have been widely used in the treatment of refractory status epilepticus and the medical management of increased intracranial pressure whenever the goal is therapeutic burst suppression. Periodic patterns typically consisting of generalized periodic discharges (GPDs) following emergence from anesthesia have been described in several case reports. However, their clinical significance and in particular whether these patterns are epileptiform remains unclear.

METHODS

This is a single-center, retrospective, observational study examining EEG patterns following emergence from pharmacologically induced burst suppression. Clinical and EEG data were collected. Patients who developed GPDs following anesthetic wean were compared with those who did not.

RESULTS

Over 4.5 years, 14 patients developed GPDs related to anesthetic withdrawal. The GPDs had a frequency between 0.5 and 2.5 Hz. Generalized periodic discharges related to anesthetic withdrawal were transient, with a median duration of 40 hours (interquartile range, 24-48 hours). Notably, in all patients, the pattern was stimulus dependent. When compared with a control group of 19 consecutive patients who did not develop a generalized periodic pattern in the context of the anesthetic wean, there was no significant difference in the status epilepticus relapse between the two groups (29% vs. 44%; P = 0.63). Patients in the GPD group were more likely to be on pentobarbital (93% vs. 58%; P = 0.05) and were more likely to have concomitant systemic infection treated with antibiotics compared with the control group (86% vs. 42%; P = 0.02).

CONCLUSIONS

Generalized periodic patterns are common following the wean of intravenous anesthetics (particularly pentobarbital) and likely represent a transitional encephalopathic state in a subset of patients. Their morphology is distinct and can be differentiated from the reemergence of status epilepticus (if the latter was the indication for anesthetic treatment). Failure to recognize this pattern may lead to prolonged unnecessary treatments if it is mistaken for the emergence of seizure activity. The presence of concomitant systemic infection and associated antibiotic treatment may be risk factors for the development of this pattern.

Management of Status Epilepticus and Indications for Inpatient Electroencephalography Monitoring

Status epilepticus (SE) is a neurologic emergency requiring immediate time-sensitive treatment to minimize neuronal injury and systemic complications. Minimizing time to administration of first- and second-line therapy is necessary to optimize the chances of successful seizure termination in generalized convulsive SE (GCSE). The approach to refractory and superrefractory GCSE is less well defined. Multiple agents with differing complementary actions that facilitate seizure termination are recommended. Nonconvulsive SE (NCSE) has a wide range of presentations and approaches to treatment. Continuous electroencephalography is critical to the management of both GCSE and NCSE, while its use for patients without seizure continues to expand.

Hidden in plain sight: Non-convulsive status epilepticus-Recognition and management

Non-convulsive status epilepticus (NCSE) is an electroclinical state associated with an altered level of consciousness but lacking convulsive motor activity. It can present in a multitude of ways, but classification based on the clinical presentation and electroencephalographic appearances assists in determining prognosis and planning treatment. The aggressiveness of treatment should be based on the likely prognosis and the underlying cause of the NCSE.

A practical guide to the use of anti-epileptic drugs by neurosurgeons

Initiation of anti-epileptic drugs is increasingly relevant to daily neurosurgical practice. Intracranial pathologies ranging from brain tumours to subarachnoid haemorrhage and traumatic brain injury are commonly associated with the subsequent development of seizures. The scope and range of anti-epileptic drugs available has increased dramatically in recent years and understanding the evidence base behind this class of drugs in addition to their interaction/side effect profiles is essential. In this review we aim to generate a practical guide for neurosurgeons regarding the use of different anti-epileptic medications in common neurosurgical conditions, including considerations for their use in pregnancy.

Epidural focal brain cooling abolishes neocortical seizures in cats and non-human primates

Focal brain cooling (FBC) is under investigation in preclinical trials of intractable epilepsy (IE), including status epilepticus (SE). This method has been studied in rodents as a possible treatment for epileptic disorders, but more evidence from large animal studies is required. To provide evidence that FBC is a safe and effective therapy for IE, we investigated if FBC using a titanium cooling plate can reduce or terminate focal neocortical seizures without having a significant impact on brain tissue. Two cats and two macaque monkeys were chronically implanted with an epidural FBC device over the somatosensory and motor cortex. Penicillin G was delivered via the intracranial cannula for induction of local seizures. Repetitive FBC was performed using a cooling device implanted for a medium-term period (FBC for 30min at least twice every week; 3 months total) in three of the four animals. The animals exhibited seizures with repetitive epileptiform discharges (EDs) after administration of penicillin G, and these discharges decreased at less than 20°C cooling with no adverse histological effects. The results of this study suggest that epidural FBC is a safe and effective potential treatment for IE and SE.

Propofol versus thiopental sodium for the treatment of refractory status epilepticus

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (Issue 6, 2015).Failure to respond to antiepileptic drugs in patients with uncontrolled seizure activity such as refractory status epilepticus (RSE) has led to the use of anaesthetic drugs. Coma is induced with anaesthetic drugs to achieve complete control of seizure activity. Thiopental sodium and propofol are popularly used for this purpose. Both agents have been found to be effective. However, there is a substantial lack of evidence as to which of the two drugs is better in terms of clinical outcomes.

OBJECTIVES

To compare the efficacy, adverse effects, and short- and long-term outcomes of refractory status epilepticus (RSE) treated with one of the two anaesthetic agents, thiopental sodium or propofol.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (16 August 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 16 August 2016), MEDLINE (Ovid, 1946 to 16 August 2016), ClinicalTrials.gov (16 August 2016), and the South Asian Database of Controlled Clinical Trials (16 August 2016). Previously we searched IndMED, but this was not accessible at the time of the latest update.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-RCTs (regardless of blinding) assessing the control of RSE using either thiopental sodium or propofol in patients of any age and gender.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results and reviewed the abstracts of relevant and eligible trials before retrieving the full-text publications.

MAIN RESULTS

One study with a total of 24 participants was available for review. This study was a small, single-blind, multicentre trial studying adults with RSE receiving either propofol or thiopental sodium for the control of seizure activity. This study was terminated early due to recruitment problems. For our primary outcome of total control of seizures after the first course of study drug, there were 6/14 patients versus 2/7 patients in the propofol and thiopental sodium groups, respectively (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.40 to 5.61, low quality evidence). Mortality was seen in 3/14 patients versus 1/7 patients in the propofol and thiopental sodium groups, respectively (RR 1.50, 95% CI 0.19 to 11.93, low quality evidence). Our third primary outcome of length of ICU stay was not reported. For our secondary outcomes of adverse events, infection was seen in 7/14 patients versus 5/7 patients in the propofol and thiopental sodium groups, respectively (RR 0.70; 95% CI 0.35 to 1.41). Hypotension during administration of study drugs and requiring use of vasopressors was seen in 7/14 patients versus 4/7 patients in the propofol and thiopental sodium groups, respectively (RR 0.87; 95% CI 0.38 to 2.00). The other severe complication noted was non-fatal propofol infusion syndrome in one patient. Patients receiving thiopental sodium required more days of mechanical ventilation when compared with patients receiving propofol: (median (range) 17 days (5 to 70 days) with thiopental sodium versus four days (2 to 28 days) with propofol). At three months there was no evidence of a difference between the drugs with respect to outcome measures such as control of seizure activity and functional outcome.

AUTHORS' CONCLUSIONS

Since the last version of this review we have found no new studies.There is a lack of robust, randomised, controlled evidence to clarify the efficacy of propofol and thiopental sodium compared to each other in the treatment of RSE. There is a need for large RCTs for this serious condition.

Treatment of Convulsive Status Epilepticus

OPINION STATEMENT

Convulsive status epilepticus (CSE) is a medical emergency with an associated high mortality and morbidity. It is defined as a convulsive seizure lasting more than 5 min or consecutive seizures without recovery of consciousness. Successful management of CSE depends on rapid administration of adequate doses of anti-epileptic drugs (AEDs). The exact choice of AED is less important than rapid treatment and early consideration of reversible etiologies. Current guidelines recommend the use of benzodiazepines (BNZ) as first-line treatment in CSE. Midazolam is effective and safe in the pre-hospital or home setting when administered intramuscularly (best evidence), buccally, or nasally (the latter two possibly faster acting than intramuscular (IM) but with lower levels of evidence). Regular use of home rescue medications such as nasal/buccal midazolam by patients and caregivers for prolonged seizures and seizure clusters may prevent SE, prevent emergency room visits, improve quality of life, and lower health care costs. Traditionally, phenytoin is the preferred second-line agent in treating CSE, but it is limited by hypotension, potential arrhythmias, allergies, drug interactions, and problems from extravasation. Intravenous valproate is an effective and safe alternative to phenytoin. Valproate is loaded intravenously rapidly and more safely than phenytoin, has broad-spectrum efficacy, and fewer acute side effects. Levetiracetam and lacosamide are well tolerated intravenous (IV) AEDs with fewer interactions, allergies, and contraindications, making them potentially attractive as second- or third-line agents in treating CSE. However, data are limited on their efficacy in CSE. Ketamine is probably effective in treating refractory CSE (RCSE), and may warrant earlier use; this requires further study. CSE should be treated aggressively and quickly, with confirmation of treatment success with epileptiform electroencephalographic (EEG), as a transition to non-convulsive status epilepticus is common. If the patient is not fully awake, EEG should be continued for at least 24 h. How aggressively to treat refractory non-convulsive SE (NCSE) or intermittent non-convulsive seizures is less clear and requires additional study. Refractory SE (RSE) usually requires anesthetic doses of anti-seizure medications. If an auto-immune or paraneoplastic etiology is suspected or no etiology can be identified (as with cryptogenic new onset refractory status epilepticus, known as NORSE), early treatment with immuno-modulatory agents is now recommended by many experts.

Pharmacotherapy for Status Epilepticus

Status epilepticus (SE) represents the most severe form of epilepsy. It is one of the most common neurologic emergencies, with an incidence of up to 61 per 100,000 per year and an estimated mortality of 20 %. Clinically, tonic-clonic convulsive SE is divided into four subsequent stages: early, established, refractory, and super-refractory. Pharmacotherapy of status epilepticus, especially of its later stages, represents an "evidence-free zone," due to a lack of high-quality, controlled trials to inform clinical decisions. This comprehensive narrative review focuses on the pharmacotherapy of SE, presented according to the four-staged approach outlined above, and providing pharmacological properties and efficacy/safety data for each antiepileptic drug according to the strength of scientific evidence from the available literature. Data sources included MEDLINE and back-tracking of references in pertinent studies. Intravenous lorazepam or intramuscular midazolam effectively control early SE in approximately 63-73 % of patients. Despite a suboptimal safety profile, intravenous phenytoin or phenobarbital are widely used treatments for established SE; alternatives include valproate, levetiracetam, and lacosamide. Anesthetics are widely used in refractory and super-refractory SE, despite the current lack of trials in this field. Data on alternative treatments in the later stages are limited. Valproate and levetiracetam represent safe and effective alternatives to phenobarbital and phenytoin for treatment of established SE persisting despite first-line treatment with benzodiazepines. To date there are no class I data to support recommendations for most antiepileptic drugs for established, refractory, and super-refractory SE. Limiting the methodologic heterogeneity across studies is required and high-class randomized, controlled trials to inform clinicians about the best treatment in established and refractory status are needed.

Robust control of burst suppression for medical coma

OBJECTIVE

Medical coma is an anesthetic-induced state of brain inactivation, manifest in the electroencephalogram by burst suppression. Feedback control can be used to regulate burst suppression, however, previous designs have not been robust. Robust control design is critical under real-world operating conditions, subject to substantial pharmacokinetic and pharmacodynamic parameter uncertainty and unpredictable external disturbances. We sought to develop a robust closed-loop anesthesia delivery (CLAD) system to control medical coma.

APPROACH

We developed a robust CLAD system to control the burst suppression probability (BSP). We developed a novel BSP tracking algorithm based on realistic models of propofol pharmacokinetics and pharmacodynamics. We also developed a practical method for estimating patient-specific pharmacodynamics parameters. Finally, we synthesized a robust proportional integral controller. Using a factorial design spanning patient age, mass, height, and gender, we tested whether the system performed within clinically acceptable limits. Throughout all experiments we subjected the system to disturbances, simulating treatment of refractory status epilepticus in a real-world intensive care unit environment.

MAIN RESULTS

In 5400 simulations, CLAD behavior remained within specifications. Transient behavior after a step in target BSP from 0.2 to 0.8 exhibited a rise time (the median (min, max)) of 1.4 [1.1, 1.9] min; settling time, 7.8 [4.2, 9.0] min; and percent overshoot of 9.6 [2.3, 10.8]%. Under steady state conditions the CLAD system exhibited a median error of 0.1 [-0.5, 0.9]%; inaccuracy of 1.8 [0.9, 3.4]%; oscillation index of 1.8 [0.9, 3.4]%; and maximum instantaneous propofol dose of 4.3 [2.1, 10.5] mg kg(-1). The maximum hourly propofol dose was 4.3 [2.1, 10.3] mg kg(-1) h(-1). Performance fell within clinically acceptable limits for all measures.

SIGNIFICANCE

A CLAD system designed using robust control theory achieves clinically acceptable performance in the presence of realistic unmodeled disturbances and in spite of realistic model uncertainty, while maintaining infusion rates within acceptable safety limits.

Propofol versus thiopental sodium for the treatment of refractory status epilepticus

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 8, 2012.Failure to respond to antiepileptic drugs in patients with uncontrolled seizure activity such as refractory status epilepticus (RSE) has led to the use of anaesthetic drugs. Coma is induced with anaesthetic drugs to achieve complete control of seizure activity. Thiopental sodium and propofol are popularly used for this purpose. Both agents have been found to be effective. However, there is a substantial lack of evidence as to which of the two drugs is better in terms of clinical outcome.

OBJECTIVES

To compare the efficacy, adverse effects, and short- and long-term outcomes of RSE treated with one of the two anaesthetic agents, thiopental sodium or propofol.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (26 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library Issue 2, February 2015) and MEDLINE (1946 to 26 March 2015). We also searched ClinicalTrials.gov (26 March 2015), the South Asian Database of Controlled Clinical Trials and IndMED (a bibliographic database of Indian Medical Journals).

SELECTION CRITERIA

All randomised or quasi-randomised controlled studies (regardless of blinding) of control of RSE using either thiopental sodium or propofol in patients of any age and gender.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results and reviewed the abstracts of relevant and eligible trials before retrieving the full-text publications.

MAIN RESULTS

One study with a total of 24 participants was available for review. This study was a small, single-blind, multicentre trial studying adults with RSE receiving either propofol or thiopental sodium for the control of seizure activity. This study cannot be considered of high methodological quality. This study was terminated early due to recruitment problems. This study showed a wide confidence interval suggesting that the drugs may differ in efficacy up to more than two-fold. Days of mechanical ventilation were more in patients receiving thiopental sodium when compared with propofol. At three months there was no evidence of a difference between the drugs with respect to outcome measures such as control of seizure activity and functional outcome. Adverse events reported in this study were infection, hypotension and intestinal ischaemia.

AUTHORS' CONCLUSIONS

Since the last version of this review we have found no new studies.There is a lack of robust, randomised, controlled evidence that can clarify the efficacy of propofol and thiopental sodium compared to each other in the treatment of RSE. There is a need for large randomised controlled trials for this serious condition.

Calculating the risk benefit equation for aggressive treatment of non-convulsive status epilepticus

OBJECTIVE

To address the question: does non-convulsive status epilepticus warrant the same aggressive treatment as convulsive status epilepticus?

METHODS

We used a decision model to evaluate the risks and benefits of treating non-convulsive status epilepticus with intravenous anesthetics and ICU-level aggressive care. We investigated how the decision to use aggressive versus non-aggressive management for non-convulsive status epilepticus impacts expected patient outcome for four etiologies: absence epilepsy, discontinued antiepileptic drugs, intraparenchymal hemorrhage, and hypoxic ischemic encephalopathy. Each etiology was defined by distinct values for five key parameters: baseline mortality rate of the inciting etiology; efficacy of non-aggressive treatment in gaining control of seizures; the relative contribution of seizures to overall mortality; the degree of excess disability expected in the case of delayed seizure control; and the mortality risk of aggressive treatment.

RESULTS

Non-aggressive treatment was favored for etiologies with low morbidity and mortality such as absence epilepsy and discontinued antiepileptic drugs. The risk of aggressive treatment was only warranted in etiologies where there was significant risk of seizure-induced neurologic damage. In the case of post-anoxic status epilepticus, expected outcomes were poor regardless of the treatment chosen. The favored strategy in each case was determined by strong interactions of all five model parameters.

CONCLUSIONS

Determination of the optimal management approach to non-convulsive status epilepticus is complex and is ultimately determined by the inciting etiology.

Pediatric intensive care treatment of uncontrolled status epilepticus

The critically ill mechanically ventilated child with ongoing seizures that are refractory to any treatment presents a distinct challenge in pediatric neurocritical care. The evidence base from randomized controlled trials on which anti-epileptic drug (AED) strategy should be used is inadequate. This review of refractory and super-refractory status epilepticus summarizes recent pediatric case series regarding definitions, the second-tier AED therapies once initial anticonvulsants have failed, and the experience of high-dose midazolam, barbiturate anesthesia, and volatile anesthetics for uncontrolled status epilepticus.

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.

Management of refractory status epilepticus in adults: still more questions than answers

Refractory status epilepticus (RSE) is defined as status epilepticus that continues despite treatment with benzodiazepines and one antiepileptic drug. RSE should be treated promptly to prevent morbidity and mortality; however, scarce evidence is available to support the choice of specific treatments. Major independent outcome predictors are age (not modifiable) and cause (which should be actively targeted). Recent recommendations for adults suggest that the aggressiveness of treatment for RSE should be tailored to the clinical situation. To minimise intensive care unit-related complications, focal RSE without impairment of consciousness might initially be approached conservatively; conversely, early induction of pharmacological coma is advisable in generalised convulsive forms of the disorder. At this stage, midazolam, propofol, or barbiturates are the most commonly used drugs. Several other treatments, such as additional anaesthetics, other antiepileptic or immunomodulatory compounds, or non-pharmacological approaches (eg, electroconvulsive treatment or hypothermia), have been used in protracted RSE. Treatment lasting weeks or months can sometimes result in a good outcome, as in selected patients after encephalitis or autoimmune disorders. Well designed prospective studies of RSE are urgently needed.

Recent and future advances in the treatment of status epilepticus

Status epilepticus (SE) is one of the most frequent neurological emergencies with an incidence of 20/100,000 per year and a mortality between 3% and 40% depending on etiology, age, SE type and duration. Generalized convulsive forms of SE (GTCSE), in particular, require aggressive treatment. Presently, only 55-80% of cases of GTCSE are controlled by initial therapy. Therefore, there is a need for new options for the treatment of SE. Here we review the current standard treatment including recent advances and provide a summary of preclinical and clinical data regarding treatment options which may become available in the near future. The initial treatment of SE usually consists of a benzodiazepine (preferably lorazepam 0.1 mg/kg) followed by phenytoin or fosphenytoin or valproic acid (where approved for SE therapy). With intravenous formulations of levetiracetam, available since 2006, and lacosamide, which is expected for autumn of 2008, new treatment options have become available, that should be evaluated in prospective controlled trials. If SE remains refractory, the induction of general anaesthesia using propofol, midazolam, thiopental, or pentobarbital is warranted in GTCSE.

Propofol

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Status epilepticus: a critical review

Status epilepticus (SE) is a major neurological emergency with an incidence of about 20/100,000 and a mortality between 3 and 40% depending on etiology, age, status type, and status duration. Generalized tonic-clonic SE, in particular, requires immediate, aggressive, and effective treatment to stop seizure activity, and to prevent neuronal damage and systemic complications and death. Benzodiazepines and phenytoin/fosphenytoin are traditionally used as first-line drugs and are effective in about 60% of all episodes. However, a notable portion of patients remain in SE. For those, narcotics and induction of general anesthesia are used as second-line treatment. Therefore, there is a need for more effective first-line treatment options. Recently, valproic acid was approved for the treatment of status epilepticus in some European countries, and two of the newer antiepileptic drugs have become available for intravenous use: Levetiracetam (LEV) and lacosamide (LCM) should be evaluated in prospective controlled trials as possible treatment options. Standardized protocols for the management of SE are useful to improve immediate care.