Clinical application of multidisciplinary team-and evidence-based practice project in gynecological patients with perioperative hypothermia

BACKGROUND Perioperative hypothermia(PH)negatively affects the physical and mental health of patients to varying degrees.Currently,there is no effective multidisciplinary team(MDT)intervention for gynecological patients with PH.AIM To apply the best evidence on the prevention and management of PH in gynecological patients,improve the quality of perioperative evidence-based care based on treatment by an MDT for gynecological patients and analyze the effect of MDT-and evidence-based practice(EBP)projects on the psychological status and cognitive function of gynecological patients with PH.METHODS Under the guidance of knowledge translation and combined with the opinions of involved stakeholders and clinical experts,the best evidence for PH prevention and management in gynecological patients was selected and adjusted to suit the practice setting.Based on the evidence,the practice plan was developed,and the MDT intervention was carried out in the preoperative ward,the preoperative preparation room,the intraoperative operating room,the postanesthesia care unit,and the 24-hour postoperative gynecological ward through the EBP program.The incidence of hypothermia,the nurses’awareness,the implementation rate of examination indicators,and the thermal comfort level,psychological status and cognitive function of patients were compared before and after the implementation of the program.RESULTS The incidence of PH in gynecological patients decreased from 43.33%to 13.33%after the implementation of the scheme.The implementation rate of examination indicators 6-10,12,14,16-18,21,and 22 reached 100%,and that of other indicators was above 90%,except for examination indicators 5 and 13,which was 66.67%;the indices were significantly improved compared with the baseline(before evidence application)(P<0.05).The score of nurses'awareness of PH prevention and management in gynecological patients increased from 60.96±9.70 to 88.08±8.96,and the difference was statistically significant(P<0.001).The total score of the perioperative thermal comfort level of patients undergoing gynecological surgery was 27.97±2.04,which was significantly increased compared with the score of 21.27±1.57 observed by researchers at baseline(P<0.001).The perioperative Hamilton Depression Scale and Hamilton Anxiety Scale scores of patients undergoing gynecological surgery decreased from 15.03±3.16 and 13.93±2.64 to 4.30±1.15 and 3.53±0.78,respectively,with statistically significant differences(P<0.001).The perioperative Montreal Cognitive Assessment Scale score of the gynecological surgery patients increased from 23.17±1.68 to 26.93±1.11,also with statistical significance(P<0.001).CONCLUSION MDT-based EBP for PH prevention and management in gynecological patients during the perioperative period can standardize nursing operations,improve nurses'awareness and behavioral compliance with gynecological hypothermia management,and reduce the occurrence of PH in gynecological patients while playing a positive role in reducing patients’negative emotions and enhancing their cognitive function.

Epileptic Seizures in Neonates Treated with Hypothermia for Hypoxo-Ischemic Encephalopathy in Brazzaville, Congo: Types and Evolution

Background: Moderate to severe hypoxic-ischemic encephalopathy (HIE) in neonates is often treated with hypothermia. However, some neonates may experience epileptic seizures during therapeutic hypothermia (TH). Data on the electrophysiologic and evolutionary aspects of these seizures are scarce in African countries. Objectives: To determine the types of epileptic seizures caused by HIE in neonates in Brazzaville;to describe the evolution of background EEG activities during TH and rewarming;to report the evolution of epileptic seizures. Methods: This was a cross-sectional, descriptive study conducted from January 2020 to July 2022. It took place in Brazzaville in the Neonatology Department of the Blanche Gomez Mother and Child Hospital. It focused on term neonates suffering from moderate or severe HIE. They were treated with hypothermia combined with phenobarbital for 72 hours. Results: Among 36 neonates meeting inclusion criteria, there were 18 boys and 18 girls. Thirty-one (86.1%) neonates had grade 2 and 5 (13.9%) grade 3 HIE. In our neonates, HIE had induced isolated electrographic seizures (n = 11;30.6%), electroclinical seizures (n = 25;69.4%), and 6 types of background EEG activity. During TH and rewarming, there were 52.8% of patients with improved background EEG activity, 41.7% of patients with unchanged background EEG activity, and 5.5% of patients with worsened background EEG activity. At the end of rewarming, only 9 (25%) patients still had seizures. Conclusion: Isolated electrographic and electroclinical seizures are the only pathological entities found in our studied population. In neonates with moderate HIE, the applied therapeutic strategy positively influences the evolution of both seizures and background EEG activity. On the other hand, in neonates with severe HIE, the same therapeutic strategy is ineffective. .

Neuroprotective mechanisms and translational potential of therapeutic hypothermia in the treatment of ischemic stroke

Stroke is a leading cause of disability and death,yet effective treatments for acute stroke has been very limited.Thus far,tissue plasminogen activator has been the only FDA-approved drug for thrombolytic treatment of ischemic stroke patients,yet its application is only applicable to less than 4–5% of stroke patients due to the narrow therapeutic window（〈 4.5 hours after the onset of stroke） and the high risk of hemorrhagic transformation.Emerging evidence from basic and clinical studies has shown that therapeutic hypothermia,also known as targeted temperature management,can be a promising therapy for patients with different types of stroke.Moreover,the success in animal models using pharmacologically induced hypothermia（PIH） has gained increasing momentum for clinical translation of hypothermic therapy.This review provides an updated overview of the mechanisms and protective effects of therapeutic hypothermia,as well as the recent development and findings behind PIH treatment.It is expected that a safe and effective hypothermic therapy has a high translational potential for clinical treatment of patients with stroke and other CNS injuries.

Mild hypothermia as a treatment for central nervous system injuries Positive or negative effects?

Besides local neuronal damage caused by the primary insult, central nervous system injuries may secondarily cause a progressive cascade of related events including brain edema, ischemia, oxida- tive stress, excitotoxicity, and dysregulation of calcium homeostasis. Hypothermia is a beneficial strategy in a variety of acute central nervous system injuries. Mild hypothermia can treat high in- tracranial pressure following traumatic brain injuries in adults. It is a new treatment that increases survival and quality of life for patients suffering from ischemic insults such as cardiac arrest, stroke, and neurogenic fever following brain trauma. Therapeutic hypothermia decreases free radical pro- duction, inflammation, excitotoxicity and intracranial pressure, and improves cerebral metabolism after traumatic brain injury and cerebral ischemia, thus protecting against central nervous system damage. Although a series of pathological and physiological changes as well as potential side ef- fects are observed during hypothermia treatment, it remains a potential therapeutic strategy for central nervous system injuries and deserves further study.

Selective brain hypothermia-induced neuroprotection against focal cerebral ischemia/reperfusion injury is associated with Fis1 inhibition

Selective brain hypothermia is considered an effective treatment for neuronal injury after stroke,and avoids the complications of general hypothermia.However,the mechanisms by which selective brain hypothermia affects mitochondrial fission remain unknown.In this study,we investigated the effect of selective brain hypothermia on the expression of fission 1 (Fis1) protein,a key factor in the mitochondrial fission system,during focal cerebral ischemia/reperfusion injury.Sprague-Dawley rats were divided into four groups.In the sham group,the carotid arteries were exposed only.In the other three groups,middle cerebral artery occlusion was performed using the intraluminal filament technique.After 2 hours of occlusion,the filament was slowly removed to allow blood reperfusion in the ischemia/reperfusion group.Saline,at 4℃ and 37℃,were perfused through the carotid artery in the hypothermia and normothermia groups,respectively,followed by restoration of blood flow.Neurological function was assessed with the Zea Longa 5-point scoring method.Cerebral infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride staining,and apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining.Fis1 and cytosolic cytochrome c levels were assessed by western blot assay.Fis1 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction.Mitochondrial ultrastructure was evaluated by transmission electron microscopy.Compared with the sham group,apoptosis,Fis1 protein and mRNA expression and cytosolic cytochrome c levels in the cortical ischemic penumbra and cerebral infarct volume were increased after reperfusion in the other three groups.These changes caused by cerebral ischemia/reperfusion were inhibited in the hypothermia group compared with the normothermia group.These findings show that selective brain hypothermia inhibits Fis1 expression and reduces apoptosis,thereby ameliorating focal cerebral ischemia/reperfusion injury in rats.Experiments were authorized by the Ethics Committee of Qingdao Municipal Hospital of China (approval No.2019008).

Can we further optimize therapeutic hypothermia for hypoxic-ischemic encephalopathy?

Perinatal hypoxic-ischemic encephalopathy is a leading cause of neonatal death and disability.Therapeutic hypothermia significantly reduces death and major disability associated with hypoxic-ischemic encephalopathy;however,many infants still experience lifelong disabilities to movement,sensation and cognition.Clinical guidelines,based on strong clinical and preclinical evidence,recommend therapeutic hypothermia should be started within 6 hours of birth and continued for a period of 72 hours,with a target brain temperature of 33.5 ±0.5℃ for infants with moderate to severe hypoxic-ischemic encephalopathy.The clinical guidelines also recommend that infants be re warmed at a rate of 0.5℃ per hour,but this is not based on strong evidence.There are no randomized controlled trials investigating the optimal rate of rewarming after therapeutic hypothermia for infants with hypoxic-ischemic encephalopathy.Preclinical studies of rewarming are conflicting and results were confounded by treatment with sub-optimal durations of hypothermia.In this review,we evaluate the evidence for the optimal start time,duration and depth of hypothermia,and whether the rate of rewarming after treatment affects brain injury and neurological outcomes.

Neuroprotective effects of cold-inducible RNA-binding protein during mild hypothermia on traumatic brain injury

Cold-inducible RNA-binding protein（CIRP）, a key regulatory protein, could be facilitated by mild hypothermia in the brain, heart and liver. This study observed the effects of mild hypothermia at 31 ± 0.5℃ on traumatic brain injury in rats. Results demonstrated that mild hypothermia suppressed apoptosis in the cortex, hippocampus and hypothalamus, facilitated CIRP m RNA and protein expression in these regions, especially in the hypothalamus. The anti-apoptotic effect of mild hypothermia disappeared after CIRP silencing. There was no correlation between mitogen-activated extracellular signal-regulated kinase activation and CIRP silencing. CIRP silencing inhibited extracellular signal-regulated kinase-1/2 activation. These indicate that CIRP inhibits apoptosis by affecting extracellular signal-regulated kinase-1/2 activation, and exerts a neuroprotective effect during mild hypothermia for traumatic brain injury.

Mild hypothermia combined with neural stem cell transplantation for hypoxic-ischemic encephalopathy: neuroprotective effects of combined therapy

Neural stem cell transplantation is a useful treatment for ischemic stroke, but apoptosis often occurs in the hypoxic-ischemic environment of the brain after cell transplantation. In this study, we determined if mild hypothermia （27-28~C） can increase the survival rate of neural stem cells （1.0 x 105/~tL） transplanted into neonatal mice with hypoxic-ischemic encephalopathy. Long-term effects on neurological functioning of the mice were also examined. After mild hy- pothermia combined with neural stem cell transplantation, we observed decreased expression levels of inflammatory factor nuclear factor-kappa B and apoptotic factor caspase-3, reduced cerebral infarct volumes, increased survival rate of transplanted cells, and marked improvements in neurological function. Thus, the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation are superior to those of monotherapy. Moreover, our findings suggest that the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation on hypoxic-ischemic encephalopathy are achieved by anti-inflammatory and an- ti-apoptotic mechanisms.

Mild hypothermia combined with a scaffold of Ng Rsilenced neural stem cells/Schwann cells to treat spinal cord injury

Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly（D,L-lactide-co-glycolic acid） （PLGA） scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells ＋ PLGA group, hindlimb motor function and nerve electrophysiological function were dearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold ＋ mild hypothermia at 34℃ for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.

Electrophysiological functional recovery in a rat model of spinal cord hemisection injury following bone marrow-derived mesenchymal stem cell transplantation under hypothermia

Following successful establishment of a rat model of spinal cord hemisection injury by resecting right spinal cord tissues, bone marrow stem cells were transplanted into the spinal cord lesions via the caudal vein while maintaining rectal temperature at 34 ± 0.5°C for 6 hours （mild hypothermia）. Hematoxylin-eosin staining showed that astrocytes gathered around the injury site and formed scars at 4 weeks post-transplantation. Compared with rats transplanted with bone marrow stem cells under normal temperature, rats transplanted with bone marrow stem cells under hypothermia showed increased numbers of proliferating cells （bromodeoxyuridine-positive cells）, better recovery of somatosensory-evoked and motor-evoked potentials, greater Basso, Beattie, and Bresnahan locomotor rating scores, and an increased degree of angle in the incline plate test. These findings suggested that hypothermia combined with bone marrow mesenchymal stem cells transplantation effectively promoted electrical conduction and nerve functional repair in a rat model of spinal cord hemisection injury.

Mild hypothermia for treatment of diffuse axonal injury: a quantitative analysis of diffusion tensor imaging

Fractional anisotropy values in diffusion tensor imaging can quantitatively reflect the consistency of nerve fibers after brain damage, where higher values generally indicate less damage to nerve fibers. Therefore, we hypothesized that diffusion tensor imaging could be used to evaluate the effect of mild hypothermia on diffuse axona[ injury. A total of 102 patients with diffuse axonal injury were randomly divided into two groups： normothermic and mild hypothermic treatment groups. Patient＇s modified Rankin scale scores 2 months after mild hypothermia were significant- ly lower than those for the normothermia group. The difference in average fractional anisotropy value for each region of interest before and after mild hypothermia was 1.32-1.36 times higher than the value in the normothermia group. Quantitative assessment of diffusion tensor imaging indicates that mild hypothermia therapy may be beneficial for patients with diffuse axonal injury.

The pathways by which mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury

Several studies have demonstrated that mild hypothermia exhibits a neuroprotective role and it can inhibit endothelial cell apoptosis following ischemia/reperfusion injury by decreasing casp- ase-3 expression, It is hypothesized that mild hypothermia exhibits neuroprotective effects on neurons exposed to ischemia/reperfusion condition produced by oxygen-glucose deprivation. Mild hypothermia significantly reduced the number of apoptotic neurons, decreased the expres- sion of pro-apoptotic protein Bax and increased mitochondrial membrane potential, with the peak of anti-apoptotic effect appearing between 6 and 12 hours after the injury. These findings indicate that mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury by protecting the mitochondria and that the effective time window is 6-12 hours after ischemia/reperfusion injury.

Combination of mild therapeutic hypothermia and adipose-derived stem cells for ischemic brain injury

Mild therapeutic hypothermia has been shown to mitigate cerebral ischemia, reduce cerebral edema, and improve the prognosis of patients with cerebral ischemia. Adipose-derived stem cell-based therapy can decrease neuronal death and infiltration of inflammatory cells, exerting a neuroprotective effect. We hypothesized that the combination of mild therapeutic hypothermia and adipose-derived stem cells would be neuroprotective for treatment of stroke. A rat model of transient middle cerebral artery occlusion was established using the nylon monofilament method. Mild therapeutic hypothermia（33°C） was induced after 2 hours of ischemia. Adipose-derived stem cells were administered through the femoral vein during reperfusion. The severity of neurological dysfunction was measured by a modified Neurological Severity Score Scaling System. The area of the infarct lesion was determined by 2,3,5-triphenyltetrazolium chloride staining. Apoptotic neurons were detected by terminal deoxynucleotidyl transferase-mediated d UTP-biotin nick end labeling（TUNEL） staining. The regeneration of microvessels and changes in the glial scar were detected by immunofluorescence staining. The inflammatory responses after ischemic brain injury were evaluated by in situ staining using markers of inflammatory cells. The expression of inflammatory cytokines was measured by reverse transcription-polymerase chain reaction. Compared with mild therapeutic hypothermia or adipose-derived stem cell treatment alone, their combination substantially improved neurological deficits and decreased infarct size. They synergistically reduced the number of TUNEL-positive cells and glial fibrillary acidic protein expression, increased vascular endothelial growth factor levels, effectively reduced inflammatory cell infiltration and down-regulated the m RNA expression of the proinflammatory cytokines interleukin-1β, tumor necrosis factor-α and interleukin-6. Our findings indicate that combined treatment is a better approach for treating stroke compared with mild therapeutic hypothermia or adipose-derived stem cells alone.

Effect of warm bladder irrigation fluid for benign prostatic hyperplasia patients on perioperative hypothermia, blood loss and shiver: A meta-analysis

Objective:To find out whether warm bladder irrigation fluid can decrease the occurrence of perioperative hypothermia,blood loss and shiver in patients treated with benign prostatic hyperplasia(BPH).Method:A comprehensive literature review and meta-analysis that included randomized controlled trials(RCTs)related to temperature of irrigation fluid in the perioperative treatment for BPH was taken by researchers.The relevant literature were searched in Chinese database,such as Retrieval Chinese Journal Full-text Database,VIP Journal Database,Wanfang database,as well as in English search engine and database,including Embase,Cochrane and Medline till January 2018.The study quality was assessed by recommended standards from Cochrane Handbook(version 5.1.0).Results:A total of 28 RCTs and 3858 patients were included.The results showed that the incidences of shiver(risk ratio[RR]Z 0.32,95%confidence interval[CI]:0.28e0.36,p<0.001,I^2 Z 0%)and hypothermia(RR Z 0.36,95%CI:0.21e0.59,p<0.001,I^2 Z 67%)in the group of warm irrigation fluid were lower than the group having room-temperature fluid.Room-temperature irrigation fluid group caused a greater drop in body temperature compared to warm irrigation fluid group(p<0.001,I^2 Z 96%).We performed a narrative descriptive statistics only because of substantial heterogeneity.Conclusions:Warm bladder irrigation fluid can decrease the drop of body temperature and the incidence of hypothermia and shiver during and after the operation for BPH.Warm irrigation fluid should be considered as a standard practice in BPH surgeries.

A safety evaluation of profound hypothermia-induced suspended animation for delayed resuscitation at 90 or 120min

Background: The successful treatment of military combat casualties with penetrating injuries is significantly dependent on the time needed to get the patient to an adequate treatment facility. Profound hypothermia induced suspended animation for delayed resuscitation(SADR) is a novel approach for inducing cardiac arrest and buying additional time for such injuries. However, the time used to safely administer circulatory arrest(CA) is controversial. The goal of this study was to evaluate the safety of hypothermia-induced SADR over 90 and 120 min time intervals.Methods: Sixteen male BAMA minipigs were randomized into two groups: CA90 group(90 min, n =8) and CA120 group(120 min, n =8). Cannulation of the right common carotid arteries and internal jugular veins was performed to establish cardiopulmonary bypass for each animal. Through the perfusion of cold organ preservation solution(OPS), cardioplegia and profound hypothermia(15℃) were induced. After CA, cardiopumonary bypass(CPB) was restarted, and the animals were gradually re-warmed and resuscitated. The animals were assisted with ventilators until spontaneous breathing was achieved. The index of hemodynamic perioperative serum chemistry values [alanine transaminase(ALT), aspartate aminotransferase(AST), creatinine(CR), lactic dehydrogenase(LDH) and troponin T(TnT)] and survival were observed from pre-operation to 7 days post-operation.Results: Fifteen animals were enrolled in the experiment, while 1 animal in CA120 group died from surgical error. All 8 animals in CA90 group recovered, with only 1 animal displaying mild disability. However, in CA120 group, only 2 animals survived with severe disability, and the other 5 animals died after 2 days post-operation. In CA90 group, the perioperative serum chemistry values increased at 1 day post-operation(ALT 84.43±18.65 U/L; AST 88.99±23.19 U/L; Cr 87.90±24.49μmol/L; LDH 1894.13±322.26 U/L; TnT 0.849±0.135 ng/ml) but decreased to normal or almost normal levels at 7 days post-operation(ALT 52.48±9.04 U/L; AST 75.23±21.46 U/L; Cr 82.69±18.41μmol/L; LDH 944.67±834.32 U/L; TnT 0.336±0.076 ng/ml).Conclusion: Profound hypothermia-induced SADR is an effective method for inducing cardiac arrest. Our results indicate that inducing CA for 90 min(at 15℃) is safer than doing so for 120 min. Our results indicate that 120 min of CA at 15℃ is dangerous and can result in high mortality and severe neurological complications. Further experimentation is needed to determine whether 120 min of CA at temperatures lower than 15℃ can lead to safe recovery.

Electrocardiographic changes during induced therapeutic hypothermia in comatose survivors after cardiac arrest

AIM: To assess the safety of therapeutic hypothermia(TH) concerning arrhythmias we analyzed serial electrocardiograms(ECG) during TH.METHODS: All patients recovered from a cardiac arrest with Glasgow < 9 at admission were treated with induced mild TH to 32-34℃. TH was obtained with cool fluid infusion or a specific intravascular device. Twelvelead ECG before,during,and after TH,as well as ECG telemetry data was recorded in all patients. From a total of 54 patients admitted with cardiac arrest during the study period,47 patients had the 3 ECG and telemetry data available. ECG analysis was blinded and performed with manual caliper by two independent cardiologists from blinded copies of original ECG,recorded at 25 mm/s and 10 mm/m V. Coronary care unit staff analyzed ECG telemetry for rhythm disturbances. Variables measured in ECG were rhythm,RR,PR,QT and corrected QT(QTc by Bazett formula,measured in lead v2) intervals,QRS duration,presence of Osborn's J wave and U wave,as well as ST segment displacement and T wave amplitude in leads Ⅱ,v2 and v5.RESULTS: Heart rate went down an average of 19 bpm during hypothermia and increased again 16 bpm with rewarming(P < 0.0005,both). There was a nonsignificant prolongation of the PR interval during TH and a significant decrease with rewarming(P = 0.041). QRS duration significantly prolonged(P = 0.041) with TH and shortened back(P < 0.005) with rewarming. QTc interval presented a mean prolongation of 58 ms(P < 0.005) during TH and a significant shortening with rewarming of 22.2 ms(P = 0.017). Osborn or J wave was found in 21.3% of the patients. New arrhythmias occurred in 38.3% of the patients. Most frequent arrhythmia was non-sustained ventricular tachycardia(19.1%),followed by severe bradycardia or paced rhythm(10.6%),accelerated nodal rhythm(8.5%) and atrial fibrillation(6.4%). No life threatening arrhythmias(sustained ventricular tachycardia,polymorphic ventricular tachycardia or ventricular fibrillation) occurred during TH. CONCLUSION: A 38.3% of patients had cardiac arrhythmias during TH but without life-threatening arrhythmias. A concern may rise when inducing TH to patients with long QT syndrome.

Mild hypothermia effects on matrix metalloproteinase-9 expression in the perihematomal region of rats following experimental intracerebral hemorrhage

BACKGROUND： Matrix metalloproteinase-9 （MMP-9） expression increases with intracerebral hemorrhage, and participates in the pathophysiological processes of secondary brain injury after intracerebral hemorrhage. OBJECTIVE： To investigate the effects of mild hypothermia on MMP-9 expression and brain edema in the perihematomal region of experimental intracerebral hemorrhage rats. DESIGN, TIME AND SETTING： The randomized, controlled experiment was performed at the Central Laboratory of Shandong Provincial Hospital between May and September 2007. MATERIALS： Seventy-two, Wistar, male rats, 12-weeks old, were used for this study. Rabbit anti-MMP-9 primary antibody was purchased from Boster, China. METHODS： Wistar rats were equally and randomly divided into normothermia and mild hypothermia groups. The two groups each comprised control, 6-hour intracerebral hemorrhage, 24-hour intracerebral hemorrhage, 48-hour intracerebral hemorrhage, 72-hour intracerebral hemorrhage, and l-week intracerebral hemorrhage subgroups, with six rats in each subgroup. Rat models of intracerebral hemorrhage were established by injecting 100 μL of autologous blood into the rat caudate nucleus. Rats in the mild hypothermia group received four hours of local mild hypothermia immediately following the injection. lntracerebral temperature was maintained at （33 ± 0.5） ℃. Subsequently, intracerebral temperature was spontaneously recovered at 25 ℃. Rats in the control subgroup were not injected with autologous blood and received only with intracerebral hemorrhage. MAIN OUTCOME MEASURES： Brain water content and MMP-9 expression surrounding the hematoma region. RESULTS： MMP-9 expression increased at 6 hours, and brain edema reached a peak at 48 hours after intracerebral hemorrhage. MMP-9 expression was significantly decreased in the mild hypothermia group compared with the normothermia group at each time point （P 〈 0.05）. CONCLUSION： Mild hypothermia can significantly inhibit MMP-9 overexpression and relieve brain edema following intracerebral hemorrhage.

Effects of mild hypothermia on the ROS and expression of caspase-3 m RNA and LC3 of hippocampus nerve cells in rats after cardiopulmonary resuscitation

BACKGROUND: Cardiac arrest(CA) is a common and serious event in emergency medicine. Despite recent improvements in resuscitation techniques, the survival rate of patients with CA is unchanged. The present study was undertaken to observe the effect of mild hypothermia(MH) on the reactive oxygen species(ROS) and the effect of neurological function and related mechanisms.METHODS: Sixty-five healthy male Sprague Dawley(SD) adult rats were randomly(random number) divided into 2 groups: blank control group(n=5) and CPR group(n=60). CA was induced by asphyxia. The surviving rats were randomly(random number) divided into two groups: normothermia CPR group(NT) and hypothermia CPR group(HT). Normothermia of 37 °C was maintained in the NT group after return of spontaneous circulation(ROSC), hypothermal intervention of 32 °C was carried out in the HT group for 4 hours immediately after ROSC. Both the NT and HT groups were then randomly divided into 2 subgroups 12 hours and 24 hours after ROSC(NT-12, NT-24, HT-12, HT-24 subgroups). During observation, the neurological defi cit scores(NDSs) was recorded, then the bilateral hippocampi were obtained from rats' head, and monoplast suspension of fresh hippocampus tissue was made immediately to determine the level of intracellular ROS by flow cytometry. Transmission electron microscope was used to observe the ultramicro changes of cellular nucleus and mitochondria. Reverse transcription-polymerase chain reaction(RT-PCR) was used to determine the expression of caspase-3 m RNA, and western-blotting(WB) was used to determine the level of LC3 in frozen hippocampus tissue. Measured data were analyzed with paired sample t test and One-Way ANOVA.RESULTS: Of 60 rats with CA, 44(73%) were successfully resuscitated and 33(55%) survived until the end of the experiment. The NDSs of rats in the NT and HT groups were more signifi cantly reduced than those in the BC group(F=8.107, P<0.05), whereas the NDSs of rats in the HT-12 and HT-24 subgroups were significantly increased in comparison with those NDSs of rats in the NT-12 and NT-24 subgroups, respectively(t=9.692, P<0.001; t=14.374, P<0.001). The ROS in hippocampus nerve cells in the NT and HT groups signifi cantly increased compared to the BC group(F=16.824, P<0.05), whereas the ROS in the HT-12 and HT-24 subgroups significantly reduced compared with that ROS in the NT-12 and NT-24 subgroups, respectively(t=9.836, P<0.001; t=7.499, P<0.001). The expression of caspase-3 m RNA in hippocampus nerve cells in the NT and HT groups were signifi cantly increased compared to the BC group(F=24.527, P<0.05), whereas the expression of caspase-3 m RNA in rats of the HT-12 and HT-24 subgroups was signifi cantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=6.935, P<0.001; t=4.317, P<0.001). The expression of LC3B-II/I in hippocampus nerve cells of rats in the NT and HT groups signifi cantlyincreased compared to the BC group(F=6.584, P<0.05), whereas the expression of LC3B-II/I in rats of the HT-12 and HT-24 subgroups significantly reduced compared to the NT-12 and NT-24 subgroups, respectively(t=10.836, P<0.001; t=2.653, P=0.02). Ultrastructure damage of nucleus and mitochondria in the NT group was more evident than in the BC group, and eumorphism of nucleus and mitochondria were maintained in rats of the HT group compared with the NT group.CONCLUSION: Mild hypothermia lessened the injury of nerve cells and improved the neurological function of rats that survived from cardiac arrest by reducing the ROS production of nerve cells and inhibiting the expression of caspase-3 m RNA and LC3, leading to cellular apoptosis and massive autophagy in rats that survived from cardiac arrest after CPR.

Induction of therapeutic hypothermia via the esophagus:a proof of concept study

BACKGROUND:Induction of hypothermia(a 4℃decrease from baseline)improves outcomes in adult cardiac arrest and neonatal hypoxic ischemic encephalopathy,and may benefit other conditions as well.Methods used to implement or prevent hypothermia typically require skin contact with blankets or pads or intravascular access with catheter devices.The study was to evaluate the potential to induce mild therapeutic hypothermia via an esophageal route in a porcine model.METHODS:Single-animal proof-of-concept study of a prototype esophageal device in a 70 kg Yorkshire swine.We measured the rate of temperature change after placement of a prototype device to induce hypothermia via the esophagus,and compared this rate to known temperature changes that occur under similar laboratory conditions without a hypothermic device.RESULTS:Swine temperature decreased from a starting temperature of 37.8℃to 33.8℃(achieving the goal of a 4℃decrease)in 175 minutes,resulting in a cooling rate of 1.37℃/h.Histopathology of the esophagus showed normal tissue without evidence of injury.CONCLUSION:A prototype of an esophageal cooling device induced hypothermia effectively in a large single-swine model.

Effects of mild hypothermia on the expression of microtubule-associated protein 2 in neurons of the hippocampal dentate gyrus in a rat model of cerebral ischemia/reperfusion

BACKGROUND： It is widely accepted that mild hypothermia can protect against injury to cerebral ischemia/reperfusion. OBJECTIVE： To observe the effects of mild hypothermia on microtubule-associated protein 2 （MAP2） expression in the hippocampal dentate gyms in rats following cerebral ischemia/reperfusion. Also, to study neuronal ultrastmctural changes in the dentate gyms to investigate the mechanism of the protection against injury to cerebral ischemia/reperfusion conferred by mild hypothermia. DESIGN, TIME AND SETTING： This randomized grouping, neural cell morphology trial was performed at the Laboratory Animal Center of Yijishan Hospital between March and June 2007. MATERIALS： Eighty-five healthy male Sprague Dawley rats were randomly allocated to three groups： mild hypothermia （n = 40）, normothermia （n = 40）, and sham-operated （n = 5）. METHODS： Cerebral ischemia/reperfusion injury was induced by the suture method in the mild hypothermia and normothermia groups, with a threading depth of 180.5 mm. In the sham-operated group, the suture was inserted 15 mm, with no vascular ligafion, and was followed by reperfusion 2 hours later. In the sham-operated and normothermia groups, the rat rectal temperature was maintained at 36-37 ℃ ; in the mild hypothermia group, it was controlled at 32-33 ℃. MAIN OUTCOME MEASURES： The hippocampal dentate gyms was serially sectioned for hematoxylin-eosin staining and MAP2 immunohistochemistry. Ultrastructural changes and the MAP2 absorbance value of the hippocampal dentate gyms were examined by transmission electron microscopy. RESULTS： The sham-operated group exhibited approximately normal ultrastructure of neurons in the bilateral hippocampal dentate gyms. In the normothermia group, ischemic hippocampal dentate gyms neurons were found with markedly fewer normal mitochondria, greatly proliferated rough endoplasmic reticulum, and a swollen and dysmorphic Golgi. In the mild hypothermia group, at each corresponding time point, these abnormal changes were noticeably alleviated. The number of necrotic mitochondria, as well as the degree of degeneration, was obviously reduced compared with the normothermia group. At days 6, 8 and 10 following reperfusion, the normothermia group exhibited lower neurological function scores than the mild hypothermia group （P 〈 0.05）. In the normothermia group, the absorbance value of MAP2 expression in the ischemic hippocampal dentate gyms was significantly decreased compared with the sham-operated group （P 〈 0.01 ）, was slightly increased at 4 days, and reached a peak on day 8. The mild hypothermia group showed an absorbance value of MAP2 expression in the ischemic hippocampal dentate gyms similar to the normothermia group, but it reached a peak on day 6. On days 1, 2, 4 and 6 following repeffusion, MAP2 expression was lower in the mild hypothermia group than in the sham-operated group, but it was higher than the normothermia group （P 〈 0.05）. CONCLUSION： Mild hypothermia applied in early ischemia can alleviate brain injury. This may be due to an enhancement of MAP2 expression.