The effect of barbiturate coma therapy for the patients with severe intracranial hypertension: a 10-year experience

Deep Sedation in Traumatic Brain Injury Patients

Traumatic brain injury (TBI) is one of the leading causes of mortality and disability in adults. In cases of severe TBI, preventing secondary brain injury by managing intracranial hypertension during the acute phase is a critical treatment challenge. Among surgical and medical interventions to control intracranial pressure (ICP), deep sedation can provide comfort to patients and directly control ICP by regulating cerebral metabolism. However, insufficient sedation does not achieve the intended treatment goals, and excessive sedation can lead to fatal sedative-related complications. Therefore, it is important to continuously monitor and titrate sedatives by measuring the appropriate depth of sedation. In this review, we discuss the effectiveness of deep sedation, techniques to monitor the depth of sedation, and the clinical use of recommended sedatives, barbiturates, and propofol in TBI.

From head micro-motions towards CSF dynamics and non-invasive intracranial pressure monitoring

Continuous monitoring of the intracranial pressure (ICP) is essential in neurocritical care. There are a variety of ICP monitoring systems currently available, with the intraventricular fluid filled catheter transducer currently representing the “gold standard”. As the placement of catheters is associated with the attendant risk of infection, hematoma formation, and seizures, there is a need for a reliable, non-invasive alternative. In the present study we suggest a unique theoretical framework based on differential geometry invariants of cranial micro-motions with the potential for continuous non-invasive ICP monitoring in conservative traumatic brain injury (TBI) treatment. As a proof of this concept, we have developed a pillow with embedded mechanical sensors and collected an extensive dataset (> 550 h on 24 TBI coma patients) of cranial micro-motions and the reference intraparenchymal ICP. From the multidimensional pulsatile curve we calculated the first Cartan curvature and constructed a ”fingerprint” image (Cartan map) associated with the cerebrospinal fluid (CSF) dynamics. The Cartan map features maxima bands corresponding to a pressure wave reflection corresponding to a detectable skull tremble. We give evidence for a statistically significant and patient-independent correlation between skull micro-motions and ICP time derivative. Our unique differential geometry-based method yields a broader and global perspective on intracranial CSF dynamics compared to rather local catheter-based measurement and has the potential for wider applications.

Pentobarbital Coma With Therapeutic Hypothermia for Treatment of Refractory Intracranial Hypertension in Traumatic Brain Injury Patients: A Single Institution Experience

Introduction Traumatic brain injury (TBI) results in primary and secondary brain injuries. Secondary brain injury can lead to cerebral edema resulting in increased intracranial pressure (ICP) secondary to the rigid encasement of the skull. Increased ICP leads to decreased cerebral perfusion pressure which leads to cerebral ischemia. Refractory intracranial hypertension (RICH) occurs when ICP remains elevated despite first-tier therapies such as head elevation, straightening of the neck, analgesia, sedation, paralytics, cerebrospinal fluid (CSF) drainage, mannitol and/or hypertonic saline administration. If unresponsive to these measures, second-tier therapies such as hypothermia, barbiturate infusion, and/or surgery are employed. Methods This was a retrospective review of patients admitted at Arrowhead Regional Medical Center from 2008 to 2019 for severe TBI who developed RICH requiring placement into a pentobarbital-induced coma with therapeutic hypothermia. Primary endpoints included mortality, good recovery which was designated at Glasgow outcome scale (GOS) of 4 or 5, and improvement in ICP (goal is <20 mmHg). Secondary endpoints included complications, length of intensive care unit (ICU) stay, length of hospital stay, length of pentobarbital coma, length of hypothermia, need for vasopressors, and decompressive surgery versus no decompressive surgery. Results Our study included 18 patients placed in pentobarbital coma with hypothermia for RICH. The overall mortality rate in our study was 50%; with 60% mortality in pentobarbital/hypothermia only group, and 46% mortality in surgery plus pentobarbital/hypothermia group. Maximum ICP prior to pentobarbital/hypothermia was significantly lower in patients who had a prior decompressive craniectomy than in patients who were placed into pentobarbital/hypothermia protocol first (28.3 vs 35.4, p<0.0238). ICP was significantly reduced at 4 hours, 8 hours, 12 hours, 24 hours, and 48 hours after pentobarbital and hypothermia treatment. Initial ICP and maximum ICP prior to pentobarbital/hypothermia was significantly correlated with mortality (p=0.022 and p=0.026). Patients with an ICP>25 mmHg prior to pentobarbital/hypothermia initiation had an increased risk of mortality (p=0.0455). There was no statistically significant difference in mean ICP after 24 hours after pentobarbital/hypothermia protocol in survivors vs non-survivors. Increased time to reach 33°C was associated with increased mortality (r=0.47, p=0.047); with a 10.5-fold increase in mortality for >7 hours (OR 10.5, p=0.039). Conclusion Prolonged cooling time >7 hours was associated with a 10.5-fold increase in mortality and ICP>25 mmHg prior to initiation of pentobarbital and hypothermia is suggestive of a poor response to treatment. We recommend patients with severe TBI who develop RICH should first undergo a 12 x 15 cm decompressive hemicraniectomy because they have better survival and are more likely to have ICP <25 mmHg as the highest elevation of ICP if the ICP were to become and stay elevated again. Pentobarbital and hypothermia should be initiated if the ICP becomes elevated and sustained above 20 mmHg with a prior decompressive hemicraniectomy and refractory to other medical therapies. However, our data suggests that patients are unlikely to survive if there ICP does not decrease to less than 15mmHg at 8 and 12 hours after pentobarbital/hypothermia and remain less than 20 mmHg within first 48 hours.

Perioperative Treatment of Brain Arteriovenous Malformations Between 2006 and 2014: The Helsinki Protocol

Objective

We reviewed retrospectively the perioperative treatment of microsurgically resected brain arteriovenous malformations (bAVMs) at the neurosurgical department of Helsinki University Hospital between the years 2006 and 2014. We examined the performance of the treatment protocol and the incidence of delayed postoperative hemorrhage (DPH).

Methods

The Helsinki protocol for postoperative treatment of bAVMs was used for the whole patient cohort of 121. The patients who had subsequent DPH were reviewed in more detail.

Results

Five out of 121 (4.1%) patients had DPH. These patients had a higher Spetzler–Martin grade (SMG) (p = 0.043) and a more complex venous drainage pattern (p = 0.003) as compared to those who had no postoperative bleed. Patients with DPH had 43% larger intravenous fluid intake in the neurosurgical intensive care unit (p = 0.052); they were all male (p = 0.040) and had longer stay in the intensive care unit (p = 0.022).

Conclusions

The Helsinki protocol for postoperative treatment of bAVMs was found to produce comparable results to a more complex treatment algorithm. DPH was associated with high SMG, complex venous drainage pattern, male gender and high intravenous fluid intake. Our findings support the use of SMG in defining patient’s postoperative treatment as the DPHs in our study occurred in patients with grade 2–5.

Pentobarbital Induced Hypokalemia: A Worrying Sequela

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High dose barbiturate use has been linked to life threatening hypokalemia and rebound hyperkalemia.

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Pentobarbital is a barbiturates that is used in high doses to induce a coma state to lower intracranial pressures.

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Through constant monitoring of potassium levels and permissive hypokalemia, avoidance of rebound hyperkalemia is achievable.

Introduction

Intracranial hypertension that is not responsive to other therapies can be managed through the use of a barbiturate induced coma. Although potentially effective, there are known complications associated with this treatment, and as such it is typically reserved for the most severe cases. One such sequela of barbiturate induced coma therapy is refractory hypokalemia and subsequent rebound hyperkalemia.

Presentation of case

This case report discusses a patient who experienced hypokalemia during pentobarbital induced coma for unmanageable elevations in intracranial pressure and was treated conservatively to avoid rebound hyperkalemia depicting successful deployment of permissive hypokalemia.

Discussion

It is vital that clinicians understand the possible adverse effects associated with barbiturate induced coma therapy, and that a careful balance be struck between hypokalemia and potassium supplementation to avoid rebound hyperkalemia.

Conclusion

Given that the risk of rebound hyperkalemia is of significant concern in patients who experience hypokalemia on barbiturate induced coma therapy, permissive hypokalemia can be a viable treatment option achieved by lowering the potassium replacement target threshold in such patients.

Early prediction of neurological outcome after barbiturate coma therapy in patients undergoing brain tumor surgery

After a difficult brain tumor surgery, refractory intracranial hypertension (RICH) may occur due to residual tumor or post-operative complications such as hemorrhage, infarction, and aggravated brain edema. We investigated which predictors are associated with prognosis when using barbiturate coma therapy (BCT) as a second-tier therapy to control RICH after brain tumor surgery. The study included adult patients who underwent BCT after brain tumor surgery between January 2010 and December 2016. The primary outcome was neurological status upon hospital discharge, which was assessed using the Glasgow Outcome Scale (GOS). In the study period, 4,296 patients underwent brain tumor surgery in total. Of these patients, BCT was performed in 73 patients (1.7%). Among these 73 patients, 56 (76.7%) survived to discharge and 25 (34.2%) showed favorable neurological outcomes (GOS scores of 4 and 5). Invasive monitoring of intracranial pressure (ICP) was performed in 60 (82.2%) patients, and revealed that the maximal ICP within 6 h after BCT was significantly lower in patients with favorable neurological outcome as well as in survivors (p = 0.008 and p = 0.028, respectively). Uncontrolled RICH (ICP ≥ 22 mm Hg within 6 h of BCT) was an important predictor of mortality after BCT (adjusted hazard ratio 12.91, 95% confidence interval [CI] 2.788–59.749), and in particular, ICP ≥ 15 mm Hg within 6 h of BCT was associated with poor neurological outcome (adjusted odds ratio 9.36, 95% CI 1.664–52.614). Therefore, early-controlled ICP after BCT was associated with clinical prognosis. There were no significant differences in the complications associated with BCT between the two neurological outcome groups. No BCT-induced death was observed. The active and timely control of RICH may be beneficial for clinical outcomes in patients with RICH after brain tumor surgery.

Management of raised intracranial pressure in aneurysmal subarachnoid hemorrhage: time for a consensus?

Elevated intracranial pressure (ICP) is a well-recognized phenomenon in aneurysmal subarachnoid hemorrhage (aSAH) that has been demonstrated to lead to poor outcomes. Despite significant advances in clinical research into aSAH, there are no consensus guidelines devoted specifically to the management of elevated ICP in the setting of aSAH. To treat high ICP in aSAH, most centers extrapolate their treatment algorithms from studies and published guidelines for traumatic brain injury. Herein, the authors review the current management strategies for treating raised ICP within the aSAH population, emphasize key differences from the traumatic brain injury population, and highlight potential directions for future research in this controversial topic.

Life-Threatening Dyskalaemia after Barbiturate Coma Therapy: The Strategy of Management

Barbiturate coma therapy (BCT) is a treatment option that is used for refractory intracranial hypertension after all other options have been exhausted. Although BCT is a brain protection treatment, it also has several side effects such as hypotension, hepatic dysfunction, renal dysfunction, respiratory complications and electrolyte imbalances. One less concerning but potentially life-threatening complication of BCT is dyskalaemia. This complication could present as severe refractory hypokalaemia during the therapy with subsequent rebound hyperkalaemia after cessation of the therapy. Judicious potassium replacement during severe refractory hypokalaemia and gradual cessation of the therapy to prevent rebound hyperkalaemia are recommended strategies to deal with this complication, based on previous case series and reports. In this case report, we show that these strategies were applicable in improving severe hypokalaemia and preventing sudden, life-threatening rebound hyperkalaemia. However, even with use of these strategies, BCT patients could still present with mild, asymptomatic hyperkalaemia.

Prolonged pentobarbital-induced coma for the treatment of severe seizures related to posterior reversible encephalopathy syndrome

In this report, we describe a case of posterior reversible encephalopathy syndrome in a female patient after deceased donor liver transplantation. She developed posterior reversible encephalopathy syndrome on postoperative day 3 and did not improve despite adjustments in immunosuppressive therapy. The patient had symptoms of severe brain edema requiring maximal therapy, which included cooling, mannitol, 3% saline, and a pentobarbital infusion. Attempts to lighten the level of sedation failed because of recurring intractable seizure activity. Reductions in therapeutic support were ultimately successful after 62 days of continuous pentobarbital therapy. The patient awoke neurologically intact and was discharged to a rehabilitation center in good condition.

Efficacy of low dose barbiturate coma therapy for the patients with intractable intracranial hypertension using the bispectral index monitoring

OBJECTIVE

Barbiturate coma therapy (BCT) is a useful method to control increased intracranial pressure (IICP) patients. However, the complications such as hypotension and hypokalemia have caused conditions that stopped BCT early. The complications of low dose BCT with Bispectral index (BIS) monitoring and those of high dose BCT without BIS monitoring have been compared to evaluate the efficacy of low dose BCT with BIS monitoring.

METHODS

We analyzed 39 patients with high dose BCT group (21 patients) and low dose BCT group (18 patients). Because BIS value of 40-60 is general anesthesia score, we have adjusted the target dose of thiopental to maintain the BIS score of 40-60. Therefore, dose of thiopental was kept 1.3 to 2.6 mg/kg/hour during low dose BCT. However, high dose BCT consisted of 5 mg/kg/hour without BIS monitoing.

RESULTS

The protocol of BCT was successful in 72.2% and 38.1% of low dose and high dose BCT groups, respectively. The complications such as QT prolongation, hypotension and cardiac arrest have caused conditions that stopped BCT early. Hypokalemia showed the highest incidence rate in complications of both BCT. The descent in potassium level were 0.63 +/- 0.26 in low dose group, and 1.31 +/- 0.48 in high dose group. The treatment durations were 4.89 +/- 1.68 days and 3.38 +/- 1.24 days in low dose BCT and high dose BCT, respectively.

CONCLUSION

It was proved that low dose BCT showed less severe complications than high dose BCT. Low dose BCT with BIS monitoring provided enough duration of BCT possible to control ICP.