目前亚低温降温方式的研究进展

亚低温在临床的应用日益受到重视,因此其方法近年来得到不断改进和发展,目前应用的方法有:冰袋降温法、医用冰毯降温法、冷水浸泡或淋浴、静脉输注低温液体、体外血液冷却法、应用血管内冷却装置、血液滤过、选择性头部降温、全身亚低温疗法等。尽管目前降温方法很多,但无论何种方法,依然存在不少缺点,而且肯定的结果都只限于小样本和单中心实验。     

选择性脑亚低温治疗重型颅脑损伤

目的　比较选择性脑亚低温与全身亚低温治疗重型颅脑损伤的治疗效果。方法　将 6 9例重型颅脑损伤 (GCS≤ 8分 )患者分成 3组 :(1 )选择性脑亚低温组 2 3例 ,头部局部降温 ,将脑温降至 33～ 35℃ ,治疗 3～ 5日 ;(2 )全身亚低温组 2 2例 ,全身降温 ,将脑温降至 33～ 35℃ ,治疗 3～ 5日 ;(3)常温对照组 2 4例 ,予常规治疗。结果　选择性脑亚低温组预后良好率为 5 6 .5 % (1 3/ 2 3) ,病死率 2 1 .7% (5 / 2 3) ,与全身亚低温组相仿 [分别为 5 4 .5 % (1 2 / 2 2 )和 2 2 .7% (5 / 2 2 ) ],与对照组比较 (良好率 2 5 % ,病死率 4 5 .8% ) ,有显著差异(P <0 .0 5 )。全身组与对照组总并发症发生率比较无显著差异 (P >0 .0 5 ) ,而选择性脑亚低温组总并发症发生率明显低于全身组与对照组 (P <0 .0 1 )。结论　选择性脑亚低温对重型颅脑损伤的疗效与全身亚低温相仿 ,明显优于常温对照组 ,是目前治疗重型颅脑损伤安全而有效的方法之一。     

亚低温疗法治疗重型脑炎患儿的疗效观察与护理

小儿脑炎起病急,发展快,重症者可留下不同程度的永久性神经系统后遗症.近年来动物实验研究表明,轻度降低体温对脑损害有保护作用,又可避免深度低温的副作用.目前,亚低温治疗重型脑外伤已广泛用于临床,且疗效肯定。     

AKT信号通路通过亚低温对大鼠局脑缺血再灌注损伤神经元的保护作用

目的通过检测AKT及Bcl-2蛋白的表达,探讨亚低温对局脑缺血再灌注后神经元存活的影响。方法用线拴法制作大鼠大脑中动脉闭塞（MCAO）局脑缺血再灌注模型,将36只SD大鼠随机分成假手术组、常温缺血再灌注组和亚低温缺血再灌注组,缺血组分别缺血6h再灌注4h、24h、72h、1w（n=4）后处死,亚低温组于缺血后13~14min实施病灶侧亚低温持续4h。免疫组织化学法检测AKT、Bcl-2蛋白的表达,电镜检测自噬小体。结果不同缺血时间再灌注4h,亚低温组比常温组缺血侧半暗带AKT表达水平显著增高（P〈0.05）,Bcl-2表达明显降低（P〈0.01）;亚低温组自噬小体明显减少。结论病灶侧亚低温通过促进缺血半暗带脑组织AKT表达,抑制Bcl-2表达,从而抑制神经元凋亡,抑制自噬的产生,从而对神经元起保护作用,促进脑缺血后神经功能恢复。     

亚低温治疗仪在急性重度中暑患者降温中的应用及护理

目的：探讨亚低温治疗仪在急性重度中暑患者降温中的临床应用及相关的护理措施。方法实验组：选取急性重度中暑患者22例，采用在药物降温的基础上配合亚低温治疗仪进行降温并观察其临床疗效，总结其护理措施。对照组采用传统的物理及药物降温方法，比较其降温效果。结果实验组明显高于对照组，两组比较有显著差异性（ P＜0．05）。结论正确使用亚低温治疗仪，能在合理的时间内降低急性重度中暑患者体温，减轻脑水肿，降低其死亡率。     

亚低温在治疗颅脑外伤中的应用

亚低温治疗颅脑外伤实验研究已取得令人瞩目的进展，研究证实亚低温能显著减轻脑缺血厦脑外伤后的脑损害程度。促进其神经功能恢复。本文对近年来亚低温治疗颅脑外伤的进展，降温及复温方法厦低温的监护等问题作简要介绍。     

亚低温在劳力型热射病治疗中的应用

目的 探讨快速亚低温处理在劳力型热射病(EHS)救治中的作用.方法 回顾性总结2001年9月-2009年8月间7所部队医院收治的28例EHS患者的临床资料,将发病后4h内将肛温降低到亚低温(35.0±0.5℃)的患者归入亚低温组(n=16),将肛温大于40℃超过3h的患者归入延迟降温组(n=12),比较两组患者入院后0、12、24、48、72h的肌酸激酶(CK)和乳酸脱氢酶(LDH)水平,并比较两组的病死率和升压药使用时间,分析亚低温在热射病治疗中的作用.结果 入院24h后延迟降温组CK值显著高于亚低温组(P<0.05或P<0.01),亚低温组LDH值在24～48h后开始下降,48、72h时显著低于延迟降温组(P<0.01).亚低温组与延迟降温组的病死率分别为0%和25.0%(P<0.05).亚低温组使用升压药的时间(68.5±39.7h)明显短于延迟降温组(228.7±139.7h,P<0.01).结论 迅速应用亚低温处理能有效减轻脏器损伤程度,改善热射病患者全身情况及预后,是治疗EHS的重要措施.     

犬颈内动脉内冷灌注脑选择性降温对脑保护的实验研究

目的观察颈内动脉内冷灌注犬脑选择性降温对缺血性脑组织的保护作用。方法夹闭左侧颈总动脉、双侧椎动脉、左侧颈外静脉后,自右侧颈内动脉灌入低温灌注液以选择性降低脑温。将颅脑回流的低温稀释静脉血超滤并复温至３８℃后再输入体循环。结果１８只犬中有１４只完成了脑的选择性降温：（５．０±２．０）分钟内降至２８℃,（１０．３±７．２）分钟内降至２０℃,并维持在（１９±１．０）℃达５０分钟,直肠温度保持在（３２．５±２．０）℃以上。１０只长期存活,分别于术后１,２,８,１２周处死,病理检查示犬脑无神经细胞缺血性损伤改变。另４只实验初期因降温后血压显著下降而死亡。结论颈动脉内冷灌注液灌注,可选择性快速、安全地降低脑温,防止脑组织的缺血性损伤,为开展无血手术提供了实验依据。     

局部亚低温对大鼠脑缺血组织钙调神经磷酸酶活性的影响

为探讨局部亚低温的脑保护作用，制备大鼠大脑中动脉脑缺血模型。分为常温组、FK－506组、亚低温组和正常对照组，测定缺血后不同时间脑组织中钙调神经磷酸酶（CaN）的活性。结果发现，常温组、FK－506组于缺血后6h CaN活性开始下降，而亚低温组CaN活性无明显变化，差异有显著意义。说明局部亚低温治疗可明显抑制缺血脑组织中CaN活性的变化，具有明确的脑保护作用。     

亚低温脑保护的研究和应用

亚低温脑保护的研究和应用朱诚江基尧早在５０年代，人们就将深低温（体温降至２７～２８℃以上）应用于心血管直视手术，以保护脑和其他重要脏器．但由于深低温易发生室颤和凝血功能障碍，增加患者死亡率，已很少被临床医师所采用，目前仅被选择性用于某些复杂的心血管直...     

Locally induced hypothermia for treatment of acute ischaemic stroke: a physical feasibility study

During the treatment of stroke by local intra-arterial thrombolysis (LIT) it is frequently possible to pass the blood clot with a micro-catheter, allowing perfusion of brain tissue distally to the occlusion. This possibility allows for new early treatments of ischaemic brain tissue, even before the blood clot has been removed. One potential new approach to preserve brain tissue at risk may be locally induced endovascular hypothermia. Physical parameters such as the required micro-catheter input pressure, output velocity and flow rates, and a heat exchange model, applicable in the case of a micro-catheter placed within a guiding catheter, are presented. Also, a simple cerebral temperature model is derived that models the temperature response of the brain to the perfusion with coolant fluids. Based on this model, an expression has been derived for the time needed to reach a certain cerebral target temperature. Experimental in vitro measurements are presented that confirm the usability of standard commercially available micro-catheters to induce local hypothermia of the brain. If applied in vivo, the model predicts a local cooling rate of ischaemic brain tissue of 300 g of approximately 1°C in 1 min, which is up to a factor 30-times faster than the time-consuming systemic hypothermia via the skin. Systemic body temperature is only minimally affected by application of local hypothermia, thus avoiding many limitations and complications known in systemic hypothermia.     

Effect of temperature in focal ischemia of rat brain studied by 31P and 1H spectroscopic imaging

³¹P, ¹H and lactate spectroscopic imaging was used to evaluate the effects of hypothermia on focal cerebral ischemia produced by middle cerebral artery occlusion. The effects on high energy phosphate metabolism, pH, lactate and NAA were investigated in 24 spontaneously hypertensive rats subjected to either permanent or transient ischemia. Under either normothermic (37.5°C) or hypothermic (32°C) conditions, with permanent 6-h occlusion, there was little difference between groups in either the NMR measurements or the volume of infarction. In animals that underwent 3 h of ischemia followed by 12 h of reperfusion, the ischemic changes in lactate, pH, NAA, and high-energy phosphate returned toward control values, and there was a protective effect of hypothermia (infarct volume of 211 ± 26 and 40 ± 14 mm³ in normothermic and hypothermic groups, respectively). Thus, hypothermia did not ameliorate the changes in lactate, pH, NAA, or high energy phosphate levels occurring during ischemia, however, during reperfusion there was an improvement in both the recovery of these metabolites and pathological outcome in hypothermic compared with normothermic animals.     

可控性大鼠急性脑局部缺血模型的建立及CT灌注成像与病理学评价

目的 建立稳定、可控的脑局部缺血动物模型，并通过CT灌注成像和病理学方法对其进行评价。方法 雄性Wistar大鼠28只，随机分为4组(假手术组、脑梗死15min组、脑梗死30min、再灌注1h组及低灌注6h组)，每组7只鼠。在激光多普勒血流仪监测下采用改良的线栓法制作可控性脑局部缺血动物模型。利用CT灌注成像对各组动物模型的缺血状态进行观察，并与光学显微镜、电子显微镜结果以及红四氮唑(TTC)染色标本对照。结果 脑梗死15min组在激光多普勒血流仪监测下将局部脑血流量(rCBF)控制为5％～22％，CT灌注成像显示7只大鼠局部脑血流量均下降，TIC染色呈浅红色，未见明确梗死病灶，病理学检查显示部分神经元变性和星形细胞肿胀。脑梗死30min再灌注1h组在激光多普勒血流仪监测下将rCBF控制为4％～23％，病理学检查显示7只大鼠脑缺血灶内星形细胞肿胀明显，可见大量神经元变性，标本TTC染色所示的白色梗死区与CT灌注成像异常区域一致。在低灌注6h组，由于rCBF下降程度较小(为38％～55％)，病理学显示7只大鼠星形细胞肿胀明显而神经元变性轻微，TTC染色未见明确梗死病灶。假手术组7只大鼠均未见上述各种异常表现。结论 可控性大鼠急性脑局部缺血模型稳定可靠，能模拟出不同灌注程度的缺血状态，除了可用于脑梗死的研究外，更适用于脑梗死前期的急性脑局部缺血的研究。功能CT灌注成像是评价急性脑局部缺血模型的1种准确、敏感的方法。     

Acute cerebral vascular accident associated with hyperperfusion.

Cerebral radionuclide angiography can demonstrate decreased or normal radioactivity in the affected region during the arterial phase in patients who have sustained a cerebral vascular accident and thus enhances the diagnostic specificity of the static brain image. In an occasional patient, however, a seemingly paradoxical pattern of regional hyperperfusion with a return to normal or subnormal perfusion following the acute phase has been observed. This phenomenon, called "luxury perfusion," has been defined using intra-arterial 133Xe for semiquantitative cerebral blood flow measurements and should be kept in mind as a potentially misleading cerebral imaging pattern.     

PC机辅助MR脑灌注成像初步研究

目的:研究PC机辅助MR脑灌注成像软件,探讨其临床应用价值。方法:在PC机上使用MR脑灌注成像软件,对5例健康人和18例脑缺血患者的灌注图像进行后处理,计算出有关脑灌注参数图,包括相对脑血流量(rrCBF)图、相对脑血容量(rrCBV)图、局部灌注达峰时间(TTP)图和团注平均通过时间(bMTT)图。结果:应用MR脑灌注成像软件可以在PC机上实现灌注图像的后处理,脑灌注参数图能够为脑缺血患者提供有价值的脑血液动力学信息,显示灌注异常的范围。结论:PC机辅助MR脑灌注成像软件简单易行,可显示常规MR无法显示的血流动力学异常,对临床和科研具有重要价值。     

Arterial spin-labeling in routine clinical practice, part 3: hyperperfusion patterns

Arterial spin-labeled (ASL) perfusion imaging can be implemented successfully into a routine clinical neuroimaging protocol and can accurately demonstrate alterations in brain perfusion. We have observed patterns of focal, regional, and global hyperperfusion in a wide variety of disease processes. The causes of hyperperfusion at clinical ASL have not been previously characterized. Focal lesions such as brain tumors and vascular malformations with increased perfusion can be well depicted by ASL. More global causes of hyperperfusion, including postanoxia vasodilation and hypercapnia, may go undetected on conventional MR images, whereas the regional hyperperfusion, which may occur in reversible encephalopathies and luxury perfusion, has been consistently illustrated on ASL cerebral blood flow maps at our institution.     

Brain imaging with emission computed tomography and radiolabeled amines

The noninvasive measurement of regional cerebral blood flow in man has been limited to expensive and specialized instrumentation available in only a few facilities throughout the world. Radiolabeled amines, such as I-123 iodoamphetamine, are lipophilic compounds, which are extracted by the brain proportional to blood flow. Scintigraphic maps of regional cerebral blood flow can therefore be obtained using commercially available radionuclides and standard single photon emission computed tomography instrumentation. I-123 iodoamphetamine imaging, therefore, permits the detection and assessment of altered perfusion in neurologic diseases, such as cerebral infarction and epilepsy. This physiologic information complements the anatomic and morphologic information provided by transmission computerized tomography.