Whole-Body Hypothermia, Cerebral Magnetic Resonance Biomarkers, and Outcomes in Neonates With Moderate or Severe Hypoxic-Ischemic Encephalopathy Born at Tertiary Care Centers vs Other Facilities: A Nested Study Within a Randomized Clinical Trial.

Importance: The association between place of birth and hypothermic neuroprotection after hypoxic-ischemic encephalopathy (HIE) in low- and middle-income countries (LMICs) is unknown. Objective: To ascertain the association between place of birth and the efficacy of whole-body hypothermia for protection against brain injury measured by magnetic resonance (MR) biomarkers among neonates born at a tertiary care center (inborn) or other facilities (outborn). Design, Setting, and Participants: This nested cohort study within a randomized clinical trial involved neonates at 7 tertiary neonatal intensive care units in India, Sri Lanka, and Bangladesh between August 15, 2015, and February 15, 2019. A total of 408 neonates born at or after 36 weeks' gestation with moderate or severe HIE were randomized to receive whole-body hypothermia (reduction of rectal temperatures to between 33.0 °C and 34.0 °C; hypothermia group) for 72 hours or no whole-body hypothermia (rectal temperatures maintained between 36.0 °C and 37.0 °C; control group) within 6 hours of birth, with follow-up until September 27, 2020. Exposure: 3T MR imaging, MR spectroscopy, and diffusion tensor imaging. Main Outcomes and Measures: Thalamic N-acetyl aspartate (NAA) mmol/kg wet weight, thalamic lactate to NAA peak area ratios, brain injury scores, and white matter fractional anisotropy at 1 to 2 weeks and death or moderate or severe disability at 18 to 22 months. Results: Among 408 neonates, the mean (SD) gestational age was 38.7 (1.3) weeks; 267 (65.4%) were male. A total of 123 neonates were inborn and 285 were outborn. Inborn neonates were smaller (mean [SD], 2.8 [0.5] kg vs 2.9 [0.4] kg; P = .02), more likely to have instrumental or cesarean deliveries (43.1% vs 24.7%; P = .01), and more likely to be intubated at birth (78.9% vs 29.1%; P = .001) than outborn neonates, although the rate of severe HIE was not different (23.6% vs 17.9%; P = .22). Magnetic resonance data from 267 neonates (80 inborn and 187 outborn) were analyzed. In the hypothermia vs control groups, the mean (SD) thalamic NAA levels were 8.04 (1.98) vs 8.31 (1.13) among inborn neonates (odds ratio [OR], -0.28; 95% CI, -1.62 to 1.07; P = .68) and 8.03 (1.89) vs 7.99 (1.72) among outborn neonates (OR, 0.05; 95% CI, -0.62 to 0.71; P = .89); the median (IQR) thalamic lactate to NAA peak area ratios were 0.13 (0.10-0.20) vs 0.12 (0.09-0.18) among inborn neonates (OR, 1.02; 95% CI, 0.96-1.08; P = .59) and 0.14 (0.11-0.20) vs 0.14 (0.10-0.17) among outborn neonates (OR, 1.03; 95% CI, 0.98-1.09; P = .18). There was no difference in brain injury scores or white matter fractional anisotropy between the hypothermia and control groups among inborn or outborn neonates. Whole-body hypothermia was not associated with reductions in death or disability, either among 123 inborn neonates (hypothermia vs control group: 34 neonates [58.6%] vs 34 [56.7%]; risk ratio, 1.03; 95% CI, 0.76-1.41), or 285 outborn neonates (hypothermia vs control group: 64 neonates [46.7%] vs 60 [43.2%]; risk ratio, 1.08; 95% CI, 0.83-1.41). Conclusions and Relevance: In this nested cohort study, whole-body hypothermia was not associated with reductions in brain injury after HIE among neonates in South Asia, irrespective of place of birth. These findings do not support the use of whole-body hypothermia for HIE among neonates in LMICs. Trial Registration: ClinicalTrials.gov Identifier: NCT02387385.

Temperature difference between jugular bulb and pulmonary artery is associated with neurological outcome in patients with severe traumatic brain injury: A post hoc analysis of a brain hypothermia study.

BACKGROUND: The purpose of this study was to examine whether the temperature difference between the jugular bulb and pulmonary artery (ΔTjb-pa) is associated with the neurological outcome of patients with severe traumatic brain injury (TBI). METHODS: We conducted a post hoc analysis of a multicenter randomized controlled trial of mild therapeutic hypothermia (TH, 32.0-34.0°C) or fever control (FC, 35.5-37.0°C) for the patients with severe TBI. ΔTjb-pa averaged every 12 h and the variation in ΔTjb-pa were compared between patients with favorable (n = 39) and unfavorable (n = 37) neurological outcomes. These values were also compared in the TH and FC subgroups. RESULTS: The average ΔTjb-pa values in patients with favorable and unfavorable outcomes were 0.24 ± 0.23 and 0.06 ± 0.36°C, respectively (P < 0.001). ΔTjb-pa trended significantly higher in the favorable outcome patients than in the unfavorable outcome patients throughout the 120 h after onset of severe TBI (P < 0.001). The variation in ΔTjb-pa from 0 to 72 h was significantly lower in the favorable outcome patients than in the unfavorable outcome patients (0.8 ± 0.8 vs 1.8 ± 2.5°C, respectively, P = 0.013). From 72 to 120 h, there was no significant difference in the variation in ΔTjb-pa. Significant differences between patients with favorable and unfavorable outcomes in ΔTjb-pa and the variation in ΔTjb-pa were similar in the TH subgroup, but not evident in the FC subgroup. CONCLUSIONS: A reduction in ΔTjb-pa and greater variation in ΔTjb-pa were associated with an unfavorable outcome in patients with severe TBI, especially those treated with TH. When treating severe TBI patients, it is important to understand that there will be differences in temperature reflecting the brain environment and the systemic temperature, depending on the severity and outcome of TBI during TH.

Hypothermia for neuroprotection in adults after cardiac arrest.

BACKGROUND: Good neurological outcome after cardiac arrest is difficult to achieve. Interventions during the resuscitation phase and treatment within the first hours after the event are critical for a favourable prognosis. Experimental evidence suggests that therapeutic hypothermia is beneficial, and several clinical studies on this topic have been published. This review was originally published in 2009; updated versions were published in 2012 and 2016. OBJECTIVES: To evaluate the benefits and harms of therapeutic hypothermia after cardiac arrest in adults compared to standard treatment. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 30 September 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs in adults comparing therapeutic hypothermia after cardiac arrest with standard treatment (control). We included studies with adults cooled by any method, applied within six hours of cardiac arrest, to target body temperatures of 32 °C to 34 °C. Good neurological outcome was defined as no or only minor brain damage allowing people to live an independent life. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcome was 1. neurological recovery. Our secondary outcomes were 2. survival to hospital discharge, 3. quality of life, 4. cost-effectiveness and 5. ADVERSE EVENTS: We used GRADE to assess certainty. MAIN RESULTS: We found 12 studies with 3956 participants reporting the effects of therapeutic hypothermia on neurological outcome or survival. There were some concerns about the quality of all the studies, and two studies had high risk of bias overall. When we compared conventional cooling methods versus any type of standard treatment (including a body temperature of 36 °C), we found that participants in the therapeutic hypothermia group were more likely to reach a favourable neurological outcome (risk ratio (RR) 1.41, 95% confidence interval (CI) 1.12 to 1.76; 11 studies, 3914 participants). The certainty of the evidence was low. When we compared therapeutic hypothermia with fever prevention or no cooling, we found that participants in the therapeutic hypothermia group were more likely to reach a favourable neurological outcome (RR 1.60, 95% CI 1.15 to 2.23; 8 studies, 2870 participants). The certainty of the evidence was low. When we compared therapeutic hypothermia methods with temperature management at 36 °C, there was no evidence of a difference between groups (RR 1.78, 95% CI 0.70 to 4.53; 3 studies; 1044 participants). The certainty of the evidence was low. Across all studies, the incidence of pneumonia, hypokalaemia and severe arrhythmia was increased amongst participants receiving therapeutic hypothermia (pneumonia: RR 1.09, 95% CI 1.00 to 1.18; 4 trials, 3634 participants; hypokalaemia: RR 1.38, 95% CI 1.03 to 1.84; 2 trials, 975 participants; severe arrhythmia: RR 1.40, 95% CI 1.19 to 1.64; 3 trials, 2163 participants). The certainty of the evidence was low (pneumonia, severe arrhythmia) to very low (hypokalaemia). There were no differences in other reported adverse events between groups. AUTHORS' CONCLUSIONS: Current evidence suggests that conventional cooling methods to induce therapeutic hypothermia may improve neurological outcomes after cardiac arrest. We obtained available evidence from studies in which the target temperature was 32 °C to 34 °C.

Citicoline in hypoxic ischemic encephalopathy in neonates: a randomized controlled trial.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) is one of the major complications that can lead to death or disability in neonates. We assessed the effect of citicoline as a neuroprotector in neonates with moderate and severe HIE. METHODS: This clinical trial was carried on 80 neonates with moderate to severe HIE who were not candidates for therapeutic cooling. They were subdivided randomly into two groups; citicoline treatment group which included 40 neonates who received citicoline 10 mg / kg /12 h IV for 4 weeks plus other supportive measures and the control group which included 40 neonates who were managed with placebo and the same supportive measures. All patients were evaluated for duration of mechanical ventilation (MV), need for inotropes, seizures (type, frequency, and duration), and duration of NICU. Cranial ultrasounds and brain magnetic resonance image (MRI) were performed for all included neonates after 4 weeks of treatment. Follow- ups of all neonates for the neurodevelopmental outcomes were done at 3, 6, 9, and 12 months. RESULTS: There was a significant reduction in the number of neonates having seizures after discharge in the citicoline-treated group (2 neonates) compared to the control group (11 neonates). Cranial ultrasound and MRI findings at 4 weeks were significantly better in the treatment group compared to the control group. Moreover, neurodevelopmental outcome showed significant improvement at 9 and 12 months in the citicoline treated neonates compared to the control group. There was statistically significant reduction in the duration of seizures, NICU stay, inotrope use, and MV in the treatment group compared to the control group. Citicoline was well tolerated with no remarkable side effects. CONCLUSION: Citicoline could be a promising neuroprotector drug in neonates with HIE. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov (NCT03949049). Registered at 14 May 2019, https://clinicaltrials.gov/ct2/show/NCT03949049.

Effects of Therapeutic Hypothermia on Macrophages in Mouse Cochlea Explants.

Globally, over the next few decades, more than 2.5 billion people will suffer from hearing impairment, including profound hearing loss, and millions could potentially benefit from a cochlea implant. To date, several studies have focused on tissue trauma caused by cochlea implantation. The direct immune reaction in the inner ear after an implantation has not been well studied. Recently, therapeutic hypothermia has been found to positively influence the inflammatory reaction caused by electrode insertion trauma. The present study aimed to evaluate the hypothermic effect on the structure, numbers, function and reactivity of macrophages and microglial cells. Therefore, the distribution and activated forms of macrophages in the cochlea were evaluated in an electrode insertion trauma cochlea culture model in normothermic and mild hypothermic conditions. In 10-day-old mouse cochleae, artificial electrode insertion trauma was inflicted, and then they were cultured for 24 h at 37 °C and 32 °C. The influence of mild hypothermia on macrophages was evaluated using immunostaining of cryosections using antibodies against IBA1, F4/80, CD45 and CD163. A clear influence of mild hypothermia on the distribution of activated and non-activated forms of macrophages and monocytes in the inner ear was observed. Furthermore, these cells were located in the mesenchymal tissue in and around the cochlea, and the activated forms were found in and around the spiral ganglion tissue at 37 °C. Our findings suggest that mild hypothermic treatment has a beneficial effect on immune system activation after electrode insertion trauma.

Epicardial electrical heterogeneity after amiodarone treatment increases vulnerability to ventricular arrhythmias under therapeutic hypothermia.

BACKGROUND: Amiodarone is commonly used during therapeutic hypothermia (TH) following cardiac arrest due to ventricular arrhythmias. However, electrophysiological changes and proarrhythmic risk after amiodarone treatment have not yet been explored in TH. METHODS: Epicardial high-density bi-ventricular mapping was performed in pigs under baseline temperature (BT), TH (32-34°C), and amiodarone treatment during TH. The total activation time (TAT), conduction velocity (CV), local electrogram (LE) duration, and wavefront propagation from pre-specified segments were analyzed during sinus rhythm (SR) or right ventricular (RV) pacing (RVP), along with tissue expression of connexin 43. The vulnerability to ventricular arrhythmias was assessed. RESULTS: Compared to BT, TH increased the global TAT, decreased the CV, and generated heterogeneous electrical substrate during SR and RVP. During TH, the CV reduction and LE duration prolongation were greater in the anterior mid RV than in the other areas, which changed the wavefront propagation in all animals. Compared to TH alone, amiodarone treatment during TH further increased the TAT and LE duration and decreased the CV. Heterogeneous conduction was partially attenuated after amiodarone treatment. After TH and amiodarone treatment, the connexin 43 expression in the anterior mid RV was lower than that in the other areas, compatible with the heterogeneous CV reduction. The animals under TH and amiodarone treatment had a higher incidence of inducible ventricular arrhythmias than those under BT or TH without amiodarone. CONCLUSION: Electrical heterogeneity during amiodarone treatment and TH was associated with vulnerability to ventricular arrhythmias.

Population Pharmacokinetics and Dosing Optimization of Ceftazidime in Term Asphyxiated Neonates during Controlled Therapeutic Hypothermia.

Ceftazidime is an antibiotic commonly used to treat bacterial infections in term neonates undergoing controlled therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy after perinatal asphyxia. We aimed to describe the population pharmacokinetics (PK) of ceftazidime in asphyxiated neonates during hypothermia, rewarming, and normothermia and propose a population-based rational dosing regimen with optimal PK/pharmacodynamic (PD) target attainment. Data were collected in the PharmaCool prospective observational multicenter study. A population PK model was constructed, and the probability of target attainment (PTA) was assessed during all phases of controlled TH using targets of 100% of the time that the concentration in the blood exceeds the MIC (T>MIC) (for efficacy purposes and 100% T>4×MIC and 100% T>5×MIC to prevent resistance). A total of 35 patients with 338 ceftazidime concentrations were included. An allometrically scaled one-compartment model with postnatal age and body temperature as covariates on clearance was constructed. For a typical patient receiving the current dose of 100 mg/kg of body weight/day in 2 doses and assuming a worst-case MIC of 8 mg/L for Pseudomonas aeruginosa, the PTA was 99.7% for 100% T>MIC during hypothermia (33.7°C; postnatal age [PNA] of 2 days). The PTA decreased to 87.7% for 100% T>MIC during normothermia (36.7°C; PNA of 5 days). Therefore, a dosing regimen of 100 mg/kg/day in 2 doses during hypothermia and rewarming and 150 mg/kg/day in 3 doses during the following normothermic phase is advised. Higher-dosing regimens (150 mg/kg/day in 3 doses during hypothermia and 200 mg/kg/day in 4 doses during normothermia) could be considered when achievements of 100% T>4×MIC and 100% T>5×MIC are desired.

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OBJECTIVES: To investigate the clinical efficacy of mild therapeutic hypothermia (MTH) with different rewarming time on neonatal hypoxic-ischemic encephalopathy (HIE). METHODS: A prospective study was performed on 101 neonates with HIE who were born and received MTH in Zhongshan Hospital, Xiamen University, from January 2018 to January 2022. These neonates were randomly divided into two groups: MTH1 group (n=50; rewarming for 10 hours at a rate of 0.25°C/h) and MTH2 group (n=51; rewarming for 25 hours at a rate of 0.10°C/h). The clinical features and the clinical efficacy were compared between the two groups. A binary logistic regression analysis was used to identify the factors influencing the occurrence of normal sleep-wake cycle (SWC) on amplitude-integrated electroencephalogram (aEEG) at 25 hours of rewarming. RESULTS: There were no significant differences between the MTH1 and MTH2 groups in gestational age, 5-minute Apgar score, and proportion of neonates with moderate/severe HIE (P>0.05). Compared with the MTH2 group, the MTH1 group tended to have a normal arterial blood pH value at the end of rewarming, a significantly shorter duration of oxygen dependence, a significantly higher proportion of neonates with normal SWC on aEEG at 10 and 25 hours of rewarming, and a significantly higher Neonatal Behavioral Neurological Assessment score on days 5, 12, and 28 after birth (P<0.05), while there was no significant difference in the incidence rate of rewarming-related seizures between the two groups (P>0.05). There were no significant differences between the two groups in the incidence rate of neurological disability at 6 months of age and the score of Bayley Scale of Infant Development at 3 and 6 months of age (P>0.05). The binary logistic regression analysis showed that prolonged rewarming time (25 hours) was not conducive to the occurrence of normal SWC (OR=3.423, 95%CI: 1.237-9.469, P=0.018). CONCLUSIONS: Rewarming for 10 hours has a better short-term clinical efficacy than rewarming for 25 hours. Prolonging rewarming time has limited clinical benefits on neonates with moderate/severe HIE and is not conducive to the occurrence of normal SWC, and therefore, it is not recommended as a routine treatment method.

Adrenal congestion in perinatal hypoxia: Sonographic assessment and relationship with hypoxic ischemic encephalopathy.

BACKGROUND: During hypoxia, blood flow to the brain, myocardium, and adrenal glands is preserved or even increased to maintain homeostasis. Adrenal congestion occurs when venous return remains insufficient. Several different ultrasound measurements of adrenal glands in neonates have been reported in the literature. However, there is no data related on adrenal gland size in neonates with perinatal hypoxia. AIMS: To evaluate the adrenal congestion using by ultrasound (US) measurements in perinatal hypoxia, and to reveal the relationship of adrenal congestion with hypoxic-ischemic encephalopathy (HIE) grades and magnetic resonance imaging (MRI) findings. STUDY DESIGN: Prospective cohort study. SUBJECTS: Infants with perinatal hypoxia who met therapeutic hypothermia criteria and were being cooled were included in the present study. The control group was established from healthy neonates admitted to our center during the recruitment. OUTCOME MEASURES: The gland area was measured by tracing, and both the corpus and crura widths were measured. RESULTS: We reported adrenal gland area data of 110 newborns with HIE and compared them with 56 normal neonates. The adrenal size was significantly higher in the HIE group than in the control group (p<0,01). The frequency of adrenal congestion was 72.7% based on the selected cut-off values. The adrenal gland measurements were increased in the patients with perinatal hypoxia than those of the controls. CONCLUSIONS: In the systemic evaluation of newborns with perinatal hypoxia, additional care should be taken regarding adrenal congestion. The measurement of adrenal size with 2D US will help us to diagnose or confirm adrenal congestion and possible hemorrhagic changes. The morphological data and cut-off values given in our study will be useful for neonatologists and pediatric radiologists to evaluate the patient while managing perinatal hypoxia.

Multi-organ dysfunction in infants with acidosis at birth in the absence of moderate to severe hypoxic ischemic encephalopathy.

INTRODUCTION: Infants with perinatal asphyxia are at risk for organ failure aside from the brain, regardless of the severity of the asphyxial insult. We aimed to evaluate the presence of organ dysfunction other than the brain in newborns with moderate to severe acidosis at birth, in the absence of moderate to severe hypoxic ischemic encephalopathy. MATERIALS AND METHODS: Data of 2 years were retrospectively recorded. Late preterm and term infants admitted to the intensive care unit with ph < 7.10 and BE < -12 mmol/l in the first hour were included in the absence of moderate to severe hypoxic ischemic encephalopathy. Respiratory dysfunction, hepatic dysfunction, renal dysfunction, myocardial depression, gastrointestinal problems, hematologic system dysfunction, and circulatory failure were evaluated. RESULTS: Sixty-five infants were included [39 (37-40) weeks, 3040 (2655-3380) grams]. Fifty-six (86 %) infants had one or more dysfunction in any system [respiratory: 76.9 %, hepatic: 20.0 %, coagulation: 18.5 %, renal: 9.2 %, hematologic: 7.7 %, gastrointestinal: 3.0 %, and cardiac: 3.0 %]. Twenty infants had at least two affected systems. The incidence of coagulation dysfunctions was higher in the infants with severe acidosis (n = 25, ph < 7.00) than the infants with moderate acidosis (n = 40: pH = 7.00-7.10); 32 % vs 10 %; p = 0.03. CONCLUSIONS: Moderate to severe fetal acidosis is associated with the development of extra-cranial organ dysfunctions in infants who do not require therapeutic hypothermia. A monitoring protocol is needed for infants with mild asphyxia in order to identify and manage potential complications. Coagulation system should be carefully evaluated.

Long-term consequences of neonatal encephalopathy in the hypothermia era: protocol for a follow-up cohort study at 9 years of age.

INTRODUCTION: Therapeutic hypothermia (TH) became the standard of care treatment for neonates with moderate and severe neonatal encephalopathy (NE) in most industrialized countries about 10 years ago. Although TH is effective in reducing mortality and the incidence of severe developmental disabilities, the recent literature converges in reporting frequent cognitive and behavioural difficulties at school entry in children with NE-TH. Although these challenges are deemed minor compared with cerebral palsy and intellectual disability, their impacts on a child's self-determination and family's well-being are quite significant. Therefore, the nature and extent of these difficulties need to be comprehensively described so that appropriate care can be offered. METHODS AND ANALYSIS: The current study will be the largest follow-up study of neonates with NE treated with TH to characterize their developmental outcomes and associated brain structural profiles at 9 years of age. Specifically, we will compare executive function, attention, social cognition, behaviour, anxiety, self-esteem, peer problems, brain volume, cortical features, white matter microstructure and myelination between children with NE-TH and matched peers without NE. Associations of perinatal risk factors and structural brain integrity with cognitive, behavioural and psycho-emotional deficits will be evaluated to inform about the potential aggravating and protective factors associated with function. ETHICS AND DISSEMINATION: This study is supported by the Canadian Institute of Health Research (202203PJT-480065-CHI-CFAC-168509), and received approval from the Pediatric Ethical Review Board of the McGill University Health Center (MP-37-2023-9320). The study findings will be disseminated in scientific journals and conferences and presented to parental associations and healthcare providers to inform best practices. TRIAL REGISTRATION NUMBER: NCT05756296.

Minimal added value of wetting hair before scalp cooling to prevent chemotherapy-induced alopecia in cancer patients - results from the Dutch Scalp Cooling Registry.

PURPOSE: Preventing chemotherapy-induced alopecia (CIA) is related to the degree of temperature reduction during scalp cooling. Wetting hair before scalp cooling reduces the scalp skin temperature. This observational study investigated the effects of wetting hair before scalp cooling on preventing CIA and on tolerance in cancer patients. METHODS: This Dutch multi-center cohort study comprised 1825 patients receiving ≥1 cycle of docetaxel (D), 5-fluorouracil-epirubicin-cyclophosphamide (FEC), 5-fluorouracil-epirubicin-cyclophosphamide-docetaxel (FECD), paclitaxel (P), or paclitaxel-carboplatin (PC). Patients underwent scalp cooling with wet or dry hair. Primary and secondary outcomes were the effects of wetting hair on head cover use and tolerance, respectively. RESULTS: None of the associations between wetting hair and head cover use in patients on D, FEC, P, or PC was significant; however, results all tended to be in favor of wetting hair. For FECD, univariate (p=0.005; OR=1.6; CI=1.1-2.1) and multivariable associations (p=0.007; OR=1.8; CI=1.2-2.6) were significant. Scalp cooling discontinuation due to intolerance differed significantly between groups that wetted hair or not (3% and 1% respectively; p=0.034). CONCLUSION: In a large patient group with mainly a European hair type and a high hair mass, no convincing evidence was found whether wetting hair prior to scalp cooling contributes to better prevention of CIA. Since it is argued that a higher reduction in scalp skin temperature by wetting hair contributes positively to scalp cooling efficacy, only a randomized controlled trial can provide an ultimate conclusion at the highest level of evidence. Until that time, healthcare professionals have to take into account that wetting hair may introduce lower compliance to the scalp cooling procedure.

Achieving Mild Therapeutic Hypothermia in the Human Cochlea.

OBJECTIVE: To determine temperature and duration of cooling necessary for achieving cochlear mild therapeutic hypothermia (MTH) via ear canal cooling using cool water and earmold attached to a Peltier device. STUDY DESIGN AND SETTING: Human temporal bone lab study performed at the University of Mississippi Medical Center. INTERVENTIONS: Cochlear cooling via the ear canal using water irrigation and an earmold attached to a Peltier device. Temperature analysis through implanted thermal probes within the cochlea. MAIN OUTCOME MEASURES: Temperature changes in the cochlea. RESULTS: Irrigation of the ear canal with water resulted in achieving MTH in approximately 4 minutes using cool water (30°C) and in approximately 2 minutes using ice-chilled water. After 20 minutes, irrigation of the ear canal using cool water plateaued at a ∆2°C while cooling with ice-chilled water results in an average ∆4.5°C. We observed MTH using a medium-length earmold attached to a Peltier device after approximately 22 minutes of cooling and achieved a maximal average ∆ of 2.3°C after 60 minutes of cooling. Finally, we observed that a longer earmold (C2L) with greater proximity to the eardrum resulted in more efficient intracochlear temperature change, achieving MTH in approximately 16 minutes. CONCLUSIONS: MTH of the cochlea can be achieved with water-based ear canal irrigation and via a Peltier device connected to an aluminum earmold.

Novel serum biomarkers for predicting neurological outcomes in postcardiac arrest patients treated with targeted temperature management.

OBJECTIVE: To determine the clinical feasibility of novel serum biomarkers in out-of-hospital cardiac arrest (OHCA) patients treated with target temperature management (TTM). METHODS: This study was a prospective observational study conducted on OHCA patients who underwent TTM. We measured conventional biomarkers, neuron­specific enolase and S100 calcium-binding protein (S-100B), as well as novel biomarkers, including tau protein, neurofilament light chain (NFL), glial fibrillary acidic protein (GFAP), and ubiquitin C-terminal hydrolase-L1 (UCH-L1), at 0, 24, 48, and 72 h after the return of spontaneous circulation identified by SIMOA immunoassay. The primary outcome was poor neurological outcome at 6 months after OHCA. RESULTS: A total of 100 patients were included in this study from August 2018 to May 2020. Among the included patients, 46 patients had good neurologic outcomes at 6 months after OHCA. All conventional and novel serum biomarkers had the ability to discriminate between the good and poor neurological outcome groups (p < 0.001). The area under the curves of the novel serum biomarkers were highest at 72 h after cardiac arrest (CA) (0.906 for Tau, 0.946 for NFL, 0.875 for GFAP, and 0.935 for UCH-L1). The NFL at 72 h after CA had the highest sensitivity (77.1%, 95% CI 59.9-89.6) in predicting poor neurological outcomes while maintaining 100% specificity. CONCLUSION: Novel serum biomarkers reliably predicted poor neurological outcomes for patients with OHCA treated with TTM when life-sustaining therapy was not withdrawn. Cutoffs from two large existing studies (TTM and COMACARE substudy) were externally validated in our study. The predictive power of the novel biomarkers was the highest at 72 h after CA.

Temperature Control After Cardiac Arrest: A Narrative Review.

Cardiac arrest (CA) is a critical public health issue affecting more than half a million Americans annually. The main determinant of outcome post-CA is hypoxic-ischemic brain injury (HIBI), and temperature control is currently the only evidence-based, guideline-recommended intervention targeting secondary brain injury. Temperature control is a key component of a post-CA care bundle; however, conflicting evidence challenges its wide implementation across the vastly heterogeneous population of CA survivors. Here, we critically appraise the available literature on temperature control in HIBI, detail how the evidence has been integrated into clinical practice, and highlight the complications associated with its use and the timing of neuroprognostication after CA. Future clinical trials evaluating different temperature targets, rates of rewarming, duration of cooling, and identifying which patient phenotype benefits from different temperature control methods are needed to address these prevailing knowledge gaps.