PubMed Health⌕ Search

Biomedical subjects

Robert A Berg

Publications and source records attributed to Robert A Berg.

At least 19 recordsLinked to original sources
PubMed2006

Single rescuer cardiopulmonary resuscitation: can anyone perform to the guidelines 2000 recommendations?

BACKGROUND: The Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that for adult cardiac arrest the single rescuer performs "two quick breaths followed by 15 chest compressions." This cycle is continued until additional help arrives. Previous studies have shown that lay persons and medical students take 16 +/- 1 and 14 +/- 1 s, respectively, to perform these "two quick breaths." The purpose of this study was to determine the time required for trained professional paramedic firefighters to deliver these two breaths and the effects that any increase in the time it takes to perform rescue breathing would have on the number of chest compressions delivered during single rescuer BLS CPR. We hypothesized that trained professional rescuers would also take substantially longer then the Guidelines recommendation for delivering the two rescue breaths before every 15 compressions during simulated single rescuer BLS CPR. METHODS: Twenty-four paramedic firefighters currently certified to perform BLS CPR were evaluated for their ability to deliver the two recommended breaths within 4 s according to the AHA 2000 CPR Guidelines. Alternatively, a simplified technique of continuous chest compression BLS CPR (CCC) was also taught and compared with standard BLS CPR (STD). Without revealing the purpose of the study the paramedics were asked to perform single rescuer BLS CPR on a recording Resusci Anne while being videotaped. RESULTS: The mean length of time needed to provide the "two quick breaths" during STD-CPR was 10 +/- 1 s. The mean number of chest compressions/min delivered with AHA BLS CPR was only 44 +/- 2. Continuous chest compression CPR resulted in 88 +/- 5 compressions delivered per minute (STD versus CCC; p < 0.0001). CONCLUSIONS: Trained professional emergency rescue workers perform rescue breathing somewhat faster than lay rescuers or medical students, but still require two and one half times longer than recommended. The time required to perform these breaths significantly decreases the number of chest compressions delivered per minute. This may affect outcome as experimental studies have shown that more than 80 compressions delivered per minute are necessary for survival from prolonged cardiac arrest.

Allied Health Personnel↗
PubMed2006

Outcomes of in-hospital ventricular fibrillation in children.

BACKGROUND: Ventricular fibrillation and ventricular tachycardia are less common causes of cardiac arrest in children than in adults. These tachyarrhythmias can also begin during cardiopulmonary resuscitation (CPR), presumably as reperfusion arrhythmias. We determined whether the outcome is better for initial than for subsequent ventricular fibrillation or tachycardia. METHODS: All cardiac arrests in persons under 18 years of age were identified from a large, multicenter, in-hospital cardiac-arrest registry. The results from children with initial ventricular fibrillation or tachycardia, children in whom ventricular fibrillation or tachycardia developed during CPR, and children with no ventricular fibrillation or tachycardia were compared by chi-square and multivariable logistic-regression analysis. RESULTS: Of 1005 index patients with in-hospital cardiac arrest, 272 (27 percent) had documented ventricular fibrillation or tachycardia during the arrest. In 104 patients (10 percent), ventricular fibrillation or tachycardia was the initial pulseless rhythm; in 149 patients (15 percent), it developed during the arrest. The time of initiation of ventricular fibrillation or tachycardia was not documented in 19 patients. Thirty-five percent of patients with initial ventricular fibrillation or tachycardia survived to hospital discharge, as compared with 11 percent of patients with subsequent ventricular fibrillation or tachycardia (odds ratio, 2.6; 95 percent confidence interval, 1.2 to 5.8). Twenty-seven percent of patients with no ventricular fibrillation or tachycardia survived to hospital discharge, as compared with 11 percent of patients with subsequent ventricular fibrillation or tachycardia (odds ratio, 3.8; 95 percent confidence interval, 1.8 to 7.6). CONCLUSIONS: In pediatric patients with in-hospital cardiac arrests, survival outcomes were highest among patients in whom ventricular fibrillation or tachycardia was present initially than among those in whom it developed subsequently. The outcomes for patients with subsequent ventricular fibrillation or tachycardia were substantially worse than those for patients with asystole or pulseless electrical activity.

Adolescent↗
PubMed2006

Ventricular fibrillation waveform characteristics are different in ischemic heart failure compared with structurally normal hearts.

BACKGROUND: For prolonged VF, perfusion of the myocardium by pre-shock chest compressions can improve myocardial readiness for successful defibrillation. Characteristics of the VF waveform correlate with the duration of VF when there is no structural heart disease. A "smart" automated external defibrillator (AED) could therefore analyze the VF waveform, determine if VF has been prolonged, and then direct rescuers to either deliver a shock first or chest compressions first. We hypothesized that ischemic heart failure might alter the waveform content of ventricular fibrillation compared with normal hearts, complicating the determination of VF duration. METHODS: Myocardial infarction was induced by ligating the proximal left coronary artery. Six weeks later, VF was then induced in 10 rats with myocardial infarction and heart failure (MI-CHF) and 9 control rats. Waveforms were analyzed for total signal amplitude, median frequency, dominant frequency and bandwidth (the frequency interval containing 50% of the total amplitude about the median frequency). RESULTS: All of these VF waveform characteristics were altered substantially in MI-CHF rats compared to normal controls. In particular, MI-CHF rats had decreased signal amplitude early in VF (p=0.02), a broader bandwidth (p=0.001) and different frequency characteristics over time (p<0.001). CONCLUSIONS: VF waveforms vary over time in a typical manner among rats with and without ischemic heart failure. However, the time-course and waveform characteristics of ventricular fibrillation are altered in rats with myocardial infarctions and ischemic heart failure compared to normal controls. These findings have important implications regarding the use of waveform analyses to determine the duration of VF.

Animals↗
PubMed2006

First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults.

CONTEXT: Cardiac arrests in adults are often due to ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), which are associated with better outcomes than asystole or pulseless electrical activity (PEA). Cardiac arrests in children are typically asystole or PEA. OBJECTIVE: To test the hypothesis that children have relatively fewer in-hospital cardiac arrests associated with VF or pulseless VT compared with adults and, therefore, worse survival outcomes. DESIGN, SETTING, AND PATIENTS: A prospective observational study from a multicenter registry (National Registry of Cardiopulmonary Resuscitation) of cardiac arrests in 253 US and Canadian hospitals between January 1, 2000, and March 30, 2004. A total of 36,902 adults (> or =18 years) and 880 children (<18 years) with pulseless cardiac arrests requiring chest compressions, defibrillation, or both were assessed. Cardiac arrests occurring in the delivery department, neonatal intensive care unit, and in the out-of-hospital setting were excluded. MAIN OUTCOME MEASURE: Survival to hospital discharge. RESULTS: The rate of survival to hospital discharge following pulseless cardiac arrest was higher in children than adults (27% [236/880] vs 18% [6485/36,902]; adjusted odds ratio [OR], 2.29; 95% confidence interval [CI], 1.95-2.68). Of these survivors, 65% (154/236) of children and 73% (4737/6485) of adults had good neurological outcome. The prevalence of VF or pulseless VT as the first documented pulseless rhythm was 14% (120/880) in children and 23% (8361/36,902) in adults (OR, 0.54; 95% CI, 0.44-0.65; P<.001). The prevalence of asystole was 40% (350) in children and 35% (13 024) in adults (OR, 1.20; 95% CI, 1.10-1.40; P = .006), whereas the prevalence of PEA was 24% (213) in children and 32% (11,963) in adults (OR, 0.67; 95% CI, 0.57-0.78; P<.001). After adjustment for differences in preexisting conditions, interventions in place at time of arrest, witnessed and/or monitored status, time to defibrillation of VF or pulseless VT, intensive care unit location of arrest, and duration of cardiopulmonary resuscitation, only first documented pulseless arrest rhythm remained significantly associated with differential survival to discharge (24% [135/563] in children vs 11% [2719/24,987] in adults with asystole and PEA; adjusted OR, 2.73; 95% CI, 2.23-3.32). CONCLUSIONS: In this multicenter registry of in-hospital cardiac arrest, the first documented pulseless arrest rhythm was typically asystole or PEA in both children and adults. Because of better survival after asystole and PEA, children had better outcomes than adults despite fewer cardiac arrests due to VF or pulseless VT.

Adolescent↗
PubMed2006

Cardiocerebral resuscitation for cardiac arrest.

Survival rates from out-of-hospital cardiac arrest continue to be low despite periodic updates in the Guidelines for Emergency Medical Services and periodic improvements such as the addition of automatic external defibrillators (AEDs). The low incidence of bystander cardiopulmonary resuscitation (CPR), substantial time without chest compressions throughout the resuscitation effort, and a lack of response to initial defibrillation after prolonged ventricular fibrillation contribute to these unacceptably poor results. Resuscitation guidelines are only revised every 5 to 7 years and can be difficult to change because of the lack of randomized controlled trials in humans. Such trials are rare because of a number of logistical difficulties, including the problem of obtaining informed consent. An alternative approach to advancing resuscitation science is for evidence-based demonstration projects in areas that have adequate records, so that one may determine whether the new approach improves survival. This is reasonable because the current guidelines make provisions for deviations under certain local circumstances or as directed by the emergency medical services medical director. A wealth of experimental evidence indicates that interruption of chest compressions for any reason in patients with cardiac arrest is deleterious. Accordingly, a new approach to out-of-hospital cardiac arrest called cardiocerebral resuscitation (CCR) was developed that places more emphasis on chest compressions for witnessed cardiac arrest in adults and de-emphasizes ventilation. There is also emphasis on chest compressions before defibrillation in circulatory phase of cardiac arrest. CCR was initiated in Tucson, Arizona, in November 2003, and in two rural Wisconsin counties in early 2004.

Cardiopulmonary Resuscitation↗
PubMed2006

Cardiopulmonary resuscitation algorithms, defibrillation and optimized ventilation during resuscitation.

PURPOSE OF REVIEW: In 2005, the American Heart Association released its Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. This article reviews the treatment algorithms for Advanced Cardiac Life Support, citing the evidence on which the Guidelines are based. Additional focus is placed on defibrillation and optimized ventilation. RECENT FINDINGS: Major changes include a reorganization of the algorithms for cardiac arrest. Emphasis on effective cardiopulmonary resuscitation is placed as the key to improved survival. Single defibrillation shocks are recommended (compared with three 'stacked' shocks) with immediate provision of cardiopulmonary resuscitation and minimal interruptions in chest compressions. The recommended chest compression : ventilation rate for single rescuers has been changed to 30:2. SUMMARY: Despite advances in resuscitation science, basic life support remains the key to improving survival outcomes. Ultimately, as new knowledge is gained, we believe resuscitation therapies will be more individualized, on the basis of pathophysiology and etiology of the initial cardiac arrest.

Algorithms↗
PubMed2006

Rescuer fatigue: standard versus continuous chest-compression cardiopulmonary resuscitation.

OBJECTIVES: Continuous chest-compression cardiopulmonary resuscitation (CCC-CPR) has been advocated as an alternative to standard CPR (STD-CPR). Studies have shown that CCC-CPR delivers substantially more chest compressions per minute and is easier to remember and perform than STD-CPR. One concern regarding CCC-CPR is that the rescuer may fatigue and be unable to maintain adequate compression rate or depth throughout an average emergency medical services response time. The specific aim of this study was to compare the effects of fatigue on the performance of CCC-CPR and STD-CPR on a manikin model. METHODS: This was a prospective, randomized crossover study involving 53 medical students performing CCC-CPR and STD-CPR on a manikin model. Students were randomized to their initial CPR group and then performed the other type of CPR after a period of at least two days. Students were evaluated on their performance of 9 minutes of CPR for each method. The primary endpoint was the number of adequate chest compressions (at least 38 mm of compression depth) delivered per minute during each of the 9 minutes. The secondary endpoints were total compressions, compression rate, and the number of breaks taken for rest. The students' performance was evaluated on the basis of Skillreporter Resusci Anne (Laerdal, Wappingers Falls, NY) recordings. Primary and secondary endpoints were analyzed by using the generalized linear mixed model for counting data. RESULTS: In the first 2 minutes, participants delivered significantly more adequate compressions per minute with CCC-CPR than STD-CPR, (47 vs. 32, p = 0.004 in the 1st minute and 39 vs. 29, p = 0.04 in the 2nd minute). For minutes 3 through 9, the differences in number of adequate compressions between groups were not significant. Evaluating the 9 minutes of CPR as a whole, there were significantly more adequate compressions in CCC-CPR vs. STD-CPR (p = 0.0003). Although the number of adequate compressions per minute declined over time in both groups, the rate of decline was significantly greater in CCC-CPR compared with STD-CPR (p = 0.0003). The mean number of total compressions delivered in the first minute was significantly greater with CCC-CPR than STD-CPR (105 per minute vs. 58 per minute, p < 0.001) and did not change over 9 minutes in either group. There were no differences in compression rates or number of breaks between groups. CONCLUSIONS: CCC-CPR resulted in more adequate compressions per minute than STD-CPR for the first 2 minutes of CPR. However, the difference diminished after 3 minutes, presumably as a result of greater rescuer fatigue with CCC-CPR. Overall, CCC-CPR resulted in more total compressions per minute than STD-CPR during the entire 9 minutes of resuscitation.

Adult↗
PubMed2006

Higher survival rates among younger patients after pediatric intensive care unit cardiac arrests.

BACKGROUND: Age is an important determinant of outcome from adult cardiac arrests but has not been identified previously as an important factor in pediatric cardiac arrests except among premature infants. Chest compressions can result in more effective blood flow during cardiac arrest in an infant than an older child or adult because of increased chest wall compliance. We, therefore, hypothesized that survival from cardiac arrest would be better among infants than older children. METHODS: We evaluated 464 pediatric ICU arrests from the National Registry of Cardiopulmonary Resuscitation from 2000 to 2002. NICU cardiac arrests were excluded. Data from each arrest include >200 variables describing facility, patient, prearrest, arrest intervention, outcome, and quality improvement data. Age was categorized as newborn (<1 month; N = 62), infant (1 month to <1 year; N = 105), younger child (1 year to <8 years; N = 90), and older child (8 years to <21 years; N = 207). Multivariable logistic regression was performed to examine the association between age and survival. RESULTS: Overall survival was 22%, with 27% of newborns, 36% of infants, 19% of younger children and 16% of older children surviving to hospital discharge. Newborns and infants demonstrated double and triple the odds of surviving to hospital discharge from a cardiac arrest in an intensive care setting when compared with older children. When potential confounders were controlled, newborns increased their advantage to almost fivefold, while infants maintained their survival advantage to older children. CONCLUSIONS: Survival from pediatric ICU cardiac arrest is age dependent. Newborns and infants have better survival rates even after adjusting for potential confounding variables.

Age Factors↗
PubMed2005

Interruptions of chest compressions during emergency medical systems resuscitation.

BACKGROUND: Survival after nontraumatic out-of-hospital (OOH) cardiac arrest in Tucson, Arizona, has been flat at 6% (121/2177) for the decade 1992 to 2001. We hypothesized that interruptions of chest compressions occur commonly and for substantial periods during treatment of OOH cardiac arrest and could be contributing to the lack of improvement in resuscitation outcome. METHODS AND RESULTS: Sixty-one adult OOH cardiac arrest patients treated by automated external defibrillator (AED)-equipped Tucson Fire Department first responders from November 2001 through November 2002 were retrospectively reviewed. Reviews were performed according to the code arrest record and verified with the AED printout. Validation of the methodology for determining the performance of chest compressions was done post hoc. The median time from "9-1-1" call receipt to arrival at the patient's side was 6 minutes, 27 seconds (interquartile range [IQR, 25% to 75%], 5 minutes, 24 seconds, to 7 minutes, 34 seconds). An additional 54 seconds (IQR, 38 to 74 seconds) was noted between arrival and the first defibrillation attempt. Initial defibrillation shocks never restored a perfusing rhythm (0/21). Chest compressions were performed only 43% of the time during the resuscitation effort. Although attempting to follow the 2000 guidelines for cardiopulmonary resuscitation, chest compressions were delayed or interrupted repeatedly throughout the resuscitation effort. Survival to hospital discharge was 7%, not different from that of our historical control (4/61 versus 121/2177; P=0.74). CONCLUSIONS: Frequent interruption of chest compressions results in no circulatory support during more than half of resuscitation efforts. Such interruptions could be a major contributing factor to the continued poor outcome seen with OOH cardiac arrest.

Adult↗
PubMed2005

Out-of-hospital pediatric cardiac arrest: an epidemiologic review and assessment of current knowledge.

STUDY OBJECTIVE: We systematically summarize pediatric out-of-hospital cardiac arrest epidemiology and assess knowledge of effects of specific out-of-hospital interventions. METHODS: We conducted a comprehensive review of published articles from 1966 to 2004, available through MEDLINE, Cumulative Index to Nursing and Allied Health Literature, EmBase, and the Cochrane Registry, describing outcomes of children younger than 18 years with an out-of-hospital cardiac arrest. Patient characteristics, process of care, and outcomes were compared using pediatric Utstein outcome report guidelines. Effects of out-of-hospital care processes on survival outcomes were summarized. RESULTS: Forty-one studies met inclusion criteria; 8 complied with Utstein reporting guidelines. Included in the review were 5,363 patients: 12.1% survived to hospital discharge, and 4% survived neurologically intact. Trauma patients (n=2,299) had greater overall survival (21.9%, 6.8% intact); a separate examination of studies with more rigorous cardiac arrest definition showed poorer survival (1.1% overall, 0.3% neurologically intact). Submersion injury-associated arrests (n=442) had greater overall survival (22.7%, 6% intact). Pooled data analysis of bystander cardiopulmonary resuscitation and witnessed arrest status showed increased likelihood of survival (relative risk 1.99, 95% confidence interval 1.54 to 2.57) for witnessed arrests. The effect of bystander cardiopulmonary resuscitation is difficult to determine because of study heterogeneity. CONCLUSION: Outcomes from out-of-hospital pediatric cardiac arrest are generally poor. Variability may exist in survival by patient subgroups, but differences are hard to accurately characterize. Conformity with Utstein guidelines for reporting and research design is incomplete. Witnessed arrest status remains associated with improved survival. The need for prospective controlled trials remains a high priority.

Adolescent↗
PubMed2005

Better outcome after pediatric defibrillation dosage than adult dosage in a swine model of pediatric ventricular fibrillation.

OBJECTIVES: This study was designed to compare outcome after adult defibrillation dosing versus pediatric dosing in a piglet model of prolonged prehospital ventricular fibrillation (VF). BACKGROUND: Weight-based 2 to 4 J/kg monophasic defibrillation dosing is recommended for children in VF, but impractical for automated external defibrillator (AED) use. Present AEDs can only provide adult shock doses or newly developed attenuated adult doses intended for children. A single escalating energy sequence (50/75/86 J) of attenuated adult-dose biphasic shocks (pediatric dosing) is at least as effective as escalating monophasic weight-based dosing for prolonged VF in piglets, but this approach has not been compared to standard adult biphasic dosing. METHODS: Following 7 min of untreated VF, piglets weighing 13 to 26 kg (19 +/- 1 kg) received either biphasic 50/75/86 J (pediatric dose) or biphasic 200/300/360 J (adult dose) therapies during simulated prehospital life support. RESULTS: Return of spontaneous circulation was attained in 15 of 16 pediatric-dose piglets and 14 of 16 adult-dose piglets. Four hours postresuscitation, pediatric dosing resulted in fewer elevations of cardiac troponin T (0 of 12 piglets vs. 6 of 11 piglets, p = 0.005) and less depression of left ventricular ejection fraction (p < 0.05). Most importantly, more piglets survived to 24 h with good neurologic scores after pediatric shocks than adult shocks (13 of 16 piglets vs. 4 of 16 piglets, p = 0.004). CONCLUSIONS: In this model, pediatric shocks resulted in superior outcome compared with adult shocks. These data suggest that adult defibrillation dosing may be harmful to pediatric patients with VF and support the use of attenuating electrodes with adult biphasic AEDs to defibrillate children.

Age Factors↗
PubMed2005

Magnetic resonance imaging during untreated ventricular fibrillation reveals prompt right ventricular overdistention without left ventricular volume loss.

BACKGROUND: Most out-of-hospital ventricular fibrillation (VF) is prolonged (>5 minutes), and defibrillation from prolonged VF typically results in asystole or pulseless electrical activity. Recent visual epicardial observations in an open-chest, open-pericardium model of swine VF indicate that blood flows from the high-pressure arterial system to the lower-pressure venous system during untreated VF, thereby overdistending the right ventricle and apparently decreasing left ventricular size. Therefore, inadequate left ventricular stroke volume after defibrillation from prolonged VF has been postulated as a major contributor to the development of pulseless rhythms. METHODS AND RESULTS: Ventricular dimensions were determined by MRI for 30 minutes of untreated VF in a closed-chest, closed-pericardium model in 6 swine. Within 1 minute of untreated VF, mean right ventricular volume increased by 29% but did not increase thereafter. During the first 5 minutes of untreated VF, mean left ventricular volume increased by 34%. Between 20 and 30 minutes of VF, stone heart occurred as manifested by dramatic thickening of the myocardium and concomitant substantial decreases in left ventricular volume. CONCLUSIONS: In this closed-chest swine model of VF, substantial right ventricular volume changes occurred early and did not result in smaller left ventricular volumes. The changes in ventricular volumes before the late development of stone heart do not explain why defibrillation from brief duration VF (<5 minutes) typically results in a pulsatile rhythm with return of spontaneous circulation, whereas defibrillation from prolonged VF (5 to 15 minutes) does not.

Animals↗
PubMed2005

Effects of intravenous arginine vasopressin on epicardial coronary artery cross sectional area in a swine resuscitation model.

Although arginine vasopressin (AVP) has been shown to be a promising drug during cardiopulmonary resuscitation (CPR), concern has been raised about the potential for AVP-mediated vasoconstriction of the coronary arteries. In a prospective, randomized laboratory investigation employing an established porcine model, the effects of AVP on haemodynamic variables, left anterior descending (LAD) coronary artery cross sectional area employing intravascular ultrasound (IVUS), and return of spontaneous circulation were studied. During sinus rhythm, the LAD coronary artery cross sectional area was measured by IVUS at baseline, and 90 s and 5 min after AVP (0.4 U/kg IV). Following a 60 min recovery, ventricular fibrillation was induced. At 4 min, chest compressions were initiated; AVP (0.4 U/kg IV) was injected at 5.5 min, and defibrillation performed at 8 min. LAD coronary artery cross sectional area was measured by IVUS at the pre-arrest baseline, 90 s after drug injection during CPR, and 5 min after return of spontaneous circulation. Compared with baseline, the mid-LAD coronary artery cross sectional area increased significantly (P<.05) 90 s and 5 min after AVP administration (9.2+/-.5mm2 versus 10.7+/-.6mm2 versus 11.7+/-.6mm2, respectively) during normal sinus rhythm. Similarly during ventricular fibrillation and CPR plus AVP, the mid-LAD coronary artery cross sectional area increased at 90 s after AVP compared with baseline (9.5+/-.6mm2 versus 11.0+/-.7mm2; P<.05). Moreover, the cross sectional area increased further 5 min after return of spontaneous circulation (9.5+/-.6mm2 versus 14.0+/-.8mm2, P<.05). In conclusion, in this experimental model with normal coronary arteries, AVP resulted in significantly increased LAD coronary artery cross sectional area during normal sinus rhythm, during ventricular fibrillation with CPR, and after return of spontaneous circulation.

Anatomy, Cross-Sectional↗
PubMed2005

Post-shock chest compression delays with automated external defibrillator use.

PRIMARY OBJECTIVE: In a swine model of out-of-hospital ventricular fibrillation (VF) cardiac arrest, we established that automated external defibrillator (AED) defibrillation could worsen outcome from prolonged VF compared with manual defibrillation. Worse outcomes were due to substantial interruptions and delays in chest compressions for AED rhythm analyses and shock advice. In particular, the mean interval from first AED shock to first post-shock compressions was 46+/-6s. We hypothesized that the delay from shock to provision of chest compressions is similar in the out-of-hospital setting. MATERIALS AND METHODS: We conducted a retrospective observational review of AED-treated adult VF cardiac arrest victims over a 26-month period to determine the interval from the first AED defibrillation attempt to the initial provision of post-shock chest compressions for out-of-hospital VF cardiac arrests. A two-tiered, single emergency medical service (EMS) system with AED-equipped first responders serves our area of 400 km2 with a population of 487,000 people. The defibrillators record a detailed sequence of events during the resuscitation effort that includes the electrocardiogram with real clock times and a recording of surrounding audible actions. RESULTS: A median of 38 s (IQR 15, 61 s) elapsed between the first shock and the initiation of chest compressions. Approximately half of the delay was due to mechanical/electronic factors and the remainder due to human factors. Of 64 adults in VF, 45 (70%) died before hospital admission, 19 (30%) survived to admission and 10 (16%) survived to hospital discharge. CONCLUSION: Substantial delays in the provision of post-shock chest compressions are typical in this EMS system with AED-equipped first responders.

Adult↗
PubMed2005

An alternative approach to advancing resuscitation science.

Stagnant survival rates in out-of-hospital cardiac arrest remain a great impetus for advancing resuscitation science. International resuscitation guidelines, with all their advantages for standardizing resuscitation therapeutic protocols, can be difficult to change. A formalized evidence-based process has been adopted by the International Liason Committee on Resuscitation (ILCOR) in formulating such guidelines. Currently, randomized clinical trials are considered optimal evidence, and very few major changes in the Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care are made without such. An alternative approach is to allow externally controlled clinical trials more weight in Guideline formulation and resuscitation protocol adoption. In Tucson, Arizona (USA), the Fire Department cardiac arrest database has revealed a number of resuscitation issues. These include a poor bystander CPR rate, a lack of response to initial defibrillation after prolonged ventricular fibrillation, and substantial time without chest compressions during the resuscitation effort. A local change in our previous resuscitation protocols had been instituted based upon this historical database information.

Cardiopulmonary Resuscitation↗
PubMed2005

Pediatric defibrillation doses often fail to terminate prolonged out-of-hospital ventricular fibrillation in children.

BACKGROUND: The recommended dose for pediatric defibrillation is 2 J/kg, based on animal studies of brief duration ventricular fibrillation (VF) and a single pediatric study of short duration in-hospital VF. In a piglet model of out-of-hospital (prolonged) cardiac arrest, this recommended dose was usually ineffective at terminating VF. We, therefore, hypothesized that pediatric dose defibrillation may be less effective for prolonged out-of-hospital pediatric VF. METHODS: We evaluated retrospectively all cardiac arrests in children less than 13 years old in Tucson from November 1998 to April 2003, with special attention to all children in ventricular fibrillation. We determined the rate of ventricular fibrillation termination after pediatric dose shocks in this cohort, and compared this rate with a published historical pediatric in-hospital defibrillation control group. A pediatric dose shock was defined as 2 J/kg (+/-10 J). All shocks in both groups were provided as monophasic damped sinusoidal waveforms. RESULTS: Thirteen of 151 (9%) children with out-of-hospital cardiac arrest had documented VF. Eleven children received a total of 14 pediatric dose shocks. The median minimum untreated dispatch-to-shock time in unwitnessed arrest or collapse-to-shock in witnessed arrest for those 11 children was 11 min (interquartile range 25-75%; 9-15.5 min). Seven of the 14 pediatric dose shocks terminated the VF (six to asystole, one to pulseless electrical activity). Nine children (68%) died in the emergency department and four (31%) in the pediatric intensive care unit; none survived to hospital discharge. Failure to terminate VF after a pediatric dose shock in this study group with prolonged out-of-hospital ventricular fibrillation was substantially more common than the previously reported in-hospital data (7/14 versus 5/57; OR 10.4; 95% CI 2.6-42; P=0.001). CONCLUSIONS: Termination of VF after a pediatric defibrillation dose is substantially worse for prolonged pediatric out-of-hospital VF cardiac arrest compared with in-hospital (short duration) ventricular fibrillation. The optimal pediatric defibrillation dose for prolonged VF is not known.

Adolescent↗