Focal Neurologic Deficit After Epidural Catheter Removal Leads to Meningioma Diagnosis

We present an unusual case of a 60-year-old female who developed subtle, new-onset left upper and lower extremity weakness on day five of perioperative thoracic epidural placement. The onset of a focal neurological deficit after epidural placement usually raises suspicion for the presence of an epidural hematoma, abscess, or traumatic cord lesion. However, in this patient, brain imaging revealed a large, previously undiagnosed intracranial mass. Classically, the risk of mass-related intracranial pressure shifts leading to neurological changes is associated with spinal techniques, including diagnostic lumbar puncture, combined spinal-epidural catheter analgesia, and unintended dural puncture during epidural placement. However, based on this case and our summary of case reports in the literature, we determined that symptom onset associated with an intracranial mass may also arise after apparently uncomplicated epidural placement. Symptom onset in our case series ranged from six hours to ten days and was highly variable depending on tumor location, with reported signs and symptoms including headache, vision changes, focal deficits, or alterations of consciousness. Further studies are required to establish definitive causation between the epidural technique and changes in cerebrospinal fluid pressures leading to symptom onset. Though rare, this is a time-sensitive diagnosis that must be considered for any patient with unexplained neurological findings after neuraxial anesthesia.

Fluidic Considerations of Measuring Intracranial Pressure Using an Open External Ventricular Drain

Measurement of intracranial pressure (ICP) during cerebrospinal fluid (CSF) drainage with an external ventricular drain (EVD) typically requires stopping the flow during measurement. However, there may be benefits to simultaneous ICP measurement and CSF drainage. Several studies have evaluated whether accurate ICP measurements can be obtained while the EVD is open. They report differing outcomes when it comes to error, and hypothesize several sources of error. This study presents an investigation into the fluidic sources of error for ICP measurement with concurrent drainage in an EVD. Our experiments and analytical model both show that the error in pressure measurement increases linearly with flow rate and is not clinically significant, regardless of drip chamber height. At physiologically relevant flow rates (40 mL/hr) and ICP set points (13.6 - 31.3 cmH₂O or 10 - 23 mmHg), our model predicts an underestimation of 0.767 cmH₂O (0.56 mmHg) with no observed data point showing error greater than 1.09 cmH₂O (0.8 mmHg) in our experiment. We extrapolate our model to predict a realistic worst-case clinical scenario where we expect to see a mean maximum error of 1.06 cmH₂O (0.78 mmHg) arising from fluidic effects within the drainage system for the most resistive catheter. Compared to other sources of error in current ICP monitoring, error in pressure measurement due to drainage flow is small and does not prohibit clinical use. However, other effects such as ventricular collapse or catheter obstruction could affect ICP measurement under continuous drainage and are not investigated in this study.

Neurocritical Management of Traumatic Acute Subdural Hematomas

Acute subdural hematoma (ASDH) has been a major part of traumatic brain injury. Intracranial hypertension may be followed by ASDH and brain edema. Regardless of the complicated pathophysiology of ASDH, the extent of primary brain injury underlying the ASDH is the most important factor affecting outcome. Ongoing intracranial pressure (ICP) increasing lead to cerebral perfusion pressure (CPP) decrease and cerebral blood flow (CBF) decreasing occurred by CPP decrease. In additionally, disruption of cerebral autoregulation, vasospasm, decreasing of metabolic demand may lead to CBF decreasing. Various protocols for ICP lowering were introduced in neuro-trauma field. Usage of anti-epileptic drugs (AEDs) for ASDH patients have controversy. AEDs may reduce the risk of early seizure (<7 days), but, does not for late-onset epilepsy. Usage of anticoagulants/antiplatelets is increasing due to life-long medical disease conditions in aging populations. It makes a difficulty to decide the proper management. Tranexamic acid may use to reducing bleeding and reduce ASDH related death rate. Decompressive craniectomy for ASDH can reduce patient's death rate. However, it may be accompanied with surgical risks due to big operation and additional cranioplasty afterwards. If the craniotomy is a sufficient management for the ASDH, endoscopic surgery will be good alternative to a conventional larger craniotomy to evacuate the hematoma. The management plan for the ASDH should be individualized based on age, neurologic status, radiologic findings, and the patient's conditions.

An overview of management of intracranial hypertension in the intensive care unit

Intracranial hypertension (IH) is a clinical condition commonly encountered in the intensive care unit, which requires immediate treatment. The maintenance of normal intracranial pressure (ICP) and cerebral perfusion pressure in order to prevent secondary brain injury (SBI) is the central focus of management. SBI can be detected through clinical examination and invasive and non-invasive ICP monitoring. Progress in monitoring and understanding the pathophysiological mechanisms of IH allows the implementation of targeted interventions in order to improve the outcome of these patients. Initially, general prophylactic measures such as patient's head elevation, fever control, adequate analgesia and sedation depth should be applied immediately to all patients with suspected IH. Based on specific indications and conditions, surgical resection of mass lesions and cerebrospinal fluid drainage should be considered as an initial treatment for lowering ICP. Hyperosmolar therapy (mannitol or hypertonic saline) represents the cornerstone of medical treatment of acute IH while hyperventilation should be limited to emergency management of life-threatening raised ICP. Therapeutic hypothermia could have a possible benefit on outcome. To control elevated ICP refractory to maximum standard medical and surgical treatment, at first, high-dose barbiturate administration and then decompressive craniectomy as a last step are recommended with unclear and probable benefit on outcomes, respectively. The therapeutic strategy should be based on a staircase approach and be individualized for each patient. Since most therapeutic interventions have an uncertain effect on neurological outcome and mortality, future research should focus on both studying the long-term benefits of current strategies and developing new ones.

Optic nerve sheath diameter changes during gynecologic surgery in the Trendelenburg position: comparison of propofol-based total intravenous anesthesia and sevoflurane anesthesia

Background

Elevated intracranial pressure (ICP), a disadvantage of laparoscopic or robotic surgery, is caused by the steep angle of the Trendelenburg position and the CO₂ pneumoperitoneum. Recently, sonographically measured optic nerve sheath diameter (ONSD) was suggested as a simple and non-invasive method for detecting increased ICP. This study aimed to explore the changes in ONSD in relation to different anesthetic agents used in gynecologic surgery.

Methods

Fifty patients were randomly allocated to two groups, sevoflurane (group SEV, n = 25) and propofol-based total intravenous anesthesia (TIVA) group (group TIVA, n = 25). The ONSD was measured at five time points (T0–T4): T0 was measured 5 min after induction of anesthesia in the supine position; T1, T2, and T3 were measured at 5, 15, and 30 min after CO₂ pneumoperitoneum induction in the Trendelenburg position; and T4 was measured at 5 min after discontinuation of CO₂ pneumoperitoneum in the supine position. Respiratory and hemodynamic variables were also recorded.

Results

The intra-group changes in mean ONSD in the Trendelenburg position were significantly increased in both groups. However, inter-group changes in mean ONSD were not significantly different at T0, T1, T2, T3, and T4. Heart rates in group TIVA were significantly lower than those in group SEV at points T1–T4.

Conclusions

There was no significant difference in the ONSD between the two groups until 30 min into the gynecologic surgery with CO₂ pneumoperitoneum in the Trendelenburg position. This study suggests that there is no difference in the ONSD between the two anesthetic methods.

Use of intraosseous hypertonic saline in critically ill patients

BACKGROUND

Rapid administration of hypertonic saline 23.4% is crucial in treatment of herniation syndromes. Hypertonic 23.4% saline must be administered via a central line. In cases where central line access is difficult to obtain and leads to delay in therapy, placement of intraosseous access can be lifesaving.

MAIN BODY

The purpose of this case series is to describe the use of intraosseous administration of 23.4% saline in critically ill patients and to assess feasibility.

CONCLUSION

Intraosseous administration of 23.4% saline in 6 adult patients with neurological emergencies was feasible and should be considered in cases where obtaining intravenous access is time consuming.

Full Recovery After a Bihemispheric Gunshot Wound to the Head: Case Report, Clinical Management, and Literature Review

BACKGROUND

Nearly 33,600 people die each year in the United States as a result of gunshot wounds (GSWs). Penetrating craniocerebral GSWs are often fatal with a nearly 70% death rate at the scene of the trauma. Overall combined mortality rate for patients who die at the scene or at the hospital is almost 91%. Poor outcome is associated with initial low Glasgow Coma Scale score and bihemispheric and transventricular gunshot trajectory. We summarize current understanding in management, prognostic factors, and survival outcomes in patients with a penetrating GSWs to the head. We report a patient with return to full function despite bihemispheric, multilobar involvement. Full function is defined here as ability to return to previous work and perform activities of daily living.

CASE DESCRIPTION

A 33-year-old man sustained a GSW to the head under unknown circumstances. On initial presentation, he had a Glasgow Coma Scale score of 15. He was verbalizing and communicating but was amnestic for the event. From a left frontal entry wound, the bullet traversed both frontal lobes of the brain reaching the right frontal-parietal junction. Physical examination and vital signs were normal. Appropriate surgical and medical management resulted in complete recovery.

CONCLUSIONS

Craniocerebral GSWs have a high mortality rate and usually require aggressive management. Evaluation of most GSWs requires appropriate imaging studies followed by proactive treatment against infection, seizure, and increased intracranial pressure. Surgical intervention is often necessary and ranges from local wound débridement to craniectomy, decompression, and wound exploration.

Management of Subdural Hematomas: Part I. Medical Management of Subdural Hematomas

PURPOSE OF REVIEW

Subdural hematomas (SDH) represent common neurosurgical problem associated with significant morbidity, mortality, and high recurrence rates. SDH incidence increases with age; numbers of patients affected by SDH continue to rise with our aging population and increasing number of people taking antiplatelet agents or anticoagulation. Medical and surgical SDH management remains a subject of investigation.

RECENT FINDINGS

Initial management of patients with concern for altered mental status with or without trauma starts with Emergency Neurological Life Support (ENLS) guidelines, with a focus on maintaining ICP < 22 mmHg, CPP > 60 mmHg, MAP 80-110 mmHg, and PaO₂ > 60 mmHg, followed by rapid sequence intubation if necessary, and expedited acquisition of imaging to identify a space-occupying lesion. Patients are administered anti-seizure medications, and their antiplatelet medications or anticoagulation may be reversed if neurosurgical interventions are anticipated, or until hemorrhage is stabilized on imaging. Medical SDH care focuses on (a) management of intracranial hypertension; (b) maintenance of adequate cerebral perfusion; (c) seizure prevention and treatment; (d) maintenance of normothermia, eucarbia, euglycemia, and euvolemia; and (e) early initiation of enteral feeding, mobilization, and physical therapy. Post-operatively, SDH patients require ICU level care and are co-managed by neurointensivists with expertise in treating increased intracranial pressure, seizures, and status epilepticus, as well as medical complications of critical illness. Here, we review various aspects of medical management with a brief overview of pertinent literature and clinical trials for patients diagnosed with SDH.

Acute Ischaemic Stroke: Management, Recent Advances and Controversies

Acute ischaemic stroke is a major cause of death and disability. It may become an enormous burden to the patients themselves, their families as well as the health care systems. Patients at risk of airway, breathing and circulatory compromise should receive prompt resuscitation. Vital parameters and neurological status should be closely monitored. Attentions to blood pressure, temperature and sugar profile are important. The significance of early and correct diagnosis and subsequent treatment cannot be over-emphasised. There have been tremendous recent advances in different treatment modalities in acute stroke management. Various recanalisation modalities include intravenous and/or intra-arterial thrombolysis, acute defibrinogenation, anti-platelet treatment and anticoagulation. Carotid endarterectomy and endovascular strategies are recommended in selected patients. Advanced neuro-imaging techniques and neuroprotectants are being evaluated. Multidisciplinary stroke teams have been shown to improve patient survival and functional outcome. Pre-defined algorithms and protocols should be in place to expedite smooth and effective delivery of stroke service. Future directions should be aimed at exploring safer recanalisation modalities and extending the limit of the current 3-hour treatment window for thrombolysis.

Neurocritical Care of Acute Subdural Hemorrhage

Although urgent surgical hematoma evacuation is necessary for most patients with subdural hematoma (SDH), well-orchestrated, evidenced-based, multidisciplinary, postoperative critical care is essential to achieve the best possible outcome. Acute SDH complicates approximately 11% of mild to moderate traumatic brain injuries (TBIs) that require hospitalization, and approximately 20% of severe TBIs. Acute SDH usually is related to a clear traumatic event, but in some cases can occur spontaneously. Management of SDH in the setting of TBI typically conforms to the Advanced Trauma Life Support protocol with airway taking priority, and management breathing and circulation occurring in parallel rather than sequence.

[Guidelines for the diagnosis and treatment of severe traumatic brain injury. Part 2. Intensive care and neuromonitoring]

Traumatic brain injury (TBI) is one of the major causes of death and disability in young and middle-aged people. The most problematic group is comprised of patients with severe TBI who are in a coma. The adequate diagnosis of primary brain injuries and timely prevention and treatment of the secondary injury mechanisms largely define the possibility of reducing mortality and severe disabling consequences. When developing these guidelines, we used our experience in the development of international and national recommendations for the diagnosis and treatment of mild traumatic brain injury, penetrating gunshot wounds to the skull and brain, severe traumatic brain injury, and severe consequences of brain injuries, including a vegetative state. In addition, we used international and national guidelines for the diagnosis, intensive care, and surgical treatment of severe traumatic brain injury, which had been published in recent years. The proposed guidelines concern intensive care of severe TBI in adults and are particularly intended for neurosurgeons, neurologists, neuroradiologists, anesthesiologists, and intensivists who are routinely involved in the treatment of these patients.

Definition, evaluation, and management of brain relaxation during craniotomy

The term 'brain relaxation' is routinely used to describe the size and firmness of the brain tissue during craniotomy. The status of brain relaxation is an important aspect of neuroanaesthesia practice and is relevant to the operating conditions, retraction injury, and likely patient outcomes. Brain relaxation is determined by the relationship between the volume of the intracranial contents and the capacity of the intracranial space (i.e. a content-space relationship). It is a concept related to, but distinct from, intracranial pressure. The evaluation of brain relaxation should be standardized to facilitate clinical communication and research collaboration. Both advantageous and disadvantageous effects of the various interventions for brain relaxation should be taken into account in patient care. The outcomes that matter the most to patients should be emphasized in defining, evaluating, and managing brain relaxation. To date, brain relaxation has not been reviewed specifically, and the aim of this manuscript is to discuss the current approaches to the definition, evaluation, and management of brain relaxation, knowledge gaps, and targets for future research.

Management of Refractory Intracranial Pressure

Patients with refractory intracranial pressure represent a challenge to the multidisciplinary critical care team. Myriad diagnoses: traumatic brain injury, subarachnoid hemorrhage, intracranial hemorrhage, and ischemic stroke, are among the causes commonly seen in patients with elevated intracranial pressure. Clinicians tasked with caring for these patients must be aware of available interventions and management strategies to improve outcomes. Nurses as the bedside clinician most frequently assessing these patients are ideally situated to detect changes and act efficiently to lower refractory intracranial pressure.

A noninvasive estimation of cerebral perfusion pressure using critical closing pressure

OBJECT

Cerebral blood flow is associated with cerebral perfusion pressure (CPP), which is clinically monitored through arterial blood pressure (ABP) and invasive measurements of intracranial pressure (ICP). Based on critical closing pressure (CrCP), the authors introduce a novel method for a noninvasive estimator of CPP (eCPP).

METHODS

Data from 280 head-injured patients with ABP, ICP, and transcranial Doppler ultrasonography measurements were retrospectively examined. CrCP was calculated with a noninvasive version of the cerebrovascular impedance method. The eCPP was refined with a predictive regression model of CrCP-based estimation of ICP from known ICP using data from 232 patients, and validated with data from the remaining 48 patients.

RESULTS

Cohort analysis showed eCPP to be correlated with measured CPP (R = 0.851, p < 0.001), with a mean ± SD difference of 4.02 ± 6.01 mm Hg, and 83.3% of the cases with an estimation error below 10 mm Hg. eCPP accurately predicted low CPP (< 70 mm Hg) with an area under the curve of 0.913 (95% CI 0.883-0.944). When each recording session of a patient was assessed individually, eCPP could predict CPP with a 95% CI of the SD for estimating CPP between multiple recording sessions of 1.89-5.01 mm Hg.

CONCLUSIONS

Overall, CrCP-based eCPP was strongly correlated with invasive CPP, with sensitivity and specificity for detection of low CPP that show promise for clinical use.

The impact of arterial hypertension on polytrauma and traumatic brain injury

BACKGROUND

Pre-hospital hypotension in trauma patients is associated with high mortality. Especially for patients with severe traumatic brain injury (TBI), arterial normotension or even hypertension (AHT) is considered an important mechanism for sustaining adequate cerebral perfusion pressure. The effect of pre-hospital arterial hypertension (pAHT) on in-hospital mortality after trauma has not been studied to date.

METHODS

We retrospectively analyzed data in the trauma registry of the German Society for Trauma Surgery (DGU) on all trauma patients in Germany from 1993 to 2008 who were 16 to 80 years old at the time of the trauma and had an injury severity score (ISS) of 9 or above (total, 42 500 patient data sets). For the analysis, we divided the patients into two groups: those with and those without TBI. We further divided the TBI patients into five subgroups depending on the course of their systolic blood pressure up to the moment of their arrival at the hospital. We also analyzed the patients' demographic data, patterns of injury, and accident mechanisms.

RESULTS

Trauma patients with TBI and pAHT (142 of 561 patients) had a significantly higher mortality than normotensive TBI patients (25.3% vs. 13.5%, p<0.001). Arterial hypertension that either rises or falls before the patient reaches the hospital is associated with higher in-hospital mortality. A logistical regression analysis of 5384 patients revealed that patients with pAHT (n = 561) had an odds ratio of 1.9 (95% confidence interval, 1.4 to 1.6) for death in the hospital compared to normotensive patients (n = 6020).

CONCLUSION

Systolic blood pressure values above 160 mm Hg before arrival in the hospital worsen the outcome of trauma patients with TBI.

Multimodality monitoring for cerebral perfusion pressure optimization in comatose patients with intracerebral hemorrhage

BACKGROUND AND PURPOSE

Limited data exist to recommend specific cerebral perfusion pressure (CPP) targets in patients with intracerebral hemorrhage. We sought to determine the feasibility of brain multimodality monitoring for optimizing CPP and potentially reducing secondary brain injury after intracerebral hemorrhage.

METHODS

We retrospectively analyzed brain multimodality monitoring data targeted at perihematomal brain tissue in 18 comatose intracerebral hemorrhage patients (median monitoring, 164 hours). Physiological measures were averaged over 1-hour intervals corresponding to each microdialysis sample. Metabolic crisis was defined as a lactate/pyruvate ratio >40 with a brain glucose concentration <0.7 mmol/L. Brain tissue hypoxia (BTH) was defined as P(bt)O(2) <15 mm Hg. Pressure reactivity index and oxygen reactivity index were calculated.

RESULTS

Median age was 59 years, median Glasgow Coma Scale score was 6, and median intracerebral hemorrhage volume was 37.5 mL. The risk of BTH, and to a lesser extent metabolic crisis, increased with lower CPP values. Multivariable analyses showed that CPP <80 mm Hg was associated with a greater risk of BTH (odds ratio, 1.5; 95% confidence interval, 1.1-2.1; P=0.01) compared to CPP >100 mm Hg as a reference range. Six patients died (33%). Survivors had significantly higher CPP and P(bt)O(2) and lower ICP values starting on postbleed day 4, whereas lactate/pyruvate ratio and pressure reactivity index values were persistently lower, indicating preservation of aerobic metabolism and pressure autoregulation.

CONCLUSIONS

P(bt)O(2) monitoring can be used to identify CPP targets for optimal brain tissue oxygenation. In patients who do not undergo multimodality monitoring, maintaining CPP >80 mm Hg may reduce the risk of BTH.

Cerebral perfusion pressure thresholds for brain tissue hypoxia and metabolic crisis after poor-grade subarachnoid hemorrhage

BACKGROUND AND PURPOSE

To identify a minimally acceptable cerebral perfusion pressure threshold above which the risks of brain tissue hypoxia (BTH) and oxidative metabolic crisis are reduced for patients with subarachnoid hemorrhage (SAH).

METHODS

We studied 30 poor-grade SAH patients who underwent brain multimodality monitoring (3042 hours). Physiological measures were averaged over 60 minutes for each collected microdialysis sample. Metabolic crisis was defined as a lactate/pyruvate ratio>40 with a brain glucose concentration≤0.7 mmol/L. BTH was defined as PbtO2<20 mm Hg. Outcome was assessed at 3 months with the Modified Rankin Scale.

RESULTS

Multivariable analyses adjusting for admission Hunt-Hess grade, intraventricular hemorrhage, systemic glucose, and end-tidal CO2 revealed that cerebral perfusion pressure≤70 mm Hg was significantly associated with an increased risk of BTH (OR, 2.0; 95% CI, 1.2-3.3; P=0.007) and metabolic crisis (OR, 2.1; 95% CI, 1.2-3.7; P=0.007). Death or severe disability at 3 months was significantly associated with metabolic crisis (OR, 5.4; 95% CI, 1.8-16; P=0.002) and BTH (OR, 5.1; 95% CI, 1.2-23; P=0.03) after adjusting for admission Hunt-Hess grade.

CONCLUSIONS

Metabolic crisis and BTH are associated with mortality and poor functional recovery after SAH. Cerebral perfusion pressure levels<70 mm Hg was associated with metabolic crisis and BTH, and may increase the risk of secondary brain injury in poor-grade SAH patients.

Intracerebral hemorrhage: getting ready for effective treatments

PURPOSE OF REVIEW

Spontaneous intracerebral hemorrhage (ICH) is the most devastating type of stroke and a leading cause of disability and mortality in the United States and the rest of the world. The purpose of this article is to review recent advances in the management of spontaneous intracerebral hemorrhage.

RECENT FINDINGS

Although no interventions have consistently shown an improvement of mortality or functional outcomes after ICH, results from multicenter prospective randomized controlled trials have shown that early hemostasis to prevent hematoma growth, removal of clot by surgical or minimally invasive interventions, clearance of intraventricular hemorrhage, and adequate blood pressure control for the optimization of cerebral perfusion pressure may constitute the most important therapeutic goals to ameliorate secondary neurological damage, decrease mortality, and improve functional outcomes after ICH.

CONCLUSION

Several promising methods may be ready for routine clinical use in a few years to decrease disability and mortality from ICH.

Hypertonic saline and its effect on intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen

OBJECTIVE

Hypertonic saline is emerging as a potentially effective single osmotic agent for control of acute elevations in intracranial pressure (ICP) caused by severe traumatic brain injury. This study examines its effect on ICP, cerebral perfusion pressure (CPP), and brain tissue oxygen tension (PbtO2).

METHODS

Twenty-five consecutive patients with severe traumatic brain injury who were treated with 23.4% NaCl for elevated ICP were evaluated. Bolt catheter probes were placed in the noninjured hemisphere, and hourly ICP, mean arterial pressure, CPP, and PbtO2 values were recorded. Thirty milliliters of 23.4% NaCl was infused over 15 minutes for intracranial hypertension, defined as ICP greater than 20 mm Hg. Twenty-one male patients and 4 female patients aged 16 to 64 years were included. The mean presenting Glasgow Coma Scale score was 5.7.

RESULTS

Mean pretreatment values included an ICP level of 25.9 mm Hg and a PbtO2 value of 32 mm Hg. The posttreatment ICP level was decreased by a mean of 8.3 mm Hg (P < 0.0001), and there was an improvement in PbtO2 of 3.1 mm Hg (P < 0.01). ICP of more than 31 mm Hg decreased by 14.2 mm Hg. Pretreatment CPP values of less than 70 mm Hg increased by a mean of 6 mm Hg (P < 0.0001). No complications occurred from this treatment, with the exception of electrolyte and chemistry abnormalities. At 6 months postinjury, the mortality rate was 28%, with 48% of patients achieving a favorable outcome by the dichotomized Glasgow Outcome Scale.

CONCLUSION

Hypertonic saline as a single osmotic agent decreased ICP while improving CPP and PbtO2 in patients with severe traumatic brain injury. Patients with higher baseline ICP and lower CPP levels responded to hypertonic saline more significantly.

The pathophysiology and causes of raised intracranial pressure

This article explains the pathophysiology and causes of raised intracranial pressure (ICP), and the significance of assessing and recording vital observations for all patients when admitted to hospital. It discusses the nursing care, treatment and management required in order to minimize the risk of further increases in ICP.

Methods of cooling: practical aspects of therapeutic temperature management

OBJECTIVES

To review traditional and newer means of inducing, maintaining, and withdrawing therapeutic hypothermia and normothermia. To suggest treatment algorithms for temperature modulation and review neuromonitoring options.

DESIGN

A review of current literature describing methods of performing therapeutic temperature management and neuromonitoring during the cooling, maintenance, and decooling periods. Algorithms for performing therapeutic temperature management are suggested.

RESULTS

Temperature management can be safely and effectively performed using traditional or newer modalities. Although traditional means of cooling are feasible and efficacious, modern devices utilizing feedback loops to maintain steady body temperature and prevent overcooling have advantages in ease of application, patient safety, maintenance of target temperature, and control of decooling. Neuromonitoring options should be adapted to an individual patient and situation.

CONCLUSIONS

Intensivists should be familiar with techniques to induce, maintain, and withdraw therapeutic temperature management, and select the most appropriate method for a given patient and situation.

Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure

BACKGROUND

Measurements of the optic nerve sheath diameter (ONSD) using bedside ultrasound (US) have been shown to correlate with clinical and radiologic signs and symptoms of increased intracranial pressure (ICP).

OBJECTIVES

Previous literature has identified 5 mm as the ONSD measurement above which patients exhibit either clinical or radiologic signs of elevated ICP. The goals of this study were to evaluate the association between ONSD and ICP and to validate the commonly used ONSD threshold of 5 mm using direct measurements of ICP as measured by ventriculostomy.

METHODS

A prospective blinded observational study was performed using a convenience sample of adult patients in both the emergency department (ED) and the neurologic intensive care unit (ICU) who had invasive intracranial monitors placed as part of their clinical care. Ocular USs were performed with a 10(-5) MHz linear probe. Emergency physicians (EPs) with previous ocular US experience performed ONSD measurements while blinded to the contemporaneous ICP reading obtained directly from invasive monitoring. The association between ONSD and ICP was assessed with the Spearman rank correlation coefficient, and a receiver operator characteristic (ROC) curve was created to determine the optimal ONSD cutoff to detect ICP > 20 cm H2O.

RESULTS

Thirty-eight ocular USs were performed on 15 individual patients. Spearman rank correlation coefficient of ONSD and ICP was 0.59 (p < 0.0005) demonstrating a significant positive correlation. An ROC curve was created to assess the ability of ONSD to distinguish an abnormal ICP greater than 20 cm H2O. The area under the ROC curve was 0.93 (95% confidence interval [CI] = 0.84 to 0.99). Based on inspection of the ROC curve, ONSD > 5 mm performed well to detect ICP > 20 cm H(2)O with a sensitivity of 88% (95% CI = 47% to 99%) and specificity of 93% (95% CI = 78% to 99%).

CONCLUSIONS

Using an ROC curve the authors systematically confirmed the commonly used threshold of ONSD > 5 mm to detect ICP > 20 cm H2O. This study directly correlates ventriculostomy measurements of ICP with US ONSD measurements and provides further support for the use of ONSD measurements as a noninvasive test for elevated ICP.

The “Lund Concept” for the treatment of severe head trauma – physiological principles and clinical application

The Lund Concept is an approach to the treatment of severe brain trauma that is mainly based on hypotheses originating from basic physiological principles regarding brain volume and cerebral perfusion regulation. Its main attributes have found support in experimental and clinical studies. This review explains the principles of the Lund Concept and is intended to serve as the current guide for its clinical application. The therapy has two main goals: (1) to reduce or prevent an increase in ICP (ICP-targeted goal) and (2) to improve perfusion and oxygenation around contusions (perfusion-targeted goal). The Lund therapy considers the consequences of a disrupted blood-brain barrier for development of brain oedema and the specific consequences of a rigid dura/cranium for general cerebral haemodynamics. It calls attention to the importance of improving perfusion and oxygenation of the injured areas of the brain. This is achieved by normal blood oxygenation, by maintaining normovolaemia with normal haematocrit and plasma protein concentrations, and by antagonizing vasoconstriction through reduction of catecholamine concentration in plasma and sympathetic discharge (minimizing stress and by refraining from vasoconstrictors and active cooling). The therapeutic measures mean normalization of all essential haemodynamic parameters (blood pressure, plasma oncotic pressure, plasma and erythrocyte volumes, PaO(2), PaCO(2)) the use of enteral nutrition, and avoidance of overnutrition. To date, clinical outcome studies using the Lund Concept have shown favourable results.