Induction Of Mild Hypothermia Research Articles

Abstract TMP111: Selective Activation of Peritoneal TRPV1-Containing Vagal Afferents Promotes Sustained Mild Hypothermia and Neuroprotection Following Stroke

Intro: Mild hypothermia has been clinically effective at improving outcomes in cardiac arrest patients for decades. Similarly, mild hypothermia has been shown to neuroprotective in experimental stroke models. Unfortunately, hypothermia protocols in awake subjects are hampered by inconsistent temperature management due to incomplete suppression of cold defense mechanisms (e.g. shiver response). To address a need for better strategies for cooling conscious subjects, we sought to promote mild hypothermia by pharmacological activation of heat-sensing nerve fibers in the thermoregulatory system. We hypothesize that selective activation of TRPV1-containing vagal afferents in the peritoneal cavity can promote sustained hypothermia and protection following stroke. Methods: Aged (18-20 mo) and young (11 weeks) C57BL6 mice of both sexes were given a capsinoid mixture consisting of capsiate and dihydrocapsiate. Mice from both the aged and young cohorts underwent permanent distal middle cerebral artery occlusion (pdMCAO) or sham before recovering for 2hrs in warming cages to maintain normal body temperatures during post-stroke recovery. At 2 hours after stroke, mice were given capsinoids or vehicle (4 IP injections, 90 min interval) to produce 6 hours of mild hypothermia (or normothermic control). After 3 days brains were collected for histological analysis. Results: Capsinoids are particularly suited for region selective activation of TRPV1 targets, as they are degraded by ubiquitous esterases, and thus limited in biodistribution to distant targets. This regionally restricted activation was demonstrated through induction of mild hypothermia with IP capsinoid administration, but not with oral or subcutaneous delivery. We demonstrated that the hypothermic effect is TRPV1 dependent and that IP capsinoid delivery increases activity of the cervical vagus (hook electrode). We applied this capsinoid-mediated hypothermia approach to the pdMCAO model and demonstrated a significant reduction of brain infarct at 3 days post-stroke in both young and aged mice of both sexes. Conclusion: Selective activation of TRPV1-containing peritoneal vagal afferents is sufficient to promote sustained mild hypothermia and protection following ischemic stroke.

OGT upregulates myogenic IL-6 by mediating O-GlcNAcylation of p65 in mouse skeletal muscle under cold exposure.

Cold exposure is an unavoidable and severe challenge for people and animals residing in cold regions of the world, and may lead to hypothermia, drastic changes in systemic metabolism, and inhibition of protein synthesis. O-linked-N-acetylglucoseaminylation (O-GlcNAcylation) directly regulates the activity and function of target proteins involved in multiple biological processes by acting as a stress receptor and nutrient sensor. Therefore, our study aimed to examine whether O-GlcNAcylation affected myogenic IL-6 expression, regulation of energy metabolism, and promotion of survival in mouse skeletal muscle under acute cold exposure conditions. Total protein was extracted from C2C12 cells that had been cultured at 32°C for 3, 6, 9, and 12 h. Western blot analysis showed that mild hypothermia enhanced O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) expression. Furthermore, global OGT-dependent glycosylation and interleukin-6 (IL-6) levels peaked 3 h after induction of mild hypothermia. Enhanced activation of the NF-κB pathway was also observed in response to mild hypothermia. Alloxan and Thiamet G were used to reduce and increase global OGT glycosylation levels in C2C12 cells, respectively. Increased O-GlcNAcylation was associated with significant upregulation of IL-6 expression, as well as enhanced activity and nuclear translocation of p65, while decreased O-GlcNAcylation had the opposite effect. In addition, increased O-GlcNAcylation was associated with significantly increased glucose metabolism, and OGT-mediated O-GlcNAcylation of p65. We generated skeletal muscle-specific OGT knockout mice and exposed them to cold at 4°C for 3 h per day for 1 week. OGT deficiency attenuated the O-GlcNAcylation, activity, and nuclear translocation of p65, resulting in downregulation of IL-6 in mouse skeletal muscle of mice exposed to cold conditions. Taken together, our data suggested that O-GlcNAcylation of p65 enhanced p65 activity and nuclear translocation leading to the upregulation of IL-6, which maintained energy homeostasis and promotes cell survival in mouse skeletal muscle during cold exposure.

Effect of mild hypothermia on behaviors of rats with intracerebral hemorrhage and the possible mechanism

To explore the effect of mild hypothermia on inflammatory response and angiogenesis in brain tissues of rats with intracerebral hemorrhage (ICH) and its possible mechanism for improving behavioral deficits of the rats After ICH. A total of 120 healthy male SD rats were randomly divided into sham operation group, ICH group and mild hypothermia group. Rat models of ICH were established in the latter two groups by stereotactic injection of autogenous blood in the brain, and the rats in the sham operation group received injection of normal saline in the same manner. At 15 min after modeling, the rats in hypothermia group were subjected to mild hypothermia (30-32 ℃) for 8 h followed by rewarming (37-38 ℃); the body temperature was maintained at 37-38 ℃ in the other two groups. At 2, 4, 7, 14 and 21 days after the treatment, Longa scoring, balance beam scoring and Berderson scoring were used to evaluate the behavioral deficits of the rats. Immunohistochemical staining was used to detect the protein expressions of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the brain tissue of the rats, and the mRNA expressions of α subunit of hypoxia-inducible factor 1 (HIF1-α) and vascular endothelial growth factor (VEGF) were detected using RT- PCR. At 2, 4, 7, 14 and 21 days after the treatment, the behavioral scores of the rats were significantly higher in ICH group and mild induced hypothermia group than in the sham operation group (P < 0.05 or 0.01). The protein expressions of TNF-α and NF-κB and mRNA expressions of HIF1-α and VEGF were significantly higher in ICH group and mild hypothermia group than in the sham operation group (P < 0.01). The behavioral scores were significantly lower in mild hypothermia group than in ICH group (P < 0.05), and the protein expressions of TNF-α and NF-κB were lower and the mRNA expressions of HIF1- α and VEGF were higher in mild hypothermia group than in ICH group (P < 0.05 or 0.01). Mild hypothermia can improve behavioral deficits in rats with ICH possibly by antagonizing brain inflammation and promoting angiogenesis.

Effect of hypothermia on haemostasis and bleeding risk: a narrative review.

It must be remembered that clinically important haemostasis occurs in vivo and not in a tube, and that variables such as the number of bleeding events and bleeding volume are more robust measures of bleeding risk than the results of analyses.In this narrative review, we highlight trauma, surgery, and mild induced hypothermia as three clinically important situations in which the effects of hypothermia on haemostasis are important. In observational studies of trauma, hypothermia (body temperature <35°C) has demonstrated an association with mortality and morbidity, perhaps owing to its effect on haemostatic functions. Randomised trials have shown that hypothermia causes increased bleeding during surgery. Although causality between hypothermia and bleeding risk has not been well established, there is a clear association between hypothermia and negative outcomes in connection with trauma, surgery, and accidental hypothermia; thus, it is crucial to rewarm patients in these clinical situations without delay. Mild induced hypothermia to ≥33°C for 24 hours does not seem to be associated with either decreased total haemostasis or increased bleeding risk.

Targeted Temperature Management; Review of Literature and Guidelines; A Cardiologist's Perspective.

Background:Out of Hospital Cardiac Arrest (OHCA) remains not an uncommon occurrence in USA and the rest of the world. However, the survival to discharge following an episode of OHCA in adults is still very disappointing at around 10%. Several areas of improvement including education of general public in early Cardio Pulmonary Resuscitation (CPR) by bystander, chest compression first, and improvement of Emergency Medical response time have had a positive effect on the outcomes and survival but still much needs to be done. Recently, new data has emerged with regards to post resuscitation care and mild induced hypothermia (now preferably called; Targeted Temperature Management {TTM}) and several advances have been made.Conclusion:The purpose of this review is to summarize and compare the most recent guidelines and also provide a practical approach to TTM especially with regards to the field of cardiology.

Comparison of Electronic Learning Versus Lecture-based Learning in Improving Emergency Medicine Residents' Knowledge About Mild Induced Hypothermia After Cardiac Arrest.

BackgroundThe process of medical education depends on several issues such as training materials, students, professors, educational fields, and the applied technologies. The current study aimed at comparing the impacts of e-learning and lecture-based learning of mild induced hypothermia (MIH) after cardiac arrest on the increase of knowledge among emergency medicine residents.MethodsIn a pre- and post-intervention study, MIH after cardiac arrest was taught to 44 emergency medicine residents. Residents were randomly divided into 2 groups. The first group included 21 participants (lecture-based learning) and the second had 23 participants (e-learning). A 19-item questionnaire with approved validity and reliability was employed as the pretest and posttest. Then, data were analyzed with SPSS software version 17.0.ResultsThere was no statistically significant difference in terms of the learning method between the test scores of the 2 groups (P = 0.977).ConclusionsE-learning and lecture-based learning methods was effective in augmentation of residents of emergency medicine knowledge about MIH after cardiac arrest; nevertheless, there was no significant difference between these mentioned methods.

Effect of Adipose-Derived Mesenchymal Stem Cell Administration and Mild Hypothermia Induction on Delayed Neuronal Death After Transient Global Cerebral Ischemia

Global cerebral ischemia is a cause of poor prognosis after resuscitation from cardiac arrest. Various attempts have been made to minimize global cerebral ischemia but none been more effective than mild hypothermia induction. A few studies have shown the effect of mesenchymal stem cells on global cerebral ischemia, but no studies have compared this effect with mild hypothermia or assessed any possible interaction. We aimed to show the effect of mesenchymal stem cells on delayed neuronal death after global cerebral ischemia and to compare this effect with mild hypothermia. Experimental study. Animal research laboratory. Adult male Sprague-Dawley rats weighing 250-300 g. Rats were subjected to 7 minutes of transient global cerebral ischemia and randomized into four groups: control, mild hypothermia, injection of human adipose-derived mesenchymal stem cells, and combined application of mild hypothermia and mesenchymal stem cells, along with four sham groups treated identically. Rats were euthanized 7 days after global cerebral ischemia. Degree of neuronal death in hippocampus was significantly higher in control than in other groups. The number of activated microglia was higher in control group than in other groups and was higher in mild hypothermia than shams, mesenchymal stem cells, mild hypothermia/mesenchymal stem cells. Degree of blood-brain barrier disruption and the count of infiltrated neutrophils were significantly higher in control than in other groups. Degree of oxidative injury was significantly higher in control than other groups. It was higher in mild hypothermia than sham groups, mesenchymal stem cells, mild hypothermia/mesenchymal stem cells and was higher in mesenchymal stem cells group than sham groups. Significantly, worse functional results were found in control than in other groups. Administration of mesenchymal stem cells after transient global cerebral ischemia has a prominent protective effect on delayed neuron death, even compared with mild hypothermia.

Model-based investigation of intracellular processes determining antibody Fc-glycosylation under mild hypothermia.

ABSTRACTDespite the positive effects of mild hypothermic conditions on monoclonal antibody (mAb) productivity (q mAb) during mammalian cell culture, the impact of reduced culture temperature on mAb Fc‐glycosylation and the mechanism behind changes in the glycan composition are not fully established. The lack of knowledge about the regulation of dynamic intracellular processes under mild hypothermia restricts bioprocess optimization. To address this issue, a mathematical model that quantitatively describes Chinese hamster ovary (CHO) cell behavior and metabolism, mAb synthesis and mAb N‐linked glycosylation profile before and after the induction of mild hypothermia is constructed. Results from this study show that the model is capable of representing experimental results well in all of the aspects mentioned above, including the N‐linked glycosylation profile of mAb produced under mild hypothermia. Most importantly, comparison between model simulation results for different culture temperatures suggests the reduced rates of nucleotide sugar donor production and galactosyltransferase (GalT) expression to be critical contributing factors that determine the variation in Fc‐glycan profiles between physiological and mild hypothermic conditions in stable CHO transfectants. This is then confirmed using experimental measurements of GalT expression levels, thereby closing the loop between the experimental and the computational system. The identification of bottlenecks within CHO cell metabolism under mild hypothermic conditions will aid bioprocess optimization, for example, by tailoring feeding strategies to improve NSD production, or manipulating the expression of specific glycosyltransferases through cell line engineering. Biotechnol. Bioeng. 2017;114: 1570–1582. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals Inc.

Protective effect of mild-induced hypothermia against moderate traumatic brain injury in rats involved in necroptotic and apoptotic pathways

ABSTRACTAim: To investigate the protective effect of hypothermia (HT) on brain injury in moderate traumatic brain injury (TBI) rat models and the potential mechanisms, especially the involvement of RIPK1 in apoptosis and necroptosis.Methods: Adult Sprague-Dawley rats were randomized to four groups: sham+normothermia (sham+NT), sham+hypothermia (sham+HT), moderate TBI+normothermia (TBI+NT) and moderate TBI+hypothermia (TBI+HT). The sham+HT and TBI+HT groups were submitted to 32°C for 6 hours. The regional cerebral blood flow (rCBF) was assessed 24 hours after TBI; 24 and 48 hours after TBI, the modified neurological severity score (mNSS) was assessed. Immediately after behavioural tests, rats were sacrificed to harvest the brain tissues.Results: mNSS scores were lower in the TBI+HT group compared with the TBI+NT group (p < 0.01) and cerebral blood flow was better (p < 0.01). H&E staining of the cortex and ipsilateral hippocampus showed pyknotic and irregularly shaped neurons in TBI+NT rats, which were less frequent in TBI+HT rats. The TBI+NT and TBI+HT groups showed higher TNF-α, TRAIL, FasL, FADD, caspase-3, caspase-8, PARP-1, RIPK-1 and RIPK-3 levels than the sham+NT group (all p < 0.05), but the levels of these proteins were all lower in the TBI+HT group compared with the TBI+NT group (all p < 0.01).Conclusion: HT treatment significantly reduced RIPK-1 upregulation, which may inhibit necroptosis and apoptosis pathways after moderate TBI.

Mild induced hypothermia for patients with severe traumatic brain injury after decompressive craniectomy

PurposeTo evaluate the efficacy and safety of mild induced hypothermia for intracranial hypertension in patients with traumatic brain injury after decompressive craniectomy. MethodsA total of 60 adults with intracranial pressure (ICP) of more than 20 mm Hg after decompressive craniectomy were randomly assigned to standard care (control group) or hypothermia (32°C-35°C) plus standard care. Then, ICP, cerebral perfusion pressure, Glasgow Outcome Scale score, and complications were assessed. ResultsThere was a significant difference in ICP and cerebral perfusion pressure between the 2 groups. Favorable outcomes occurred in 12 (40.0%) and 7 (36.5%) patients in the hypothermia and control groups, respectively (P=.267). Kaplan-Meier curves revealed a marked difference in survival between the hypothermia and control groups (P=.032). There were significant differences in pulmonary infection and electrolyte disorders between the hypothermia and control groups (P=.038 and .033, respectively). ConclusionMild induced hypothermia can reduce intracranial hypertension after decompressive craniectomy, decreasing patient mortality. Hypothermia should be considered one of the main treatments for intracranial hypertension after decompressive craniectomy in patients with traumatic brain injury.

Optimal control of inspired perfluorocarbon temperature for induction of hypothermia by total liquid ventilation in juvenile lamb model.

Mild hypothermia is well known for its therapeutic value in cardio- and neuroprotection. Many recent experimental studies have shown that the swiftness of the cooling offered by total liquid ventilation (TLV) holds great promise in achieving maximal therapeutic effect. TLV is an emerging ventilation technique in which the lungs are filled with breathable liquids, namely perfluorocarbons (PFCs). A liquid ventilator ensures subject ventilation by periodically renewing a volume of oxygenated, CO2-free and temperature-controlled breathable PFC. The substantial difference between breathing air and liquid is related to the fact that PFCs have over 500 times the volumetric thermal capacity of air 100% relative humidity. The PFC-filled lungs thus turn into an efficient heat exchanger with pulmonary circulation. The objective of the present study was to compute a posteriori the optimal inspired PFC temperature for ultrafast induction of mild hypothermia by TLV in a juvenile lamb experimentation using direct optimal control. The continuous time model and the discretized cycle-by-cycle model are presented. The control objectives of the direct optimal control are also presented and the results are compared with experimental data in order to validate the improved control performances. The computed direct optimal control showed that the inspired PFC temperature command can be improved to avoid temperature undershoots without altering the cooling performances.

Neuroprotective effects of bloodletting at Jing points combined with mild induced hypothermia in acute severe traumatic brain injury.

Bloodletting at Jing points has been used to treat coma in traditional Chinese medicine. Mild induced hypothermia has also been shown to have neuroprotective effects. However, the therapeutic effects of bloodletting at Jing points and mild induced hypothermia alone are limited. Therefore, we investigated whether combined treatment might have clinical effectiveness for the treatment of acute severe traumatic brain injury. Using a rat model of traumatic brain injury, combined treatment substantially alleviated cerebral edema and blood-brain barrier dysfunction. Furthermore, neurological function was ameliorated, and cellular necrosis and the inflammatory response were lessened. These findings suggest that the combined effects of bloodletting at Jing points (20 μL, twice a day, for 2 days) and mild induced hypothermia (6 hours) are better than their individual effects alone. Their combined application may have marked neuroprotective effects in the clinical treatment of acute severe traumatic brain injury.

Temperature Management After Cardiac Arrest: An Advisory Statement by the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation and the American Heart Association Emergency Cardiovascular Care Committee and the Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation.

For more than a decade, mild induced hypothermia (32 °C-34 °C) has been standard of care for patients remaining comatose after resuscitation from out-of-hospital cardiac arrest with an initial shockable rhythm, and this has been extrapolated to survivors of cardiac arrest with initially nonshockable rhythms and to patients with in-hospital cardiac arrest. Two randomized trials published in 2002 reported a survival and neurological benefit with mild induced hypothermia. One recent randomized trial reported similar outcomes in patients treated with targeted temperature management at either 33 °C or 36 °C. In response to these new data, the International Liaison Committee on Resuscitation Advanced Life Support Task Force performed a systematic review to evaluate 3 key questions: (1) Should mild induced hypothermia (or some form of targeted temperature management) be used in comatose post-cardiac arrest patients? (2) If used, what is the ideal timing of the intervention? (3) If used, what is the ideal duration of the intervention? The task force used Grading of Recommendations Assessment, Development and Evaluation methodology to assess and summarize the evidence and to provide a consensus on science statement and treatment recommendations. The task force recommends targeted temperature management for adults with out-of-hospital cardiac arrest with an initial shockable rhythm at a constant temperature between 32 °C and 36 °C for at least 24 hours. Similar suggestions are made for out-of-hospital cardiac arrest with a nonshockable rhythm and in-hospital cardiac arrest. The task force recommends against prehospital cooling with rapid infusion of large volumes of cold intravenous fluid. Additional and specific recommendations are provided in the document.

Association of gender to outcome after out-of-hospital cardiac arrest--a report from the International Cardiac Arrest Registry.

IntroductionPrevious studies have suggested an effect of gender on outcome after out-of-hospital cardiac arrest (OHCA), but the results are conflicting. We aimed to investigate the association of gender to outcome, coronary angiography (CAG) and adverse events in OHCA survivors treated with mild induced hypothermia (MIH).MethodsWe performed a retrospective analysis of prospectively collected data from the International Cardiac Arrest Registry. Adult patients with a non-traumatic OHCA and treated with MIH were included. Good neurological outcome was defined as a cerebral performance category (CPC) of 1 or 2.ResultsA total of 1,667 patients, 472 women (28%) and 1,195 men (72%), met the inclusion criteria. Men were more likely to receive bystander cardiopulmonary resuscitation, have an initial shockable rhythm and to have a presumed cardiac cause of arrest. At hospital discharge, men had a higher survival rate (52% vs. 38%, P <0.001) and more often a good neurological outcome (43% vs. 32%, P <0.001) in the univariate analysis. When adjusting for baseline characteristics, male gender was associated with improved survival (OR 1.34, 95% CI 1.01 to 1.78) but no longer with neurological outcome (OR 1.24, 95% CI 0.92 to 1.67). Adverse events were common; women more often had hypokalemia, hypomagnesemia and bleeding requiring transfusion, while men had more pneumonia. In a subgroup analysis of patients with a presumed cardiac cause of arrest (n = 1,361), men more often had CAG performed on admission (58% vs. 50%, P = 0.02) but this discrepancy disappeared in an adjusted analysis.ConclusionsGender differences exist regarding cause of arrest, adverse events and outcome. Male gender was independently associated with survival but not with neurological outcome.

The effect of mild induced hypothermia on outcomes of patients after cardiac arrest: a systematic review and meta-analysis of randomised controlled trials.

IntroductionMild induced hypothermia (MIH) is believed to reduce mortality and neurological impairment after out-of-hospital cardiac arrest. However, a recently published trial demonstrated that hypothermia at 33 °C did not confer a benefit compared with that of 36 °C. Thus, a systematic review and meta-analysis of randomised controlled trials (RCTs) was made to investigate the impact of MIH compared to controls on the outcomes of adult patients after cardiac arrest.MethodsWe searched the following electronic databases: PubMed/MEDLINE, the Cochrane Library, Embase, the Web of Science, and Elsevier Science (inception to December 2014). RCTs that compared MIH with controls with temperature >34 °C in adult patients after cardiac arrest were retrieved. Two investigators independently selected RCTs and completed an assessment of the quality of the studies. Data were analysed by the methods recommended by the Cochrane Collaboration. Random errors were evaluated with trial sequential analysis.ResultsSix RCTs, including one abstract, were included. The meta-analysis of included trials revealed that MIH did not significantly decrease the mortality at hospital discharge (risk ratio (RR) = 0.92; 95 % confidence interval (CI), 0.82–1.04; p = 0.17) or at 6 months or 180 days (RR = 0.94; 95 % CI, 0.73–1.21; p = 0.64), but it did reduce the mortality of patients with shockable rhythms at hospital discharge (RR = 0.74; 95 % CI, 0.59–0.92; p = 0.008) and at 6 months or 180 days. However, MIH can improve the outcome of neurological function at hospital discharge (RR = 0.80; 95 % CI, 0.64–0.98; p = 0.04) especially in those patients with shockable rhythm but not at 6 months or 180 days. Moreover, the incidence of complications in the MIH group was significantly higher than that in the control group. Finally, trial sequential analysis indicated lack of firm evidence for a beneficial effect.ConclusionThe available RCTs suggest that MIH does not appear to improve the mortality of patients with cardiac arrest while it may have a beneficial effect for patients with shockable rhythms. Although MIH may result in some adverse events, it helped lead to better outcomes regarding neurological function at hospital discharge. Large-scale ongoing trials may provide data better applicable to clinical practice.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-1133-0) contains supplementary material, which is available to authorized users.

Temperature Management After Cardiac Arrest: An Advisory Statement by the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation and the American Heart Association Emergency Cardiovascular Care Committee and the Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation

For more than a decade, mild induced hypothermia (32°C–34°C) has been standard of care for patients remaining comatose after resuscitation from out-of-hospital cardiac arrest with an initial shockable rhythm, and this has been extrapolated to survivors of cardiac arrest with initially nonshockable rhythms and to patients with in-hospital cardiac arrest. Two randomized trials published in 2002 reported a survival and neurological benefit with mild induced hypothermia. One recent randomized trial reported similar outcomes in patients treated with targeted temperature management at either 33°C or 36°C. In response to these new data, the International Liaison Committee on Resuscitation Advanced Life Support Task Force performed a systematic review to evaluate 3 key questions: (1) Should mild induced hypothermia (or some form of targeted temperature management) be used in comatose post–cardiac arrest patients? (2) If used, what is the ideal timing of the intervention? (3) If used, what is the ideal duration of the intervention? The task force used Grading of Recommendations Assessment, Development and Evaluation methodology to assess and summarize the evidence and to provide a consensus on science statement and treatment recommendations. The task force recommends targeted temperature management for adults with out-of-hospital cardiac arrest with an initial shockable rhythm at a constant temperature between 32°C and 36°C for at least 24hours. Similar suggestions are made for out-of-hospital cardiac arrest with a nonshockable rhythm and in-hospital cardiac arrest. The task force recommends against prehospital cooling with rapid infusion of large volumes of cold intravenous fluid. Additional and specific recommendations are provided in the document.

Effect of mild hypothermia on gastrointestinal motility after traumatic brain injury: an experimental study

Objective To investigate the effect of mild hypothermia on gastrointestinal motility after traumatic brain injury (TBI). Methods A total of 75 adult male SD rats were randomly divided into a sham operation (Sham) group, a traumatic brain injury (TBI) group, and a mild hypothermia (MIH) group according to a random number table. A rat model of TBI was induced by using the electric cortical contusion impactor (eCCI), and then the mild hypothermia intervened for 4 h. The changes of gastric motility, gastric emptying rate, and intestinal propulsive rate in each group were detected. After the animals were sacrificed, the brain, stomach, ileocecal junction, and small intestine tissue 15 cm from ileocecal junction were obtained respectively. HE staining was used to observe its pathological changes. Results After TBI in rats, the stomach obviously dilated, the stomach wall became thinner, gastric mucosa was congested and edematous, part of the mucosa had epithelial shedding, there was bleeding in submucosa, there was lumen expansion and flatulence, intestinal mucosa had hemorrhage and necrosis, intestinal villi desquamated, there was neutrophil infiltration, the gaps of intestinal villi increased, and Goblet cells decreased. The blood vessel count of gastric mucosal congestion and the numbers of intestinal mucosa villi fracture showed that there was no significant difference between the 6 h TBI group and the MIH group (P>0.05). Compared with the TBI group, there were significant differences in the 24, 48 and 72 h MIH groups (P 0.05); the value of gastric motor amplitude of the TBI and MIT groups was higher than that of the sham group (P 0.05). Compared with the TBI group, there were significant differences among the 24, 48 and 72 h MIH groups (P<0.05). Conclusions TBI had effect on rat gastrointestinal mucosa and gastrointestinal motility. The short-term effect after MIH intervention was not significant, but the long-term efficacy was remarkable. Key words: Traumatic brain injury; Gastrointestinal motility disturbances; Mild-induced hypothermia

Mild induced hypothermia after return of spontaneous circulation.

There is evidence to suggest that the use of mild induced hypothermia (MIH) in patients who have had cardiac arrest can improve neurological prognosis and long-term survival to discharge rates, although there is some debate in the literature on the efficacy of the procedure. This article reviews the literature on MIH with the aim of increasing emergency nurses' awareness, knowledge and understanding of the evidence for the procedure.

Difference Between Bladder and Esophageal Temperatures in Mild Induced Hypothermia

BackgroundMild induced hypothermia is an established treatment strategy for comatose survivors of cardiac arrest. The goal of the induction phase of mild induced hypothermia is to cool the patient's core body temperature to 32°–34°C. ObjectiveThe main goal of this study was to compare temperature changes measured in the esophagus and urinary bladder in survivors of cardiac arrest undergoing mild induced hypothermia using cold saline infusion. MethodsWe performed a prospective study in a 12-bed adult medical intensive care unit at a tertiary level hospital in comatose adult survivors of nontraumatic cardiac arrest admitted from January to April 2012. Paired temperature readings from bladder and esophageal probes were recorded every 5 min for 95 min (20 readings). Cold fluid infusion was terminated when the measured temperature from either of the probes reached 33.9°C. Factorial repeated-measures analysis of variance was used to determine the effect of time and site of measurement on temperature readings. ResultsMeasurements were performed in 8 patients. Target temperature was achieved in 33 ± 15 min in the esophagus and in 63 ± 15 min in the bladder (p = 0.006). We discovered a significant interaction effect (p < 0.001) between time and site of measurement, indicating that temperature changes differently depending on the site of measurement, with esophageal temperatures decreasing faster than temperatures measured in urinary bladder. ConclusionsOur results indicate that esophageal temperature measurements show a faster response rate compared to temperature measured in the bladder when cold saline infusion is used to induce mild hypothermia.

High resolution ECG-aided early prognostic model for comatose survivors of out of hospital cardiac arrest

Out of hospital cardiac arrest (OHCA) has a high mortality despite modern treatment. Reliable early prognosis in OHCA could significantly improve clinical decision making. We explored prognostic utility of advanced ECG parameters, obtained from high-resolution ECG, in combination with clinical and OHCA-related parameters during treatment with mild induced hypothermia (MIH) and after rewarming in unconscious survivors of OHCA. Ninety-two patients during MIH and 66 after rewarming were included. During MIH, a score based on initial rhythm, QRS-upslope and systolic pressure resulted in an area under curve (AUC) of 0.82 and accuracy of 80% for survival. After rewarming, a score based on admission rhythm, sum of 12 lead QRS voltages, and mean lateral ST segment level in leads I and V6 resulted in an AUC of 0.88 and accuracy of 85% for survival. ECG can assist with early prognostication in unconscious survivors of OHCA during MIH and after rewarming.