不同降温方法对大鼠心肺脑复苏的作用

目的研究亚低温脑复苏时不同降温方法的效果及对大鼠脑的保护作用。方法建立心肺复苏模型，SD大鼠45只，分成对照组、常温复苏组及低温复苏A组（体表降温）、低温复苏B组（0．5ml·kg^-1·min^-1静注4℃ NS）、低温复苏C组（0．5ml·kg^-1·min^-1静注4℃NS结合体表降温）、低温复苏D组（1ml·kg^-1·min^-1静注4℃NS）和低温复苏E组（1ml·kg-^1·min^-1静注4℃NS结合体表降温），分别观察各组血清及大脑皮质SOD、MDA、NO、Na^＋ K^＋ -ATP酶及P53、Bax、Bcl-2表达和脑组织含水量比。结果低温复苏各组均能达到亚低温状态，特别是低温复苏D、E组达到亚低温状态仅需（26．71±4．65）min及（10．00±2．52）min。低温复苏D组脑组织含水量比、MDA、NO、P53和Bax光密度值分别为（79．58±0．40）％、（14．16±2．36）nmol／gprot、（35．28±4．94）μmol／gprot、（0．0136±0．0001）和（0．0304±0．0019），低温复苏E组分别为（79．46±0．30）％、（10．30±3．16）nmol／gprot、（33．18±4．93）μmol／gpmt、（0．0134±0．0040）和（0．0323±0．0029）．均较常温复苏组明显下降（P〈0．05）。低温复苏D组脑组织SOD、Na^＋ K^＋ -ATP酶分别为（114．45±3．07）U／mgprot、（30．50±2．06）μmolpi／（mgpnt·hour），低温复苏E组分别为（114．45±8．11）U／mgprot、（28．10±5．67）μmolpi／（mgpnt·hour），均较常温复苏组明显升高（P〈0．05）。结论静脉快速灌注冷生理盐水或同时结合体表降温均能在较短的时间内达到理想的亚低温状态并产生良好的脑保护效果。     

Mild therapeutic hypothermia is associated with favourable outcome in patients after cardiac arrest with non-shockable rhythms

Aim

Mild therapeutic hypothermia (32-34 °C) improves neurological recovery and reduces the risk of death in comatose survivors of cardiac arrest when the initial rhythm is ventricular fibrillation or pulseless ventricular tachycardia. The aim of the presented study was to investigate the effect of mild therapeutic hypothermia (32-34 °C for 24 h) on neurological outcome and mortality in patients who had been successfully resuscitated from non-ventricular fibrillation cardiac arrest.

Methods

In this retrospective cohort study we included cardiac arrest survivors of 18 years of age or older suffering a witnessed out-of-hospital cardiac arrest with asystole or pulseless electric activity as the first documented rhythm. Data were collected from 1992 to 2009. Main outcome measures were neurological outcome within six month and mortality after six months.

Results

Three hundred and seventy-four patients were analysed. Hypothermia was induced in 135 patients. Patients who were treated with mild therapeutic hypothermia were more likely to have good neurological outcomes in comparison to patients who were not treated with hypothermia with an odds ratio of 1.84 (95% confidence interval: 1.08-3.13). In addition, the rate of mortality was significantly lower in the hypothermia group (odds ratio: 0.56; 95% confidence interval: 0.34-0.93).

Conclusion

Treatment with mild therapeutic hypothermia at a temperature of 32-34 °C for 24 h is associated with improved neurological outcome and a reduced risk of death following out-of-hospital cardiac arrest with non-shockable rhythms.     

亚低温治疗犬心脏骤停复苏后心功能研究

目的 明确亚低温对室颤复苏后犬心功能及心律失常的影响.方法 12头比格犬随机(随机数字法)分成两组(n=6):常温复苏组(37.0±0.2)℃和亚低温组(34.0±0.2)℃,通过快速电刺激诱导室颤,7 min后行心肺复苏,动态观察比较两组犬的心率、左心室收缩力指数、室性心律失常、除颤能量、肾上腺素用量及复苏后1周心超变化.结果 ①与室颤前比较,两组犬左心室收缩力指数在复苏后均有不同程度降低(P＜0.05),但亚低温组下降幅度小于常温组,且心率低于常温组(141±19)次/minvs.(163±31)次/min,P＜0.05.②与常温组比较,亚低温组犬室性心律失常发生的次数明显减少(P＜0.05),但是除颤次数、肾上腺素用量差异无统计学意义(P＞0.05).③复苏后1周,两组犬的心超结果显示,心脏结构及射血分数均恢复正常.结论 亚低温治疗可改善心脏骤停复苏后心肌收缩力,降低室性心律失常发生率.本研究结果提示,亚低温对复苏后心功能有一定的保护作用.     

亚低温对心肺复苏后患者神经功能状况及生活质量的影响

目的　探讨亚低温对心肺复苏后患者神经功能状况及生活质量的影响及其机制。方法　采用格拉斯哥昏迷评分 (GCS)、神经功能缺损评分 (NFI)、Barthel指数 (MBI)及生活质量评分 (QOL)对心肺复苏后患者的神经功能状况及生活质量进行评定 ,并观察亚低温对他们的影响。结果　在心肺复苏后第7d ,亚低温组GCS评分明显比常规治疗组高 (P <0 0 5 ) ;在复苏后第 12周和 2 4周 ,亚低温组NFI评分及QOL评分均明显较常规治疗组低 (P <0 0 5 ) ,MBI评分明显较常规治疗组高 (P <0 0 1)。结论　亚低温可改善心肺复苏后患者的神经功能状况 ,提高患者的生活质量     

Rapid induction of mild therapeutic hypothermia by extracorporeal veno-venous blood cooling in humans

Aim

Mild therapeutic hypothermia is beneficial in patients successfully resuscitated from non-traumatic out-of-hospital cardiac arrest. The effect of fast induction of hypothermia in these patients remains to be investigated. The aim of this study was to evaluate the efficacy and safety of extracorporeal veno-venous blood cooling in humans successfully resuscitated from cardiac arrest.

Methods

We performed an interventional study in patients after successful resuscitation from cardiac arrest admitted to the emergency department of a tertiary care centre. The extracorporeal veno-venous circulation was established via a percutaneously introduced double lumen dialysis catheter in the femoral vein, and a tubing circuit and heat exchanger. A paediatric cardiopulmonary bypass roller pump and a heater-cooler system were used to circulate the blood. Main outcome measures were feasibility, efficacy, and safety.

Results

We included eight consecutive cardiac arrest patients with a median oesophageal temperature of 35.9 °C (interquartile range 34.9–37.0). A median time of 8 min elapsed (interquartile range 5–15 min) to reach oesophageal temperatures below 34 °C, which reflects a cooling rate of 12.2 °C/h (interquartile range 10.8 °C/h to 14.1 °C/h). The predefined target temperature of 33.0 °C was reached after 14 min (interquartile range 8–21 min). No device or method related adverse events were reported.

Conclusion

Extracorporeal veno-venous blood cooling is a feasible, safe, and very fast approach for induction of mild therapeutic hypothermia in patients successfully resuscitated from cardiac arrest.     

Effects of adenosine monophosphate on induction of therapeutic hypothermia and neuronal damage after cardiopulmonary resuscitation in rats

Background

Animal studies and pathophysiological considerations suggest that therapeutic hypothermia after cardiopulmonary resuscitation is the more effective the earlier it is induced. Therefore this study is sought to examine whether pharmacological facilitated hypothermia by administration of 5′-adenosine monophosphate (AMP) is neuroprotective in a rat model of cardiac arrest (CA) and resuscitation.

Methods

Sixty-one rats were subjected to CA. After 6 min of ventricular fibrillation advanced cardiac life support was started. After successful return of spontaneous circulation (ROSC, n = 40), animals were randomized either to placebo group (n = 14) or AMP group (800 mg/kg body weight, n = 14). Animals were kept at an ambient temperature of 18 °C for 12 h after ROSC and core body temperature was measured using a telemetry temperature probe. Neuronal damage was analyzed by counting Nissl-positive (i.e. viable) neurons and TUNEL-positive (i.e. apoptotic) cells in coronal brain sections 7 days after ROSC. Functional status evaluated on days 1, 3 and 7 after ROSC by a tape removal test.

Results

Time until core body temperature dropped to <34.0 °C was 31 min [28; 45] in AMP-treated animals and 125 min [90; 180] in the control group (p = 0.003). Survival until 7 days after ROSC was comparable in both groups. Also number of Nissl-positive cells (AMP: 1 [1; 7] vs. placebo: 2 [1; 3] per 100 pixel; p = 0.66) and TUNEL-positive cells (AMP: 56 [44; 72] vs. placebo: 53 [41; 67] per 100 pixel; p = 0.70) did not differ. Neither did AMP affect functional neurological outcome up to 7 days after ROSC. Mean arterial pressure 20 min after ROSC was 49 [45; 55] mmHg in the AMP group in comparison to 91 [83; 95] mmHg in the control group (p < 0.001).

Conclusion

Although application of AMP reduced the time to reach a core body temperature of <34 °C neither survival was improved nor neuronal damage attenuated. Reason for this is probably induction of marked hypotension as an adverse reaction to AMP treatment.     

亚低温对心肺复苏后患者神经功能预后的影响

目的:探讨亚低温技术在心肺复苏后对患者神经功能预后的影响。方法:回顾性分析我院2001-03-2008-05急诊抢救室收治的30例心肺复苏患者的临床资料,根据是否采用亚低温技术,患者随机分为两组:常温组与亚低温组,每组各15例。对复苏后患者的平均脑部温度、血氧饱和度(SaO2)、血酸碱值(pH)、平均动脉压(MAP)、意识障碍评分(GCS)等指标进行分析,3个月后对两组病人神经功能预后进行评定。结果:常温组与亚低温组患者复苏时平均脑部温度分为(36.7±1.3)℃和(33.5±1.1)℃(P<0.05),血氧饱和度(SaO2)、血酸碱值(pH)、平均动脉压(MAP)、意识障碍评分(GCS)等基本相近(P>0.05);3个月后两组神经功能转归良好率分别为40%和73%(P<0.05),其中亚低温6h内实施者优于6h后实施者;神经功能缺损评分(nerve functional in-sufficent,NFI)分别18.7±4.3和14.9±3.7(P<0.05),修改后的Barthel指数(modified Barthel index,MBI)分别为69.5±3.6和74.4±4.5(P<0.05)。结论:亚低温技术在心肺复苏后患者的脑复苏中具有显著的神经功能保护作用,可改善心肺复苏后患者的神经功能状况,实施降温越早,对脑复苏越有利。     

心肺复苏后早期注射冰盐水的有效性和安全性临床评价

目的：评价心搏骤停患者早期注射冰盐水实现亚低温治疗的可行性、安全性和有效性。方法采用单中心前瞻性随机对照的临床研究方法,以2011年3月到2013年10月北京市大兴区人民医院抢救的心搏骤停进行心肺复苏（CPR）后自主循环恢复（ROSC）的患者为研究对象,按随机数字表法将患者分为两组。ROSC后,冰盐水组患者立即快速静脉注射4℃生理盐水1000 mL来实现亚低温治疗,对照组给予常规头部冰袋降温治疗和腋温监测。所有患者在ROSC即刻和1 h后分别测量直肠温度;记录复苏后6 h胸片出现急性肺水肿、48 h内出现寒战、48 h再次发生心室纤颤（室颤）以及14 d内成功苏醒和死亡的患者例数。结果共有45例患者纳入本研究,其中冰盐水组23例,对照组22例。冰盐水组患者ROSC即刻直肠温度为（36.7±0.9）℃,1 h后降至（34.9±0.7）℃;对照组患者ROSC即刻直肠温度为（36.5±1.0）℃,1 h后升高至（37.9±0.9）℃,两组ROSC后1 h直肠温度比较差异有统计学意义（t＝2.228,P＝0.031）。冰盐水组14 d内成功苏醒患者例数明显多于对照组（13例比7例,χ2＝65.710,P＝0.021）,而出现急性肺水肿（4例比6例）、寒战（2例比0例）、再次发生室颤（4例比5例）和14 d内死亡（11例比12例）的患者例数与对照组比较差异均无统计学意义（均P＞0.05）。结论早期快速静脉注射4℃生理盐水来实现复苏后亚低温治疗脑复苏效果更佳理想,且是可行的、安全的、有效的。     

短时程复合亚低温改善长时间室颤家猪复苏预后的研究

目的 比较短时程亚低温对长时间室颤家猪短期复苏预后的影响.方法 采取体质量34～ 36 kg左右健康雄性种猪14头,通过右心室致颤电极诱发室颤并维持11 min,之后采取人工胸外按压及球囊面罩通气,按压通气比为30:2,每2 min轮换操作者.复苏6 min后给予120 J双向波除颤,若未能获得自主循环恢复(return of spontaneous circulation,ROSC),继续给予心肺复苏及必要时电除颤.连续复苏12 min仍无ROSC认为复苏失败.对ROSC家猪,随机(随机数字法)分为常温组(normothermia group,NT)及复合降温组(combined hypothermia group,CH).CH组立即给予4℃生理盐水静脉输注并联合体表物理降温,在120 min内将核心体温降至32 ～ 34℃并维持2h后主动复温,2h将体温升至基础体温水平.记录两组家猪致颤前基础状态下血流动力学、血气及乳酸.记录ROSC后心输出量、心率、核心体温变化.每24h评估动物神经功能直至观察终点.组间比较采用Fisher检验或方差分析,以P＜0.05为差异有统计学意义.结果 两组动物基础状态下体质量、平均动脉压、心输出量、Ph、呼气末二氧化碳水平、血乳酸水平差异均无统计学意义(P＞0.05).在复苏过程中,两组动物在总复苏时间、首次除颤成功率、ROSC比例、首次除颤ROSC比例、总除颤次数及肾上腺素用量差异均无统计学意义(P＞0.05).存活时间上,CH组明显长于NT组[(96.00±0.00) h vs.(49.71 ±43.65)h,P=0.031],同时NT组96 h生存率亦高于NT组,差异有统计学意义(P＜0.05).神经功能方面,CH组在复苏后96 h内各时间段均优于NT组,差异有统计学意义(P＜0.05).结论 即使2h短时程的亚低温,也可以明显改善11 min室颤家猪的短期复苏预后.     

The beneficial effect of mild therapeutic hypothermia depends on the time of complete circulatory standstill in patients with cardiac arrest

Aim

Mild therapeutic hypothermia has shown to improve long-time survival as well as favorable functional outcome after cardiac arrest. Animal models suggest that ischemic durations beyond 8 min results in progressively worse neurologic deficits. Based on these considerations, it would be obvious that cardiac arrest survivors would benefit most from mild therapeutic hypothermia if they have reached a complete circulatory standstill of more than 8 min.

Methods

In this retrospective cohort study we included cardiac arrest survivors of 18 years of age or older suffering a witnessed out-of-hospital cardiac arrest, which remain comatose after restoration of spontaneous circulation. Data were collected from 1992 to 2010. We investigated the interaction of ‘no-flow’ time on the association between post arrest mild therapeutic hypothermia and good neurological outcome. ‘No-flow’ time was categorized into time quartiles (0, 1–2, 3–8, >8 min).

Results

One thousand-two-hundred patients were analyzed. Hypothermia was induced in 598 patients. In spite of showing a statistically significant improvement in favorable neurologic outcome in all patients treated with mild therapeutic hypothermia (odds ratio [OR]: 1.49; 95% confidence interval [CI]: 1.14–1.93) this effect varies with ‘no-flow’ time. The effect is significant in patients with ‘no-flow’ times of more than 2 min (OR: 2.72; CI: 1.35–5.48) with the maximum benefit in those with ‘no-flow’ times beyond 8 min (OR: 6.15; CI: 2.23–16.99).

Conclusion

The beneficial effect of mild therapeutic hypothermia increases with cumulative time of complete circulatory standstill in patients with witnessed out-of-hospital cardiac arrest.     

Association of serum lactate and survival outcomes in patients undergoing therapeutic hypothermia after cardiac arrest

Introduction

Recent studies have suggested that serum lactate may serve as a marker to predict mortality after resuscitation from cardiac arrest (CA). The relationship between serum lactate and CA outcomes requires further characterization, especially among patients treated with therapeutic hypothermia (TH) and aggressive post-arrest care.

Methods

A retrospective analysis of patients resuscitated from non-traumatic CA at three urban U.S. hospitals was performed using an established internet-based post-arrest registry. Adult (≥18 years) patients resuscitated from CA and receiving TH treatment were included. Logistic regression analysis was used to adjust for potential confounders to survival outcomes. Survival to discharge served as the primary endpoint.

Results

A total of 199 post-CA patients treated with TH between 5/2005 and 11/2011 were included in this analysis. The mean age was 56.9 ± 16.5 years, 85/199 (42.7%) patients were female, and survival to discharge was attained in 84/199 (42.2%). While lower initial post-CA serum lactate levels were not associated with increased survival to discharge, subsequent lactate measurements were significantly associated with outcomes (24-h serum lactate levels in survivors vs. non-survivors, 2.7 ± 0.5 vs. 4.2 ± 0.4 mmol/L, p < 0.01). Multivariable logistic regression confirmed this relationship with survival to discharge (p < 0.01).

Conclusion

Lower serum lactate levels at 12 h and 24 h, but not initially following cardiac arrest, are associated with survival to hospital discharge after resuscitation from CA and TH treatment. Prospective investigation of serum lactate as a potential prognostic tool in CA is needed.     

Pharmacokinetics of intraosseous and central venous drug delivery during cardiopulmonary resuscitation

We compared the pharmacokinetics of intraosseous (IO) drug delivery via tibia or sternum, with central venous (CV) drug delivery during cardiopulmonary resuscitation (CPR).

Methods

CPR of anesthetized KCl arrest swine was initiated 8 min post arrest. Evans blue and indocyanine green, each were simultaneously injected as a bolus with adrenaline through IO sternal and tibial needles, respectively, n = 7. In second group (n = 6) simultaneous IO sternal and IV central venous (CV) injections were made.

Results

Peak arterial blood concentrations were achieved faster for sternal IO vs. tibial IO administration (53 ± 11 s vs. 107 ± 27 s, p = 0.03). Tibial IO dose delivered was 65% of sternal administration (p = 0.003). Time to peak blood concentration was similar for sternal IO and CV administration (97 ± 17 s vs. 70 ± 12 s, respectively; p = 0.17) with total dose delivered of sternal being 86% of the dose delivered via CV (p = 0.22).

Conclusions

IO drug administrations via either the sternum or tibia were effective during CPR in anesthetized swine. However, IO drug administration via the sternum was significantly faster and delivered a larger dose.     

Intra-arrest cooling with delayed reperfusion yields higher survival than earlier normothermic resuscitation in a mouse model of cardiac arrest

BACKGROUND: Therapeutic hypothermia (TH) represents an important method to attenuate post-resuscitation injury after cardiac arrest. Laboratory investigations have suggested that induction of hypothermia before return of spontaneous circulation (ROSC) may confer the greatest benefit. We hypothesized that a short delay in resuscitation to induce hypothermia before ROSC, even at the expense of more prolonged ischemia, may yield both physiological and survival advantages. METHODS: Cardiac arrest was induced in C57BL/6 mice using intravenous potassium chloride; resuscitation was attempted with CPR and fluid administration. Animals were randomized into three groups (n=15 each): a normothermic control group, in which 8 min of arrest at 37 degrees C was followed by resuscitation; an early intra-arrest hypothermia group, in which 6.5 min of 37 degrees C arrest were followed by 90s of cooling, with resuscitation attempted at 30 degrees C (8 min total ischemia); and a delayed intra-arrest hypothermia group, with 90s cooling begun after 8 min of 37 degrees C ischemia, so that animals underwent resuscitation at 9.5 min. RESULTS: Animals treated with TH demonstrated improved hemodynamic variables and survival compared to normothermic controls. This was the case even when comparing the delayed intra-arrest hypothermia group with prolonged ischemia time against normothermic controls with shorter ischemia time (7-day survival, 4/15 vs. 0/15, p<0.001). CONCLUSIONS: Short resuscitation delays to allow establishment of hypothermia before ROSC appear beneficial to both cardiac function and survival. This finding supports the concept that post-resuscitation injury processes begin immediately after ROSC, and that intra-arrest cooling may serve as a useful therapeutic approach to improve survival.     

Influence of mild therapeutic hypothermia on the inflammatory response after successful resuscitation from cardiac arrest

Purpose

Although animal studies document conflicting data on the influence of hypothermia on cytokine release in various settings, no data exist if hypothermia affects the inflammatory response after successful cardiopulmonary resuscitation.

Materials and Methods

Arrest- and treatment-related variables of 71 patients were documented, and serum samples were analyzed for levels of interleukin 6, tumor necrosis factor-α, C-reactive protein, and procalcitonin immediately after hospital admission and after 6, 24, and 120 hours. At day 14, patients were dichotomized in those with good and bad neurological outcome.

Results

Regardless of outcomes, interleukin 6 levels were significantly elevated by the use of hypothermia (n = 39). The rate of bacterial colonization was significantly higher in hypothermic patients (64.1 vs 12.5 %; P < .001). On the contrary, procalcitonin levels were, independent of the use of hypothermia, only significantly elevated in patients with bad neurological outcome. Hypothermic patients showed a strong trend to reduced mortality. However, there was no influence on neurological recovery.

Conclusions

In this observational study, hypothermia influenced the inflammatory response after cardiopulmonary resuscitation and lead to a higher rate of bacterial colonization without altering ultimate neurologic recovery.     

亚低温对兔心肺复苏后凝血及脑微循环的影响

目的 探讨亚低温治疗对兔心肺复苏后凝血异常及脑微循环血流变化的干预作用.方法 本实验在中山大学卫生部辅助循环重点实验室进行.24只成年新西兰大白兔随机(随机数字法)分为常温(normothermic,NT)治疗组和亚低温治疗(therapeutic hypothermia,TH)组,每组12只,采用交流电致颤的方式建立心肺复苏(CPR)模型,自主循环恢复后(ROSC)NT组动物置于室温下观察12 h,TH组动物采用体表降温的方法诱导亚低温,达到目标温度后维持12 h.所有动物CPR前及ROSC后4,8,12 h分别测定PT,APTT,INR,D-D,血小板计数(BPC);测定抗凝血酶Ⅲ活性(AT-Ⅲ)和血浆蛋白C活性(PC);用PERIMED Multichannel Laser Doppler系统监测大脑皮层微循环血流.各组数据依据正态检验结果用单因素方差分析或秩和检验,多重比较用LSD-t检验,两样本均数的比较用成组t检验,相关性采用Pearson相关性分析,以P＜0.05为差异具有统计学意义.结果 NT组动物ROSC后PT,APTT,INR逐渐缩短的趋势,ROSC后12 h APTT明显短于基础值(P=0.025),而AT-Ⅲ和PC活性显著下降.和NT组相比,TH组PT,APTT,INR值显著增大,差异具有统计学意义;但AT-Ⅲ,PC活性、D-D浓度,两组差异无统计学意义.CPR前、ROSC后4,8和12 h NT组大脑皮层血流分别(401.60±11.76),(258.86±34.58),(317.59±23.36)和(371.98±5.79)mL/min,TH组为398.18±12.91.336.19±19.27,347.76±13.80和383.78±3.29 mL/min.ROSC后各时间点TH组大脑皮层血流量明显高于NT组(4 h:t=-6.025,df=16,P=0.000;8 h:t=-2.942,df=12,P=0.012;12 h:t=-3.959,df=8,P=0.004).Pearson相关分析显示ROSC后大脑皮层血流和APTT正相关(4 h:R=0.503,P=0.033;8 h:R=0.565,P=0.035;12 h:R=0.774,P=0.009),与其他凝血指标无关.结论 ROSC后亚低温治疗使凝血功能下降的同时伴随脑微循环血流的增加,CPR后亚低温治疗对ROSC后凝血失衡的影响可能是其发挥脑保护作用的机制之一.

Abstract：

Objective To study the effects of mild hypothermia (MH) on blood coagulation and cerebral microcirculation in rabbits after cardiopulmonary resuscitation (CPR). Method A total of 24 New Zealand rabbits were randomly (random number) divided equally into normothermic group (NT) and MH group. CPR model was established by ventricular fibrillation induced by using alternating current. The rabbits of NT group were observed for 12 h in room temperature after restoration of spontaneous circulation (ROSC). The mild hypothermia was induced in the rabbits of group MH by surface cooling after ROSC, and maintained for 12 h after the aimed low temperature reached. The PT (prothrombin time), APTT (activated partial thromboplastin time), INR (international normalized ratio of prothrombin), D-dimmer (DD) , blood platelet count (BPC) , anti-thrombin Ⅲ activity (AT-Ⅲ) and protein C activity (PC) were measured before CPR and 4 h, 8 h and 12 h after ROSC, and at the same time the cerebral microcirculation was measured by using PERIMED Multichannel Laser Doppler system. One-way ANOVA or Mann-Whitney rank was used to determine the statistical significance between two groups. LSD-t test was used for multiple comparisons,t test for comparisons of means between two independent samples, and Pearson correlation test for correlation analysis. Results The PT, APTT and INR showed a trend of gradually shortening during the course. The APTT in 12 h after ROSC was significantly shorter than that before CPR (23.32 ±5.19 vs. 29.53 ±5.10,P = 0.025), and the activity of AT- Ⅲ and PC were decreased significantly. Compared with the group NT,the PT, APTT and INR in group MH were increased significantly, while there were no differences in the activity of AT- Ⅲ, PC and D-D between two groups. The rates of cerebral microcirculation in group NT before CPR and 4 h, 8 h and 12 h after ROSC were 401.60 ± 11.76 mL/min, 258.86 ± 34. 58 mL/min,317.59 ± 23.36 mL/min and 371.98 ± 5.79 mL/min, respectively, and those in group MT were 398.18 ±12.91 mL/min, 336.19 ± 19.27 mL/min, 347.76 ± 13.80 mL/min and 383.78 ± 3.29 mL/min, respectively. There were significant differences between two groups at each interval after ROSC (4 h: t = - 6.025,df=16, P=0.000;8 h: t= -2.942, df=12, P=0.012;12 h: t= -3.959, df=8, P=0.004). The Pearson correlation test showed that the rate of cerebral microcirculation was positive correlated with APTT after ROSC (4 h:R =0.503,P=0.033;8 h:R=0. 565,P=0. 035;12 h:R=0. 774,P=0. 009), and was not correlated with the other blood coagulants. Conclusions The mild hypothermia led to the inhibition of blood coagulation and improved the cerebral microcirculation concomitantly, which may be one of the mechanism of cerebral protection.     

Use of ice-cold crystalloid for inducing mild therapeutic hypothermia following out-of-hospital cardiac arrest

Objective

Out of hospital cardiac arrest (OHCA) results in a significant mortality and neurological disability in survivors. The application of mild therapeutic hypothermia (MTH) to patients who have suffered an OHCA with a ventricular rhythm results in a significant reduction in mortality and neurological disability in survivors. The optimal timing of this intervention has not been clearly established; however there is emerging evidence to suggest that maximal benefit is gained from initiation at the earliest time point. Despite this, recent surveys have shown a considerable delay in initiating MTH, with variable uptake in emergency departments (EDs), where a number of impediments to delivery have been identified.

Method

We have reviewed the literature to determine what are the barriers to the initiation of MTH in the ED. We also reviewed the literature on the use of ice-cold crystalloids as a practical, simple, effective, and safe method to induce MTH.

Results

Among the several reasons, the perception of a lack of a practical method and logistical constraints are cited as common barriers. However, the available literature on the use of ice-cold crystalloids suggests that this is a safe and effective method of inducing MTH.

Conclusion

ED staff need to be aware that the use of ice-cold fluids is an inexpensive, readily available and easy to perform method of inducing MTH in patients who suffer an out-of hospital cardiac arrest with a ventricular rhythm. We therefore suggest that ice-cold crystalloid is routinely stocked in emergency departments and, unless contraindicated, is used to induce MTH. Optimal post-resuscitation care also includes timely treatment of the cause of the OHCA and maintenance of MTH. Staff education and care bundles may help to facilitate optimal inter-departmental management of the patient.     

Intraosseous infusion of ice cold saline is less efficacious than intravenous infusion for induction of mild therapeutic hypothermia in a swine model of cardiac arrest

Background

Intravenous (IV) infusion of ice cold saline is an effective method to initiate induction of mild therapeutic hypothermia (MTH) following resuscitation from out-of-hospital cardiac arrest (OOHCA). Intraosseous (IO) infusion of cold saline may be an alternative method to induce MTH.

Objective

The goal of this study was to determine if IO infusion of cold saline is a comparable alternative to IV infusion for inducing MTH in a laboratory swine model of cardiac arrest.

Methods

Ten mixed breed swine were resuscitated from cardiac arrest and randomized post-resuscitation to infusion with ice cold saline using either IO (n = 5) or IV (n = 5) access. The study endpoints were either a goal esophageal temperature of 34 °C or the elapse of a 30 min time period, simulating a long prehospital transport.

Results

Four of five pigs in the IV infusion group achieved goal temperature within 30 min compared to 0/5 in the IO infusion group (p = 0.048). The mean esophageal temperature change was significantly higher in the IV group when compared to the IO group (p < 0.001). Post-arrest hemodynamic parameters were similar between the two groups.

Conclusions

IV infusion of ice cold saline is an efficacious method to achieve MTH in this swine model of cardiac arrest. Furthermore, IO infusion of cold saline is not sufficient to induce MTH in the time routinely available in the prehospital setting following OOHCA.     

The emergency cardiac arrest response team (eCART): A novel strategy for improving therapeutic hypothermia utilization following out-of-hospital cardiac arrest

BackgroundOut-of hospital cardiac arrest (OHCA) is associated with significant mortality. Therapeutic hypothermia is one of the few interventions that have been shown to increase post-arrest survival as well as enhance neurologic recovery. Despite clinical guidelines recommending the use of therapeutic hypothermia (TH) following cardiac arrest, utilization rates by physicians remain low. We hypothesized that the development of a multi-disciplinary emergency cardiac arrest response team (eCART) would enhance therapeutic hypothermia utilization in the emergency department for OHCA.Methods and resultsAn eCART (emergency department cardiac arrest response team) was created at a single site academic urban emergency department. The eCART team consisted of a physician hypothermia consultant, a cardiologist, a clinical pharmacist, a respiratory therapist and a chaplain. These providers were notified by page prior to the arrival of an OHCA patient and responded to the ED in person or by phone to support the resuscitation. Analysis of pre- and post-intervention data demonstrated a significant increase in the rate of TH utilization (64% to 96%). There was a non-significant decrease in the time to target temperature.ConclusionsThe creation of a coordinated, multi-disciplinary care team, providing real-time support for OHCA patients increased TH utilization in an emergency department.