Early defibrillation and the chain of survival in 'in-hospital' adult cardiac arrest; minutes count

OBJECTIVE: To report the outcomes from and the impact of the chain of survival in 'in-hospital' cardiac arrest where the presenting rhythm was VF/VT, the arrest was witnessed, defibrillation was conducted rapidly and no other resuscitation interventions were required. Outcome measures: Any return of spontaneous circulation and discharge from hospital. METHODS: A 2-year prospective resuscitation audit using the Utstein style was conducted within a major London NHS Hospital Group. RESULTS: There were 124 patients who had primary VF/VT arrest. Eight were excluded from the study and 14 had non-witnessed cardiac arrest. Twenty one patients had witnessed VF/VT arrest but with delayed defibrillation, 81 patients had witnessed VF/VT arrest with rapid defibrillation, 69 patients had witnessed VF/VT arrest with rapid defibrillation, CPR and other additional interventions. There were 15 patients that had witnessed cardiac arrest with a presenting rhythm of VF/VT, who received rapid defibrillation and had no ventilation or chest compression prior to or following defibrillation. All 15 patients achieved a return of spontaneous circulation, and 12 were discharged alive. CONCLUSIONS: Rapid defibrillation prior to any other resuscitation intervention is associated with increased survival from witnessed VF/VT arrest in in-hospital cardiac arrest victims, and that the time to first shock is critical in enhancing the prospects of long-term survival in these patients.     

院内复苏Utstein模式的临床应用

目的：对国外推荐的院内Utstein模式的适用性及影响复苏预后有关因素等进行初步的探讨。方法：前瞻性地研究本部门一年内心肺复苏抢救的情况。结果：（1）2000年中山医附一院急诊科内执行内肺复苏抢救228例;属于心源性起病者64例,6例（9．4％）存活出院;心源性患者中以室颤为初始心电图者21例,4例（19．0％）存活出院。（2）心源性发病,心室颤为初始心电图,气管插管是影响预后的有利因素,开始复苏间期,开始使用肾上腺素间期,开始除颤间期越短,预后越好。结论：（1）此模式在应用于本部门的心肺复苏研究过程中体现出较好的可行性。（2）为了提高心肺复苏的成功率,对确诊为心搏骤停的患者应尽早开始复苏,尽早使用肾上腺素,室颤患者应尽早行电击除颤,经基本生命支持尚未实现自主呼吸者宜行气管插管。     

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.     

A model of survival following pre-hospital cardiac arrest based on the Victorian Ambulance Cardiac Arrest Register

AIMS: This study describes the epidemiology of sudden cardiac arrest patients in Victoria, Australia, as captured via the Victorian Ambulance Cardiac Arrest Register (VACAR). We used the VACAR data to construct a new model of out-of-hospital cardiac arrest (OHCA), which was specified in accordance with observed trends. PATIENTS: All cases of cardiac arrest in Victoria that were attended by Victorian ambulance services during the period of 2002-2005. RESULTS: Overall survival to hospital discharge was 3.8% among 18,827 cases of OHCA. Survival was 15.7% among 1726 bystander witnessed, adult cardiac arrests of presumed cardiac aetiology, presenting in ventricular fibrillation or ventricular tachycardia (VF/VT), where resuscitation was attempted. In multivariate logistic regression analysis, bystander CPR, cardiac arrest (CA) location, response time, age and sex were predictors of VF/VT, which, in turn, was a strong predictor of survival. The same factors that affected VF/VT made an additional contribution to survival. However, for bystander CPR, CA location and response time this additional contribution was limited to VF/VT patients only. There was no detectable association between survival and age younger than 60 years or response time over 15min. CONCLUSION: The new model accounts for relationships among predictors of survival. These relationships indicate that interventions such as reduced response times and bystander CPR act in multiple ways to improve survival.     

Results of the first five years of the prehospital automatic external defibrillation project in Singapore in the "Utstein style"

In 1994, all emergency medical services (EMS) ambulance officers in Singapore were trained to perform pre-hospital defibrillation with semi-automated external defibrillators (AED). All non-traumatic cardiac arrest patients over 10 years old were included, excluding those who were obviously dead and children below 36 kg. The data were collected by the ambulance officers according to the Utstein guidelines. From 1 February 1994 to 31 January 1999; resuscitation was attempted in 968 non-trauma cardiac arrests. Fifteen percent of the cases were of non-cardiac origin. The overall survival rate was 40/968 (4.1%, 95% CI 2.9-5.6%). Of 968 patients, 22/136 (16.2%, 95% CI 10.4-23.5%), 18/622 (2.9%, 95% CI 1.7-4.5%) and 0/210 (0%, 95% CI 0-1.7%) survived in the EMS witnessed, bystander witnessed and un-witnessed groups, respectively (P < 0.001). Within the EMS witnessed group, those with an initial rhythm of VF/VT had a higher survival rate (30.6%) than those without VF/VT (4.1%). P < 0.001, OR = 10.3, 95% CI 2.9-36.9. Similarly, the VF/VT survival rate in the bystander witnessed group (4.5%) was higher than the non-VF/VT (1.0%) (P = 0.011, OR = 4.4, 95% CI 1.3-15.4). The survival rate of patients with bystander witnessed VF/VT arrest who received bystander CPR was 9.4% compared to 1.0% in those who did not (P = 0.037, OR = 4.4, 95% CI 1.01-20.1). Our survival rate of bystander witnessed VF/VT arrest is comparable to large metropolitan cities in the USA. The determinants of survival include EMS witnessed arrest and VF/VT arrest. Increased quantity and quality of bystander CPR rate may improve the outcome in bystander witnessed cardiac arrest.     

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.     

Interactions between CPR and defibrillation waveforms: effect on resumption of a perfusing rhythm after defibrillation

BACKGROUND: Cardiopulmonary resuscitation (CPR) improves survival from cardiac arrest. The interactions between CPR and the new biphasic (BiP) defibrillation waveforms have not been defined. Our purpose was to compare the effect of CPR versus no CPR during BiP and damped sinusoidal (DS) shocks on the termination of ventricular fibrillation (VF) and the resumption of a perfusing rhythm. METHODS: We studied 20 pigs; VF was induced electrically and allowed to persist for 6 min. During VF episodes each pig received (in random order): (a) 6 min of full CPR (continuous ventilation and closed chest mechanical compression (Thumper, Michigan Instruments)) followed by DS defibrillation at 100 J; (b) no CPR, DS defibrillation; (c) 6 min of full CPR and BiP defibrillation at 100 J; and (d) no CPR, BiP defibrillation. RESULTS: BiP shocks with CPR terminated VF in 83% of attempts versus 45% without CPR (15/18 and 5/11 respectively, P<0.05). DS shocks with CPR were successful in terminating VF in 53% of attempts; DS shocks without CPR were successful in 44% (8/15 and 7/16, respectively, P=NS). No animal achieved a perfusing rhythm after shocks of either waveform if CPR did not precede the shocks during the 6-min VF period, whereas if CPR was administered during VF 46% (11/24) of the combined BiP/DS shocks restored a perfusing rhythm (P<0.01). CONCLUSION: In this experimental long duration VF model, CPR was essential for a perfusing rhythm after termination of VF by shocks with either waveform. CPR facilitated the termination of VF and resumption of a perfusing rhythm after biphasic waveform defibrillation but not after damped sinusoidal waveform defibrillation.     

Bystander vs EMS First–responder CPR: Initial Rhythm and Outcome in Witnessed Nonmonitored Out–of–hospital Cardiac Arrest

Objectives: To assess whether outcome and first–monitored rhythm for patients who sustain a witnessed, nonmonitored, out–of–hospital cardiac arrest are associated with on–scene CPR provider group.
Methods: A retrospective, cohort analysis was conducted in a suburban, heterogeneous EMS system. Patients studied were ± 19 years of age, had had an arrest of presumed cardiac origin between July 1989 and January 1993, had gone into cardiac arrest prior to ALS arrival, and had received CPR on collapse. First–monitored rhythms and survival rates were compared for two patient groups who on collapse either: 1) had received CPR by nonprofessional bystanders (BCPR) or 2) had received CPR by on–scene EMS system first responders (FRCPR).
Results: Of 217 cardiac arrest victims, 153 (71%) had received BCPR and 64 (29%) had received FRCPR. The BCPR patients were slightly younger (62. 4 vs 68. 4 years, p = 0. 01) and had slightly shorter ALS response intervals (6. 4 vs 7. 7 minutes, p = 0. 02). There was no difference in BLS response time intervals or automatic external defibrillator (AED) use rates. The percentage of patients with a first–monitored rhythm of pulseless ventricular tachycardia/ventricular fibrillation (VT/VF) and the percentage of patients grouped by CPR provider who survived to hospital admission or to hospital discharge were:
Controlling for age, the odds ratio for VT/VF with BCPR was 5. 45 (95% CI 2. 8, 10. 3).
Conclusion: Patients who receive BCPR more often have a first–monitored rhythm of VT/VF than do FRCPR patients, despite both CPR–provider groups' initiating CPR essentially immediately after patient collapse. Hence, BCPR and FRCPR groups have different first–monitored arrest rhythms, which may affect survival rate. These patient populations should not be considered to be homogeneous groups in CPR research.     

Epidemiology and outcomes of out-of-hospital cardiac arrest in Rochester, New York

OBJECTIVE: To characterize out-of-hospital cardiac arrest (OHCA) and factors that affect survival in a medium sized city that uses system status management for dispatch. METHODS: A retrospective cohort study of all adult OHCA patients treated by EMS between 1998 and 2001 was conducted using Utstein definitions. The primary endpoint was 1-year survival. RESULTS: Of the 1177 patients who experienced OHCA during the study period, 539 (46%) met inclusion criteria. Age ranged from 18 to 98 years (median 67). The median call-response interval was 5 min (range 0-21), and 93% were 9 min or less. There was no significant difference in the median call-response intervals between call location zip (Post) codes (p=0.07). Twenty percent of experienced ROSC (95% CI 17-23), 7% survived more than 30 days (95% CI 5-9%), and 5% survived to 1 year (95% CI 3-7%). In bivariate analysis, first rhythm and bystander CPR affected survival to 1 year. There was no significant difference in survival between male (4%) and female (7%), black (4%) and white (6%), or witnessed (7%) and unwitnessed arrest (4%). Logistic regression identified younger age, CPR initiated by bystander (19%) or first responder (41%), and presenting rhythm of VF/VT (32%) as factors associated with survival to 1 year. CONCLUSIONS: This study finds a 5% survival to 1 year among OHCA patients in Rochester, NY. A presenting rhythm of VF/VT and bystander CPR were associated with increased survival.     

Rapid on-site defibrillation versus community program

INTRODUCTION: For patients who suffer out-of-hospital cardiac arrest, the time from collapse to initial defibrillation is the single most important factor that affects survival to hospital discharge. The purpose of this study was to compare the survival rates of cardiac arrest victims within an institution that has a rapid defibrillation program with those of its own urban community, tiered EMS system. METHODS: A logistic regression analysis of a retrospective data series (n = 23) and comparative analysis to a second retrospective data series (n = 724) were gathered for the study period September 1994 to September 1999. The first data series included all persons at Casino Windsor who suffered a cardiac arrest. Data collected included: age, gender, death/survival (neurologically intact discharge), presenting rhythm (ventricular fibrillation (VF), ventricular tachycardia (VT), or other), time of collapse, time to arrival of security personnel, time to initiation of cardiopulmonary resuscitation (CPR) prior to defibrillation (when applicable), time to arrival of staff nurse, time to initial defibrillation, and time to return of spontaneous circulation (if any). Significantly, all arrests within this series were witnessed by the surveillance camera systems, allowing time of collapse to be accurately determined rather than estimated. These data were compared to those of similar events, times, and intervals for all patients in the greater Windsor area who suffered cardiac arrest. This second series was based upon the Ontario Prehospital Advanced Life Support (OPALS) Study database, as coordinated by the Clinical Epidemiology Unit of the Ottawa Hospital, University of Ottawa. RESULTS: The Casino Windsor had 23 cases of cardiac arrests. Of the cases, 13 (56.5%) were male and 10 (43.5%) were female. All cases (100%) were witnessed. The average of the ages was 61.1 years, of the time to initial defibrillation was 7.7 minutes, and of the time for EMS to reach the patient was 13.3 minutes. The presenting rhythm was VF/VT in 91% of the case. Fifteen patients were discharged alive from hospital for a 65% survival rate. The Greater Windsor Study area included 668 cases of out-of-hospital cardiac arrest: Of these, 410 (61.4%) were male and 258 (38.6%) were female, 365 (54.6%) were witnessed, and 303 (45.4%) were not witnessed. The initial rhythm was VF/VT was in 34.3%. Thirty-seven (5.5%) were discharged alive from the hospital. CONCLUSION: This study provides further evidence that PAD Programs may enhance cardiac arrest survival rates and should be considered for any venue with large numbers of adults as well as areas with difficult medical access.     

Very high survival among patients defibrillated at an early stage after in-hospital ventricular fibrillation on wards with and without monitoring facilities

BACKGROUND: The association between the interval between collapse and defibrillation and outcome is well described in out of hospital cardiac arrest but not as well in in-hospital cardiac arrest. We report the outcome among patients who suffered an in-hospital cardiac arrest and were found in ventricular fibrillation (VF) with the emphasis on the delay to defibrillation. METHODS AND RESULTS: In patients who suffered an in-hospital cardiac arrest at Sahlgrenska University Hospital in G?teborg between 1994 and 2002 there were 1.570 calls for the rescue team of which 71% had suffered a cardiac arrest. Among cardiac arrests 47% took place on monitored wards. The proportion of patients found in VF was 59% on wards with monitoring facilities and 45% on wards without (p<0.0001). Approximately 90% of these patients were defibrillated 12 min. On monitored wards, the survival was 63% if defibrillated 3 min after collapse (NS). The corresponding values for non-monitored wards were 72% and 35%, respectively (p=0.0003). Cerebral function among survivors at discharge appeared to be good among the majority of patients both in monitored and non monitored wards. CONCLUSION: If patients with in hospital VF were defibrillated early in both monitored and non monitored wards survival to hospital discharge was high. This highlights the importance of being prepared for the rapid defibrillation on wards without monitoring facilities.     

The Increased Mortality from Witnessed Out-of-Hospital Cardiac Arrest in the Home

Abstract

Background. Research in 2008 demonstrated that the majority of out-of-hospital cardiac arrests (OHCAs) occur in the home, and many important characteristics differ between private and public locations. However, the influence of the location of collapse on survival from OHCA is not well understood. Furthermore, most of the reports have been from Western countries; there is little research from Asia that differentiates the conditions of OHCA. Objective. To investigate the influence of the location of collapse on being discharged alive from OHCA and whether the location of collapse is also an independent predictor of survival from OHCA in Japan. Methods. We analyzed 463 consecutive cases of witnessed OHCA with cardiac etiology that occurred between October 2004 and September 2008 in Japan. We investigated the characteristics of OHCA patients who collapsed in private and public locations, and assessed the influence of the location of collapse on survival from OHCA. Results. Patients who collapsed outside the home were younger, more likely to be male, more likely to receive bystander cardiopulmonary resuscitation (CPR), and more likely to have ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT) and had a shorter time interval between collapse and 9-1-1 call than patients who collapsed in the home. Mortality was significantly higher in the group who collapsed in the home. The independent influence of the location of collapse was eliminated by additional adjustment for time interval from collapse to 9-1-1 call, age, bystander CPR, and initial cardiac rhythm. Finally, VF/pulseless VT as the initial rhythm and bystander CPR were independently associated with the patient's being discharged alive; the location of collapse was not an independently associated variable. Conclusions. The present analysis demonstrated that there were significant differences in survival between groups of patients who suffered from cardiac arrest inside and outside the home in Japan. The outside-the-home group had a higher rate of survival from OHCA; however, the location of collapse was not an independent predictor of survival from OHCA. Education of the families of high-risk patients in placing a rapid emergency call and performing effective CPR might be needed to improve survival from cardiac arrest in the home.     

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.     

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.     

Sudden cardiac arrest in Israel: factors associated with successful resuscitation

Out-of-hospital cardiac arrests were studied in Israel from 1984 to 1985. More than 3,500 patients in cardiac arrest received paramedic care. Eighty-three percent of cases were caused by underlying heart disease. Overall, 17% of patients with arrest caused by heart disease were admitted and 7% were discharged from the hospital. There was a wide variation in the percent discharged among the 15 paramedic service areas, ranging from 0% to 13%. Factors associated with successful resuscitation included witnessed collapse, rhythm of ventricular fibrillation, short interval from collapse to cardiopulmonary resuscitation (CPR) and delivery of advanced cardiac life support, collapse at public location, and bystander initiation of CPR. Improvements in survival are likely to result if CPR is more frequently and promptly initiated and the time to arrival of definitive paramedic care can be improved.     

Cardiac arrest outcomes at the Melbourne Cricket Ground and shrine of remembrance using a tiered response strategy-a forerunner to public access defibrillation

The provision of medical, paramedical and first aid services at major public events is an important concern for pre-hospital emergency medical care providers. Patient outcomes of a cardiac arrest response strategy employed at the Melbourne Cricket Ground (MCG) and the Shrine of Remembrance by St John Ambulance Australia volunteers are reported. Twenty-eight consecutive events occurring between December 1989 and December 1997 have been analysed. Included are three cardiac arrests managed at ANZAC day parades utilising the same response strategy by the same unit. The incidence of cardiac arrest at the MCG was 1:500000 attendances. Of the 28 patients, 24 (86%) left the venue alive and 20 (71%) were discharged home from hospital. In all cases the initial rhythm was ventricular fibrillation (VF). All 26 patients (93%) who were defibrillated by St John teams had this intervention within 5 min from the documented time of collapse. One patient in VF spontaneously reverted during CPR. Of the eight fatalities, four died at the scene. At major public venues and events, a co-ordinated emergency life support provision strategy, tailor made for the venue, is necessary for the delivery of prompt CPR, timely defibrillation and advanced life support.     

A Utstein-style analysis of prognostic factors related to survival in out-of-hospital cardiac arrests in Akita-City, Japan

To analyze the epidemiology of out-of-hospital cardiac arrests and to elucidate modifiable factors affecting survival, we conducted a prospective cohort study in a middle-sized urban city served by a single emergency medical service (EMS) system in which emergency medical technicians use an automated external defibrillator. Data were collected from out-of-hospital cardiac arrests occurring between 1 January, 1994 and 31 December, 1998 by applying the Utstein style. The main outcome measure was survival at 1 year after hospital discharge. The overall incidence of out-of-hospital cardiac arrest was 71.7/100 000 inhabitants/year. Resuscitations were attempted in 762 of 1118 patients with confirmed cardiac arrest. Of the 762 patients, 37 (4.86%) survived. The cause of cardiac arrest was presumed to be cardiac in 340 (44.6%). Of the 340 cardiac arrests, 180 (52.9%) were witnessed by bystanders. Ventricular fibrillation (VF) was recorded as an initial rhythm in 56 (31.1%) of the 180 patients, and cardiopulmonary resuscitation (CPR) was performed by bystanders in 89 (49.4%). The survival rate was 39.2% (22/56) when cardiac arrest was bystander-witnessed and of cardiac origin with VF as an initial rhythm. VF as an initial rhythm, age of the patients and intervals of call-to-first CPR attempt and collapse-to-arrival at patient's side were major factors relating to survival in the witnessed cardiac arrests of cardiac origin. The age, and gender of the patients, place of collapse and intervals of collapse-to-first CPR and collapse-to-arrival at patient's side were representative factors affecting the incidence of VF as an initial rhythm. The survival rate in Akita-City from bystander-witnessed cardiac arrests of cardiac origin with VF as an initial rhythm was comparable to those in other regions with advanced EMS systems. However, the incidence of VF as an initial rhythm is extremely low. Reduction of intervals of call (collapse)-to-first CPR attempt and collapse-to-arrival at patient's side or authorization of use of automated external defibrillator in basic life support may increase the incidence of VF as an initial rhythm and improve the survival from witnessed cardiac arrests with cardiac origin.     

Out-of-hospital cardiac arrests occurring in primary health care facilities in Singapore

OBJECTIVES: To study out-of-hospital cardiac arrests (OHCA) occurring in primary healthcare facilities (HCF) in Singapore and to compare these with arrests occurring in the community. METHODS: This prospective observational study was part of the Cardiac Arrest and Resuscitation Epidemiology (CARE) project. Included were all patients with OHCA occurring in HCF. Patient characteristics, cardiac arrest circumstances, EMS response and outcomes were recorded according to the Utstein style. RESULTS: From 1 October 2001 to 14 October 2004, the data from 2428 subjects were received of which 138 patients were OHCA occurring in HCF. This is an incidence of 1.12/100,000 population per year and constituted 6.0% of all OHCA. Arrest occurring in HCF were more likely to be witnessed (p<0.01), or have bystander CPR (p<0.01). The HCF group was also more likely to receive CPR with both compression and ventilation (p<0.01) and have a non-trauma cause of arrest (p=0.03). HCF arrests also had a shorter collapse to call (EMS number) than the non-HCF group (HCF 1.54min versus non-HCF 5.36min, p=0.01). However, no HCF patient received defibrillation prior to EMS arrival. HCF patients were more likely to have return of spontaneous circulation at any time (p=0.05), survival to hospital admission (p<0.01) and survival to discharge (p<0.01) compared to non-HCF patients. CONCLUSION: This study suggests that primary health care providers do have an important role locally in managing out-of-hospital cardiac arrest. We propose an initiative to encourage early defibrillation by primary health care providers.     

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.     

Assessment of a three-phase model of out-of-hospital cardiac arrest in patients with ventricular fibrillation

AIM: Cardiac arrest with ventricular fibrillation (VF) has been divided into three phases in which phase-specific therapy may improve outcome. The aim of this study was to assess the relationship between call-to-shock time, bystander CPR (BCPR), and cardiac arrest outcomes. METHODS: In a retrospective analysis of prospectively-acquired data from witnessed VF out-of-hospital cardiac arrests (OHCA), patients were classified as phases 1, 2, or 3 based on call-to-shock time (<5, 5-8, and >8 min) and further stratified based on performance of BCPR. Groups were compared with regard to survival, neurological outcome, and restoration of spontaneous circulation (ROSC) with defibrillation only (no ALS interventions to achieve sustained ROSC). RESULTS: Survival, neurologically intact survival, and ROSC with defibrillation were different between phases 1 and 2 (p=0.014 and p=0.005, p<0.01) but not between phases 2 and 3. Patients were further classified as having received BCPR (N=111) or no BCPR (N=107). Neurologically intact survival with and without BCPR, respectively, was 61% versus 72% (phase 1), 44% versus 41% (phase 2), and 42% versus 29% (phase 3). ROSC with defibrillation only with and without BCPR, respectively, was 64% versus 56% (phase 1), 37.0% versus 29% (phase 2), and 33% versus 8% (phase 3). ROSC with defibrillation alone was statistically higher in univariate analysis in phase 3 with BCPR (p=0.033) but not in multivariate analysis (p=0.068). CONCLUSIONS: BCPR did not significantly improve survival in any phase of OHCA, though there was a trend toward increased neurologically intact survival and increased ROSC with defibrillation alone in phase 3.