Delirium Associated with COVID-19 in Critically ill Children: An Observational Cohort Study.

OBJECTIVE: Delirium is an under-recognized problem in critically ill children. Although delirium is common in adults hospitalized with COVID-19, the relationship between pediatric COVID-19 and delirium has not been described. To address this gap, we characterized delirium in critically ill children with different manifestations of COVID-19 and investigated associations among demographic, disease, and treatment factors. We hypothesized that multisystem inflammatory syndrome in children (MIS-C) would be associated with a higher incidence of delirium given its underlying pathophysiology of hyperinflammation. DESIGN: Retrospective, single-center cohort study. SETTING: Quaternary-care pediatric intensive care unit (PICU). PATIENTS: Children less than 18 years of age hospitalized in the PICU between March 2020 and March 2023 with either active SARS-CoV-2 infection or serological evidence of prior infection. MEASUREMENTS AND MAIN RESULTS: The cohort included 149 PICU hospitalizations among children with evidence of COVID-19. Patients were categorized by reason for PICU admission: 75 (50%) for COVID-19 respiratory disease, 36 (24%) MIS-C, and 38 (26%) any other primary reason with positive COVID-19 testing. Delirium was diagnosed in 43 (29%) patients. Delirium incidence was highest in patients requiring invasive mechanical ventilation (IMV) (56% vs 7.5% in patients who did not require IMV, p < .001). Patients who were exposed to opioids, dexmedetomidine, paralytics or benzodiazepines more frequently experienced delirium compared to those unexposed (p < .001, p < .001, p < .001 and p = .001, respectively). After multivariable adjustment, delirium was associated with IMV (HR 3 [95% CI 1.5-5.7]), female sex (HR 2.4 [1.2-4.7]), and developmental disability (HR 3.4 [95% CI 1-11.1]). There was no association between delirium and reason for PICU hospitalization. CONCLUSIONS: Delirium was common among children hospitalized with COVID-19. The overall incidence was much less than has been reported in adults with COVID-19. Delirium reduction efforts should focus on children with developmental disability and minimizing ongoing risks during IMV.

Early Treatment of Multisystem Inflammatory Syndrome in Children.

BACKGROUND AND OBJECTIVES: Multisystem inflammatory syndrome in children (MIS-C) is a severe hyperinflammatory illness occurring after severe acute respiratory syndrome coronavirus 2 infection. The optimal treatment of MIS-C is unknown, although prior studies have indicated benefits of intravenous immunoglobulin (IVIG) and glucocorticoids. We hypothesize that early treatment with glucocorticoids is associated with shorter hospital length of stay (LOS). METHODS: This study is a multicenter retrospective cohort study of patients hospitalized with MIS-C over a roughly 1-year period. The primary outcome was hospital LOS comparing subjects who received glucocorticoids within 48 hours of arrival to the treating hospital to those who did not. Secondary outcomes included ICU LOS. Unadjusted and adjusted analyses were performed. RESULTS: The final analysis included 131 subjects. Subjects who received early glucocorticoids were more likely to receive early IVIG and to require ICU admission. Early glucocorticoid administration was associated with shorter ICU LOS (4 vs 9 days, P = .004) in the unadjusted analysis. In the adjusted analysis, early glucocorticoid administration and early IVIG administration were both independently associated with shorter hospital LOS (incidence rate ratio 0.75, P = .025; incidence rate ratio 0.56, P = .026, respectively). CONCLUSIONS: Glucocorticoids and intravenous immunoglobulin were independently associated with shorter hospital length of stay when given early in hospitalization to MIS-C patients after accounting for potential confounding factors. The optimal dose and duration of treatment require further investigation, but this study supports early combination therapy with both IVIG and glucocorticoids for all children hospitalized with MIS-C.

Effect of Standing Intravenous Acetaminophen on Postoperative Opioid Exposure in a Pediatric Cardiac Intensive Care Unit.

This study assessed the association between standing intravenous acetaminophen and opioid exposure after cardiac surgery. Before vs after implementation of a standardized pain pathway, we report decreased opioid exposure, 0.38 milligram per kilogram of morphine equivalents [IQR 0.10-0.81] vs 0.26 milligram per kilogram of morphine equivalents [0.09-0.56] (P = .01) and increased acetaminophen exposure, 3 [2-4] vs 4 [4-5] doses (P < .001).

Scoping Review: Neurocognitive Outcome Assessments After Critical Illness in Children.

OBJECTIVES: To map the literature regarding assessment of neurocognitive outcomes in PICU survivors. Secondary objectives were to identify literature gaps and to provide data for development of a Core Outcome Measures Set in the domain. METHODS: Planned, a priori analysis was performed of data from an over-all scoping review of Post-Intensive Care Syndrome-pediatrics (PICS-p) functional outcomes. English-language databases and registries from 1970 to 2017 were searched by a medical librarian to identify manuscripts reporting on Post Intensive Care Syndrome-pediatrics (PICS-p). Further, detailed data extraction for neurocognitive outcomes was performed focusing on study characteristics, instruments used, and populations. RESULTS: 114 instruments evaluated neurocognitive function in 183 manuscripts. 83% of manuscripts were published after 2000. Median of 3 (IQR 2-5) neurocognitive instruments per manuscript were reported. Wechsler Scales (45%), clinical neurologic evaluations (21%), Pediatric Cerebral Performance Category (20%), Bayley Scales of Infant Development (16%), and Vineland Adaptive Behavior Scales (11%) were the most commonly used instruments. Median sample size was 65 (IQR 32-129) subjects. Most (63%) assessments were conducted in-person and parents/guardians (40%) provided the information. Patients with congenital heart disease and traumatic brain injury were most commonly evaluated (31% and 24% of manuscripts, respectively). Adolescents were the most commonly studied age group (34%). Baseline function was infrequently assessed (11% of manuscripts); most studies assessed patients at only one time point after PICU discharge. Within studies, neurocognitive assessments were often combined with others - especially social (18%) and physical (8%). CONCLUSIONS: 183 manuscripts studied the neurocognitive domain of PICS-p. Studies were quantitative and tended to focus on populations with anticipated cognitive impairment. Considerable variability exists among the chosen 114 instruments used; however, 4 instruments were frequently chosen with focus on intelligence, cerebral functioning, and developmental and adaptive behavior. The literature is marked by lack of agreement on methodologies but reflects the burgeoning interest in studying PICS-p neurocognitive outcomes.

Risk Factors for New Neurologic Diagnoses in Hospitalized Patients With COVID-19: A Case-Control Study in New York City.

Background and Objectives: There have been numerous reports of neurologic manifestations identified in hospitalized patients infected with SARS-CoV-2, the virus that causes COVID-19. Here, we identify the spectrum of associated neurologic symptoms and diagnoses, define the time course of their development, and examine readmission rates and mortality risk posthospitalization in a multiethnic urban cohort. Methods: We identify the occurrence of new neurologic diagnoses among patients with laboratory-confirmed SARS-CoV-2 infection in New York City. A retrospective cohort study was performed on 532 cases (hospitalized patients with new neurologic diagnoses within 6 weeks of positive SARS-CoV-2 laboratory results between March 1, 2020, and August 31, 2020). We compare demographic and clinical features of the 532 cases with 532 controls (hospitalized COVID-19 patients without neurologic diagnoses) in a case-control study with one-to-one matching and examine hospital-related data and outcomes of death and readmission up to 6 months after acute hospitalization in a secondary case-only analysis. Results: Among the 532 cases, the most common new neurologic diagnoses included encephalopathy (478, 89.8%), stroke (66, 12.4%), and seizures (38, 7.1%). In the case-control study, cases were more likely than controls to be male (58.6% vs 52.8%, p = 0.05), had baseline neurologic comorbidities (36.3% vs 13.0%, p < 0.0001), and were to be treated in an intensive care unit (62.0% vs 9.6%, p < 0.0001). Of the 394 (74.1%) cases who survived acute hospitalization, more than half (220 of 394, 55.8%) were readmitted within 6 months, with a mortality rate of 23.2% during readmission. Discussion: Hospitalized patients with SARS-CoV-2 and new neurologic diagnoses have significant morbidity and mortality postdischarge. Further research is needed to define the effect of neurologic diagnoses during acute hospitalization on longitudinal post-COVID-19-related symptoms including neurocognitive impairment.

Intraoperative Blood Pressure and Long-Term Neurodevelopmental Function in Children Undergoing Ambulatory Surgery.

BACKGROUND: Some studies have found surgery and anesthesia in children to be associated with neurodevelopmental deficits, but specific reasons for this association have not been fully explored. This study evaluates intraoperative mean arterial pressure (MAP) during a single ambulatory procedure in children and subsequent mental disorder diagnoses. METHODS: A retrospective observational study was performed including children ≥28 days and <18 years of age with intraoperative electronic anesthetic records between January 1, 2009, and April 30, 2017, at our institution. Eligible children were categorized based on their mean intraoperative MAP relative to other children of the same sex and similar age: category 1 (very low): children with mean intraoperative MAP values below the 10th percentile, category 2 (low): mean MAP value ≥10th and <25th percentiles, category 3 (reference): mean MAP value ≥25th and <75th percentiles, category 4 (high): mean MAP value ≥75th and <90th percentile, and category 5 (very high): mean MAP value ≥90th percentile. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) and ICD, Tenth Revision, Clinical Modification (ICD-10)-coded mental disorders were identified in hospital and outpatient claims, with a median duration of follow-up after surgery of 120 days (interquartile range [IQR], 8-774.5 days). Cox proportional hazards models evaluated the hazard ratio (HR) of time to first mental disorder diagnosis associated with intraoperative blood pressure category between the end of surgery and censoring, with the primary analysis adjusting for demographic, anesthetic, comorbidity, and procedure-type variables as potential confounders. RESULTS: A total of 14,724 eligible children who received general anesthesia for a single ambulatory surgical procedure were identified. After adjusting for all available potential confounders, when compared to the reference, there were no statistically significant differences in mental disorder diagnosis risk based on intraoperative mean MAP category. Compared to reference, children in the very low and low blood pressure categories reported HRs of 1.00 (95% confidence interval [CI], 0.74-1.35) and 1.10 (95% CI, 0.87-1.41) for a mental disorder diagnosis, respectively, and children in the high and very high categories reported HRs of 0.87 (95% CI, 0.68-1.12) and 0.76 (95% CI, 0.57-1.03), respectively. CONCLUSIONS: Presence in a predefined mean intraoperative MAP category was not associated with subsequent mental disorder diagnoses within our follow-up period. However, the limitations of this study, including uncertainty regarding what constitutes an adequate blood pressure in children, may limit the ability to form definitive conclusions.

Improving Ventilation Rates During Pediatric Cardiopulmonary Resuscitation.

BACKGROUND: Excessive ventilation at rates of 30 breaths per minute (bpm) or more during cardiopulmonary resuscitation (CPR) decreases venous return and coronary perfusion pressure, leading to lower survival rates in animal models. A review of our institution's pediatric CPR data revealed that patients frequently received excessive ventilation. METHODS: We designed a multifaceted quality improvement program to decrease the incidence of clinically significant hyperventilation (≥30 bpm) during pediatric CPR. The program consisted of provider education, CPR ventilation tools (ventilation reminder cards, ventilation metronome), and individual CPR team member feedback. CPR events were reviewed pre- and postintervention. The first 10 minutes of each CPR event were divided into 20 second epochs, and the ventilation rate in each epoch was measured via end-tidal carbon dioxide waveform. Individual epochs were classified as within the target ventilation range (<30 bpm) or clinically significant hyperventilation (≥30 bpm). The proportion of epochs with clinically significant hyperventilation, as well as median ventilation rates, were analyzed in the pre- and postintervention periods. RESULTS: In the preintervention period (37 events, 699 epochs), 51% of CPR epochs had ventilation rates ≥30 bpm. In the postintervention period (24 events, 426 epochs), the proportion of CPR epochs with clinically significant hyperventilation decreased to 29% (P < .001). Median respiratory rates decreased from 30 bpm (interquartile range 21-36) preintervention to 21 bpm (interquartile range 12-30) postintervention (P < .001). CONCLUSIONS: A quality improvement initiative grounded in improved provider education, CPR team member feedback, and tools focused on CPR ventilation rates was effective at reducing rates of clinically significant hyperventilation during pediatric CPR.

OARD: Open annotations for rare diseases and their phenotypes based on real-world data.

Diagnosis for rare genetic diseases often relies on phenotype-driven methods, which hinge on the accuracy and completeness of the rare disease phenotypes in the underlying annotation knowledgebase. Existing knowledgebases are often manually curated with additional annotations found in published case reports. Despite their potential, real-world data such as electronic health records (EHRs) have not been fully exploited to derive rare disease annotations. Here, we present open annotation for rare diseases (OARD), a real-world-data-derived resource with annotation for rare-disease-related phenotypes. This resource is derived from the EHRs of two academic health institutions containing more than 10 million individuals spanning wide age ranges and different disease subgroups. By leveraging ontology mapping and advanced natural-language-processing (NLP) methods, OARD automatically and efficiently extracts concepts for both rare diseases and their phenotypic traits from billing codes and lab tests as well as over 100 million clinical narratives. The rare disease prevalence derived by OARD is highly correlated with those annotated in the original rare disease knowledgebase. By performing association analysis, we identified more than 1 million novel disease-phenotype association pairs that were previously missed by human annotation, and >60% were confirmed true associations via manual review of a list of sampled pairs. Compared to the manual curated annotation, OARD is 100% data driven and its pipeline can be shared across different institutions. By supporting privacy-preserving sharing of aggregated summary statistics, such as term frequencies and disease-phenotype associations, it fills an important gap to facilitate data-driven research in the rare disease community.

Prevalence and Risk Factors of Neurologic Manifestations in Hospitalized Children Diagnosed with Acute SARS-CoV-2 or MIS-C.

BACKGROUND: Our objective was to characterize the frequency, early impact, and risk factors for neurological manifestations in hospitalized children with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or multisystem inflammatory syndrome in children (MIS-C). METHODS: Multicenter, cross-sectional study of neurological manifestations in children aged <18 years hospitalized with positive SARS-CoV-2 test or clinical diagnosis of a SARS-CoV-2-related condition between January 2020 and April 2021. Multivariable logistic regression to identify risk factors for neurological manifestations was performed. RESULTS: Of 1493 children, 1278 (86%) were diagnosed with acute SARS-CoV-2 and 215 (14%) with MIS-C. Overall, 44% of the cohort (40% acute SARS-CoV-2 and 66% MIS-C) had at least one neurological manifestation. The most common neurological findings in children with acute SARS-CoV-2 and MIS-C diagnosis were headache (16% and 47%) and acute encephalopathy (15% and 22%), both P < 0.05. Children with neurological manifestations were more likely to require intensive care unit (ICU) care (51% vs 22%), P < 0.001. In multivariable logistic regression, children with neurological manifestations were older (odds ratio [OR] 1.1 and 95% confidence interval [CI] 1.07 to 1.13) and more likely to have MIS-C versus acute SARS-CoV-2 (OR 2.16, 95% CI 1.45 to 3.24), pre-existing neurological and metabolic conditions (OR 3.48, 95% CI 2.37 to 5.15; and OR 1.65, 95% CI 1.04 to 2.66, respectively), and pharyngeal (OR 1.74, 95% CI 1.16 to 2.64) or abdominal pain (OR 1.43, 95% CI 1.03 to 2.00); all P < 0.05. CONCLUSIONS: In this multicenter study, 44% of children hospitalized with SARS-CoV-2-related conditions experienced neurological manifestations, which were associated with ICU admission and pre-existing neurological condition. Posthospital assessment for, and support of, functional impairment and neuroprotective strategies are vitally needed.

Long-Term Increases in Mental Disorder Diagnoses After Invasive Mechanical Ventilation for Severe Childhood Respiratory Disease: A Propensity Matched Observational Cohort Study.

OBJECTIVES: To evaluate neurodevelopmental and mental disorders after PICU hospitalization in children requiring invasive mechanical ventilation for severe respiratory illness. DESIGN: Retrospective longitudinal observational cohort. SETTING: Texas Medicaid Analytic eXtract data from 1999 to 2012. PATIENTS: Texas Medicaid-enrolled children greater than or equal to 28 days old to less than 18 years old hospitalized for a primary respiratory illness, without major chronic conditions predictive of abnormal neurodevelopment. INTERVENTIONS: We examined rates of International Classification of Diseases, 9th revision-coded mental disorder diagnoses and psychotropic medication use following discharge among children requiring invasive mechanical ventilation for severe respiratory illness, compared with general hospital patients propensity score matched on sociodemographic and clinical characteristics prior to admission. Children admitted to the PICU for respiratory illness not necessitating invasive mechanical ventilation were also compared with matched general hospital patients as a negative control exposure. MEASUREMENTS AND MAIN RESULTS: Of 115,335 eligible children, 1,351 required invasive mechanical ventilation and were matched to 6,755 general hospital patients. Compared with general hospital patients, children requiring invasive mechanical ventilation had increased mental disorder diagnoses (hazard ratio, 1.43 [95% CI, 1.26-1.64]; p < 0.0001) and psychotropic medication use (hazard ratio, 1.67 [1.34-2.08]; p < 0.0001) following discharge. Seven-thousand seven-hundred eighty children admitted to the PICU without invasive mechanical ventilation were matched to 38,900 general hospital patients and had increased mental disorder diagnoses (hazard ratio, 1.08 [1.02-1.15]; p = 0.01) and psychotropic medication use (hazard ratio, 1.11 [1.00-1.22]; p = 0.049). CONCLUSIONS: Children without major comorbidity requiring invasive mechanical ventilation for severe respiratory illness had a 43% higher incidence of subsequent mental disorder diagnoses and a 67% higher incidence of psychotropic medication use. Both increases were substantially higher than in PICU patients with respiratory illness not necessitating invasive mechanical ventilation. Invasive mechanical ventilation is a life-saving therapy, and its application is interwoven with underlying health, illness severity, and PICU management decisions. Further research is required to determine which factors related to invasive mechanical ventilation and severe respiratory illness are associated with abnormal neurodevelopment. Given the increased risk in these children, identification of strategies for prevention, neurodevelopmental surveillance, and intervention after discharge may be warranted.

Multisystem Inflammatory Syndrome in Children Associated With Coronavirus Disease 2019 in a Children's Hospital in New York City: Patient Characteristics and an Institutional Protocol for Evaluation, Management, and Follow-Up.

OBJECTIVES: The disease caused by severe acute respiratory syndrome coronavirus 2, known as coronavirus disease 2019, has resulted in a global pandemic. Reports are emerging of a new severe hyperinflammatory syndrome related to coronavirus disease 2019 in children and adolescents. The Centers for Disease Control and Prevention has designated this disease multisystem inflammatory syndrome in children. Our objective was to develop a clinical inpatient protocol for the evaluation, management, and follow-up of patients with this syndrome. DATA SOURCES: The protocol was developed by a multidisciplinary team based on relevant literature related to coronavirus disease 2019, multisystem inflammatory syndrome in children, and related inflammatory syndromes, as well as our experience caring for children with multisystem inflammatory syndrome in children. Data were obtained on patients with multisystem inflammatory syndrome in children at our institution from the pre-protocol and post-protocol periods. DATA SYNTHESIS: Our protocol was developed in order to identify cases of multisystem inflammatory syndrome in children with high sensitivity, stratify risk to guide treatment, recognize co-infectious or co-inflammatory processes, mitigate coronary artery abnormalities, and manage hyperinflammatory shock. Key elements of evaluation include case identification using broad clinical characteristics and comprehensive laboratory and imaging investigations. Treatment centers around glucocorticoids and IV immunoglobulin with biologic immunomodulators as adjuncts. Multidisciplinary follow-up after discharge is indicated to manage continued outpatient therapy and evaluate for disease sequelae. In nearly 2 months, we admitted 54 patients with multisystem inflammatory syndrome in children, all of whom survived without the need for invasive ventilatory or mechanical circulatory support. After institution of this protocol, patients received earlier treatment and had shorter lengths of hospital stay. CONCLUSIONS: This report provides guidance to clinicians on evaluation, management, and follow-up of patients with a novel hyperinflammatory syndrome related to coronavirus disease 2019 known as multisystem inflammatory syndrome in children. It is based on the relevant literature and our experience. Instituting such a protocol during a global pandemic is feasible and is associated with patients receiving treatment and returning home more quickly.

Neurological issues in children with COVID-19.

Coronavirus disease 2019 (COVID-19) usually leads to a mild infectious disease course in children, but serious complications may occur in conjunction with both acute infection and associated phenomena such as the multisystem inflammatory syndrome in children (MIS-C). Neurological symptoms, which have been predominantly reported in adults, range from mild headache to seizure, peripheral neuropathy, stroke, demyelinating disorders, and encephalopathy. Similar to respiratory and cardiac manifestations of COVID-19, neurological complications present differently based on age and underlying comorbidities. This review provides a concise overview of the neurological conditions seen in the context of COVID-19, as well as potential mechanisms and long-term implications of COVID-19 in the pediatric population from literature reviews and primary data collected at NewYork-Presbyterian Morgan Stanley Children's Hospital.

Implementation of a Formal Debriefing Program After Pediatric Rapid Response Team Activations.

BACKGROUND: Debriefing after pediatric rapid response team activations (RRT-As) in a tertiary care children's hospital was identified to occur only sporadically. The lack of routine debriefing after RRT-As was identified as a missed learning opportunity. OBJECTIVE: We implemented a formal debriefing program and assessed staff attitudes toward and experiences with debriefing after pediatric RRT-As. METHODS: Real-time feedback for pediatrics residents captured clinical and debriefing data for each RRT-A from July 2014 to June 2016. The debriefing on physiology, team communication, and anticipation of clinical deterioration was introduced in July 2015. To assess debriefing perceptions, residents, intensive care fellows, nurses, and respiratory therapists participated in anonymous preintervention and postintervention surveys. We also developed a workshop to teach residents how to lead debriefing. RESULTS: Debriefing after RRT-As increased from 26% preintervention to 46% postintervention (P < .0001). A total of 43 of 76 pediatrics residents (57%) attended at least 1 of 4 debriefing workshops. Both preintervention and postintervention, more than 80% (70 of 78 preintervention and 54 of 65 postintervention) of health professionals surveyed strongly agreed or agreed that there was a benefit to debriefing after RRT-As. Postintervention, 65% (26 of 40) of respondents strongly agreed or agreed that debriefing improved their understanding of the RRT-A process. The rate of debriefing was sustained at 46% (6 months after the end of the study period). CONCLUSIONS: Debriefing frequency after pediatric RRT-As significantly increased with the introduction of a formal debriefing program. A majority of health professionals and trainees reported this practice was a valuable experience.

Pediatric intermediate care and pediatric intensive care units: PICU metrics and an analysis of patients that use both.

PURPOSE: To examine how intermediate care units (IMCUs) are used in relation to pediatric intensive care units (PICUs), characterize PICU patients that utilize IMCUs, and estimate the impact of IMCUs on PICU metrics. MATERIALS & METHODS: Retrospective study of PICU patients discharged from 108 hospitals from 2009 to 2011. Patients admitted from or discharged to IMCUs were characterized. We explored the relationships between having an IMCU and several PICU metrics: physical length-of-stay (LOS), medical LOS, discharge wait time, admission severity of illness, unplanned PICU admissions from wards, and early PICU readmissions. RESULTS: Thirty-three percent of sites had an IMCU. After adjusting for known confounders, there was no association between having an IMCU and PICU LOS, mean severity of illness of PICU patients admitted from general wards, or proportion of PICU readmissions or unplanned ward admissions. At sites with an IMCU, patients waited 3.1h longer for transfer from the PICU once medically cleared (p<0.001). CONCLUSIONS: There was no association between having an IMCU and most measures of PICU efficiency. At hospitals with an IMCU, patients spent more time in the PICU once they were cleared for discharge. Other ways that IMCUs might affect PICU efficiency or particular patient populations should be investigated.

Tissue hypoxia correlates with intensity of interictal spikes.

Interictal spikes (IISs) represent burst firing of a small focal population of hypersynchronous, hyperexcitable cells. Whether cerebral blood flow (CBF) is adequate to meet the metabolic demands of this dramatic increase in membrane excitability is unknown. Positron emission tomography, single photon emission computed tomography, and functional magnetic resonance imaging studies have shown increases in CBF and hypometabolism, thus indicating the likelihood of adequate perfusion. We measured tissue oxygenation and CBF in a rat model of IIS using oxygen electrodes and laser-Doppler flowmetry. A ∼3-second dip in tissue oxygenation was shown, followed by more prolonged tissue hyperoxygenation, in spite of a 25% increase in CBF. Increases in the number of spikes, as well as in their amplitude and spike width further amplified these responses, and a decrease in interspike interval decreased the CBF response. Altering the anesthetic did not influence our results. Taken together, these findings indicate that frequent, high-amplitude IISs may produce significant tissue hypoxia, which has implications for patients with epilepsy and noninvasive techniques of seizure localization.

The importance of latency in the focality of perfusion and oxygenation changes associated with triggered afterdischarges in human cortex.

The spatiotemporal dynamics of neurovascular coupling during epilepsy are not well understood, and there are little data from studies of the human brain. We investigated changes in total hemoglobin (Hbt) and hemoglobin oxygenation in patients undergoing epilepsy surgery with intraoperative intrinsic optical spectroscopy (IOS) during triggered afterdischarges (ADs). We found an early (approximately 0.5 secs) focal dip in hemoglobin oxygenation, arising precisely in the stimulated gyrus that lasted for 11.5+/-10.0 secs, approximately the length of the AD (10.4+/-4.4 secs). A later oxygen overshoot and increase in blood volume occurred in the adjacent surrounding gyri. After a significant delay (approximately 20 to 30 secs), the overshoot and blood volume signal became extremely focal to the area of the onset of the AD. A smaller very late undershoot, the last phase of the 'triphasic' response, was also identified, although localization was inconsistent. In this study, we show that a 'late focal overshoot' and late Hbt signal may be extremely useful, in addition to the early dip, for the localization of seizure onset. It is likely that a separate mechanism underlies the persistent focal increase in cerebral blood volume after a long-duration cortical stimulation, compared with the nonspecific mechanism that causes the initial increase in cerebral blood flow.

Focal increases in perfusion and decreases in hemoglobin oxygenation precede seizure onset in spontaneous human epilepsy.

PURPOSE: Optical recording of intrinsic signals provides the highest combined spatial and temporal resolution with broad spatial sampling for measuring cerebral blood volume (CBV) and hemoglobin oxygenation in cerebral cortex. Few opportunities arise to apply this laboratory method to record spontaneous seizures in unanesthetized human brain during neurosurgery. We report such a rare opportunity in a man with recurrent focal epilepsy arising from a cavernous malformation. METHODS: We recorded intrinsic optical signals (IOS) from human cortex intraoperatively during spontaneous seizures arising from brain surrounding a small cavernous malformation in an awake patient using only local anesthesia with simultaneous electrocorticography. The IOS was recorded at two wavelengths, one an isosbestic point for hemoglobin to measure CBV (570 nm) and the other at a wavelength more sensitive to deoxygenated hemoglobin (Hbr) (610 nm). A modified Beer-Lambert calculation was used on two separate but similar seizures to approximate changes in Hbr, CBV as well as oxygenated hemoglobin (HbO(2)). RESULTS: Electrographically recorded seizures (n = 3) elicited a focal increase in both Hbr and CBV that lasted for the duration of the seizure, indicating that perfusion was inadequate to meet metabolic demand. Remarkably, these hemodynamic changes preceded the onset of the seizures by approximately 20 s and occurred focally over the known location of the lesion and the seizure onsets. DISCUSSION: These findings demonstrate that the hemoglobin becomes deoxygenated in spite of large increase in CBV during spontaneous human focal seizures and that optically recorded hemodynamic events can be used both to predict and localize human focal epilepsy. Such data may someday be useful to assist in the presurgical evaluation of patients considered for epilepsy surgery and to predict the timing and location of seizure onsets.