Potential Utility of Near-Infrared Spectroscopy in Out-of-Hospital Cardiac Arrest: An Illustrative Case Series

Abstract Objective. We evaluated the measurement of tissue oxygen content (StO(2)) by continuous near-infrared spectroscopy (NIRS) during and following cardiopulmonary rescuscitation (CPR) and compared the changes in StO(2) and end-tidal carbon dioxide (ETCO(2)) as a measure of return of spontaneous circulation (ROSC) or rearrest. Methods. This was a case series of five patients who experienced out-of hospital cardiac arrest. Patients included those who had already experienced ROSC, who were being transported to the hospital, or who were likely to have a reasonable amount of time remaining in the resuscitation efforts. Patients were continuously monitored from the scene using continuous ETCO(2) monitoring and a NIRS StO(2) monitor until they reached the hospital. The ETCO(2) and StO(2) values were continuously recorded and analyzed for comparison of the time points when patients were clinically identified to have ROSC or rearrest. Results. Four of five patients had StO(2) and EtCO(2) recorded during an episode of CPR and all were monitored during the postarrest period. Three patients experienced rearrest en route to the hospital. Downward trends were noted in StO(2) prior to each rearrest, and rapid increases were noted after ROSC. The StO(2) data showed less variance than the ETCO(2) data in the periarrest period. Conclusions. This preliminary study in humans demonstrates that StO(2) dynamically changes during periods of hemodynamic instability in postarrest patients. These data suggest that a decline in StO(2) level may correlate with rearrest and may be useful as a tool to predict rearrest in post-cardiac arrest patients. A rapid increase in StO(2) was also seen upon ROSC and may be a better method of identifying ROSC during CPR than pauses for pulse checks or ETCO(2) monitoring. Key words: resuscitation; hemodynamics; tissue oxygen content; near-infrared spectroscopy; cardiopulmonary resuscitation; return of spontaneous circulation; rearrest.     

潮气末二氧化碳分压对心肺复苏结果的指导和预测作用

目的 探讨潮气末二氧碳(PetCO2)监测在心肺复苏(CPR)期间的临床意义并寻求定值以指导临床抢救.方法 采用回顾性研究方法,选择2003年5月至2009年3月解放军第四五一医院急诊科院内外非外伤性心搏骤停已明确原因的患者124例,监测心搏骤停患者在CPR过程中PetCO2的变化.结果 ①恢复自主循环(ROSC)的71例与未恢复的53例气管插管后性别、年龄、抢救时间比较P值分别为＜0.05,＜0.05,＜0.01,差异具有统计学意义,说明上述因素与复苏成功正相关,但性别和年龄与最终存活率无相关性.②最终存活者PetCO2水平高于未复苏成功者和虽复苏成功但最终院内死亡者,并与施救时间相关.③经过20 min的高级生命支持没有恢复自主循环者PetCO2平均水平在(6.7±1.2) mmHg(1mmHg =0.133 kPa),恢复自主循环者在(33.9±7.8) mmHg (P＜0.01),以20 min高级生命支持后PetCO2水平高于14.4 mmHg作为参考值预期死亡,阳性率和阴性率均为100％.结论 CPR过程中PetCO2的监测对复苏有指导和预测作用.     

Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study

Introduction

Prognosis in patients suffering out-of-hospital cardiac arrest is poor. Higher survival rates have been observed only in patients with ventricular fibrillation who were fortunate enough to have basic and advanced life support initiated soon after cardiac arrest. An ability to predict cardiac arrest outcomes would be useful for resuscitation. Changes in expired end-tidal carbon dioxide levels during cardiopulmonary resuscitation (CPR) may be a useful, noninvasive predictor of successful resuscitation and survival from cardiac arrest, and could help in determining when to cease CPR efforts.

Methods

This is a prospective, observational study of 737 cases of out-of-hospital cardiac arrest. The patients were intubated and measurements of end-tidal carbon dioxide taken. Data according to the Utstein criteria, demographic information, medical data, and partial pressure of end-tidal carbon dioxide (Pet CO ₂) values were collected for each patient in cardiac arrest by the emergency physician. We hypothesized that an end-tidal carbon dioxide level of 1.9 kPa (14.3 mmHg) or more after 20 minutes of standard advanced cardiac life support would predict restoration of spontaneous circulation (ROSC).

Results

Pet CO ₂ after 20 minutes of advanced life support averaged 0.92 ± 0.29 kPa (6.9 ± 2.2 mmHg) in patients who did not have ROSC and 4.36 ± 1.11 kPa (32.8 ± 9.1 mmHg) in those who did (P < 0.001). End-tidal carbon dioxide values of 1.9 kPa (14.3 mmHg) or less discriminated between the 402 patients with ROSC and 335 patients without. When a 20-minute end-tidal carbon dioxide value of 1.9 kPa (14.3 mmHg) or less was used as a screening test to predict ROSC, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%.

Conclusions

End-tidal carbon dioxide levels of more than 1.9 kPa (14.3 mmHg) after 20 minutes may be used to predict ROSC with accuracy. End-tidal carbon dioxide levels should be monitored during CPR and considered a useful prognostic value for determining the outcome of resuscitative efforts and when to cease CPR in the field.     

Difference in end-tidal CO2 between asphyxia cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest in the prehospital setting

IntroductionThere has been increased interest in the use of capnometry in recent years. During cardiopulmonary resuscitation (CPR), the partial pressure of end-tidal carbon dioxide (PetCO₂) correlates with cardiac output and, consequently, it has a prognostic value in CPR. This study was undertaken to compare the initial PetCO₂ and the PetCO₂ after 1 min during CPR in asphyxial cardiac arrest versus primary cardiac arrest.MethodsThe prospective observational study included two groups of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity, and cardiac arrest due to acute myocardial infarction or malignant arrhythmias with initial rhythm ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). The PetCO₂ was measured for both groups immediately after intubation and then repeatedly every minute, both for patients with and without return of spontaneous circulation (ROSC).ResultsWe analyzed 44 patients with asphyxial cardiac arrest and 141 patients with primary cardiac arrest. The first group showed no significant difference in the initial value of the PetCO₂, even when we compared those with and without ROSC. There was a significant difference in the PetCO₂ after 1 min of CPR between those patients with ROSC and those without ROSC. The mean value for all patients was significantly higher in the group with asphyxial arrest. In the group with VF/VT arrest there was a significant difference in the initial PetCO₂ between patients without and with ROSC. In all patients with ROSC the initial PetCO₂ was higher than 10 mmHg.ConclusionsThe initial PetCO₂ is significantly higher in asphyxial arrest than in VT/VF cardiac arrest. Regarding asphyxial arrest there is also no difference in values of initial PetCO₂ between patients with and without ROSC. On the contrary, there is a significant difference in values of the initial PetCO₂ in the VF/VT cardiac arrest between patients with and without ROSC. This difference could prove to be useful as one of the methods in prehospital diagnostic procedures and attendance of cardiac arrest. For this reason we should always include other clinical and laboratory tests.     

海南省多中心心肺复苏Utstien模式注册研究

目的 本研究以心肺复苏乌斯坦因(Utstein)评估模式评价海南省13家医院心搏骤停患者流行病学特征、心肺复苏结果及其影响因素。方法 在Utstein指南基础上设计“海南省心肺复苏Utstein注册登记表”,在2007年1月1日至2010年12月31日期间对海南省13家医院急诊科心搏骤停心肺复苏患者实施注册登记。通过方差分析等统计学方法,对心肺复苏患者实施前瞻性描述性研究。结果 1125例心搏骤停患者男性占73.8％,女性26.2％,年龄为(53.9±13.1)岁,既往病史以冠心病最为多见,其次为高血压病;自主循环恢复率为23.8％,成活出院为7.4％。自主循环恢复和成活出院的患者中发病l min内获得心肺复苏患者所占比例分别为41.8％和49.4％。院内心搏骤停(IHCA)患者和院外心搏骤停(OHCA)患者ROSC率分别为36.3％,11.6％,成活出院率分别为11.5％,3.3％。心室纤颤/无脉性室性心动过速患者188例(16.7％),其自主循环恢复率及成活出院率分别为58.0％,21.8％。心源性心搏骤停448例(39.8％);其中院内与院外心搏骤停患者自主循环恢复率分别为36.3％,11.6％,成活出院率分别为11.5％,3.3％。非心源性心搏骤停677例(60.2％)。三级医院和二级医院自主循环恢复率分别为69.8％和30.2％,成活出院率分别为7.4％和7.3％。结论 心搏骤停更常见于男性。慢性疾病在本组患者中普遍存在,其中以冠心病和高血压病最为多见。院内心搏骤停患者自主循环恢复和成活出院率均明显高于院外心搏骤停患者。心室纤颤/无脉室性心动过速患者心肺复苏自主循环恢复及成活出院率高于其他类型初始心律的患者。缩短心肺复苏启动时间有助于提高自主循环恢复率及成活出院率。     

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.     

Extracorporeal cardiopulmonary resuscitation for adult cardiac arrest patients

Cardiac arrest is a major cause of unexpected death in developed countries, and patients with cardiac arrest generally have a poor prognosis. Despite the use of conventional cardiopulmonary resuscitation (CPR), few patients could achieve return of spontaneous circulation (ROSC). Even if ROSC was achieved, some patients showed re-arrest and many survivors were unable to fully resume their former lifestyles because of severe neurological deficits. Safar et al reported the effectiveness of emergency cardiopulmonary bypass in an animal model and discussed the possibility of employing cardiopulmonary bypass as a CPR method. Because of progress in medical engineering, the system of veno-arterial extracorporeal membrane oxygenation (ECMO) became small and portable, and it became easy to perform circulatory support in cardiac arrest or shock patients. Extracorporeal cardiopulmonary resuscitation (ECPR) has been reported to be superior to conventional CPR in in-hospital cardiac arrest patients. Veno- arterial ECMO is generally performed in emergency settings and it can be used to perform ECPR in patients with out-of-hospital cardiac arrest. Although there is no sufficient evidence to support the efficacy of ECPR in patients with out-of-hospital cardiac arrest, encouraging results have been obtained in small case series.     

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.     

Out-of-hospital cardiopulmonary resuscitation with the AutoPulse system: a prospective observational study with a new load-distributing band chest compression device

OBJECTIVE: To evaluate the effectiveness, the safety, and the practicability of the new automated load-distributing band resuscitation device AutoPulse in out-of-hospital cardiac arrest in the midsized urban emergency service of Bonn city. STUDY DESIGN: Prospective, observational study. METHODS: Measurements of effectiveness were the proportion of patients with a return of spontaneous circulation (ROSC) and end-tidal carbon-dioxide (etCO(2)) values during cardiopulmonary resuscitation (CPR). The indications of safety was the proportion of injuries caused by the device, and practicability was assessed by the measurement of the time taken to setup the AutoPulse. RESULTS: Forty-six patients were resuscitated with the device from September 2004 to May 2005. In 25 patients (54.3%) ROSC was achieved, 18 patients (39.1%) were admitted to intensive care unit (ICU), and 10 patients (21.8%) were discharged from ICU. End-tidal capnography showed significantly higher etCO(2) values in patients with ROSC than in patients without ROSC. The mean time to setup the AutoPulse was 4.7+/-5.9 min, but activation of the device after arrival at the scene in 2 min or less was possible in 67.4%. No injuries were detected after use of the AutoPulse-CPR. CONCLUSION: The AutoPulse system is an effective and safe mechanical CPR device useful in out-of-hospital cardiac arrest CPR. Automated CPR devices may play an increasingly important role in CPR in the future because they assure continuous chest compressions of a constant quality.     

Association of delay to first intervention with return of spontaneous circulation in a swine model of cardiac arrest

OBJECTIVE: No single drug improves survival after cardiac arrest, despite success in animal studies. We sought to determine the duration of circulatory arrest after which maximal drug treatment and a rescue shock would fail to achieve return of spontaneous circulation (ROSC). DESIGN/SUBJECTS: Retrospective analysis of 271 swine (20-30 kg) resuscitation attempts during ventricular fibrillation. Protocols were divided into five categories: immediate countershock, cardiopulmonary resuscitation (CPR) with standard-dose drugs, CPR alone, CPR and high-dose epinephrine (CPR+HDE) (0.1 mg/kg), and CPR with a drug cocktail (CPR+DC) of propanolol (1 mg), epinephrine (adrenaline) (0.1 mg/kg) and vasopressin (40IU). Time to first CPR, time to first drug administration, time to first shock, and protocol were examined as predictors of ROSC using logistic regression with Hosmer-Lemeshow test of fit. Probability of ROSC was calculated from logistic curves. MAIN RESULTS: ROSC occurred in 119 of the 271 swine (44%). Time to first drug and the CPR+DC group were predictors of ROSC. Time to first CPR, the CPR+DC group, and the CPR+HDE group were also predictors of ROSC. Time to first rescue shock, the CPR+DC group, and the CPR+HDE groups were predictors of ROSC. In the CPR+DC group, 50% ROSC occurred at a first CPR time of 13.4 min, first drug time of 14.1 min and first rescue shock time of 17.5 min. CONCLUSIONS: Pre-shock delivery of CPR+DC increases the likelihood of ROSC, and reaches 50% with a time of drug delivery of 14.1 min. ROSC rates of 50% may be achievable using an optimized resuscitation in experimental CPR.     

犬室颤心脏骤停模型的研究与改进

目的建立一种简单、有效、稳定的犬心脏骤停（CA）模型,为心肺脑复苏的实验研究奠定基础。方法选用健康成年犬30只,体质量（15±2）kg,雌雄不限,麻醉后经右颈外静脉置电极导管至右心室,以5mA电流诱发室颤的方法制作CA模型,根据CA时间不同随机分为CA3 min组、CA5 min组和CA8 min组,每组10只,随后进行电除颤及标准胸外心肺复苏术,比较各组的复苏成功率及存活情况。结果诱颤后所有犬心电图均显示室颤波,动脉血压下降并失去波动;各组自主循环恢复（ROSC）情况为CA 3min组：90％（9／10）、CA5min：80％（8／10）、CA8min：20％（2／10）;ROSC率CA3 min组和CA5 min组比较差异无统计学意义（P〉0.05）,CA8 min组与其他2组之间比较差异具有统计学意义（P〈0.05）;CA3rain组与CA5min、CA8 min组存活时间比较差异有统计学意义（P〈0.05）。结论犬经右心室导管诱发室颤制作的心脏骤停模型稳定且可靠,CA3 min后开始复苏具有较好的ROSC率和存活时间,能满足心肺脑复苏基础研究的需要。     

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.     

The prognostic value of end tidal carbon dioxide during cardiac arrest: A systematic review

Introduction

Cardiac arrest is a common presentation to the emergency care system. The decision to terminate CPR is often challenging to heath care providers. An accurate, early predictor of the outcome of resuscitation is needed. The purpose of this systematic review is to evaluate the prognostic value of ETCO₂ during cardiac arrest and to explore whether ETCO₂ values could be utilised as a tool to predict the outcome of resuscitation.

Method

Literature search was performed using Medline and EMBASE databases to identify studies that evaluated the relationship between ETCO₂ during cardiac arrest and outcome. Studies were thoroughly evaluated and appraised. Summary of evidence and conclusions were drawn from this systematic literature review.

Results

23 observational studies were included. The majority of studies showed that ETCO₂ values during CPR were significantly higher in patients who later developed ROSC compared to patients who did not. Several studies suggested that initial ETCO₂ value of more than 1.33 kPa is 100% sensitive for predicting survival making ETCO₂ value below 1.33 kPa a strong predictor of mortality. These studies however had several limitations and the 100% sensitivity for predicting survival was not consistent among all studies.

Conclusion

ETCO₂ values during CPR do correlate with the likelihood of ROSC and survival and therefore have prognostic value. Although certain ETCO₂ cut-off values appears to be a strong predictor of mortality, the utility of ETCO₂ cut-off values during CPR to accurately predict the outcome of resuscitation is not fully established. Therefore, ETCO₂ values cannot be used as a mortality predictor in isolation.     

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.     

Effects of diaspirin cross-linked hemoglobin (DCLHb) during and post-CPR in swine

The purpose of the study was to test the hypothesis that diaspirin cross-linked hemoglobin (DCLHb) can produce improved resuscitation during cardiac arrest. DCLHb, a derivative of human hemoglobin, has previously been demonstrated to produce a vasopressor response that is associated with increased blood flow to vital organs. In addition, it is an oxygen carrier. These effects may be beneficial to extreme low flow states, such as that during cardiac arrest and cardiopulmonary resuscitation (CPR). Experimental cardiac arrest and CPR were carried out in 32 anesthetized immature pigs. In each animal, ventricular fibrillation was induced for 5 min, followed by 10 min of standard CPR with a pneumatic device and room air ventilation. High (15 ml/kg) and low (5 ml/kg) doses of DCLHb or equivalent volume of normal saline were infused at the beginning of CPR in a random and blind manner. Cardiac output, organ blood flow, aortic pressure, coronary perfusion pressure, blood gases, and lactate concentrations were obtained before and during CPR. Following the 10-min CPR, the animals were defibrillated and the return of spontaneous circulation (ROSC) determined. DCLHb treatment achieved 75% ROSC compared with 25% in the saline group (p < 0.05). In addition, a better (p < 0.05) myocardial O(2) delivery, venous blood O(2) content, and myocardial and cerebral perfusion pressure were observed in the DCLHb group. DCLHb treatment during cardiac arrest and CPR significantly improves ROSC. This is most likely related to its improvement in coronary perfusion and myocardial oxygen delivery.     

Transoesophageal cardiac pacing is effective for cardiopulmonary resuscitation in a rat of asphyxial model

OBJECTIVE: To investigate effectiveness of transoesophageal cardiac pacing in a rat model of asphyxial cardiac arrest. METHODS: Ten minutes after the tracheal tube had been clamped, cardiac arrest (CA) occurred in 20 Sprague-Dawley rats, and the rats were assigned randomly to receive cardiopulmonary resuscitation (CPR) in a control group or CPR combined with transoesophageal cardiac pacing in a pacing group. Restoration of spontaneous circulation (ROSC) was defined as an unassisted pulse with a mean arterial pressure (MAP) of >or=20 mmHg for >or=1 min. RESULTS: ROSC was significantly more frequent in the pacing group compared with the control group (7/10 versus 1/10, P<0.05). Faster ROSC and longer survival trend in the pacing group were seen compared with the control group. CONCLUSION: Transoesophageal cardiac pacing is effective for CPR in a rat of asphyxial model. However, the precise mechanism is not clear and further experiments will be necessary.     

Predicting survival from out-of-hospital cardiac arrest.

OBJECTIVE: To determine the effect of a return of spontaneous circulation (RO SC) on survival to hospital discharge as compared to other established predictors of survival. METHODS: A retrospective case review of all out-of-hospital primary cardiac arrests from 01 January, 1992 to 31 December 1994 was conducted. The relative values of age, race, gender, presenting cardiac rhythm, witnessed event, initiation of CPR by bystanders, response time intervals, and return of spontaneous circulation (ROSC) in an Utstein-template database were tested as predictors of survival of patients who had suffered a cardiac arrest in the out-of-hospital setting. The ROSC was defined as return of spontaneous circulation prior to and present upon arrival at the emergency department. Predictors were evaluated for statistical significance using a logistic regression analysis (p < 0.05). Odds ratios (OR) and 95% confidence intervals (CI) with positive and negative predictive values (PPV, NPV) were calculated. RESULTS: Of 832 patients with primary cardiac arrest, 153 (18.4%) had ROSC and 67 (8.1%) survived to hospital discharge. Comparing survivors to nonsurvivors, the mean values for age were 64 to 67 years, with 59.7% to 36.1% being witnessed, 35.8% to 23.9% having bystander CPR initiated, 88.1% to 48.4% having ventricular fibrillation (V-fib) and 82.1% to 64.0% having ROSC. An initial electrocardiographic rhythm of V-fib (p = 0.009; OR = 2.2; CI = 1.2-3.9), and ROSC (p < 0.0001; OR = 5.2; CI = 3.6-7.5) are statistically significant predictors of survival to hospital discharge. The PPV was 13.8% for V-fib and 35.9% for ROSC, and the NPV was 98.0% for V-fib and 98.2% for ROSC. CONCLUSION: Presenting V-fib and out-of-hospital ROSC are significant predictors of survival from cardiac arrest. Failure to obtain ROSC in the out-of-hospital setting strongly suggests consideration for terminating resuscitation efforts.     

延迟使用升压素与肾上腺素在窒息家兔心肺复苏中的疗效比较

目的 观察心肺复苏时延迟使用升压素或肾上腺素对自主循环恢复率的影响，比较两者对窒息性心跳停搏家兔心肺复苏的疗效。方法 62只家兔均在呼气末夹闭气管8min，造成窒息性心脏停搏模型后，开始人工胸外心脏按压及机械通气，期间不用任何药物，复苏5min内恢复自主循环的家兔定义为常规心肺复苏成功，对5min内复苏不成功者，再随机分为两组，分别给予升压素（0．8IU／kg）或肾上腺素（0．2mg／kg）静脉注射，并继续常规心肺复苏：结果 常规心肺复苏的自主循环恢复率为24．19％（15／62），加用升压素和肾上腺素后总的自主循环恢复率提高到48．39％（30／62）。其中升压素组23只家兔中2只复苏成功（8．70％），肾上腺素组24只家兔中13只复苏成功（54．16％），肾上腺素组复苏成功率明显高于升压素组（P=0．001）。结论 对窒息性心脏停搏的家兔心肺复苏时应用升压素或肾上腺素可提高自主循环恢复率。肾上腺素在提高窒息家兔冠脉灌注压及复苏成功率方面明显优于升压素。     

In-hospital cardiac arrest: Is outcome related to the time of arrest?

BACKGROUND: Whether outcome from in-hospital cardiopulmonary resuscitation (CPR) is poorer when it occurs during the night remains controversial. This study examined the relationship between CPR during the various hospital shifts and survival to discharge. METHODS: CPR attempts occurring in a tertiary hospital with a dedicated, certified resuscitation team were recorded prospectively (Utstein template guidelines) over 24 months. Medical records and patient characteristics were retrieved from patient admission files. RESULTS: Included were 174 in-hospital cardiac arrests; 43%, 32% and 25% in morning evening and night shifts, respectively. Shift populations were comparable in demographic and treatment related variables. Asystole (p < 0.01) and unwitnessed arrests (p = 0.05) were more common during the night. Survival to discharge was poorer following night shift CPR than following morning and evening shift CPR (p = 0.04). When asystole (being synonymous with death) was excluded from the analysis, the odds of survival to discharge was not higher for witnessed compared to unwitnessed arrest but was 4.9 times higher if the cardiac arrest did not occur during the night shift (p = 0.05, logistic regression). The relative risk of eventual in-hospital death for patients with return of spontaneous circulation (ROSC) following night shift resuscitation was 1.9 that of those with ROSC following morning or evening resuscitation (Cox regression). CONCLUSIONS: Although unwitnessed arrest is more prevalent during night shift, resuscitation during this shift is associated with poorer outcomes independently of witnessed status. Further research is required into the causes for the increased mortality observed after night shift resuscitation.     

Does the end-tidal carbon dioxide (EtCO2) concentration have prognostic value during out-of-hospital cardiac arrest?

We aimed to investigate the utility of end-tidal carbon dioxide concentration as a prognostic indicator of initial outcome of resuscitation, we conducted a prospective study of EtCO2 in adult victims of out-of-hospital non-traumatic cardiac arrest. We prospectively studied 139 adult patients. The initial, final, average, minimal and maximal EtCO2 was significantly higher in resuscitated patients than in non-resuscitated patients. Using an initial, average and final EtCO2 value of 10 mmHg correctly identified 100% of the patients who were subsequently resuscitated with an acceptable specificity (74.1%; 90%; 81.4%). Important observation from this study is that none of the patients with an average, initial and final EtCO2 level of less than 10 mmHg were resuscitated. Data from this prospective clinical trial indicate that initial, average and final EtCO2 monitoring during CPR is correlated with resuscitation. End-tidal CO2 monitoring has potential as a noninvasive indicator of cardiac output during resuscitation and a prognostic indicator for resuscitation.