Demographic and technological factors influencing virtual seizure clinic visit satisfaction before and during the Covid-19 pandemic in rural Hawaii.

BACKGROUND: Telemedicine clinic visits traditionally originated from spoke clinic sites, but recent trends have favored home-based telemedicine, particularly in the time of Covid-19. Our study focused on identification of barriers and factors influencing perceptions of care with use of home-based telemedicine in patients with seizures living in rural Hawaii. We additionally compared characteristics of patients using telemedicine versus in-person clinic visits prior to the Covid-19 pandemic. METHODS: For the retrospective portion of our study, we queried charts of adult outpatients treated by the two full-time epileptologists at a Level 4 epilepsy center accredited by the National Association of Epilepsy Centers between November 2018 and December 2019. We included patients who live on the neighbor islands of Hawaii but not on Oahu, i.e., patients who would require air travel to see an epileptologist. There had been no set protocol at the epilepsy center for telemedicine referral; our practice had been to offer telemedicine visits to all neighbor island patients when felt to be appropriate. We collected demographic and clinic visit data. For the prospective portion we surveyed neighbor island patients or their caregivers, seen via home-based telemedicine between March 2020 and December 2020. We obtained verbal consent for study participation. Survey questions addressed satisfaction with clinical care, visit preferences, and potential barriers to care. RESULTS: In a 14-month period prior to the Covid-19 pandemic, 75 (61%) neighbor island patients were seen exclusively in-person in seizure clinic while 47 (39%) had at least one telemedicine visit. 39% of patients seen only in-person were female whereas 38% of patients seen by telemedicine were female. Patients seen in-person had an older median age (47.2 years) compared to those seen at least once by telemedicine (42.4 years). The no-show rate was 13% for in-person visits versus 4% for telemedicine visits. Among patients seen in person, 17% were Asian, 32% Native Hawaiian, and 47% White, whereas patients seen by telemedicine were 15% Asian, 23% Native Hawaiian, and 57% White. Patients who were seen in person lived in zip codes with median household income of $68,516 and patients who were seen by telemedicine lived in zip codes with median household income of $67,089. Patients who were seen in person lived in zip codes in which 78% of the population had access to broadband internet, whereas patients who were seen by telemedicine lived in zip codes in which 79% of the population had access to broadband internet. During the Covid-19 pandemic, we surveyed 47 consecutive patients seen by telemedicine, 45% female with median age of 33 years. Telemedicine connection was set up by the patient in 74% of cases, or by the patient's mother (15%), other family member (9%), or other caregiver (2 %). Median patient satisfaction score was 5 ("highly satisfied") on a 5-point Likert scale with mean score of 4.6. Telemedicine visit was done using a smartphone by 62% of patients, a computer by 36% of patients, and a tablet by 2% of patients. A home WiFi connection was used in 83% of patients. CONCLUSIONS: Home-based telemedicine visits provide a high-satisfaction method for seizure care delivery despite some obstacles. Demographic disparities may be an obstacle to telemedicine care and seem to relate to race and possibly age, rather than to sex/gender, household income, or access to broadband internet. Additionally, despite high satisfaction overall, more patients felt the physical exam was superior at in-person clinic visits and more patients expressed a preference for in-person visits. During the Covid-19 pandemic when there may be barriers to in-person clinic visits, home-based telemedicine is a feasible alternative.

Racial and Ethnic Disparities in Hospital Mortality among Ischemic Stroke Patients in Hawaii.

BACKGROUND: We evaluated disparities in in-hospital mortality rates among whites, Native Hawaiians and other Pacific Islanders (NHOPI), Filipinos, and other Asian groups in Hawaii who were hospitalized for acute ischemic stroke. MATERIALS AND METHODS: Using a statewide hospital claims database, we performed a retrospective study including sequential acute ischemic stroke patients between 2010 and 2015. We compared in-hospital mortality rates among whites, NHOPI, Filipinos, other Asian groups excluding Filipinos, and other races (Blacks, Hispanics, Native Americans, mixed race). RESULTS: A total of 13,030 patient discharges were included in this study. The mean (±SD) age in years at the time of stroke was 63.5 ± 14.3 for NHOPI, 69.6 ± 14.4 for Filipinos, 67.8 ± 14.2 for other race, 71.4 ± 13.8 for whites, and 76.1 ± 13.5 for other Asians (P < .001). NHOPI patients had higher rates of diabetes (48.8%), obesity (18.4%), and tobacco use (31.3%) compared with patients in other racial-ethnic categories. Filipino patients had the highest rate of hemorrhagic transformation (9.7%). Age-adjusted stroke mortality rates were highest among Filipinos (15.9%; 95% confidence interval [CI] = 14.3%-17.6%), followed by other Asian groups (15.1%; 95% CI = 14.0%-16.2%), NHOPI (14.8%; 95% CI = 12.8%-16.8%), other race (14.4%; 95% CI = 11.3%-17.4%), and lowest among whites (12.8%; 11.5%-14.2%). After adjusting for other confounding variables, Filipinos had higher mortality (odds ratio = 1.22, 95% CI = 1.03-1.45), whereas other Asian groups, NHOPI, and other race patients had mortality rates that were similar to whites. CONCLUSION: In Hawaii, Filipino ethnicity is an independent risk factor for higher in-hospital stroke mortality compared with whites.

Derivation of a Predictive Score for Hemorrhagic Progression of Cerebral Contusions in Moderate and Severe Traumatic Brain Injury.

BACKGROUNDS: After traumatic brain injury (TBI), hemorrhagic progression of contusions (HPCs) occurs frequently. However, there is no established predictive score to identify high-risk patients for HPC. METHODS: Consecutive patients who were hospitalized (2008-2013) with non-penetrating moderate or severe TBI were studied. The primary outcome was HPC, defined by both a relative increase in contusion volume by ≥30 % and an absolute increase by ≥10 mL on serial imaging. Logistic regression models were created to identify independent risk factors for HPC. The HPC Score was then derived based on the final model. RESULTS: Among a total of 286 eligible patients, 61 (21 %) patients developed HPC. On univariate analyses, HPC was associated with older age, higher initial blood pressure, antiplatelet medications, anticoagulants, subarachnoid hemorrhage (SAH) subdural hematoma (SDH), skull fracture, frontal contusion, larger contusion volume, and shorter interval from injury to initial CT. In the final model, SAH (OR 6.33, 95 % CI, 1.80-22.23), SDH (OR 3.46, 95 % CI, 1.39-8.63), and skull fracture (OR 2.67, 95 % CI, 1.28-5.58) were associated with HPC. Based on these factors, the HPC Score was derived (SAH = 2 points, SDH = 1 point, and skull fracture = 1 point). This score had an area under the receiver operating curve of 0.77. Patients with a score of 0-2 had a 4.0 % incidence of HPC, while patients with a score of 3-4 had a 34.6 % incidence of HPC. CONCLUSIONS: A simple HPC Score was developed for early risk stratification of HPC in patients with moderate or severe TBI.

24/7 Neurocritical Care Nurse Practitioner Coverage Reduced Door-to-Needle Time in Stroke Patients Treated with Tissue Plasminogen Activator.

BACKGROUND: Stroke centers with limited on-site neurovascular physician coverage may experience delays in acute stroke treatment. We sought to assess the impact of providing 24/7 neurocritical care acute care nurse practitioner (ACNP) "stroke code" first responder coverage on treatment delays in acute stroke patients who received tissue plasminogen activator (tPA). METHODS: Consecutive acute ischemic stroke patients treated with intravenous tPA at a primary stroke center on Oahu between 2009 and 2014were retrospectively studied. 24/7 ACNP stroke code coverage (intervention) was introduced on July 1, 2011. The tPA utilization, door-to-needle (DTN) time, imaging-to-needle (ITN) time, and independent ambulation at hospital discharge were compared between the preintervention period (24 months) and the postintervention period (33 months). RESULTS: We studied 166 stroke code patients who were treated with intravenous tPA, 44 of whom were treated during the preintervention period and 122 of whom were treated during the postintervention period. After the intervention, the median DTN time was reduced from 53 minutes (interquartile range [IQR] 45-73) to 45 minutes (IQR 35-58) (P = .001), and the median ITN time was reduced from 36 minutes (IQR 28-64) to 21 minutes (IQR 16-31) (P < .0001). Compliance with the 60-minute target DTN improved from 61.4% (27 of 44 patients) in the preintervention period to 81.2% (99 of 122 patients) in the postintervention period (P = .004). The tPA treatment rates were similar between the preintervention and postintervention periods (P = .60). CONCLUSIONS: Addition of 24/7 on-site neurocritical care ACNP first responder coverage for acute stroke code significantly reduced the DTN time among acute stroke patients treated with tPA.

Early Quantitative Gamma-Band EEG Marker is Associated with Outcomes After Cardiac Arrest and Targeted Temperature Management.

BACKGROUND: Brain recovery after cardiac arrest (CA) is sensitive to temperature. Yet the effect of temperature management on different EEG frequency bands has not been elucidated. A novel quantitative EEG algorithm, sub-band information quantity (SIQ), was applied to evaluate EEG recovery and outcomes after CA. METHODS: Twenty-four Wistar rats undergoing 7-min CA were randomly assigned to immediate hypothermia (32-34 °C), normothermia (36.5-37.5 °C), or hyperthermia (38.5-39.5 °C) (n = 8). EEG was recorded continuously for the first 8 h and then for serial 30-min epochs daily. The neurologic deficit score (NDS) at 72-h was the primary functional outcome. Another four rats without brain injury were added as a control. RESULTS: Better recovery of gamma-band SIQ was found in the hypothermia group (0.60 ± 0.03) compared with the normothermia group (0.40 ± 0.03) (p < 0.01) and in the normothermia group compared with the hyperthermia group (0.34 ± 0.03) (p < 0.05). The NDS was also improved in the lower temperature groups: hypothermia [median (25th, 75th), 74 (61, 74)] versus normothermia [49 (47, 61)] versus hyperthermia [43 (0, 50)] (p < 0.01). Throughout the 72-h experiment, the gamma-band SIQ showed the strongest correlation at every time point (ranging 0.520-0.788 from 30-min to 72-h post-resuscitation, all p < 0.05) whereas the delta-band SIQ had poor correlation with the 72-h NDS. No significant difference of sub-band EEG was found with temperature manipulation alone. CONCLUSIONS: Recovery of gamma-band SIQ-qEEG was strongly associated with functional outcomes after CA. Induced hypothermia was associated with faster recovery of gamma-band SIQ and improved functional outcomes. Targeted temperature management primarily affected gamma frequency oscillations but not delta rhythm.

MRI default mode network connectivity is associated with functional outcome after cardiopulmonary arrest.

BACKGROUND: We hypothesized that the degree of preserved functional connectivity within the DMN during the first week after cardiopulmonary arrest (CPA) would be associated with functional outcome at hospital discharge. METHODS: Initially comatose CPA survivors with indeterminate prognosis at 72 h were enrolled. Seventeen CPA subjects between 4 and 7 days after CPA and 17 matched controls were studied with task-free fMRI. Independent component analysis was performed to delineate the DMN. Connectivity strength in the DMN was compared between CPA subjects and controls, as well as between CPA subjects with good outcome (discharge Cerebral Performance Category or CPC 1-2) and those with bad outcome (CPC 3-5). The relationship between connectivity strength in the posterior cingulate cortex (PCC) and precuneus (PC) within the DMN with discharge CPC was evaluated using linear regression. RESULTS: Compared to controls, CPA subjects had significantly lower connectivity strength in subregions of the DMN, the PCC and PC (p < 0.0001). Furthermore, connectivity strength in the PCC and PC was greater in CPA subjects with good outcome (n = 8) than those with bad outcome (n = 9) (p < 0.003). Among CPA subjects, the connectivity strength in the PCC and PC showed strong linear correlations with the discharge CPC (p < 0.005). CONCLUSIONS: Among initially comatose CPA survivors with indeterminate prognosis, task-free fMRI demonstrated graded disruption of DMN connectivity, especially in those with bad outcomes. If confirmed, connectivity strength in the PC/PCC may provide a clinically useful prognostic marker for functional recovery after CPA.

Sex differences in the use of early do-not-resuscitate orders after intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Studies show that women are more likely to receive do-not-resuscitate (DNR) orders after acute medical illnesses than men. However, the sex differences in the use of DNR orders after acute intracerebral hemorrhage (ICH) have not been described. METHODS: We conducted a retrospective study of consecutive patients hospitalized for acute ICH at a tertiary stroke center between 2006 and 2010. Unadjusted and multivariable logistic regression analyses were performed to test for associations between female sex and early (<24 hours of presentation) DNR orders. RESULTS: A total of 372 consecutive ICH patients without preexisting DNR orders were studied. Overall, 82 (22%) patients had early DNR orders after being hospitalized with ICH. In the fully adjusted model, early DNR orders were more likely in women (odds ratio, 3.18; 95% confidence interval, 1.51-6.70), higher age (odds ratio, 1.09 per year; 95% confidence interval, 1.05-1.12), larger ICH volume (odds ratio, 1.01 per cm(3); 95% confidence interval, 1.01-1.02), and lower initial GCS score (odds ratio, 0.76 per point; 95% confidence interval, 0.69-0.84). Early DNR orders were less likely when the patients were transferred from another hospital (odds ratio, 0.28, 95% confidence interval, 0.11-0.76). CONCLUSIONS: Women are more likely to receive early DNR orders after ICH than men. Further prospective studies are needed to determine factors contributing to the sex variation in the use of early DNR order after ICH.

Clinical neurophysiology in acute coma and disorders of consciousness.

Over the last decade, significant improvements have been made in understanding and categorizing coma and disorders of consciousness. Although imaging techniques have been paramount in exploring disorders of consciousness, electrophysiologic techniques continue to be important for studying brain function in behaviorally unresponsive patients. In acute coma, electroencephalogram and evoked potentials have important roles in excluding nonconvulsive seizures, determining prognosis, monitoring for signs of improvement or worsening, and examining for markers of conscious response to external stimuli. Absence of cortical SSEPs is the most specific marker of poor prognosis after cardiac arrest. Recognition of stimulus-induced epileptiform discharges and clinical seizures has further blurred the lines along the ictal-interictal spectrum in coma. For chronic disorders of consciousness, more experimental techniques, such as cognitive event-related potentials and long-latency evoked potentials, have demonstrated an expanded role in determining prognosis and examining for indicators of consciousness. Like functional magnetic resonance imaging, these specialized techniques have demonstrated signs of preserved cognition in patients who otherwise appear unconscious. Future directions for clinical electrophysiologic testing in disorders of consciousness are likely to include automated and quantitative signal processing techniques and better standardization of cognitive event-related potentials.

Treatment of elevated intracranial pressure with hyperosmolar therapy in patients with renal failure.

BACKGROUND: To evaluate the use of hyperosmolar therapy in the management of elevated intracranial pressure (ICP) and transtentorial herniation (TTH) in patients with renal failure and supratentorial lesions. METHODS: Patients with renal failure undergoing renal replacement therapy treated with 23.4% saline (30-60 mL) and/or mannitol for high ICP or clinical evidence of TTH were analyzed in a retrospective cohort. RESULTS: The primary outcome measure was reversal of TTH or ICP crisis. Secondary outcome measures were modified Rankin scale on hospital discharge, survival to hospital discharge, and adverse effects. Of 254 subjects over 7 years, 6 patients with end-stage renal disease had 11 events. All patients received a 23.4% saline bolus, along with mannitol (91%), hypertonic saline (HS) maintenance fluids (82%), and surgical interventions (n = 2). Reversal occurred in 6/11 events (55%); 2 of 6 patients survived to discharge. ICP recording of 6 TTH events showed a reduction from ICP of 41 ± 3.8 mmHg (mean ± SEM) with TTH to 20.8 ± 3.9 mmHg (p = 0.05) 1 h after the 23.4% saline bolus. Serum sodium increased from 141.4 to 151.1 mmol/L 24 h after 23.4% saline bolus (p = 0.001). No patients were undergoing hemodialysis at the time of the event. There were no cases of pulmonary edema, clinical volume overload, or arrhythmia after HS. CONCLUSIONS: Treatment with hyperosmolar therapy, primarily 23.4% saline solution, was associated with clinical reversal of TTH and reduction in ICP and had few adverse effects in this cohort. Hyperosmolar therapy may be safe and effective in patients with renal failure and these initial findings should be validated in a prospective study.

Quantitative assessment of somatosensory-evoked potentials after cardiac arrest in rats: prognostication of functional outcomes.

OBJECTIVE: High incidence of poor neurologic sequelae after resuscitation from cardiac arrest underscores the need for objective electrophysiological markers for assessment and prognosis. This study aims to develop a novel marker based on somatosensory evoked potentials (SSEPs). Normal SSEPs involve thalamocortical circuits suggested to play a role in arousal. Due to the vulnerability of these circuits to hypoxic-ischemic insults, we hypothesize that quantitative SSEP markers may indicate future neurologic status. DESIGN: Laboratory investigation. SETTING: University Medical School and Animal Research Facility. SUBJECTS: : Sixteen adult male Wistar rats. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: SSEPs were recorded during baseline, during the first 4 hrs, and at 24, 48, and 72 hrs postasphyxia from animals subjected to asphyxia-induced cardiac arrest for 7 or 9 mins (n = 8/group). Functional evaluation was performed using the Neurologic Deficit Score (NDS). For quantitative analysis, the phase space representation of the SSEPs-a plot of the signal vs. its slope-was used to compute the phase space area bounded by the waveforms recorded after injury and recovery. Phase space areas during the first 85-190 mins postasphyxia were significantly different between rats with good (72 hr NDS >or=50) and poor (72 hr NDS <50) outcomes (p = .02). Phase space area not only had a high outcome prediction accuracy (80-93%, p < .05) during 85-190 mins postasphyxia but also offered 78% sensitivity to good outcomes without compromising specificity (83-100%). A very early peak of SSEPs that precedes the primary somatosensory response was found to have a modest correlation with the 72 hr NDS subscores for thalamic and brainstem function (p = .066) and not with sensory-motor function (p = .30). CONCLUSIONS: Phase space area, a quantitative measure of the entire SSEP morphology, was shown to robustly track neurologic recovery after cardiac arrest. SSEPs are among the most reliable predictors of poor outcome after cardiac arrest; however, phase space area values early after resuscitation can enhance the ability to prognosticate not only poor but also good long-term neurologic outcomes.

Brain death.

Declaration of brain death requires demonstration of irreversible injury to the whole brain including the brainstem. Current guidelines rely on bedside clinical examination to determine that the patient has irreversible coma, absent cranial nerve reflexes, and apnea. Neurophysiologic testing to support the clinical diagnosis of brain death has primarily consisted of EEG and evoked potentials-typically a combination of somatosensory evoked potential and brainstem auditory evoked potential. The diagnostic accuracy of these ancillary tests has been studied for the last few decades but the role of ancillary neurophysiologic testing in brain death continues to be a source of controversy. This chapter reviews the relevant studies and guidelines about EEG and evoked potentials in ancillary testing for brain death. Clinical scenarios in which neurophysiologic testing may aid the declaration of brain death include equivocal results of clinical examination findings, inability to perform some aspects of the neurologic examination, concern for residual sedative effects, suspected spinal cord or neuromuscular injury, and posterior fossa lesions with brainstem involvement. In these scenarios, EEG and evoked potentials may offer supportive evidence for irreversible injury to the whole brain. This chapter also discusses differences between current adult and pediatric guidelines for the role of ancillary testing in brain death.

Impact of Statewide Telestroke Network on Acute Stroke Treatment in Hawai'i.

Hawai'i faces unique challenges in providing access to subspecialty care, particularly on the islands outside of O'ahu. Telemedicine allows remote treatment of patients with acute ischemic stroke by a neurologist with stroke expertise. The Hawai'i Telestroke Program was implemented in 2012 to connect hospitals with limited neurology coverage to a tertiary stroke center on O'ahu with 24/7 stroke neurology coverage. By 2017, seven hospitals were included in the program. The clinical data and revascularization therapy rate for all telestroke cases between January 2012 and July 2017 were analyzed. Annual telestroke consultations increased from 11 in 2012 to 203 in 2016. Among a total of 490 telestroke consultations, 318 patients (64.9%) were diagnosed with ischemic stroke while the remaining 172 patients had other diagnoses. Revascularization therapies, including intravenous tissue plasminogen activator and mechanical thrombectomy, were provided in 190 patients (38.8%). Using the discharge modified Rankin Scale, 141 (44.3%) patients were functionally independent at the time of hospital discharge, while 162 (50.9%) were disabled or dependent, and 15 (4.7%) died while in the hospital. Of the 490 telestroke consultations, 151 patients (30.8%) were transferred to the hub hospital while 69.2% of patients were able to remain in their local hospital. In summary, development of the Hawai'i Telestroke Program resulted in an increasing number of acute telestroke consultations and revascularization therapies at seven hospitals with limited neurological subspecialty coverage. Utilization of telemedicine in acute stroke treatment is feasible and may help address existing disparities of subspecialty care in Hawai'i.

Early electrophysiologic markers predict functional outcome associated with temperature manipulation after cardiac arrest in rats.

OBJECTIVE: Therapeutic hypothermia after cardiac arrest improves survival and functional outcomes, whereas hyperthermia is harmful. The optimal method of tracking the effect of temperature on neurologic recovery after cardiac arrest has not been elucidated. We studied the recovery of cortical electrical function by quantitative electroencephalography after 7-min asphyxial cardiac arrest, using information quantity (IQ). DESIGN: Laboratory investigation. SETTING: University medical school and animal research facility. SUBJECTS: A total of 28 male Wistar rats. INTERVENTIONS: Using an asphyxial cardiac arrest rodent model, we tracked quantitative electroencephalography of 6-hr immediate postresuscitation hypothermia (at 33 degrees C), normothermia (37 degrees C), or hyperthermia (39 degrees C) (n = 8 per group). Neurologic recovery was evaluated using the Neurologic Deficit Score. Four rats were included as a sham control group. MEASUREMENTS AND MAIN RESULTS: Greater recovery of IQ was found in rats treated with hypothermia (IQ = 0.74), compared with normothermia (IQ = 0.60) and hyperthermia (IQ = 0.56) (p < .001). Analysis at different intervals demonstrated a significant separation of IQ scores among the temperature groups within the first 2 hrs postresuscitation (p < .01). IQ values of >0.523 at 60 mins postresuscitation predicted good neurologic outcome (72-hr Neurologic Deficit Score of > or = 60), with a specificity of 100% and sensitivity of 81.8%. IQ was also significantly lower in rats that died prematurely compared with survivors (p < .001). IQ values correlated strongly with 72-hr Neurologic Deficit Score as early as 30 mins post-cardiac arrest (Pearson's correlation 0.735, p < .01) and maintained a significant association throughout the 72-hr experiment. No IQ difference was noted in sham rats with temperature manipulation. CONCLUSIONS: The enhanced recovery provided by hypothermia and the detrimental effect by hyperthermia were robustly detected by early quantitative electroencephalographic markers. IQ values during the first 2 hrs after cardiac arrest accurately predicted neurologic outcome at 72 hrs.

Post-cardiac arrest temperature manipulation alters early EEG bursting in rats.

OBJECTIVES: Hypothermia improves outcomes after cardiac arrest (CA), while hyperthermia worsens injury. EEG recovers through periodic bursting from isoelectricity after CA, the duration of which is associated with outcome in normothermia. We quantified burst frequency to study the effect of temperature on early EEG recovery after CA. METHODS: Twenty-four rats were divided into three groups, based on 6h of hypothermia (T=33 degrees C), normothermia (T=37 degrees C), or hyperthermia (T=39 degrees C) immediately post-resuscitation from 7-min asphyxial CA. Temperature was maintained using surface cooling and re-warming. Neurological recovery was defined by 72-h neurological deficit score (NDS). RESULTS: Burst frequency was higher during the first 90min in rats treated with hypothermia (25.6+/-12.2min(-1)) and hyperthermia (22.6+/-8.3min(-1)) compared to normothermia (16.9+/-8.5min(-1)) (p<0.001). Burst frequency correlated strongly with 72-h NDS in normothermic rats (p<0.05) but not in hypothermic or hyperthermic rats. The 72-h NDS of the hypothermia group (74, 61-74; median, 25-75th percentile) was significantly higher than the normothermia (49, 47-61) and hyperthermia (43, 0-50) groups (p<0.001). CONCLUSIONS: In normothermic rats resuscitated from CA, early EEG burst frequency is strongly associated with neurological recovery. Increased bursting followed by earlier restitution of continuous EEG activity with hypothermia may represent enhanced recovery, while heightened metabolic rate and worsening secondary injury is likely in the hyperthermia group. These factors may confound use of early burst frequency for outcome prediction.

Improving neurological outcomes post-cardiac arrest in a rat model: immediate hypothermia and quantitative EEG monitoring.

OBJECTIVES: Therapeutic hypothermia (TH) after cardiac arrest (CA) improves outcomes in a fraction of patients. To enhance the administration of TH, we studied brain electrophysiological monitoring in determining the benefit of early initiation of TH compared to conventional administration in a rat model. METHODS: Using an asphyxial CA model, we compared the benefit of immediate hypothermia (IH, T=33 degrees C, immediately post-resuscitation, maintained 6h) to conventional hypothermia (CH, T=33 degrees C, starting 1h post-resuscitation, maintained 12h) via surface cooling. We tracked quantitative EEG using relative entropy (qEEG) with outcome verification by serial Neurological Deficit Score (NDS) and quantitative brain histopathological damage scoring (HDS). Thirty-two rats were divided into 4 groups based on CH/IH and 7/9-min duration of asphyxial CA. Four sham rats were included for evaluation of the effect of hypothermia on qEEG. RESULTS: The 72-h NDS of the IH group was significantly better than the CH group for both 7-min (74/63; median, IH/CH, p<0.001) and 9-min (54/47, p=0.022) groups. qEEG showed greater recovery with IH (p<0.001) and significantly less neuronal cortical injury by HDS (IH: 18.9+/-2.5% versus CH: 33.2+/-4.4%, p=0.006). The 1-h post-resuscitation qEEG correlated well with 72-h NDS (p<0.05) and 72-h behavioral subgroup of NDS (p<0.01). No differences in qEEG were noted in the sham group. CONCLUSIONS: Immediate but shorter hypothermia compared to CH leads to better functional outcome in rats after 7- and 9-min CA. The beneficial effect of IH was readily detected by neuro-electrophysiological monitoring and histological changes supported the value of this observation.

Management of brain injury after resuscitation from cardiac arrest.

The devastating neurologic injury in survivors of cardiac arrest has been recognized since the development of modern resuscitation techniques. After numerous failed clinical trials, two trials showed that induced mild hypothermia can ameliorate brain injury and improve survival and functional neurologic outcome in comatose survivors of out-of-hospital cardiac arrest. This article provides a comprehensive review of the advances in the care of brain injury after cardiac arrest, with updates on the process of prognostication, the use of therapeutic hypothermia and adjunctive intensive care unit care for cardiac arrest survivors.

Coma after global ischemic brain injury: pathophysiology and emerging therapies.

Cardiac arrest is a major cause of death and morbidity in the United States, and neurological injury contributes significantly to this. Neurological complications associated with global cerebral ischemia include disorders of responsiveness, such as coma and the vegetative state, seizures, motor deficits, and brain death. Coma, complete unresponsiveness, is the most pervasive of these. Therapies that improve neurological outcomes in general after cardiac arrest and therapies that stimulate arousal from coma could have enormous clinical impact. The authors review the physiology of arousal and describe the biochemical and pathophysiological derangements that develop after global cerebral ischemia. We then describe the potential therapeutic mechanisms of hypothermia and deep brain stimulation, which provide hope for better neurological outcomes after global cerebral ischemia.

Cerebral Edema and Elevated Intracranial Pressure.

PURPOSE OF REVIEW: This article reviews the management of cerebral edema, elevated intracranial pressure (ICP), and cerebral herniation syndromes in neurocritical care. RECENT FINDINGS: While corticosteroids may be effective in reducing vasogenic edema around brain tumors, they are contraindicated in traumatic cerebral edema. Mannitol and hypertonic saline use should be tailored to patient characteristics including intravascular volume status. In patients with traumatic brain injury who are comatose, elevated ICP should be managed with an algorithmic, multitiered treatment protocol to maintain an ICP of 22 mm Hg or less. Third-line ICP treatments include anesthetic agents, induced hypothermia, and decompressive craniectomy. Recent clinical trials have demonstrated that induced hypothermia and decompressive craniectomy are ineffective as early neuroprotective strategies and should be reserved for third-line management of refractory ICP elevation in severe traumatic brain injury. Monitoring for cerebral herniation should include bedside pupillometry in supratentorial space-occupying lesions and recognition of upward herniation in patients with posterior fossa lesions. SUMMARY: Although elevated ICP, cerebral edema, and cerebral herniation are interrelated, treatments should be based on the distinct pathophysiologic process. Focal lesions resulting in brain compression are primarily managed with surgical decompression, whereas global or multifocal brain injury requires a treatment protocol that includes medical and surgical interventions.

Measuring Depth in Still Water: Electrophysiologic Indicators of Residual Consciousness in the Unresponsive Patient.

Searching for evidence of consciousness in outwardly unresponsive patients presents significant clinical challenges as the spectrum of disorders of consciousness has become more clearly defined, with clinical examination, functional MRI, and electrophysiologic tests having complementary roles in the investigation of minimally conscious patients, those in a locked-in state, coma, or in a vegetative state. Serial bedside electrophysiologic testing can probe for higher order cortical responses temporally and spatially propagated through cortical networks, while long-latency event-related potentials may help differentiate patients with coma or vegetative state from a state of residual consciousness. Transcranial magnetic stimulation co-registered to high-density EEG may reveal widespread pulse-stimulated cortical activation of various brain regions. These emerging electrophysiologic techniques show promise as powerful diagnostic, prognostic, and therapeutic tools.