The Role of Neuromuscular Blockade in Patients with Traumatic Brain Injury: A Systematic Review

Modern Sedation and Analgesia Strategies in Neurocritical Care

PURPOSE OF REVIEW

Patients with acute neurologic injury require a specialized approach to critical care, particularly with regard to sedation and analgesia. This article reviews the most recent advances in methodology, pharmacology, and best practices of sedation and analgesia for the neurocritical care population.

RECENT FINDINGS

In addition to established agents such as propofol and midazolam, dexmedetomidine and ketamine are two sedative agents that play an increasingly central role, as they have a favorable side effect profile on cerebral hemodynamics and rapid offset can facilitate repeated neurologic exams. Recent evidence suggests that dexmedetomidine is also an effective component when managing delirium. Combined analgo-sedation with low doses of short-acting opiates is a preferred sedation strategy to facilitate neurologic exams as well as patient-ventilator synchrony. Optimal care for patients in the neurocritical care population requires an adaptation of general ICU strategies that incorporates understanding of neurophysiology and the need for close neuromonitoring. Recent data continues to improve care tailored to this population.

Airway Management of Suspected Traumatic Brain Injury Patients in the Emergency Room

The patients of trauma offers a special challenge because of the associated head injury, maxillofacial, neck and spine injuries, which puts the airway at imminent risk. The response time for the emergency team to initiate the airway management determines the outcome of the individual undergoing treatment. A judious implementatin of triage and ATLS guidelines are helpful in the allocation of resources in airway management of trauma patients. One must not get distracted with the severity of other organ systems because cerebral tissue permits a low threshold to the hypoxic insults. Adequate preparedness and a team effort result in better airway management and improved outcomes in trauma patients with variable hemodynamic response to resuscitation. All possible efforts must be made to secure a definitive airway (if required) and should be verified clinically as well as with the available adjuncts. The success of a trauma team depends on the familiarity to the airways devices and their discrete application in various situations.

Second- and Third-Tier Therapies for Severe Traumatic Brain Injury

Intracranial hypertension is a common finding in patients with severe traumatic brain injury. These patients need treatment in the intensive care unit, where intracranial pressure monitoring and, whenever possible, multimodal neuromonitoring can be applied. A three-tier approach is suggested in current recommendations, in which higher-tier therapies have more significant side effects. In this review, we explain the rationale for this approach, and analyze the benefits and risks of each therapeutic modality. Finally, we discuss, based on the most recent recommendations, how this approach can be adapted in low- and middle-income countries, where available resources are limited.

Acute Intracranial Hypertension During Pregnancy: Special Considerations and Management Adjustments

Pregnancy is associated with a number of pathophysiological changes (including modification of vascular resistance, increased vascular permeability, and coagulative disorders) that can lead to specific (eclampsia, preeclampsia) or not specific (intracranial hemorrhage) neurological complications. In addition to these disorders, pregnancy can affect numerous preexisting neurologic conditions, including epilepsy, brain tumors, and intracerebral bleeding from cerebral aneurysm or arteriovenous malformations. Intracranial complications related to pregnancy can expose patients to a high risk of intracranial hypertension (IHT). Unfortunately, at present, the therapeutic measures that are generally adopted for the control of elevated intracranial pressure (ICP) in the general population have not been examined in pregnant patients, and their efficacy and safety for the mother and the fetus is still unknown. In addition, no specific guidelines for the application of the staircase approach, including escalating treatments with increasing intensity of level, for the management of IHT exist for this population. Although some of basic measures can be considered safe even in pregnant patients (management of stable hemodynamic and respiratory function, optimization of systemic physiology), some other interventions, such as hyperventilation, osmotic therapy, hypothermia, barbiturates, and decompressive craniectomy, can lead to specific concerns for the safety of both mother and fetus. The aim of this review is to summarize the neurological pathophysiological changes occurring during pregnancy and explore the effects of the possible therapeutic interventions applied to the general population for the management of IHT during pregnancy, taking into consideration ethical and clinical concerns as well as the decision for the timing of treatment and delivery.

Management and Challenges of Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of death and disability in trauma patients, and can be classified into mild, moderate, and severe by the Glasgow coma scale (GCS). Prehospital, initial emergency department, and subsequent intensive care unit (ICU) management of severe TBI should focus on avoiding secondary brain injury from hypotension and hypoxia, with appropriate reversal of anticoagulation and surgical evacuation of mass lesions as indicated. Utilizing principles based on the Monro-Kellie doctrine and cerebral perfusion pressure (CPP), a surrogate for cerebral blood flow (CBF) should be maintained by optimizing mean arterial pressure (MAP), through fluids and vasopressors, and/or decreasing intracranial pressure (ICP), through bedside maneuvers, sedation, hyperosmolar therapy, cerebrospinal fluid (CSF) drainage, and, in refractory cases, barbiturate coma or decompressive craniectomy (DC). While controversial, direct ICP monitoring, in conjunction with clinical examination and imaging as indicated, should help guide severe TBI therapy, although new modalities, such as brain tissue oxygen (PbtO₂) monitoring, show great promise in providing strategies to optimize CBF. Optimization of the acute care of severe TBI should include recognition and treatment of paroxysmal sympathetic hyperactivity (PSH), early seizure prophylaxis, venous thromboembolism (VTE) prophylaxis, and nutrition optimization. Despite this, severe TBI remains a devastating injury and palliative care principles should be applied early. To better affect the challenging long-term outcomes of severe TBI, more and continued high quality research is required.

The neurocritical care of tuberculous meningitis

Tuberculous meningitis is the most severe form of tuberculosis and often causes critical illness with high mortality. Two primary management objectives are reducing intracranial pressure, and optimising cerebral perfusion, while killing the bacteria and controlling intracerebral inflammation. However, the evidence base guiding the care of critically ill patients with tuberculous meningitis is poor and many patients do not have access to neurocritical care units. Invasive intracranial pressure monitoring is often unavailable and although new non-invasive monitoring techniques show promise, further evidence for their use is required. Optimal management regimens of neurological complications (eg, hydrocephalus and paradoxical reactions) and of hyponatraemia, which frequently accompanies tuberculous meningitis, remain to be elucidated. Advances in the field of tuberculous meningitis predominantly focus on diagnosis, inflammatory processes, and antituberculosis chemotherapy. However, clinical trials are required to provide robust evidence guiding the most effective supportive, therapeutic, and neurosurgical interventions for tuberculous meningitis that will improve morbidity and mortality.

Does Tracheal Lidocaine Instillation Reduce Intracranial Pressure Changes After Tracheal Suctioning in Severe Head Trauma? A Prospective, Randomized Crossover Study

OBJECTIVES

Tracheal suctioning is a routine procedure in mechanically ventilated children, however, in severe head-injured patients it can result in potential deleterious increase in intracranial pressure. We aimed to assess the effect of tracheal lidocaine administration on intracranial pressure during tracheal suctioning.

DESIGN

Prospective randomized controlled crossover study.

SETTING

PICU of a tertiary hospital.

PATIENTS

Eleven patients with severe head trauma (Glasgow Coma Scale score 4-8) INTERVENTIONS:: Lidocaine (1.5 mg/kg) or saline solution was endotracheally instilled before a standardized tracheal suctioning maneuver. Each patient received both treatments in a crossover design. Cerebral hemodynamic and systemic and ventilatory effects were assessed at four time points: in baseline (T0), within 2 minutes (T1), 5 minutes (T2), and 15 minutes after tracheal instillation (T3). The 2-minute time interval around tracheal suctioning was used to assess each treatment efficacy MEASUREMENTS AND MAIN RESULTS:: The time course of intracranial pressure was different throughout the study in both treatment groups, with a significant increase of intracranial pressure from 14.82 ± 3.48 to 23.27 ± 9.06 with lidocaine (p = 0.003) and from 14.73 ± 2.41 to 30.45 ± 13.14 with saline (p = 0.02). The mean variation in intracranial pressure immediately after tracheal suctioning was smaller with lidocaine instillation than saline (8.45 vs 15.72 mm Hg; p = 0.006). Patients treated with lidocaine returned to baseline intracranial pressure value at 5 minutes after tracheal suctioning whereas those receiving saline solution returned to baseline intracranial pressure value at 15 minutes. Although patients treated with lidocaine had no significant hemodynamic changes, patients receiving saline solution experienced a higher mean value of mean arterial pressure (99.36 vs 81.73 mm Hg; p = 0.004) at T1.

CONCLUSIONS

This preliminary study showed that tracheal lidocaine instillation can attenuate increase in intracranial pressure induced by tracheal suctioning and favor a faster return to the intracranial pressure baseline levels without significant hemodynamic and ventilatory changes.

Pathophysiology and Management of Intracranial Hypertension and Tissular Brain Hypoxia After Severe Traumatic Brain Injury: An Integrative Approach

Monitoring intracranial pressure in comatose patients with severe traumatic brain injury (TBI) is considered necessary by most experts. Acute intracranial hypertension (IHT), when severe and sustained, is a life-threatening complication that demands emergency treatment. Yet, secondary anoxic-ischemic injury after brain trauma can occur in the absence of IHT. In such cases, adding other monitoring modalities can alert clinicians when the patient is in a state of energy failure. This article reviews the mechanisms, diagnosis, and treatment of IHT and brain hypoxia after TBI, emphasizing the need to develop a physiologically integrative approach to the management of these complex situations.

The currency, completeness and quality of systematic reviews of acute management of moderate to severe traumatic brain injury: A comprehensive evidence map

OBJECTIVE

To appraise the currency, completeness and quality of evidence from systematic reviews (SRs) of acute management of moderate to severe traumatic brain injury (TBI).

METHODS

We conducted comprehensive searches to March 2016 for published, English-language SRs and RCTs of acute management of moderate to severe TBI. Systematic reviews and RCTs were grouped under 12 broad intervention categories. For each review, we mapped the included and non-included RCTs, noting the reasons why RCTs were omitted. An SR was judged as 'current' when it included the most recently published RCT we found on their topic, and 'complete' when it included every RCT we found that met its inclusion criteria, taking account of when the review was conducted. Quality was assessed using the AMSTAR checklist (trichotomised into low, moderate and high quality).

FINDINGS

We included 85 SRs and 213 RCTs examining the effectiveness of treatments for acute management of moderate to severe TBI. The most frequently reviewed interventions were hypothermia (n = 17, 14.2%), hypertonic saline and/or mannitol (n = 9, 7.5%) and surgery (n = 8, 6.7%). Of the 80 single-intervention SRs, approximately half (n = 44, 55%) were judged as current and two-thirds (n = 52, 65.0%) as complete. When considering only the most recently published review on each intervention (n = 25), currency increased to 72.0% (n = 18). Less than half of the 85 SRs were judged as high quality (n = 38, 44.7%), and nearly 20% were low quality (n = 16, 18.8%). Only 16 (20.0%) of the single-intervention reviews (and none of the five multi-intervention reviews) were judged as current, complete and high-quality. These included reviews of red blood cell transfusion, hypothermia, management guided by intracranial pressure, pharmacological agents (various) and prehospital intubation. Over three-quarters (n = 167, 78.4%) of the 213 RCTs were included in one or more SR. Of the remainder, 17 (8.0%) RCTs post-dated or were out of scope of existing SRs, and 29 (13.6%) were on interventions that have not been assessed in SRs.

CONCLUSION

A substantial number of SRs in acute management of moderate to severe TBI lack currency, completeness and quality. We have identified both potential evidence gaps and also substantial research waste. Novel review methods, such as Living Systematic Reviews, may ameliorate these shortcomings and enhance utility and reliability of the evidence underpinning clinical care.

Review of Continuous Infusion Neuromuscular Blocking Agents in the Adult Intensive Care Unit

The use of continuous infusion neuromuscular blocking agents remains controversial. The clinical benefit of these medications may be overshadowed by concerns of propagating intensive care unit-acquired weakness, which may prolong mechanical ventilation and impair the inability to assess neurologic function or pain. Despite these risks, the use of neuromuscular blocking agents in the intensive care unit is indicated in numerous clinical situations. Understanding pharmacologic nuances and clinical roles of these agents will aid in facilitating safe use in a variety of acute disease processes. This article provides clinicians with information regarding pharmacologic differences, indication for use, adverse effects, recommended doses, ancillary care, and monitoring among agents used for continuous neuromuscular blockade.

Pediatric Traumatic Brain Injury: Characteristic Features, Diagnosis, and Management

Traumatic brain injury (TBI) is the leading cause of death and disability in children. Pediatric TBI is associated with several distinctive characteristics that differ from adults and are attributable to age-related anatomical and physiological differences, pattern of injuries based on the physical ability of the child, and difficulty in neurological evaluation in children. Evidence suggests that children exhibit a specific pathological response to TBI with distinct accompanying neurological symptoms, and considerable efforts have been made to elucidate their pathophysiology. In addition, recent technical advances in diagnostic imaging of pediatric TBI has facilitated accurate diagnosis, appropriate treatment, prevention of complications, and helped predict long-term outcomes. Here a review of recent studies relevant to important issues in pediatric TBI is presented, and recent specific topics are also discussed. This review provides important updates on the pathophysiology, diagnosis, and age-appropriate acute management of pediatric TBI.

The Association Between Spontaneous Hyperventilation, Delayed Cerebral Ischemia, and Poor Neurological Outcome in Patients with Subarachnoid Hemorrhage

BACKGROUND

The frequency and associations of spontaneous hyperventilation in subarachnoid hemorrhage (SAH) are unknown. Because hyperventilation decreases cerebral blood flow, it may exacerbate delayed cerebral ischemia (DCI) and worsen neurological outcome.

METHODS

This is a retrospective analysis of data from a prospectively collected cohort of SAH patients at an academic medical center. Spontaneous hyperventilation was defined by PaCO2 <35 mmHg and pH >7.45 and subdivided into moderate and severe groups. Clinical and demographic characteristics of patients with and without spontaneous hyperventilation were compared using χ (2) or t tests. Bivariate and multivariable logistic regression analyses were conducted to examine the association of moderate and severe hyperventilation with DCI and discharge neurological outcome.

RESULTS

Of 207 patients, 113 (55 %) had spontaneous hyperventilation. Spontaneously hyperventilating patients had greater illness severity as measured by the Hunt-Hess, World Federation of Neurosurgical Societies (WFNS), and SAH sum scores. They were also more likely to develop the following complications: pneumonia, neurogenic myocardial injury, systemic inflammatory response syndrome (SIRS), radiographic vasospasm, DCI, and poor neurological outcome. In a multivariable logistic regression model including age, gender, WFNS, SAH sum score, pneumonia, neurogenic myocardial injury, etiology, and SIRS, only moderate [odds ratio (OR) 2.49, 95 % confidence interval (CI) 1.10-5.62] and severe (OR 3.12, 95 % CI 1.30-7.49) spontaneous hyperventilation were associated with DCI. Severe spontaneous hyperventilation (OR 4.52, 95 % CI 1.37-14.89) was also significantly associated with poor discharge outcome in multivariable logistic regression analysis.

CONCLUSION

Spontaneous hyperventilation is common in SAH and is associated with DCI and poor neurological outcome.

The critical care management of poor-grade subarachnoid haemorrhage

Aneurysmal subarachnoid haemorrhage is a neurological syndrome with complex systemic complications. The rupture of an intracranial aneurysm leads to the acute extravasation of arterial blood under high pressure into the subarachnoid space and often into the brain parenchyma and ventricles. The haemorrhage triggers a cascade of complex events, which ultimately can result in early brain injury, delayed cerebral ischaemia, and systemic complications. Although patients with poor-grade subarachnoid haemorrhage (World Federation of Neurosurgical Societies 4 and 5) are at higher risk of early brain injury, delayed cerebral ischaemia, and systemic complications, the early and aggressive treatment of this patient population has decreased overall mortality from more than 50% to 35% in the last four decades. These management strategies include (1) transfer to a high-volume centre, (2) neurological and systemic support in a dedicated neurological intensive care unit, (3) early aneurysm repair, (4) use of multimodal neuromonitoring, (5) control of intracranial pressure and the optimisation of cerebral oxygen delivery, (6) prevention and treatment of medical complications, and (7) prevention, monitoring, and aggressive treatment of delayed cerebral ischaemia. The aim of this article is to provide a summary of critical care management strategies applied to the subarachnoid haemorrhage population, especially for patients in poor neurological condition, on the basis of the modern concepts of early brain injury and delayed cerebral ischaemia.

Management of pediatric traumatic brain injury

OPINION STATEMENT

Pediatric severe traumatic brain injury continues to be a major cause of disability and death. Rapid initial airway and hemodynamic stabilization is critical, followed by the need for immediate recognition of intracranial pathology that requires neurosurgical intervention. Intracranial hypertension and cerebral hypoperfusion have been recognized as major insults after trauma and management should be directed at preventing both. Sedation with opioids, moderate hyperventilation to arterial carbon dioxide level of 35-40 mmHg, hyperosmolar therapy with 3 % saline or mannitol, normothermia, and cerebrospinal fluid drainage continue to be the cornerstones of initial management of intracranial hypertension (intracranial pressure >20 mmHg). Refractory intracranial hypertension is treated with high-dose barbiturate therapy to achieve medical burst suppression on electroencephalography and decompressive craniectomy. In addition, those children require antiepileptic medications for seizure prophylaxis, adequate nutritional management, and early physical therapy and rehabilitation referrals. Most of the evidence for care of children with brain injury comes from center-specific practice and experience rather than objective data. This lack of evidence provides the ground for ongoing research; nevertheless, outcomes after traumatic brain injury continue to show improvement.