A MIODARONE AND R URAL E MERGENCY M EDICAL S ERVICES C ARDIAC A RREST P ATIENTS : A C OST A NALYSIS

Objective: Recent American Heart Association guidelines suggest amiodarone as an antiarrhythmic in refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). The authors sought to assess the impact of amiodarone use on outcomes and cost associated with this practice in a rural emergency medical services (EMS) state. Methods: Statewide EMS records were reviewed for the calendar year 1999. Data reviewed included prehospital diagnosis, medications given by prehospital providers to patients with cardiac arrest, and procedures performed, including cardiopulmonary resuscitation (CPR) and defibrillation. Cost-benefit analysis assumed the cost of amiodarone treatment to be $137.65 per patient encounter. Absolute risk reduction (ARR) and number needed to treat (NNT) analysis utilized resuscitation rates published in the ARREST and ALIVE trials. Results: During the study period, EMS providers diagnosed 2,189 patients as having cardiac arrest. Five hundred thirty-five (24.4%) cardiac arrest patients were defibrillated. One hundred sixty patients (7.3%), including 15 who did not receive defibrillation, were given lidocaine during resuscitation efforts. The annual cost increase from current practice for a statewide amiodarone VF/VT protocol was $21,822.40 (10,572.87%). The initial cost to stock EMS vehicles for this protocol would be $50,115.52. The cost-benefit analysis yielded a potential for one additional patient survival to hospital discharge in Maine per 3.125 years of system-wide practice at a cost of $68,840.00. Conclusion: Based on current data, instituting amiodarone treatment for refractory VF and pulseless VT in a rural EMS setting requires the investment of substantial resources, relative to current treatment strategies, for any potential survival benefit.     

EMS defibrillation-first policy may not improve outcome in out-of-hospital cardiac arrest

OBJECTIVE: Early defibrillation using automated external defibrillators (AEDs) has been advocated to improve survival in witnessed out-of-hospital cardiac arrest (OHCA) due to pulseless ventricular tachycardia (VT) and ventricular fibrillation (VF). However, when VT/VF is untreated and prolonged for more than a few minutes, defibrillation using AEDs may fail. METHODS: This retrospective study reviewed the charts from local emergency medical service (EMS) between the years 1993 to 2001 to evaluate the value of the AED after its introduction into our EMS. All witnessed OHCA due to VT/VF were analysed; cases of collapse witnessed by EMS were excluded. The primary endpoint was defined as survival to hospital discharge and at 1-year follow-up, and the secondary endpoint as survival without major neurological deficit. A total of 76 patients were treated for witnessed VT/VF before the implementation of the AED and 92 patients after its implementation. RESULTS: Before the introduction of paramedic AED defibrillation, physician defibrillation was performed at 15.6 min (+/-5.5, S.D.). After the introduction of AED defibrillation, paramedic defibrillation was performed at 5.7 min (+/-2.4, S.D.); the mean response interval from the call to defibrillation was shortened significantly (P<0.001). At the same time, survival to hospital discharge decreased from 23.7% (18/76 patients) to 14.1% (13/92) (P=0.112) and at 1-year follow-up from 17.1% (13/76) to 9.8% (9/92) (P=0.161). Favourable neurological outcome at 1-year follow-up also decreased from 14.5% (11/76) to 8.7% (8/92) (P=0.239). CONCLUSION: Implementation of the AED did not improve survival or a favourable neurological outcome in patients with OHCA due to VF/VT. However, with 5.7 min time to defibrillation, our EMS did not meet the criteria for early defibrillation. For prolonged periods of VT/VF, initial basic life support (BLS) may be superior to immediate AED. If response times of <4 min cannot be attained by the emergency systems, reconsidering of resuscitation algorithms seems to be advisable.     

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.     

Resuscitating Resuscitation: Advanced Therapies for Resistant Ventricular Dysrhythmias

BackgroundMore than 640,000 combined in-hospital and out-of-hospital cardiac arrests occur annually in the United States. However, survival rates and meaningful neurologic recovery remain poor. Although “shockable” rhythms (i.e., ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT)) have the best outcomes, many of these ventricular dysrhythmias fail to return to a perfusing rhythm (resistant VF/VT), or recur shortly after they are resolved (recurrent VF/VT).ObjectiveThis review discusses 4 emerging therapies in the emergency department for treating these resistant or recurrent ventricular dysrhythmias: beta-blocker therapy, dual simultaneous external defibrillation, stellate ganglion blockade, and extracorporeal cardiopulmonary resuscitation. We discuss the underlying physiology of each therapy, review relevant literature, describe when these approaches should be considered, and provide evidence-based recommendations for these techniques.DiscussionEsmolol may mitigate some of epinephrine's negative effects when used during resuscitation, improving both postresuscitation cardiac function and long-term survival. Dual simultaneous external defibrillation targets the region of the heart where ventricular fibrillation typically resumes and may apply a more efficient defibrillation across the heart, leading to higher rates of successful defibrillation. Stellate ganglion blocks, recently described in the emergency medicine literature, have been used to treat patients with recurrent VF/VT, resulting in significant dysrhythmia suppression. Finally, extracorporeal cardiopulmonary resuscitation is used to provide cardiopulmonary support while clinicians correct reversible causes of arrest, potentially resulting in improved survival and good neurologic functional outcomes.ConclusionThese emerging therapies do not represent standard practice; however, they may be considered in the appropriate clinical scenario when standard therapies are exhausted without success.     

Procainamide and Survival in Ventricular Fibrillation Out‐of‐hospital Cardiac Arrest

Objectives: Procainamide is an antiarrhythmic drug of unproven efficacy in cardiac arrest. The association between procainamide and survival from out‐of‐hospital cardiac arrest was investigated to better determine the drug’s potential role in resuscitation. Methods: The authors conducted a 10‐year study of all witnessed, out‐of‐hospital, ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) cardiac arrests treated by emergency medical services (EMS) in King County, Washington. Patients were considered eligible for procainamide if they received more than three defibrillation shocks and intravenous (IV) bolus lidocaine. Four logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CI) describing the relationship between procainamide and survival. Results: Of the 665 eligible patients, 176 received procainamide, and 489 did not. On average, procainamide recipients received more shocks and pharmacologic interventions and had lengthier resuscitations. Adjusted for their clinical and resuscitation characteristics, procainamide recipients had a lower likelihood of survival to hospital discharge (OR = 0.52; 95% CI = 0.36 to 0.75). Further adjustment for receipt of other cardiac medications during resuscitation negated this apparent adverse association (OR = 1.02; 95% CI = 0.66 to 1.57). Conclusions: In this observational study of out‐of‐hospital VF and pulseless VT arrest, procainamide as second‐line antiarrhythmic treatment was not associated with survival in models attempting to best account for confounding. The results suggest that procainamide, as administered in this investigation, does not have a large impact on outcome, but cannot eliminate the possibility of a smaller, clinically relevant effect on survival. ACADEMIC EMERGENCY MEDICINE 2010; 17:617–623 © 2010 by the Society for Academic Emergency Medicine     

Adherence to CPR guidelines during perioperative cardiac arrest in a developing country

BACKGROUND AND GOAL OF STUDY: Cardiopulmonary resuscitation (CPR) is an integral part of anaesthetic training. In Nigeria, these skills are taught mainly during medical school and postgraduate training. International guidelines were introduced in 2000 and new guidelines were produced in November 2005. The study sought to assess how closely anaesthetists in a Nigerian teaching hospital abide by the 2000 guidelines. MATERIALS AND METHODS: All perioperative cardiac arrests in adults that occurred in a 1-year-period were studied prospectively. All patients <15 years and cardiac arrests occurring outside the direct supervision of the anaesthetists were excluded. Time and duration of arrest, cardiac arrest rhythm and management were documented along with immediate outcome. RESULTS: Thirteen cardiac arrests occurred in 2147 perioperative cases (incidence: 6/1000). Seven patients had non ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) rhythms. The mean age of patients was 30.23+/-11.06 years. Orotracheal intubation, manual ventilation with 100% O(2) and external chest compressions were instituted in all cases. The mean duration of arrest was 25.66+/-13.34 min. All patients received adrenaline (epinephrine) and atropine. The median interval between adrenaline doses was 7.5 min. Only one cycle of defibrillation was given to patients in VF/VT. Immediate survival occurred in five patients (38.46%). CONCLUSION: Anaesthetists in our hospital are not applying proper resuscitation guidelines. The lack of organised simulation practice resulted in deficient knowledge and skills. There is a need for continuing training in basic and advanced resuscitation for all anaesthetists according to the guidelines.     

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.     

Effectiveness of Prehospital Dual Sequential Defibrillation for Refractory Ventricular Fibrillation and Ventricular Tachycardia Cardiac Arrest

Objective: Dual sequential defibrillation (DSD) — successive defibrillations with two defibrillators — offers a novel approach to refractory ventricular fibrillation (RVF) and tachycardia (VF/VT). While associated with rescue shock success, the effect of DSD upon out-of-hospital cardiac arrest (OHCA) is unknown. We evaluated the association of DSD with survival after refractory VF/VT OHCA. Methods: We used data from a large metropolitan fire-based EMS service. We included all adult OHCA during 2013–2016 with ≥3 standard defibrillations. Physicians authorized subsequent DSD use by two separate defibrillators (PhysioControl LIFEPAK® 12/15) with pads placed anterior-lateral and anterior-posterior. Evaluated outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to 72?hours, and survival to hospital discharge. Using multivariable logistic regression, we evaluated the association between defibrillation type and OHCA outcomes, adjusting for patient demographics and event characteristics. Results: We included 310 patients in the analysis, 71 patients receiving DSD and 239 receiving conventional defibrillation. Patient demographics and event characteristics were similar between both groups. ROSC was lower for DSD than standard defibrillation: 39.4% vs. 60.3%, adjusted OR 0.46 (95% CI: 0.25–0.87). There were no differences in survival to hospital admission (35.2% vs. 49.2%, adjusted OR 0.57 [95% CI: 0.30–1.08]), survival to 72?hours (21.4% vs. 32.3%, adjusted OR 0.52 [95% CI: 0.26–1.10]), or survival to hospital discharge (14.3% vs. 20.9%, adjusted OR 0.63 [95% CI: 0.27–1.45]). Conclusions: Compared with conventional defibrillation, DSD was associated with lower odds of prehospital ROSC. Defibrillation type was not associated with other OHCA endpoints. DSD may not be beneficial in refractory VF/VT OHCA.     

The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest

Introduction  

Partial pressure of end-tidal carbon dioxide (PetCO2) during cardiopulmonary resuscitation (CPR) correlates with cardiac output and consequently has a prognostic value in CPR. In our previous study we confirmed that initial PetCO2 value was significantly higher in asphyxial arrest than in ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) cardiac arrest. In this study we sought to evaluate the pattern of PetCO2 changes in cardiac arrest caused by VF/VT and asphyxial cardiac arrest in patients who were resuscitated according to new 2005 guidelines.     

Neurological outcomes in patients transported to hospital without a prehospital return of spontaneous circulation after cardiac arrest

Introduction

As emergency medical services (EMS) personnel in Japan are not allowed to perform termination of resuscitation in the field, most patients experiencing an out-of-hospital cardiac arrest (OHCA) are transported to hospitals without a prehospital return of spontaneous circulation (ROSC). As the crucial prehospital factors for outcomes are not clear in patients who had an OHCA without a prehospital ROSC, we aimed to determine the prehospital factors associated with 1-month favorable neurological outcomes (Cerebral Performance Category scale 1 or 2 (CPC 1–2)).

Methods

We analyzed the data of 398,121 adult OHCA patients without a prehospital ROSC from a prospectively recorded nationwide Utstein-style Japanese database from 2007 to 2010. The primary endpoint was 1-month CPC 1–2.

Results

The rate of 1-month CPC 1–2 was 0.49%. Multivariate logistic regression analysis indicated that the independent variables associated with CPC 1–2 were the following nine prehospital factors: (1) initial non-asystole rhythm (ventricular fibrillation (VF): adjusted odds ratio (aOR), 9.37; 95% confidence interval (CI), 7.71 to 11.4; pulseless ventricular tachycardia (VT): aOR, 8.50; 95% CI, 5.36 to 12.9; pulseless electrical activity (PEA): aOR, 2.75; 95% CI, 2.40 to 3.15), (2) age <65 years (aOR, 3.90; 95% CI, 3.28 to 4.67), (3) arrest witnessed by EMS personnel (aOR, 2.82; 95% CI, 2.48 to 3.19), (4) call-to-hospital arrival time <24 minutes (aOR, 2.58; 95% CI, 2.22 to 3.01), (5) arrest witnessed by any layperson, (6) physician-staffed ambulance, (7) call-to-response time <5 minutes, (8) prehospital shock delivery, and (9) presumed cardiac cause. When four crucial key factors (with an aOR >2.0 in the regression model: initial non-asystole rhythm, age <65 years, EMS-witnessed arrest, and call-to-hospital arrival time <24 minutes) were present, the rates of 1-month CPC 1–2 and 1-month survival were 16.1% and 23.2% in initial VF, 8.3% and 16.7% in pulseless VT, and 3.8% and 9.4% in PEA, respectively.

Conclusions

In OHCA patients transported to hospitals without a prehospital ROSC, nine prehospital factors were significantly associated with 1-month CPC 1–2. Of those, four are crucial key factors: initial non-asystole rhythm, age <65 years, EMS-witnessed arrest, and call-to-hospital arrival time <24 minutes.     

Improvements in Out-of-Hospital Cardiac Arrest Survival from 1998 to 2013

Objectives: Out-of-hospital cardiac arrest (OHCA) remains a major public health burden. Aggregate OHCA survival to hospital discharge has reportedly remained unchanged at 7.6% for almost 30 years from 1970 to 2008. We examined the trends in adult OHCA survival over a 16-year period from 1998 to 2013 within a single EMS agency. Methods: Observational cohort study of adult OHCA patients treated by Tualatin Valley Fire & Rescue (TVF&R) from 1998 to 2013. This is an ALS first response fire agency that maintains an active Utstein style cardiac arrest registry and serves a population of approximately 450,000 in 9 incorporated cities in Oregon. Primary outcomes were survival to hospital discharge in all patients and in the subgroup with witnessed ventricular fibrillation/pulseless ventricular tachycardia (VF/VT). The impact of key covariates on survival was assessed using univariate logistic regression. These included patient factors (age and sex), event factors (location of arrest, witnessed status, and first recorded cardiac arrest rhythm), and EMS system factors (response time interval, bystander CPR, and non-EMS AED shock). We used multivariate logistic regression to examine the impact of year increment on survival after multiple imputation for missing data. Sensitivity analysis was performed with complete cases. Results: During the study period, 2,528 adult OHCA had attempted field resuscitation. The survival rate for treated cases increased from 6.7% to 18.2%, with witnessed VF/VT cases increasing from 14.3% to 31.4% from 1998 to 2013. Univariate analysis showed that younger age, male sex, public location of arrest, bystander or EMS witnessed event, initial rhythm of pulseless electrical activity (PEA) or VF/VT, bystander CPR, non-EMS AED shock, and a shorter EMS response time were independently associated with survival. After adjustment for covariates, the odds of survival increased by 9% (OR 1.09, 95%CI: 1.05–1.12) per year in all treated cases, and by 6% (OR 1.06, 95% 1.01–1.10) per year in witnessed VF/VT subgroups. Findings remained consistent on sensitivity analysis. Conclusions: Overall survival from treated OHCA has increased over the last 16 years in this community. These survival increases demonstrate that OHCA is a treatable condition that warrants further investigation and investment of resources.     

Survival Increases with CPR by Emergency Medical Services before defibrillation of out-of-hospital ventricular fibrillation or ventricular tachycardia: Observations from the Resuscitation Outcomes Consortium

Background

Immediate defibrillation is the traditional approach to resuscitation of cardiac arrest due to ventricular fibrillation or tachycardia (VF/VT). Delaying defibrillation to provide chest compressions may improve survival. We examined the effect of the duration of Emergency Medical Services (EMS) cardiopulmonary resuscitation (CPR) prior to first defibrillation on survival in patients with out-of-hospital VF/VT.

Materials and methods

From a prospective multi-center observational registry of EMS-treated out-of-hospital cardiac arrest, we identified 1638 EMS-treated cardiac arrests with first recorded rhythm VF/VT or “shockable” and complete data for analysis. Survival to hospital discharge was determined as a function of EMS CPR duration prior to first shock.

Results

Compared to the reference group of first EMS CPR duration ≤45 s, the odds of survival was greater among patients who received between 46 and 195 s of EMS CPR before first shock (46-75 s odds ratio [OR] 1.15, 95% confidence interval [CI] 0.71-1.87; 76-105 s, OR 1.37, 95% CI 0.80-2.35; 106-135 s, OR 1.53, 95% CI 0.96-2.45; 136-165 s, OR 1.24, 95% CI 0.71-2.15; 166-195 s, OR 1.47, 95% CI 0.85-2.52). The benefit of EMS CPR before defibrillation was reduced when the duration of CPR exceeded 195 s (196-225 s, OR 0.95, 95% CI 0.47-1.81; 226-255 s, OR 0.91, 95% CI 0.46-1.79; 256-285 s, OR 0.46, 95% CI 0.17-1.29; 286-315 s, OR 1.29, 95% CI 0.59-2.85). An optimal EMS CPR duration was not identified and no duration achieved statistical significance.

Conclusion

In this observational analysis of VF/VT arrest, between 46 and 195 s of EMS CPR prior to defibrillation was weakly associated with improved survival compared to ≤45 s. Randomized trials are needed to confirm the optimal duration of EMS CPR prior to defibrillation and to assess the impact of first CPR duration on all initial rhythms.     

Rapid Sequence Intubation and Rapid Sequence Airway: An Airway911 Guide, 2nd Edition

Abstract

Background. Cardiac arrest as a consequence of deep accidental hypothermia is associated with high mortality. Standardized prehospital management as well as rewarming with extracorporeal circulation (ECC) are important factors to improve survival. The objective of this case report is to illustrate the importance of effective cardiopulmonary resuscitation (CPR) and ECC in a cardiac arrest following deep accidental hypothermia. Case report. A 42-year-old man was found unresponsive to external stimuli and pulseless at an outdoor temperature of 1°C. CPR was started at the scene by laypersons, and the emergency medical services (EMS) arrived 5 minutes after the emergency call. Resuscitation according to International Liaison Committee on Resuscitation (ILCOR) guidelines was initiated by EMS. The first recorded rhythm was ventricular fibrillation (VF), which persisted, despite repeated defibrillation. The patient showed signs of severe hypothermia and, during ongoing CPR, was transported to hospital where on arrival the patient's rectal temperature was measured at 22°C. Resuscitation measures were continued and warming was started at the emergency room. Due to persistent VF and deep hypothermia, the patient was transferred to a cardiothoracic surgical unit for rewarming with ECC. At commencement of ECC, CPR had been going for approximately 130 minutes and a total of 38 defibrillations had been made. During this time interval the patients was pulseless. At a core temperature of 30°C, one defibrillation restored sinus rhythm and subsequently stable circulation was achieved. The patient received a further 24 hours of hypothermia treatment at 32–34°C. He was discharged to rehabilitation facilities after 3 weeks of hospital care. Three months after the cardiac arrest the patient was fully recovered, was back to work, and had resumed normal activities. Conclusions. We demonstrate a case of cardiac arrest due to deep accidental hypothermia that stresses the importance of effective CPR and early-stage consideration of the use of ECC for safe and effective rewarming.     

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.     

The Changing Incidence of Ventricular Fibrillation in Milwaukee,Wisconsin (1992–2002)

Objectives. To investigate the changes in annual incidence andsurvival of out-of-hospital cardiac-etiology arrests of different initial rhythms, particularly ventricular fibrillation (VF) andventricular tachycardia (VT), among adults (> 21 years old) in Milwaukee County between 1992 and2002 andestablish correlations with patient andemergency medical services (EMS) system-dependent factors. Methods. The study was a retrospective, observational study of all adult (> 21-year-old) patients with out-of-hospital cardiac-etiology arrests with identifiable rhythm andresuscitation attempted by the Milwaukee County EMS system from 1992 to 2002. Nine thousand one hundred seventy cases were enrolled. Primary outcome measures were changes in annual incidence of initial cardiac arrest rhythm, with a focus on VF/VT. Secondary outcome measures were changes in survival to hospital admission andhospital discharge for VF andVT. Patient andEMS system factors potentially affecting the outcome measures were identified andmodeled using multivariate logistic regression. Results. The incidence of out-of-hospital VF/VT arrests decreased steadily from 37.1 per 100,000 in 1992 to 19.4 per 100,000 in 2002. While the incidences of pulseless electrical activity andoverall cardiac arrest remained unchanged, the incidence of asystole during the study period increased from 27.3/100,000 to 44.9/100,000. Multivariate regression analyses revealed that age < 80 years, male gender, white race, previous cardiac surgery, andcardiac history were patient-dependent factors predictive of VF/VT. Witnessed arrest, public location, andshorter response time were EMS system-dependent factors predictive of VF/VT. Based on observed trends, none of these correlated factors could explain the decrease in the incidence of VF/VT arrests. Rates of patient survival to hospital admission anddischarge were not significantly changed over time. EMS system factors predictive of survival to admission anddischarge were witnessed arrest, public location, anddecreased number of defibrillations. Prior cardiac surgery andabsence of chronic problems were the only patient factors predictive of survival to hospital admission but were not significantly related to survival to hospital discharge. Conclusions. The incidence of out-of-hospital cardiac arrests in adult patients with presenting rhythm of VF/VT declined, while an increase in asystole occurred. This was not explained by any patient or EMS system-dependent factor. Rate of survival for VF/VT arrest did not significantly change over time. Survival was primarily influenced by EMS system factors andunrelated to patient-dependent factors.     

Pharmacologic treatment of cardiac arrest

Antiarrhythmic drugs currently recommended in the American Heart Association's Advanced Cardiac Life Support (ACLS) guidelines for the treatment of cardiac arrest have not been proved in controlled clinical trials to improve survival in patients with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). Intravenous amio-darone is a promising agent for the treatment of VF and VT. Based on available evidence, amiodarone should be considered for use in patients with shock-refractory ventricular arrhythmias.     

Double Simultaneous Defibrillators for Refractory Ventricular Fibrillation

Background

Out-of-hospital cardiac arrest is a leading cause of death in the United States. Ventricular fibrillation (VF) is the most common initial rhythm after cardiac arrest.

Objective

To describe a novel approach to the patient with intractable VF after cardiac arrest.

Case Report

A 51-year old man presented in cardiac arrest after a ST-elevation myocardial infarction. He remained in VF despite receiving typical therapy including cardiopulmonary resuscitation, amiodarone, lidocaine, epinephrine, and five attempts at defibrillation with 200 J using a biphasic defibrillator. VF was eventually terminated with 400 J by the simultaneous use of two biphasic defibrillators. The patient had a full recovery.

Conclusion

We present a case and supportive literature for a novel treatment of high-energy defibrillation in a patient with refractory VF.     

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.     

beta-Blockers for the treatment of cardiac arrest from ventricular fibrillation?

More than 160,000 people suffer sudden cardiac death each year in the US. It is estimated that ventricular fibrillation (VF) is the initial rhythm in approximately 30% of these cases. Ventricular fibrillation that does not respond to the first few defibrillation attempts is associated with mortality rates of up to 97%. Currently, no pharmacological intervention has been shown to increase long-term survival in patients with shock-refractory VF. The purpose of this review article is to evaluate whether beta-blocker administration during the resuscitation of cardiac arrest from VF or pulseless ventricular tachycardia (VT) improves outcome. We searched the MEDLINE and EMBASE databases for human clinical trials, animal experimental trials, review articles, case reports and abstracts published between 1966 and September 2006. No human prospective randomized controlled trial has studied the effects of beta-blocker administration during VF directly. Prospective trials of anti-arrhythmics with beta-blocking properties have been published, as well as several case reports/case series and experimental animal studies. The evidence thus far suggests that beta-blockade during resuscitation from VF may be associated with increasing rates of resuscitation, greater post-resuscitation survival, and improved post-resuscitation myocardial function. These positive effects on outcome may be mediated by a decrease in the oxygen requirements of the fibrillating heart, thus improving the overall balance between myocardial oxygen supply and demand during resuscitation. While no significant detrimental effects directly related to low dose beta-blockade during VF have been reported in the studies reviewed, concerns relating to possible loss of myocardial contractility and hypotension remain. To this day, high quality human trials are lacking. Preliminary human studies are needed to assess the effects of beta-blockers in the treatment of cardiac arrest from ventricular fibrillation or pulseless VT further.     

Survival rate and factors associated with 1-month survival of witnessed out-of-hospital cardiac arrest of cardiac origin with ventricular fibrillation and pulseless ventricular tachycardia: the Utstein Osaka project

OBJECTIVE: We reassessed 1-month survival of patients with witnessed out-of-hospital cardiac arrest (OHCA) of cardiac origin with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) in Osaka, Japan, and identified factors associated with 1-month survival using updated data from 1998 to 2004 collected based on the Utstein Style. METHODS: Using the Utstein Osaka Project database, we analyzed 1028 cases which met the following criteria: (1) patient age 18 years or older; (2) presumed cardiac origin based on the definition of the Utstein Style; (3) witnessed by citizens; (4) VF or pulseless VT at the time of arrival of the ambulance. The main outcome measure was survival at 1 month after collapse. Variables to develop a predictive model for 1-month survival were selected by stepwise logistic regression. RESULTS: Survival at 1 month was 19.6%. Factors retained in the final logistic regression were age, sex, type of witness, and time interval from (a) ambulance call receipt to cardiopulmonary resuscitation (CPR) by the ambulance crew; (b) ambulance call to defibrillation; (c) CPR by the ambulance crew to hospital arrival. Area under the receiver-operating characteristic curve for the model developed with the six variables was 0.738 and Hosmer-Lemshow goodness-of-fit p-value was 0.94. CONCLUSION: We successfully developed a model to estimate the probability of 1-month survival using variables easy to collect in the early phase of resuscitation, and this model would help physicians and family members predict the likelihood of 1-month survival of OHCA patients on admission.