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.     

Recommended guidelines for reviewing, reporting, and conducting research on post-resuscitation care: the Utstein style

The aim of this report is to establish recommendations for reviewing, reporting, and conducting research during the post-resuscitation period in hospital. It defines data that are needed for research and more specialised registries and therefore supplements the recently updated Utstein template for resuscitation registries. The updated Utstein template and the out-of-hospital "Chain of Survival" describe factors of importance for successful resuscitation up until return of spontaneous circulation (ROSC). Several factors in the in-hospital phase after ROSC are also likely to affect the ultimate outcome of the patient. Large differences in survival to hospital discharge for patients admitted alive are reported between hospitals. Therapeutic hypothermia has been demonstrated to improve the outcome, and other factors such as blood glucose, haemodynamics, ventilatory support, etc., might also influence the result. No generally accepted, scientifically based protocol exists for the post-resuscitation period in hospital, other than general brain-oriented intensive care. There is little published information on this in-hospital phase. This statement is the result of a scientific consensus development process started as a symposium by a task force at the Utstein Abbey, Norway, in September 2003. Suggested data are defined as core and supplementary and include the following categories: pre-arrest co-morbidity and functional status, cause of death, patients' quality of life, in-hospital system factors, investigations and treatment, and physiological data at various time points during the first three days after admission. It is hoped that the publication of these recommendations will encourage research into the in-hospital post-resuscitation phase, which we propose should be included in the chain-of-survival as a fifth ring. Following these recommendations should enable better understanding of the impact of different in-hospital treatment strategies on outcome.     

Maximisation of cerebral blood flow during experimental cardiopulmonary resuscitation does not ameliorate post-resuscitation hypoperfusion.

Continuous intra-aortic balloon occlusion has been reported to improve cerebral blood flow during cardiopulmonary resuscitation (CPR) but not to ameliorate the impaired blood recirculation occurring after restoration of spontaneous circulation (ROSC). Volume expansion with hypertonic solutions may improve recovery of brain function by enhancing post-resuscitation cerebral blood flow. We hypothesised that the combination of these treatments with open-chest CPR would improve cerebral blood flow during CPR, and attenuate post-resuscitation flow disturbances. In 32 anaesthetised piglets, catheters were placed for haemodynamic and blood gas monitoring. Open-chest CPR was initiated after 9 min of ventricular fibrillation. The piglets were treated either with 3 ml kg(-1) hypertonic saline and dextran (HSD) (n = 10), HSD and balloon occlusion (n = 10) or with normal saline (n = 12). After 7 min of CPR, internal defibrillatory shocks were administered to restore spontaneous circulation. Haemodynamic variables, continuous cerebral cortical blood flow, cerebral tissue pH and pCO2 and blood gas parameters were measured during CPR and up to 210 min after ROSC. Higher cerebral perfusion pressure was found in the balloon-HSD group during CPR. This group exhibited less arterial hypertension immediately after ROSC compared with the other groups. Thereafter, a fairly rapid decrease of the perfusion pressures was observed in all groups reaching a minimum level approximately 30 min after ROSC. Cerebral cortical blood flow was significantly higher and cerebral oxygen extraction ratio significantly lower in the balloon-HSD group during CPR, but not after ROSC. In conclusion, a combination of intra-aortic balloon occlusion and HSD administration improves cerebral blood flow and brain oxygen supply during experimental open-chest CPR. In contrast, cerebral blood flow after ROSC was not shown to be influenced by this treatment.     

Effects of an angiotensin II antagonist on organ perfusion during the post-resuscitation phase in pigs

BACKGROUND: The aim of this study was to compare pre-arrest and post-resuscitation organ perfusion values and to investigate whether, during the post-resuscitation phase, administration of the angiotensin II antagonist telmisartan (TELM) 10 min after restoration of spontaneous circulation (ROSC) could improve organ flow in comparison to placebo. RESULTS: Five minutes after ROSC in the TELM group, blood flow in the cortex and myocardium increased to 583% (P < 0.05) and 137% (not significant), respectively, whereas blood flow of the colon, stomach and pancreas decreased to 50% (P < 0.05), 28% (P < 0.05) and 19% (P < 0.05) of pre-arrest values, respectively. At 90 min after ROSC, pre-arrest perfusion values both in non-splanchnic and splanchnic organs were achieved. At no point in time were there significant differences between the two groups with respect to organ blood flow or speed of recovery of organ perfusion. CONCLUSIONS: During the post-resuscitation phase, organ blood flow is characterized by the coincidence of increased cerebral and myocardial blood flow and decreased intestinal blood flow. Administration of TELM 10 min after ROSC did not improve the recovery of organ perfusion.     

Statistical analysis of joint short-term and long-term survival in resuscitation research

OBJECTIVE: To develop statistical tools that use combined initial survival data and post-resuscitation survival data to test the null hypothesis that true, population-wide outcomes following experimental CPR interventions are not different from control. METHOD: A new test statistic, d(2), for evaluating Type 1 error is derived from a bivariate, two-dimensional analysis of categorical initial resuscitation and post-resuscitation survival data, which are statistically independent because they are obtained during non-overlapping periods of time. The d(2) test statistic, which is distributed as a chi-squared distribution, is derived from first principles and validated using Monte Carlo methods of computer simulation for thousands of clinical trials. RESULTS: Under the null hypothesis, the normalized difference in the proportions of patients surviving the initial resuscitation period and the normalized difference in the proportions of such short-term survivors that also survive the post-resuscitation period are jointly distributed in a two-dimensional space as a bivariate standard normal distribution, against which observed intervention and control outcomes can be compared in a test of statistical significance. Typically this two-dimensional approach has greater statistical power to detect true differences, compared to conventional one-dimensional tests. Smaller group sizes (Ns) are usually required to reach statistical significance when both initial survival and post-resuscitation survival are considered together. Such two-dimensional analysis is easily extended to meta-analysis of multiple trials. CONCLUSIONS: A straightforward, easy-to-use bivariate test for Type I errors in statistical inference can be done for resuscitation studies reporting both short-term and long-term survival data. Acceptance of such two-dimensional tests of the null hypothesis, as proposed by Hallstrom, can save time, money, effort, and disappointment in the difficult and sometimes frustrating field of resuscitation research.     

Re-examining outcomes after unsuccessful out-of-hospital resuscitation in the era of field termination of resuscitation guidelines and regionalized post-resuscitation care

BackgroundDismal prognosis after failed out-of-hospital resuscitation has previously been demonstrated. Changes in resuscitation and post-resuscitation care may affect patient outcomes. We describe characteristics and outcomes of patients with out-of-hospital cardiac arrest (OOHCA) transported to specialty cardiac centers after failure of out-of-hospital interventions.MethodsIn Los Angeles (LA) County, patients with non-traumatic OOHCA with return of spontaneous circulation (ROSC) are transported to specialized cardiac care centers. Outcomes are reported to a registry maintained by the LA County Emergency Medical Services (EMS) Agency. We report patient characteristics and outcomes for the subset of patients treated at these specialty centers in whom initial ROSC was achieved in the ED. The primary outcome was neurologically intact survival, defined by a cerebral performance category (CPC) score of 1 or 2.Results105 patients transported to the SRC after failure to achieve ROSC with out-of-hospital resuscitation were successfully resuscitated in the ED. The median age was 68 years (IQR 57–78); 74 (70%) were male. The presenting rhythm was ventricular fibrillation or ventricular tachycardia in 40 patients (38%) and 86 (82%) were witnessed. Twenty-two patients (21%) survived to hospital discharge. Of the 103 patients with known CPC scores, 13 (13% [95% CI 7–21%]) survived to hospital discharge with a CPC score of 1 or 2. No patient who survived with good neurologic outcome met criteria for termination of resuscitation in the field.ConclusionFailure of out-of-hospital resuscitation is not universally predictive of poor neurologic outcome.     

脉搏血氧波形衍生参数对心肺复苏质量的评估价值研究北大核心CSCD

目的脉搏血氧波形(pulse oximetry plethysmographic waveform,POP)为无创监测方法获得,相比于有创监测技术,其在心肺复苏期间的临床可用性更高。本研究旨在分析基于POP波形获取的三个参数:心肺复苏质量指数(CPR quality index,CQI)、灌注指数(perfusion index,PI)与按压分数(chest compression fraction,CCF)对心肺复苏质量与患者复苏可能性的评估价值。方法本研究为前瞻性描述性研究,基于74例心肺复苏病例,以患者是否自主循环恢复(return of spontaneous circulation,ROSC)将其分为ROSC组与非ROSC组。通过导出与分析临床原始数据,获取以上参数在心肺复苏过程中的分布与变化,进而研究上述参数对患者预后的临床评估价值。结果在患者复苏终末期,三个参数在两组患者间差异均有统计学意义(P<0.05)。且CQI对于复苏患者ROSC可能性的评估价值显著高于PI与CCF(P<0.05)。结论通过POP波形获取的CQI、PI与CCF参数在复苏终末期均可对心肺复苏质量与患者ROSC可能性进行评估,其中CQI的评估价值高于PI与CCF。     

Dynamic evaluation of myocardial dysfunction in rats after cardiopulmonary resuscitation Zhao Shen北大核心CSCD

Objective: To observe the dynamic changes of myocardial structure and dysfunction during post-resuscitation period in order to establish a rat mode of post-resuscitation myocardial dysfunction after cardiac arrest resulted from electric stimulation-induced ventricular fibrillation (VF) and cardiopulmonary resuscitation (CPR). Methods: A total of 40 male Sprague-Dawley (SD) rats were randomly (random number) assigned into post-resuscitation (PR) 4 h, PR 12 h, PR 24 h, PR 72 h and sham groups. VF was induced by an alternating electric current delivered to the right ventricular endocardium and untreated for 8 min. Biphasic waveform defibrillation was attempted and mechanical ventilation was synchronized after 6 min of CPR. Myocardial function was assessed with serum myocardial enzyme activity, echocardiography, mitochondrial respiratory function and histopathologic findings at different intervals. Results: Thirty-two animals were successfully resuscitated with restoration of spontaneous circulation (ROSC) in 86% (32/37) rats. Compared with sham group, severe systolic and diastolic heart failure were found at 4 h after ROSC and then gradually improved without significant difference (P > 0. 05) in ejection fraction at PR 72 h after ROSC was found, whereas thickened ventricular wall and increased myocardial performance index as well as interstitial proliferation were observed at 72 h after ROSC. Conclusions: A rat model of post-resuscitation myocardial dysfunction after cardiac arrest resulted from electric stimulation-induced VF and CPR was successfully established.     

A comparison of electrically induced cardiac arrest with cardiac arrest produced by coronary occlusion

OBJECTIVE: The present study was undertaken to compare an animal model of electrically induced VF with ischemically induced VF. In a preponderance of models of cardiac arrest and resuscitation in intact animals, ventricular fibrillation (VF) is induced by an alternating current delivered directly to the epicardium or endocardium. Yet, the applicability of such animal models has been challenged for it is not an electrical current alone but rather a current generated in the ischemic myocardium that triggers VF. Accordingly, a potentially more clinically relevant model was investigated in which spontaneous VF followed acute myocardial ischemia. METHODS: Twenty anesthetized pigs were randomized to either electrical fibrillation or myocardial ischemia following transient occlusion of the left anterior descending (LAD) coronary artery. RESULTS: VF was untreated for 7 min in both models after which mechanical ventilation and precordial compression were begun. Defibrillation was attempted after 5 min of CPR in both groups. VF appeared within 5.7+/-2.0 min of LAD occlusion. CONCLUSIONS: A significant increase in the number of post-resuscitation premature ventricular beats and recurrent VF followed ROSC and a significantly greater number of shocks was required for restoration of spontaneous circulation (ROSC) after LAD occlusion. Nevertheless, early post-resuscitation myocardial dysfunction, neurological recovery and 72 h survival were indistinguishable between the two models.     

Cardiovascular response to epinephrine varies with increasing duration of cardiac arrest

OBJECTIVE: Epinephrine (adrenaline) is widely used as a primary adjuvant for improving perfusion pressure and resuscitation rates during cardiopulmonary resuscitation (CPR). Epinephrine is also associated with significant myocardial dysfunction in the post-resuscitation period. We tested the hypothesis that the cardiac effects of epinephrine vary according to the duration of cardiac arrest. METHODS AND MATERIALS: Cardiac arrest (CA) was induced in Sprague-Dawley rats with an IV bolus of KCl (40 microg/g). Three series of experiments were performed with CPR begun after 2, 4, or 6 min of cardiac arrest. Epinephrine (0.01 mg/kg) IV or placebo was given immediately in the 2 and 4 min CA groups. In the 6 min group, CPR was started after 6 min CA and epinephrine was given at 15 min if no return of spontaneous circulation (ROSC) occurred. Time to ROSC was recorded in all groups. Cardiac function was determined with trans-thoracic echocardiography at baseline, 5, 30 and 60 min after ROSC. RESULTS: After 2 min CA, 8/8 (100%) placebo animals and 8/8 (100%) epinephrine animals attained ROSC. Cardiac index was significantly increased during the first 60 min in the epinephrine group compared with the placebo group (p<0.01). After 4 min of cardiac arrest, 14/29 (48%) placebo animals and 14/16 (88%) epinephrine animals attained ROSC (p<0.01). Cardiac index after ROSC returned to baseline in both groups, although tended to be lower in the epinephrine group. After 6 min CA, 10/31 (32%) animals attained ROSC without epinephrine and 17/21 (81%) animals with epinephrine (p<0.01). Post-ROSC depression of cardiac index was greatest in the epinephrine group (p<0.05). CONCLUSIONS: As the duration of cardiac arrest increases, a paradoxical myocardial epinephrine response develops, in which epinephrine becomes increasingly more important to attain ROSC, but is increasingly associated with post-ROSC myocardial depression.     

Capnography as a predictor of the return of spontaneous circulation

EtCO2 monitoring is a valuable tool for clinical management of patients in cardiac arrest, near-arrest and post-arrest. During cardiac arrest, EtCO2 levels fall abruptly at the onset of cardiac arrest, increase after the onset of effective CPR and return to normal at return of spontaneous circulation (ROSC). During effective CPR, end-tidal CO2 has been shown to correlate with cardiac output, coronary perfusion pressure, efficacy of cardiac compression, ROSC and even survival. Colorimetric detectors (shown to correlate with infrared capnometry) have been shown to have prognostic value in both adult and pediatric CPR. The higher the initial value of EtCO2, the greater was short-term survival. EtCO2 is a useful tool during patient resuscitation for evaluating the current and potential effects of treatment, and could be potentially useful in determining when to terminate resuscitation efforts.     

Bench to Bedside Resuscitation from Prolonged Ventricular Fibrillation

Ventricular fibrillation (VF) remains the most common cardiac arrest heart rhythm. Defibrillation is the primary treatment and is very effective if delivered early within a few minutes of onset of VF. However, successful treatment of VF becomes increasingly more difficult when the duration of VF exceeds 4 minutes. Classically, successful cardiac arrest resuscitation has been thought of as simply achieving restoration of spontaneous circulation (ROSC). However, this traditional approach fails to consider the high early post-cardiac arrest mortality and morbidity and ignores the reperfusion injuries, which are manifest in the heart and brain. More recently, resuscitation from cardiac arrest has been divided into two phases; phase I, achieving ROSC, and phase II, treatment of reperfusion injury. The focus in both phases of resuscitation remains the heart and brain, as prolonged VF remains primarily a two-organ disease. These two organs are most sensitive to oxygen and substrate deprivation and account for the vast majority of early post-resuscitation mortality and morbidity. This review focuses first on the initial resuscitation (achieving ROSC) and then on the reperfusion issues affecting the heart and brain.     

Factors influencing the outcomes after in-hospital resuscitation in Taiwan

BACKGROUND: The effects on prognosis of some advanced interventions established before cardiopulmonary resuscitation are not clear. The outcomes and patterns of various factors of in-hospital resuscitation are also influenced by different disease patterns in different areas. We studied the factors related to outcomes in an oriental country. MATERIALS AND METHODS: We studied the in-hospital resuscitation events in a tertiary medical center in Taipei city, Taiwan. All events and variables were recorded using the Utstein style for in-hospital resuscitation. We measured the influence of patients and event variables on the outcomes of return of spontaneous circulation (ROSC) and survival to discharge. RESULTS: The rate of establishing a ROSC was 67% and the rate of survival to discharge was 17% in the studied population. The 1-year survival rate was 3.9%. Only 17% of the patients resuscitated had coronary artery disease. VT/VF was the initial rhythm in only 13.6% patients. Nearly half (49%) of the resuscitation attempts took place in emergency department (ED). Patients who were already intubated or had received mechanical ventilation before resuscitation had reduced chances of achieving ROSC. (P<0.05). Favorable prognostic factors of survival to discharge were shorter time intervals from patient collapse to arrival of the resuscitation team (69 vs. 154 s, P<0.05) and to confirmation of arrest (93 vs. 217 s, P<0.05). CONCLUSION: Intubation and mechanical ventilation already established before arrest implies an underlying critical illness and reduce the chances of ROSC. Shorter intervals from collapse to resuscitation improve the chance of survival to discharge. The high proportion of resuscitation events occurring in the ED, reflecting ED overcrowding, and low frequency of pre-existing coronary artery disease are unique to our country.     

Post-resuscitation reperfusion injury: comparison of periodic Gz acceleration versus Thumper CPR

The effects of whole body, periodic acceleration (pGz) on cardiopulmonary resuscitation outcome, organ blood flow and tissue inflammatory injury were examined in an experimental pig model, and compared with Thumper (TH)-CPR. VF was induced in 16 pigs, and remained untreated for 3 min, followed by either pGz-CPR or TH-CPR for 15 min. Defibrillation attempts were made at 18 min of VF. Six of eight animals had ROSC in both groups. Post-arrest myocardial dysfunction was present in both groups and progressed over hours. pGz-CPR animals had less wall motion abnormality and higher left ventricular ejection fraction than TH-CPR. The post-resuscitation haemodynamic variables returned to baseline after 3h of ROSC in pGz-CPR group, and remained low in TH-CPR group. The brain blood flow during CPR was similar between TH-CPR and pGz-CPR, 17% and 20% of pre-fibrillation values, respectively. The cardiac blood flow during CPR was significantly lower in pGz-CPR than TH-CPR (TH: 10.2% and pGz: 1.9% of pre-fibrillation value), as well as in other organs. The brain and heart blood flow was significantly higher than pre-fibrillation values after 30 min of ROSC in both groups. The pGz group had significantly higher blood flow in brain, heart and kidney than TH-CPR after 30 min of ROSC. Blood flow in all organs decreased below pre-fibrillation values at 2h of ROSC. Tissue inflammatory injury progressed over hours in the post-resuscitation phase. pGz-CPR group had significantly lower myeloperoxidase (MPO) activity and plasma creatine phosphokinase (CPK) and cardiac troponin I, TNF-alpha, and IL-6 than TH-CPR. Results from the present study demonstrate again that pGz-CPR is an effective method of cardiopulmonary resuscitation, with less post-reperfusion injury compared to TH-CPR.     

窒息法和室颤法致猪心脏骤停后肺损伤的研究

目的 通过窒息和室颤的心脏骤停动物模型,对心肺复苏后肺损伤进行对照研究.方法 将近交系五指山小型猪随机(随机数字法)分为窒息组(AS)和室颤组(VF),每组各24只,分别采用阻塞气管插管和程控电刺激诱导方法制模,制模成功后给予标准的心肺复苏至ROSC,分别测量基础状态、ROSC即刻、15 min、30 min、1h、2h、4h和6h的氧合指数(OI)、呼吸指数(RI)、氧输送(DO2)、血乳酸,并监测同一时刻动物的肺顺应性(Cdyn)、气道阻力(Raw)、血管外肺水指数(EVLWI)和肺血管通透性指数(PVPI);于基础状态时和ROSC 4 h时进行肺核素灌注扫描和PET-CT扫描;ROSC后6h将动物处死后取肺组织进行病理及电镜检查,检测组织中Na+-K+-ATP酶、Ca2-ATP酶、SOD、MDA、Bcl-2、Bax及Caspase3蛋白水平及凋亡指数(AI％)等.结果 窒息组的ROSC率和6h生存率均显著低于室颤组(P＜0.01);在肺组织有关酶学及蛋白(Na+-K+-ATPase、Ca2-ATPase、SOD、MDA、AI％、Bax、Bcl-2和Caspase3)检测方面,窒息组重于室颤组,且凋亡现象更严重(P＜0.01);在呼吸力学各个时间点相关指标(OI、RI、DO2、血乳酸、Cdyn、Raw、EVLWI、PVPI)的监测中,窒息组的各项指标的变化较室颤组更明显,在6h后仍未能恢复至基础状态.窒息组和室颤组在肺灌注核素扫描上,无明显的充盈缺损;而在PET-CT扫描上则可见较明显的充盈缺损区.结论 心脏骤停后肺损伤的发生与导致心脏骤停的病因密切相关,窒息明显重于室颤,而心外按压不是导致此类肺损伤的主要原因.     

Emergency Department inter-hospital transfer for post-cardiac arrest care: Initial experience with implementation of a regional cardiac resuscitation center in the United States

Objective

The American Heart Association recently recommended regional cardiac resuscitation centers (CRCs) for post-resuscitation care following out-of-hospital cardiac arrest (OHCA). Our objective was to describe initial experience with CRC implementation.

Methods

Prospective observational study of consecutive post-resuscitation patients transferred from community Emergency Departments (EDs) to a CRC over 9 months. Transfer criteria were: OHCA, return of spontaneous circulation (ROSC), and comatose after ROSC. Incoming patients were received and stabilized in the ED of the CRC where advanced therapeutic hypothermia (TH) modalities were applied. Standardized post-resuscitation care included: ED evaluation for cardiac catheterization, TH (33–34 °C) for 24 h, 24 h/day critical care physician support, and evidence-based neurological prognostication. Prospective data collection utilized the Utstein template. The primary outcome was survival to hospital discharge with good neurological function [Cerebral Performance Category 1 or 2].

Results

Twenty-seven patients transferred from 11 different hospitals were included. The majority (21/27 [78%]) had arrest characteristics suggesting poor prognosis for survival (i.e. asystole/pulseless electrical activity initial rhythm, absence of bystander cardiopulmonary resuscitation, or an unwitnessed cardiac arrest). The median (IQR) time from transfer initiation to reaching TH target temperature was 7 (5–13) h. Ten (37%) patients survived to hospital discharge, and of these 9/10 (90% of survivors, 33% of all patients) had good neurological function.

Conclusions

Despite a high proportion of patients with cardiac arrest characteristics suggesting poor prognosis for survival, we found that one-third of CRC transfers survived with good neurological function. Further research to determine if regional CRCs improve outcomes after cardiac arrest is warranted.     

Intraaortic balloon occlusion during refractory cardiac arrest. A case report

Despite recent advances in its management, the outcome from cardiac arrest is often poor despite appropriate cardiopulmonary resuscitation (CPR). The coronary perfusion pressure (CPP) achieved during CPR is associated with successful return of spontaneous circulation (ROSC). Continuous balloon occlusion of the descending aorta is an experimental method that can occlude the ‘unnecessary’ part of the circulation, thus diverting generated pressure and blood flow to the heart and brain. We present a case report with a patient unresponsive to standard CPR in which constant intraaortic balloon occlusion achieved ROSC and successful survival.     

Magnetically targeted drug delivery during cardiopulmonary resuscitation and the post-resuscitation period

Treatment with pharmacological agents is frequently required during cardiopulmonary resuscitation efforts and almost always during the post-resuscitation period. However, the lack of scientific evidence, the potent side effects and the association of resuscitation drugs with poor outcome act as a disincentive for their use. The use of magnetic nanoparticles in medicine has great potential. Magnetically targeted drug delivery may be an ideal method of pharmaceutical treatment during the resuscitation efforts and post-resuscitation period. In addition, there is evidence that magnetic nanotechnology may be used in the detection of post-cardiac arrest brain injury. In the light of poor survival of cardiac arrest victims, research in cardiopulmonary resuscitation should focus on this promising technology as soon as possible.     

Association between interval between call for ambulance and return of spontaneous circulation and survival in out-of-hospital cardiac arrest

AIM: To describe the association between the interval between the call for ambulance and return of spontaneous circulation (ROSC) and survival in out-of-hospital cardiac arrest. PATIENTS: All patients suffering an out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation (CPR) was started, included in the Swedish Cardiac Arrest Registry (SCAR) for whom information about the time of calling for an ambulance and the time of ROSC was available. RESULTS: Among 26,192 patients who were included in SCAR and were not witnessed by the ambulance crew, information about the time of call for an ambulance and the time of ROSC was available in 4847 patients (19%). There was a very strong relationship between the interval between call for an ambulance and ROSC and survival to one month. If the interval was less than or equal to 5 min, 47% survived to one month. If the interval exceeded 30 min, only 5% (n = 35) survived to one month. The vast majority of the latter survivors had a shockable rhythm either on admission of the rescue team or at some time during resuscitation. CONCLUSION: Among patients who have ROSC after an out-of-hospital cardiac arrest, there is a very strong association between the interval between the call for ambulance and ROSC and survival to one month. However, even if this delay is very long (> 30 min after calling for an ambulance), a small percentage will ultimately survive; they are mainly patients who at some time during resuscitation have a shockable rhythm. The overall percentage of patients for whom CPR continued for more than 30 min who are alive one month later can be assumed to be extremely low.     

Periodic acceleration (pGz) CPR in a swine model of asphyxia induced cardiac arrest. Short-term hemodynamic comparisons

BACKGROUND: Asphyxia is one of the most common causes of pediatric cardiac arrest, and becoming a more frequently recognized cause in adults. Periodic acceleration (pGz) is a novel method of cardiopulmonary resuscitation (CPR). pGz is achieved by rapid motion of the supine body headward-footward that generates adequate perfusion and ventilation during cardiac arrest. In a swine ventricular fibrillation cardiac arrest model, pGz produced a higher return of spontaneous circulation (ROSC), superior neurological outcome, less echocardiography evidence of post resuscitation myocardial stunning, and decreased indices of tissue injury. In contrast to standard chest compression CPR, pGz does not produce rib fractures. We investigated the feasibility of pGz in severe asphyxia cardiac arrest and assessed whether beneficial effects seen in the VF model of cardiac arrest could be realized. METHODS AND RESULTS: Sixteen swine weight 4+/-1 kg were anesthetized, tracheally intubated, and instrumented to measure, hemodynamics and echocardiography. Asphyxia was induced by occlusion of the tracheal tube. After loss of aortic pulsations (median time 10 min) animals were observed for three additional minutes following which all were in cardiac arrest. The animals were then randomized to receive 10 min of pGz or standard chest compression ventilation performed with a commercial device (Thumper). A single dose of epinephrine (adrenaline) and sodium bicarbonate were given and defibrillation attempted if appropriate for a maximum of 10 min. Both groups received fractional inspired O2 concentration of 100% during CPR and after resuscitation. Four animals in each group (50%) had an initial ROSC, however only two of the four initial survivors remained alive 3h after ROSC. There were no significant differences in blood pressure, coronary perfusion pressure during CPR and after early ROSC between groups. pGz treated animals had significantly lower pulmonary artery pressure; 20+/-4 mmHg compared to Thumper 46+/-5 mmHg, 30 min after ROSC (p<0.01). Surviving animals in both groups had severe myocardial dysfunction at 30 min after ROSC. At necropsy, 25% of the Thumper treated animals had rib fractures, while none occurred in the pGz group. CONCLUSIONS: In a lethal model of asphyxia cardiac arrest, pGz is equivalent to standard CPR, with respect to acute outcomes and resuscitation survival rates but is associated with significantly lower pulmonary artery pressures and does not produce traumatic rib fractures.