Prehospital lactate levels in blood as a seizure biomarker: A multi-center observational study.

OBJECTIVE: The objective of this study was to assess the value of prehospital measurement of lactate level in blood for diagnosis of seizures in cases of transient loss of consciousness. METHODS: Between March 2018 and September 2019, prehospital lactate was measured with a point-of-care device by the emergency medical services in an area serving a population of 900 000. A total of 383 cases of transient loss of consciousness were identified and categorized as tonic-clonic seizure (TCS), other seizure, syncope, or other cause, according to the final diagnosis in the electronic medical records system. Receiver operating characteristic curve analyses were used to identify the optimal lactate cut-off. RESULTS: A total of 383 cases were included (135 TCS, 42 other seizure, 163 syncope, and 43 other causes). The median lactate level in TCS was 7.0 mmol/L, compared to a median of 2.0 mmol/L in all other cases (P < .001). The area under the curve (AUC) of TCS vs nonepileptic causes was 0.87 (95% confidence interval [CI] 0.83-0.91). The optimal cut-off (Youden index, 67.8%) was 4.75 mmol/L, with 79% sensitivity (95% CI 71-85) and 89% specificity (95% CI 85-93) for TCS. SIGNIFICANCE: Prehospital lactate can be a valuable tool for identifying seizures in transient loss of consciousness. For acceptable specificity, a higher cut-off than that previously demonstrated for hospital-based measurements must be used when values obtained close to the time of the event are interpreted.

Plasma fluoroacetic acid concentrations: Symptoms, hematological, and biochemical characteristics in patients with fluoroacetic acid poisoning in the emergency department.

Fluoroacetic acid (FAcOH) was once a highly toxic rodenticide widely used in the world. In the past, studies on the toxicity of FAcOH have focused on animal experiments. The toxicity of FAcOH to humans and the changes of FAcOH in plasma have not been studied. Therefore, the present study aimed to describe the changes of plasma FAcOH concentrations, hematological, and biochemical characteristics in patients with FAcOH intoxication. According to clinical symptoms, 68 patients from the emergency department were divided into different groups: convulsion group, unconsciousness group, death group, and control groups. Plasma FAcOH concentrations, hematological, and biochemical parameters were investigated. Results demonstrated that patients in the convulsion group and the unconsciousness group had a significant increase (p < 0.01) in the level of neuron-specific enolase (NSE), creatine kinase MB (CKMB), glucose (GLU), and white blood cell count (WBC) and a significant decrease (p < 0.01) in serum potassium compared with the control group, respectively. Moreover, patients in the death group had a significant increase (p < 0.01) in the level of NSE, CKMB, N-terminal pro-brain natriuretic peptide, GLU, and WBC and a significant decrease (p < 0.01) in serum potassium and total calcium compared with the survival group. The concentrations of FAcOH in plasma in the convulsion group, the unconsciousness group, and the death group were 72.31 ± 42.29, 118.33 ± 55.41, and 163.78 ± 43.32 µg/mL, respectively. These changes and the plasma FAcOH concentrations may increase our understanding of the toxicity of FAcOH to humans and may help doctors to judge the clinical prognosis of patients with FAcOH intoxication.

Mild traumatic brain injuries with loss of consciousness are associated with increased inflammation and pain in military personnel.

Mild traumatic brain injuries (mTBI) are a pervasive concern for military personnel. Determining the impact of injury severity, including loss of consciousness (LOC) may provide important insights into the risk of psychological symptoms and inflammation commonly witnessed in military personnel and veterans following mTBI. US military personnel and veterans were categorized into three groups; TBI with LOC (n = 36), TBI without LOC (n = 25), Controls (n = 82). Participants reported their history of mTBI, psychological symptoms (post-traumatic stress disorder [PTSD] and depression), health-related quality of life (HRQOL), and underwent a blood draw. ANCOVA models which controlled for insomnia status and combat exposure indicated that both mTBI groups (with/without LOC) reported significantly greater depression and PTSD symptoms compared to controls; however, they did not differ from each other. The mTBI with LOC did report greater pain than both controls and mTBI without LOC. The TBI with LOC group also had significantly elevated IL-6 concentrations than both TBI without LOC and control groups. Within the mTBI groups, increased TNFα concentrations were associated with greater PTSD symptoms. These findings indicate that sustaining an mTBI, with or without LOC is detrimental for psychological wellbeing. However, LOC may be involved in perceptions of pain and concentrations of IL-6.

[Laboratory diagnostics in transient loss of consciousness : Serum lactate compared to serum creatine kinase as diagnostic indicator for generalized tonic-clonic seizures]. / Labordiagnostik bei transienten Bewusstseinsstörungen : Serumlaktatwert im Vergleich zur Serumkreatinkinase als diagnostischer Indikator für generalisierte tonisch-klonische Anfälle.

BACKGROUND: Laboratory parameters can help in the differential diagnostics of acute episodes of transient loss of consciousness. Especially serum lactate and serum creatine kinase (CK) levels may provide valuable hints to distinguish generalized tonic-clonic seizures (GTCS) from syncope. MATERIAL AND METHODS: Serum lactate levels at admission and CK levels 10-48 h after the episodes that led to admission were compared between patients with GTCS (n = 30) and those with syncope (n = 15). In addition, sensitivity and specificity of lactate and CK as diagnostic markers for syncope and GTCS were determined. RESULTS: The serum lactate and serum CK levels were significantly increased in patients with GTCS as compared to syncope patients (serum lactate: p < 0.001; CK: p < 0.005). The area under the curve (AUC) for serum lactate as an indicator for GTCS was 0.94 (95% confidence interval [CI] 0.88-1.0). For CK the receiver operating characteristics (ROC) analysis produced an AUC of only 0.77 (95% CI: 0.63-0.9). CONCLUSION: The determination of the lactate value as point-of-care diagnostics appears to be highly relevant in the rapid clarification of unclear episodes with transient loss of consciousness. The CK level at follow-up is also suitable for distinguishing GTCS from syncope but is inferior to the serum lactate value.

Alpha-1-antitrypsin: a novel predictor for long-term recovery of chronic disorder of consciousness.

BACKGROUND: The aim of this manuscript was to explore the molecular basis and identify novel biomarkers for the diagnosis and prognosis of patients with chronic disorder of consciousness. METHODS: A coupled isobaric tag for relative and absolute quantitation-based approach was used to screen differentially expressed proteins (DEPs) between patients with chronic disorder of consciousness and healthy individuals. Candidate proteins were identified and measured. The Coma Recovery Scale-Revised (CRS-R) score was used to quantify the severity, and long-term recovery was assessed by Glasgow Outcome Scale (GOS). RESULTS: Between patients and controls, a total of 77 DEPs were identified. Based on the DEPs, a network containing 50 nodes and 207 edges was built, and alpha-1-antitrypsin was marked as the hub protein. The results indicated that alpha-1-antitrypsin correlated with the CRS-R score with a correlation coefficient of 0.631, and an outcome at 12 months (8.5 ± 2.1 ng/ml in patients with GOS 1-2 vs. 6.8 ± 1.6 ng/ml in those with GOS 3-5, p = 0.002). CONCLUSIONS: The data confirm the diagnostic and prognostic potential of alpha-1-antitrypsin in chronic disorder of consciousness, which may contribute to the development of novel therapeutic agents.

Emergency department blood alcohol level associates with injury factors and six-month outcome after uncomplicated mild traumatic brain injury.

The relationship between blood alcohol level (BAL) and mild traumatic brain injury (mTBI) remains in need of improved characterization. Adult patients suffering mTBI without intracranial pathology on computed tomography (CT) from the prospective Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot study with emergency department (ED) Glasgow Coma Scale (GCS) 13-15 and recorded blood alcohol level (BAL) were extracted. BAL≥80-mg/dl was set as proxy for excessive use. Multivariable regression was performed for patients with six-month Glasgow Outcome Scale-Extended (GOSE; functional recovery) and Wechsler Adult Intelligence Scale Processing Speed Index Composite Score (WAIS-PSI; nonverbal processing speed), using BAL≥80-mg/dl and <80-mg/dl cohorts, adjusting for demographic/injury factors. Overall, 107 patients were aged 42.7±16.8-years, 67.3%-male, and 80.4%-Caucasian; 65.4% had BAL=0-mg/dl, 4.6% BAL<80-mg/dl, and 30.0% BAL≥80-mg/dl (range 100-440-mg/dl). BAL differed across loss of consciousness (LOC; none: median 0-mg/dl [interquartile range (IQR) 0-0], <30-min: 0-mg/dl [0-43], ≥30-min: 224-mg/dl [50-269], unknown: 108-mg/dl [0-232]; p=0.002). GCS<15 associated with higher BAL (19-mg/dl [0-204] vs. 0-mg/dl [0-20]; p=0.013). On univariate analysis, BAL≥80-mg/dl associated with less-than-full functional recovery (GOSE≤7; 38.1% vs. 11.5%; p=0.025) and lower WAIS-PSI (92.4±12.7, 30th-percentile vs. 105.1±11.7, 63rd-percentile; p<0.001). On multivariable regression BAL≥80-mg/dl demonstrated an odds ratio of 8.05 (95% CI [1.35-47.92]; p=0.022) for GOSE≤7 and an adjusted mean decrease of 8.88-points (95% CI [0.67-17.09]; p=0.035) on WAIS-PSI. Day-of-injury BAL>80-mg/dl after uncomplicated mTBI was associated with decreased GCS score and prolongation of reported LOC. BAL may be a biomarker for impaired return to baseline function and decreased nonverbal processing speed at six-months postinjury. Future confirmatory studies are needed.

Lactate as a diagnostic marker in transient loss of consciousness.

PURPOSE: The diagnostic classification of disorders of consciousness is often challenging, particularly the distinction between epileptic and non-epileptic seizures. The aim of the study was to examine serum lactate as a diagnostic marker of transient loss of consciousness. METHOD: Serum lactate levels in blood samples drawn within 2h of the event were compared retrospectively between patients with generalized tonic-clonic seizures (n=195) and patients with other seizures (syncopes [n=52], psychogenic non-epileptic seizures [n=17], and complex focal seizures [n=37]), respectively. RESULTS: Serum lactate in patients with generalized tonic-clonic seizures was significantly (p<0.001, Mann-Whitney-U test) increased in comparison to other forms of seizure incidences. The area under the ROC-curve was 0.94 (95% CI 0.91-0.96). For a cut-off concentration of 2.45mmol/l, the sensitivity was 0.88 and the specificity 0.87. CONCLUSIONS: Serum lactate levels in the acute diagnosis were an excellent biomarker for the discrimination of generalized seizures from psychogenic non-epileptic and syncopal events, corroborating its importance for the standard work-up of acute disturbances of consciousness.

Race-Specific Pharmacodynamic Model of Propofol-Induced Loss of Consciousness.

We present a race-specific model of propofol-induced loss of consciousness that is based on pharmacodynamic data collected and adapted from the peer-reviewed literature. In the proposed race-specific model that includes EC05 and EC95 concentrations, the median (EC50) (and where available 95%CI) propofol concentrations at the effect site compartment for propofol-induced loss of consciousness for whites, Chinese, blacks, and Indians are 2.8 (2.7-2.9), 2.2 (2.2-2.3), 2.0, and 1.9 µg/mL, respectively.

Attenuation of high-frequency (50-200 Hz) thalamocortical EEG rhythms by propofol in rats is more pronounced for the thalamus than for the cortex.

BACKGROUND: Thalamocortical EEG rhythms in gamma (30-80 Hz) and high-gamma (80-200 Hz) ranges have been linked to arousal and conscious processes. To test the hypothesis that general anesthetics attenuate these rhythms, we characterized the concentration-effect relationship of propofol on the spectral power of these rhythms. In view of the ongoing debate about cortex versus thalamus as the primary site of anesthetic action for unconsciousness, we also compared the relative sensitivity of cortex and thalamus to this effect propofol. METHODS: Adult male Long-Evans rats were chronically implanted with electrodes in somatosensory (barrel) cortex and ventroposteromedial thalamus. Propofol was delivered by a computer-controlled infusion using real-time pharmacokinetic modeling to obtain the desired plasma concentration. Spectral power was assessed during baseline, at four stable propofol plasma-concentrations (0, 3,6,9,12 µg/ml) and during recovery over four frequency ranges (30-50, 51-75, 76-125, 126-200 Hz). Unconsciousness was defined as complete loss of righting reflex. Multiple regression was used to model the change of power (after logarithmic transformation) as a function of propofol concentration and recording site. RESULTS: Unconsciousness occurred at the 9 µg/ml concentration in all animals. Propofol caused a robust linear concentration-dependent attenuation of cortical power in the 76-200 Hz range and of thalamic power in the 30-200 Hz range. In all instances the concentration-effect slope for the thalamus was markedly steeper than for the cortex. Furthermore the lowest concentration causing unconsciousness significantly reduced cortical power in the 126-200 Hz range and thalamic power in the 30-200 Hz range. CONCLUSIONS: Propofol causes a concentration-dependent attenuation of the power of thalamocortical rhythms in the 30-200 Hz range and this effect is far more pronounced for the thalamus, where the attenuation provides a robust correlate of the hypnotic action of propofol [corrected].

Profound hypoglycemia-induced by vaccinium corymbosum juice and laurocerasus fruit.

An emergency intervention was performed in a 75-year-old male patient with hypoglycemic attack and blackout. Although he was diagnosed with prediabetes before 2 years, he did not take any anti-diabetic drug or follow dietary advice. He drank Vaccinium corymbosum L (VC) juice daily with a belief that it increases sexual potency. Before the development of hypoglycemia, the patient had consumed about 500 ml VC juice in addition to eating 200-300 gram of Laurocerasus officinalis (LO) fruit. The measured plasma glucose (PG) level during loss of consciousness was 30 mg/dl. The profound hypoglycemia may be an unexpected side effect of an interaction between the chemical compositions of the two plants, occurred as a result of LO fruit intake that may have a strong PG-lowering effect or related to excessive intake of VC juice. Both plants may be considered in the alternative treatment of diabetes.

Effect of hepatic function on the EC50 of midazolam and the BIS50 at the time of loss of consciousness.

OBJECTIVE: To explore the effect of hepatic function on loss of consciousness (LOC) and bispectral index (BIS) during sedation with midazolam (MDZ). METHODS: Forty-five patients were assigned to three groups according to their liver function. Thirty of these patients with diagnoses of cholelithiasis were scheduled laparoscopic cholecystectomy, including 15 patients with normal liver function (normal group), and 15 patients with moderately abnormal liver function based on the results of ultrasonic diagnosis of a moderately fatty liver and elevated alanine transaminase levels of less than three times normal (moderate group). The other 15 patients with end-stage liver disease (severe group) underwent liver transplantation. Each patient was administered MDZ by way of target-controlled infusion to increase the concentration gradually. At the time of LOC, the BIS was recorded and a blood sample was withdrawn for measurement of the concentration of MDZ. The concentration of MDZ (EC50) and the BIS value (BIS50) at which 50% of patients lose consciousness were calculated using logistic regression. RESULTS: At the time of LOC, the EC50 of MDZ and the BIS50 were similar in the normal and moderate groups (P>0.05). LOC occurred at a lower EC50 of MDZ and at a higher BIS50 in the severe group, compared with the normal and moderate groups (P<0.01). CONCLUSIONS: Patients with end-stage liver disease were more sensitive to MDZ and this affected the prediction of their time of LOC following MDZ administration. There were no changes in response in patients with moderately abnormal hepatic function.

The prognostic significance of the serum biomarker heart-fatty acidic binding protein in comparison with s100b in severe traumatic brain injury.

The outcome after severe traumatic brain injury (TBI) is largely unfavorable, with approximately two thirds of patients suffering from severe disabilities or dying during the first 6 months. Existing predictive models displayed only limited utility for outcome prediction in individual patients. Time courses of heart-fatty acidic binding protein (H-FABP) and their association with outcome were investigated and compared with S100b. Forty-nine consecutive patients with severe TBI (sTBI; Head component of the Abbreviated Injury Scale [HAIS] >3) with mono and multiple trauma were enrolled in this study. Enzyme-linked immunosorbent assay measured blood concentrations of H-FABP and S100b at 6, 12, 24, and 48 h after TBI. Outcome measures were conscious state at 14 days (Glasgow Coma Scale), disability (Glasgow Outcome Scale Extended; GOSE), and mortality at 3 months. Univariate logistic regression analysis and receiver operating characteristic curves analysis were carried out. Maximal H-FABP and S100b concentrations were observed at 6 h after TBI (34.4±34.0 and 0.64±0.99 ng/mL, respectively). Patients with multi-trauma had significantly higher H-FABP concentrations at 24 and 48 h (22.6±25.6 and 12.4±18.2 ng/mL, respectively), compared to patients with mono trauma (6.9±5.1 and 3.7±4.2 ng/mL, respectively). In the first 48 h, H-FABP and S100b were inversely correlated with the GOSE at 3 months; H-FABP at 48 h predicted mortality with 75% sensitivity and 93% specificity. Early blood levels of H-FABP after sTBI have prognostic significance for survival and disability.

Combining nitrous oxide with carbon dioxide decreases the time to loss of consciousness during euthanasia in mice--refinement of animal welfare?

Carbon dioxide (CO(2)) is the most commonly used euthanasia agent for rodents despite potentially causing pain and distress. Nitrous oxide is used in man to speed induction of anaesthesia with volatile anaesthetics, via a mechanism referred to as the "second gas" effect. We therefore evaluated the addition of Nitrous Oxide (N(2)O) to a rising CO(2) concentration could be used as a welfare refinement of the euthanasia process in mice, by shortening the duration of conscious exposure to CO2. Firstly, to assess the effect of N(2)O on the induction of anaesthesia in mice, 12 female C57Bl/6 mice were anaesthetized in a crossover protocol with the following combinations: Isoflurane (5%)+O(2) (95%); Isoflurane (5%)+N(2)O (75%)+O(2) (25%) and N(2)O (75%)+O(2) (25%) with a total flow rate of 3 l/min (into a 7 l induction chamber). The addition of N(2)O to isoflurane reduced the time to loss of the righting reflex by 17.6%. Secondly, 18 C57Bl/6 and 18 CD1 mice were individually euthanized by gradually filling the induction chamber with either: CO(2) (20% of the chamber volume.min-1); CO(2)+N(2)O (20 and 60% of the chamber volume.min(-1) respectively); or CO(2)+Nitrogen (N(2)) (20 and 60% of the chamber volume.min-1). Arterial partial pressure (P(a)) of O(2) and CO(2) were measured as well as blood pH and lactate. When compared to the gradually rising CO(2) euthanasia, addition of a high concentration of N(2)O to CO(2) lowered the time to loss of righting reflex by 10.3% (P<0.001), lead to a lower P(a)O(2) (12.55 ± 3.67 mmHg, P<0.001), a higher lactataemia (4.64 ± 1.04 mmol.l(-1), P = 0.026), without any behaviour indicative of distress. Nitrous oxide reduces the time of conscious exposure to gradually rising CO(2) during euthanasia and hence may reduce the duration of any stress or distress to which mice are exposed during euthanasia.

Bi-spectral index, entropy and predicted plasma propofol concentrations with target controlled infusions in Indian patients.

OBJECTIVE: Many processed electroencephalographic signals are used now to help the anaesthesiologist titrate the depth of sedation. We investigated the relationship between target plasma propofol concentration and objective end-points of sedation- Bispectral Index (BIS), State Entropy (SE) and Response Entropy (RE)-at clinical end-points as assessed by Modified Observer Assessment of Alertness/sedation Scale (MOAAS) in Indian patients. METHODS: Eighteen ASA 1 and 2 Indian adult patients scheduled to undergo elective surgery were included. The target control infusion (TCI) of propofol was administered using 'Diprifusor'. The level of sedation was assessed using MOAAS by the anaesthesiologist. BIS, SE, RE were recorded throughout. TCI was started at 0.5 µg/ml and increased by 0.5 µg/ml every 6 min till MOAAS scores reached 0 or there was sustained BIS value less than 30. RESULTS: The EC(50) and EC(95) of predicted plasma propofol concentration for loss of consciousness (assessed by loss of response to verbal command), were 2.3 and 2.8 µg/ml respectively and for loss of response to painful stimuli (trapezius squeeze) were 4.0 and 5.0 µg/ml respectively. The BIS and entropy values (EC(50) and EC(95)) for loss of consciousness and response to painful stimuli in Indian patients were estimated. The preliminary relation of target plasma propofol concentration with BIS was found to be BIS = 100.5-16.4 × (Target concentration). CONCLUSIONS: The target plasma propofol concentrations required to produce unconsciousness and loss of response to painful stimuli in Indian patients have been estimated. Also, the relations between target plasma concentration and objective measures of different levels of anaesthesia have been established.

Carbon monoxide poisoning in the United Arab Emirates.

Carbon monoxide (CO) poisoning is rare in the Arabian Peninsula and occurs almost exclusively during the winter months. Knowledge and perception of the hazards of carbon monoxide is limited. Migrant workers from warm climates appear particularly at risk. We investigated 46 cases of carbon monoxide poisoning presenting at emergency departments from 2007-2009 of the two main hospitals in Al Ain city, United Arab Emirates. Interviews, hospital records, and administered questionnaires were used to collect the data. Among the 46 cases investigated, 24 (52%) were males. Foreign nationals compromised 80% of the cases and the incidence was 3.1 cases per 100,000 residents per year. Burning charcoal in poorly ventilated residences was the predominant source of the carbon monoxide poisoning. Almost all cases (98%) were admitted during the winter months, most in the early morning hours. Carboxyhaemoglobin (COHb) was significantly increased in cases with loss of consciousness and depressed consciousness. There were no reported fatalities.

[Plasma catecholamines in consciousness recovery in patients with severe traumatic brain injury].

Changes in plasma noradrenalin (NA) and dopamine (DA) levels were evaluated in the stages of consciousness recovery in patients with severe traumatic brain injury with and without deep brain structure damage. Forty-eight patients (36 men and 12 women), aged from 12 to 56 (31,9±10,9) yeas, were enrolled in the study. Two variants of catecholamine (CA) changes were found: 1) a CA-dissociation that was oppositely directed to NA and DA changes was observed in unconsciousness; 2) a CA-dissociation (unidirectional NA and DA changes) that was observed after the restoration of consciousness. In patients with the damage of two frontal lobes and deep brain structures, CA-association periods were seen in the stage of mental confusion with psychomotor agitation or when the brain stem was damaged. The duration of CA-association was negatively correlated with the velocity, quality of consciousness recovery and outcomes evaluated by the Glasgow scale.