Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation

Records on 1,297 people with witnessed out-of-hospital cardiac arrest, caused by heart disease and treated by both emergency medical technicians (EMTs) and paramedics, were examined to determine whether or not early cardiopulmonary resuscitation (CPR) initiated by bystanders independently improved survival. Bystanders initiated CPR for 579 patients (bystander CPR); for the remaining 718 patients, CPR was delayed until the arrival of EMTs (delayed CPR). Survival was significantly better (P less than 0.05) in the bystander-CPR group (32%) than in the delayed-CPR group (22%). Multivariate analysis revealed that the superior survival in the bystander-CPR group was due almost entirely to the much earlier initiation of CPR (1.9 minutes for the Bystander-CPR group and 5.7 minutes for the delayed-CPR group; P less than 0.001). There were significantly more people with ventricular fibrillation (VF) in the bystander-CPR group (80%) than in the delayed-CPR group (68%); and, for people in VF, the survival rate was significantly better if they had received bystander-CPR (37% versus 29%). The authors conclude that early initiation of CPR by bystanders significantly improves survival from out-of-hospital cardiac arrest, and they suggest that it may do so by prolonging the duration of VF after collapse and by increasing cardiac susceptibility to defibrillation. The benefit of this early CPR, however, appears to exist within a rather narrow window of effectiveness. It must be started within 4-6 minutes from the time of collapse and must be followed within 10-12 minutes of the collapse by advanced life support in order to be effective.     

Improved Survival from Cardiac Arrest in the Community

We now know that the elements required to achieve the highest survival rates from out-of-hospital cardiac arrest include: witnessed arrest, rapid telephone notification of the emergency medical service, early initiation of cardiopulmonary resuscitation, rapid arrival within minutes of emergency personnel equipped with a defibrillator, and early advanced airway management and intravenous pharmacology. In the United States, and in several other countries innovative approaches have been tried to bring all these elements together in one system. These approaches include community-wide CPR training programs, telephone-assisted CPR instruction delivered at the time of a cardiac arrest, early defibrillation performed by family members of high risk patients, early defibrillation performed by minimally trained community responders, and early defibrillation performed by minimally trained ambulance personnel. Controlled, prospective studies have demonstrated the effectiveness and practicality of all of these approaches. New studies are in progress with the prehospital use of early transcutaneous cardiac pacing and these show promise. This article reviews the evidence that supports these multi-layered and innovative approaches to the treatment of out-of-hospital cardiac arrest.     

Prompt Advanced Life Support Improves Survival from Ventricular Fibrillation

Objective. To determine whether the interval between the arrival of basic life support (BLS) providers and the arrival of advanced life support (ALS) providers is associated with patient outcome after cardiac arrest. Methods. We conducted a retrospective cohort study of all witnessed, out-of-hospital ventricular fibrillation (VF) cardiac arrests between January 1, 1991, and December 31, 2007. Eligible patients (n = 1,781) received full resuscitation efforts from both BLS and ALS providers. Results. The BLS-to-ALS arrival interval was a significant predictor of survival to hospital discharge (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.93–0.99); the likelihood of survival decreased by 4% for every minute that ALS arrival was delayed following BLS arrival. Other significant predictors of survival were whether the arrest occurred in public (OR 1.48, 95% CI 1.19–1.85), whether a bystander administered cardiopulmonary resuscitation (CPR) (OR 1.34, 95% CI 1.07–1.68), and the interval between the 9-1-1 call and BLS arrival (OR 0.78, 95% CI 0.73–0.83). Conclusions. We found that a shorter BLS-to-ALS arrival interval increased the likelihood of survival to hospital discharge after a witnessed, out-of-hospital VF cardiac arrest. We conclude that ALS interventions may provide additional benefits over BLS interventions alone when utilized in a well-established, two-tiered emergency medical services (EMS) system already optimized for rapid defibrillation. The highest priorities in any EMS system should still be early CPR and early defibrillation, but timely ALS services can supplement these crucial interventions.     

Assessment of the success of cardiopulmonary resuscitation attempts performed in a Turkish university hospital

The success rate of cardiopulmonary resuscitation (CPR) may differ from institution to institution, even within different sites in the same institution. A variety of factors may influence the outcome. In this study, we assessed the adequacy of CPR attempts guided by the current standards and aimed to define the factors influencing the outcome following in-hospital cardiac arrest. One hundred and thirty-four patients who required CPR were studied prospectively. Different variables for the CPR performance were recorded using forms designed for this study in the light of the guidelines. In these CPR forms various data including the demographics, history, monitoring, number, composition and experience of the anaesthesiologists, the site of CPR, time of day, the delay before onset of CPR, tracheal intubation, duration of arrest, initial rhythm in ECG monitored patients, management of CPR, drug administration and reversible causes of cardiac arrest were recorded. Our rates of immediate survival, survival at 24 h and survival to discharge 49.3%, 28.5% and 13.4%, respectively. The extent of monitoring prior to arrest, the attendance of one or more experienced anesthesiologists in the CPR team, CPR during office hours, CPR in ICU or operating room, early initiation of CPR and tracheal intubation prior to arrest were found as the factors increasing discharge survival. We conclude that early initiation of CPR with an experienced team in a well-equipped hospital sites increases the discharge survival rate following cardiac arrest.     

Survival models for out-of-hospital cardiopulmonary resuscitation from the perspectives of the bystander, the first responder, and the paramedic.

Survival from out-of-hospital resuscitation depends on the strength of each component of the chain of survival. We studied, on the scene, witnessed, nontraumatic resuscitations of patients older than 17 years. The influence of the chain of survival and potential predictors on survival was analyzed by logistic regression modeling. From 1030 patients, 139 survived to hospital discharge. Three prediction models of survival were developed from the perspective of the different contributors active in out-of-hospital resuscitation: model I, bystanders; model II, first responders; and model III, paramedics. Predictors for survival (with odds ratio) were: in model I (bystanders): emergency medical service (EMS) witnessed arrest (0.50), delay to basic cardiopulmonary resuscitation (CPR) (0.74/min) and delay to EMS arrival (0.87/min); in model II (first responders): initial recorded heart rhythm (0.02 for nonshockable rhythm), delay to basic CPR (0.71/min and 0.87/min for shockable and nonshockable rhythms) and to defibrillation (0.89/min), and in model III (paramedics): need for advanced CPR (4.74 for advanced CPR not-needed), initial recorded heart rhythm (0.05 for nonshockable rhythm), and delay to basic CPR (0.77/min and 0.72/min for shockable and nonshockable rhythms), to defibrillation and to advanced CPR for shockable rhythms (0.85/min), and to advanced CPR for nonshockable rhythm (0.85/min). The area under the receiver-operator characteristic curve for model I was 0.763, for model II was 0.848, and for model III was 0.896. Of survivors, 50% had restoration of circulation without need for advanced CPR. Three survival models for witnessed nontraumatic out-of-hospital resuscitation based on the information known by bystanders, first responders and paramedics explained survival with increasing precision. Early defibrillation can restore circulation without the need for advanced CPR. When advanced CPR is needed, its delay leads to a markedly reduced survival.     

An analysis of time factors in out-of-hospital cardiac arrest in Osaka Prefecture

OBJECTIVE: To ascertain important factors in the improvement of out-of-hospital cardiac arrest survival rates through analysis of data for Osaka Prefecture with the focus on time factors. DESIGN: Prospective cohort study according to the Utstein style. SETTING: Osaka Prefecture (population 8,830,000) served by a single emergency medical services system. PATIENTS: Consecutive prehospital cardiac arrests occurring between May 1998 and April 1999. MAIN OUTCOME MEASURES: One-year survival from cardiac arrest, and time factors. RESULT: Of the 5047 cases of confirmed cardiac arrests, resuscitation was attempted in 4871 subjects. Of the 982 cases of cardiac origin and witnessed by bystanders, 31 (3.2%) were still alive, and of the 576 cases of non-cardiac origin and witnessed by bystanders, ten (1.7%) were still alive at the 1 year follow-up. The median time from receipt of the emergency call until ambulance arrival was 5 min and that from receipt of the call until the start of cardiopulmonary resuscitation (CPR) was 7 min. For the 214 patients for whom defibrillation was attempted, the median time from receipt of the call until the first shock was 15 min. The median time from receipt of the call until departure of the ambulance from the scene was 16 min and that until arrival of the ambulance at a hospital was 22 min. CONCLUSIONS: This study using the standardized format according to the Utstein style clearly elucidates the specific delay of the start of defibrillation by paramedics and also indicates the inappropriate rule for this procedure in Japan.     

Characteristics of prehospital cardiac arrest patients in Japan and determinant factors for survival

Two hundred forty-seven consecutive patients who had prehospital cardiac arrest and were transferred to a municipal hospital were studied to elucidate the characteristics of these patients and to investigate factors for improving the survival rate among prehospital cardiac arrest patients. Detailed information on 130 patients with cardiac etiology was analyzed: 110 were confirmed dead in the emergency department (group A); 14 survived less than 1 week (group B); 6 survived longer than 1 week (group C). Only one patient received cardiopulmonary resuscitation (CPR) from a bystander, and none received electrical defibrillation before arriving at hospital because, at the time, emergency personnel were not allowed to perform advanced life support (ALS) in Japan. The three characteristics for better prognosis after prehospital cardiac arrest were found to be as follows: being witnessed on collapse, receiving prompt ALS, and ventricular fibrillation on arrival at hospital. The survival rate would have been higher if more lay people could have performed CPR and if emergency unit personnel had been allowed to perform ALS.     

Improved neurologically intact survival with the use of an automated, load-distributing band chest compression device for cardiac arrest presenting to the emergency department

ABSTRACT: INTRODUCTION: It has been unclear if mechanical cardiopulmonary resuscitation (CPR) is a viable alternative to manual CPR. We aimed to compare resuscitation outcomes before and after switching from manual CPR to load-distributing band (LDB) CPR in a multi-center emergency department (ED) trial. METHODS: We conducted a phased, prospective cohort evaluation with intention-to-treat analysis of adults with non-traumatic cardiac arrest. At these two urban EDs, systems were changed from manual CPR to LDB-CPR. Primary outcome was survival to hospital discharge, with secondary outcome measures of return of spontaneous circulation, survival to hospital admission and neurological outcome at discharge. RESULTS: A total of 1,011 patients were included in the study, with 459 in the manual CPR phase (January 01, 2004, to August 24, 2007) and 552 patients in the LDB-CPR phase (August 16, 2007, to December 31, 2009). In the LDB phase, the LDB device was applied in 454 patients (82.3%). Patients in the manual CPR and LDB-CPR phases were comparable for mean age, gender and ethnicity. The mean duration from collapse to arrival at ED (min) for manual CPR and LDB-CPR phases was 34:03 (SD16:59) and 33:18 (SD14:57) respectively. The rate of survival to hospital discharge tended to be higher in the LDB-CPR phase (LDB 3.3% vs Manual 1.3%; adjusted OR, 1.42; 95% CI, 0.47, 4.29). There were more survivors in LDB group with cerebral performance category 1 (good) (Manual 1 vs LDB 12, P=0.01). Overall performance category 1 (good) was Manual 1 vs LDB 10, P=0.06. CONCLUSIONS: A resuscitation strategy using LDB-CPR in an ED environment was associated with improved neurologically intact survival on discharge in adults with prolonged, non-traumatic cardiac arrest.     

The three-phase model of cardiac arrest as applied to ventricular fibrillation in a large, urban emergency medical services system

BACKGROUND: Cardiac arrest is responsible for significant morbidity and mortality, with consistently poor outcomes despite the rapid availability of prehospital personnel for defibrillation attempts in patients with ventricular fibrillation (VF). Recent evidence suggests a period of cardiopulmonary resuscitation (CPR) prior to defibrillation attempts may improve outcomes in patients with moderate time since collapse (4-10 min). OBJECTIVES: To determine cardiac arrest outcomes in our community and explore the relationship between time since collapse, performance of bystander CPR, and survival. METHODS: Non-traumatic cardiac arrest data were collected prospectively over an 18-month period. Patients were excluded for: age <18 years, a "Do Not Attempt Resuscitation" (DNAR) directive, determination of a non-cardiac etiology for arrest, and an initially recorded rhythm other than VF. Patients were stratified by time since collapse (<4, 4-10, > 10 min, and unknown) and compared with regard to survival and neurological outcome. In addition, patients with and without bystander CPR were compared with regard to survival. RESULTS:: A total of 1141 adult non-traumatic cardiac arrest victims were identified over the 18-month study period. This included 272 patients with VF as the initially recorded rhythm. Of these, 185 had a suspected cardiac etiology for the arrest; survival to hospital discharge was 15% in this group, with 82% of these having a good outcome or only moderate disability. Survival was highest among patients with time since collapse of less than 4 min and decreased with increasing time since collapse. There were no survivors among patients with time since collapse greater than 10 min. Among patients with time since collapse of 4 min or longer, survival was significantly higher with the performance of bystander CPR; there was no survival advantage to bystander CPR among patients with time since collapse less than 4 min. CONCLUSIONS: The performance of bystander CPR prior to defibrillation by EMS personnel is associated with improved survival among patients with time since collapse longer than 4 min but not less than 4 min. These data are consistent with the three-phase model of cardiac arrest.     

Shortening of cardiopulmonary resuscitation time before the defibrillation worsens the outcome in out-of-hospital VF patients

Objective

The purpose of the study is to investigate the influence of cardiopulmonary resuscitation (CPR) time before the first defibrillation.

Methods

The present study retrospectively analyzed the Utstein template records from April 1, 2002, to June 30, 2005. Patients who had out-of-hospital–witnessed cardiac arrest caused by cardiac disease and who presented with ventricular fibrillation (VF) as the initial cardiac rhythm were included in the study. Before April 1, 2003, the emergency medical technician (EMT) needed to obtain telephone permission before attempting defibrillation, and CPR was continued until permission was received (CPR first). On and after April 1, 2003, the EMT was immediately able to attempt a defibrillation without obtaining permission (shock first).

Results

In 143 patients who had out-of-hospital–witnessed VF, 43 patients and 100 patients were treated with the CPR-first strategy and the shock-first strategy, respectively. The duration of CPR before the first defibrillation was longer in the CPR-first group than that in the shock-first group. The CPR-first group showed a higher rate of favorable neurologic outcome 30 days after (28% vs 14%; P = .048) and 1 year after cardiac arrest (26% vs 11%; P = .033) than those of the shock-first group. In the patients with witnessed VF, a stepwise multiple logistic regression analysis showed the CPR-first strategy to improve the neurologic outcome.

Conclusions

In patients with out-of-hospital–witnessed VF, sufficient CPR before the first defibrillation is considered to improve the neurologic outcome in comparison to the performance of immediate defibrillation.     

In-hospital cardiac arrest: survival depends mainly on the effectiveness of the emergency response

OBJECTIVES: To evaluate the factors affecting the outcome of in-hospital cardiac arrest. SETTING: A 1400-bed tertiary care teaching hospital with a dedicated cardiac arrest team (CAT). The CAT was immediately available in monitored areas (intensive care unit and emergency room). In the wards the staff had only BLS skills and automated external defibrillation was not available. METHODS: A 2-year prospective audit according to the Utstein style. RESULTS: A total of 114 cardiac arrests (37 with VF/VT and 77 with non-VF/VT) were included. Fifty-two cardiac arrests (46%) occurred in monitored areas, 62 (54%) occurred in non-monitored areas. The CAT arrival time in non-monitored areas was 3.98+/-1.73 min. Thirty-seven patients (32%) survived to hospital discharge. Cardiac arrests occurring in monitored areas had a significantly better outcome than those occurring in the wards. Patient survival in the wards was significantly higher when the CAT arrival time was less than 3 min. No patient whose CAT arrival time was longer than 6 min survived. CAT arrival time was significantly shorter (1.30+/-1.70) in survivors than in non-survivors (2.51+/-2.37; P<0.005). Sex, age and presence of bystanders were not significantly associated with survival. CONCLUSIONS: In our setting, where bystander defibrillation was not available, the survival of patients having cardiac arrest in non-monitored areas strongly depends on advanced life support provided by the CAT. A faster CAT response and early defibrillation from the ward staff are the most important improvements necessary to increase cardiac arrest survival in our setting.     

Utstein style analysis of rural out-of-hospital cardiac arrest [OOHCA]: total cardiopulmonary resuscitation (CPR) time inversely correlates with hospital discharge rate

OBJECTIVE: Survival after out-of-hospital cardiac arrest (OOHCA) in an urban environment is directly proportional to speed of defibrillation and effective bystander cardiopulmonary resuscitation (CPR). We hypothesized that the hospital discharge rate from rural OOHCA was affected by the same factors. METHODS: We studied all OOHCAs in 1998 for rural Alachua County, Florida, with one emergency medical system (EMS) transport provider and three hospitals. All EMS identified OOHCA were reviewed retrospectively, as were EMS and hospital records. The 1998 County population was 211403; 1495 deaths from all causes occurred (70.7/10(4) pop). Of 167 OOHCAs (7.9/10(4) pop), 145 were of cardiac etiology; 22 were excluded (13 scene deaths, four traumatic, one intraoperative and three respiratory arrests, one arrest during a hospital-to-hospital transfer) and in eight outcome data were not available in any form. A total of 137/145 (94.5%) OOHCA patients had analyzable data. Data were analyzed using Student's t-test and ANOVA. Alpha was set at 0.05. RESULTS: Of 25 patients (18.2% of OOHCA) with restoration of spontaneous circulation (ROSC), six survived (4.4% of total, 24% of those with ROSC) to discharge from hospital (four to a skilled nursing facility, one each home with and without assistance). Four patients were still alive at >or=1 year post arrest. Asystole as the initial rhythm (P=0.014), and emergency department (ED) CPR time (8 vs. 15.5 min, P=0.042 for survivors vs. non-survivors) were the only factors statistically affecting survival. While bystander CPR was not significantly different between groups, there was a significantly higher proportion of patients surviving in the ED who had ROSC, and a higher proportion who had ROSC after bystander CPR. Time to defibrillation in nonsurvivors, while not statistically different between city and county patient groups, was clinically different. Statistical significance would likely have been achieved with a larger study population. CONCLUSION: Our data suggest improvement in response time and bystander CPR might further improve survival in a rural setting.     

Cardiopulmonary resuscitation alone vs. cardiopulmonary resuscitation plus automated external defibrillator use by non-healthcare professionals: a meta-analysis on 1583 cases of out-of-hospital cardiac arrest

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) accounts for 250.000-350.000 sudden cardiac deaths per year in the United States. The availability of automated external defibrillators (AEDs) promoted the implementation of public access defibrillation programs based on out-of-hospital early defibrillation by non-healthcare professionals. AIM OF THE STUDY: To perform a systematic review and a meta-analysis of the pooled effect of studies comparing the outcome of pts receiving cardiopulmonary resuscitation plus AED therapy (CPR+AED) vs. cardiopulmonary resuscitation (CPR) alone, both delivered by non-healthcare professionals, for the treatment of OHCA. METHODS: We performed a search of the relevant literature exploring major scientific databases, carrying out a hand search of key journals, analysing conference proceedings and abstracts and discussing the topic with other researchers. Two analyses were planned to assess the outcomes of interest (survival to hospital admission and survival to hospital discharge). RESULTS: Three studies were selected for the meta-analysis. The first meta-analysis evidenced a RR of 1.22 (95% C.I.: 1.04-1.43) of surviving to hospital admission for people treated with CPR+AED as compared to CPR-only. The second meta-analysis showed a RR of 1.39 (95% C.I.: 1.06-1.83) of surviving to hospital discharge for people treated with CPR+AED as compared to CPR-only. CONCLUSIONS: The results of our meta-analysis demonstrate that programs based on CPR plus early defibrillation with AEDs by trained non-healthcare professionals offer a survival advantage over CPR-only in OHCA. The conclusions of our meta-analysis add to previous evidence in favour of developing public-health strategies based on AED use by trained layrescuers.     

An outcome study of out-of-hospital cardiac arrest using the Utstein template--a Japanese experience

Publication of the Utstein style template has made it possible to evaluate and compare national, regional, and hospital based Emergency Medical Services. This research was a national investigation to present outcome data for out-of-hospital cardiac arrest (OHCA) patients in Japan. 3029 OHCA patients who were transported to 10 Emergency and Critical Care Medical Center from November 1997 to April 1999 were recorded according to the Utstein style and the outcome evaluated by logistic regression analysis. Among 3029 OHCA patients, 109 were found dead. The remaining 2920 patients who underwent cardiopulmonary resuscitation (CPR) by emergency medical technicians (EMT) were included in this study. Among these patients, 1294 were considered of primary cardiac origin patients by the EMT and 722 of these patients suffered a witnessed cardiac arrest. Bystander CPR were performed in 28.4% of these witnessed patients and the discharge rate was 3.5% overall and 11.4% in witnessed VF/VT. Outcome analysis showed that a discharge rate in witnessed primary cardiac arrest was 30% in prehospital resuscitation which was 7.5 times higher than in-hospital emergency room resuscitation groups (4.0%). The longer the interval between an emergency telephone call and defibrillation, the lower the 1 month survival rate, which reached almost 0% at 30 min. Follow up evaluation after discharge revealed that the survival rate rapidly decreased from 24 h to 3 months, then became a plateau in primary cardiac patients was rapidly decreased from 24 h to 1 month, then became a near plateau in non-cardiac origin group. To improve the resuscitation rate in the prehospital phase, a prehospital medical control system should be developed with expansion of on scene techniques by Japanese paramedics such as tracheal intubation, administration of emergency drugs and early defibrillation with standing orders. Education and motivation of first responders will be needed and every effort should be concentrated on improving bystander CPR rate.     

Evaluation of the use of automatic external defibrillation in out-of-hospital cardiac arrest in Hong Kong.

A retrospective 6-month audit of out-of-hospital cardiac arrests in Hong Kong following the introduction of automatic external defibrillators is presented. During the 6-month period from 1 July 1995 to 31 December 1995, resuscitation was attempted on 754 patients. Of the 744 patients with cardiac arrest whose records were available, 53.6% had a witnessed arrest. Few cardiac arrest patients (8.9%) received bystander cardiopulmonary resuscitation (CPR) and the majority (80%) of arrests occurred at home. Six hundred and forty-three (86.4%) patients were declared dead on arrival at hospital or in the Accident and Emergency department; 89 (12%) died in hospital and only 12 (1.6%) were discharged alive. The average ambulance response interval (call receipt to arrival of ambulance at scene) was 6.42 min. The average arrest-to-first-shock interval was 23.77 min. Factors predicting survival included initial rhythm and arrest-to-first-shock interval. The survival rate of 1.6% is low by world standards. To improve the survival rates of people with out-of-hospital cardiac arrest, the arrest-to-call interval must be reduced and the frequency of bystander CPR assistance increased. Once these changes are in place, a beneficial effect from the use of pre-hospital defibrillation might be seen.     

Cardiac arrest in Saudi Arabia: a 7-year experience in Riyadh.

All out-of-hospital and Emergency Department (ED) cardiac arrests treated at a tertiary care hospital in Riyadh, Saudi Arabia, from 1989 through 1995 were studied. Of patients arresting out-of-hospital, 3.0% received bystander cardiopulmonary resuscitation (CPR), 9.1% had some prehospital CPR, 12.1% were transported via ambulance, and 13.6% had ventricular fibrillation (VF) on ED arrival. In the witnessed arrests (80%), the estimated interval from arrest to initiation of CPR was 21.1 +/- 14.7 min. None of these variables was shown to influence outcome. Survival to hospital discharge from out-of-hospital arrest was 5.1% for adults and 7.4% for children; all had poor neurologic outcome. For patients arresting in the ED, an initial rhythm of ventricular tachycardia (VT) or VF was strongly correlated with survival. Survival from ED arrest was 30.4% in adults, 42.9% in children; all but one had normal neurologic outcome. These results are similar to those reported from large cities and EDs elsewhere. The unique set of variables influencing out-of-hospital care and transportation in Riyadh are discussed, and potential areas for improvement are noted.     

Sodium bicarbonate improves the chance of resuscitation after 10 minutes of cardiac arrest in dogs.

The likelihood of successful defibrillation and resuscitation decreases as the duration of cardiac arrest increases. Prolonged cardiac arrest is also associated with the development of acidosis. These experiments were designed to determine whether administration of sodium bicarbonate and/or adrenaline in combination with a brief period of cardiopulmonary resuscitation (CPR) prior to defibrillation would improve the outcome of prolonged cardiac arrest in dogs. Ventricular fibrillation (VF) was induced by a.c. shock in anaesthetised dogs. After 10 min of VF, animals received either immediate defibrillation (followed by treatment with bicarbonate or control) or immediate treatment with bicarbonate or saline (followed by defibrillation). Treatment with bicarbonate was associated with increased rates of restoration of spontaneous circulation. This was achieved with fewer shocks and in a shorter time. Coronary perfusion pressure was significantly higher in NaHCO3-treated animals than in control animals. There were smaller decreases in venous pH in NaHCO3-treated animals than in controls. The best outcome in this study was achieved when defibrillation was delayed for approximately 2 min, during which time NaHCO3 and adrenaline were administered with CPR. The results of the present study indicate that in prolonged arrests bicarbonate therapy and a period of perfusion prior to defibrillation may increase survival.     

CPR before defibrillation in out-of-hospital cardiac arrest: a randomized trial

Objective: Current resuscitation guidelines recommend that defibrillation be undertaken as soon as possible in patients suffering a cardiac arrest where the cardiac rhythm is either ventricular fibrillation (VF) or ventricular tachycardia (VT). Evidence from animal and clinical studies suggests that outcomes may be improved if a period of cardiopulmonary resuscitation (CPR) is given prior to defibrillation. The objective of this study was to determine if 90 seconds of CPR before defibrillation improved survival. Methods: Patients suffering non‐paramedic witnessed VF/VT cardiac arrest were randomized to receive either 90 seconds of CPR before defibrillation (treatment) or immediate defibrillation (control). The study was carried out in Perth, Western Australia between June 2000 and June 2002. The primary endpoint was survival to hospital discharge with secondary endpoints of return of spontaneous circulation (ROSC) and survival at 1 year. Results: A total of 256 patients underwent randomization. Baseline characteristics including response intervals were similar in both groups. Survival to hospital discharge in the CPR first group was 4.2% (5/119) compared with 5.1% (7/137) for the immediate defibrillation group (OR 0.81; 95%CI. 0.25–2.64). No difference in those achieving ROSC was observed between the groups (OR 1.16; 95% CI 0.49–2.80). Conclusion: Ninety seconds of CPR before defibrillation does not improve overall survival in patients suffering VF/VT cardiac arrests. Further studies to evaluate various aspects of this treatment strategy are required as published outcomes to date are inconclusive.     

385例院前心肺复苏成败的原因及探讨

目的:通过分析院前死亡病因及现场复苏成败的原因,进一步提高院前急救复苏有效率。方法:回顾性分析我区急救中心2000年1月-2003年12月385例院前心肺复苏病例资料。结果:本组385例死亡原因以心血管疾病、外科创伤、脑血管疾病、不明原因为前4位;全部病例在急救人员到达前均未开展心肺复苏((CPR),其中有最初目击者155例(40.3％);急救中心接到呼救并派出救护车到达现场平均间期在复苏有效组与无效组中分别为8.32min和10.23 min;所有病例经现场复苏无效死亡360例(93.5％),现场复苏有效25例(6.5％),复苏成功1例(0.26％);由急救人员行除颤、气管内插管(或喉罩插管)现场复苏有效率分别为21.2％和33.3％,而未行除颤、气管内插管(或喉罩插管)现场复苏有效率分别为2.3％和0.6％,两者差别有显著意义(P<0.01)。结论:识别高危人群,在人群中普及以CPR为主的初级救护知识,由最初目击者及早开展CPR,尽可能缩短呼救-到达现场间期,早期除颤及气管内插管(或喉罩插管),可提高院前急救复苏有效率。