Biomedical subjects

Thomas D Rea

Publications and source records attributed to Thomas D Rea.

At least 19 recordsLinked to original sources

PubMed2006

Increasing use of cardiopulmonary resuscitation during out-of-hospital ventricular fibrillation arrest: survival implications of guideline changes.

BACKGROUND: The most recent resuscitation guidelines have sought to improve the interface between defibrillation and cardiopulmonary resuscitation; the survival impact of these changes is unknown, however. A year before issuance of the most recent guidelines, we implemented protocol changes that provided a single shock without rhythm reanalysis, stacked shocks, or postdefibrillation pulse check, and extended the period of cardiopulmonary resuscitation from 1 to 2 minutes. We hypothesized that survival would be better with the new protocol. METHODS AND RESULTS: The present study took place in a community with a 2-tiered emergency medical services response and an established system of cardiac arrest surveillance, training, and review. The investigation was a cohort study of persons who had bystander-witnessed out-of-hospital ventricular fibrillation arrest because of heart disease, comparing a prospectively defined intervention group (January 1, 2005, to January 31, 2006) with a historical control group that was treated according to previous guidelines of rhythm reanalysis, stacked shocks, and postdefibrillation pulse checks (January 1, 2002, to December 31, 2004). The primary outcome was survival to hospital discharge. The proportion of treated arrests that met inclusion criteria was similar for intervention and control periods (15.4% [134/869] versus 16.6% [374/2255]). Survival to hospital discharge was significantly greater during the intervention period compared with the control period (46% [61/134] versus 33% [122/374], P=0.008) and corresponded to a decrease in the interval from shock to start of chest compressions (28 versus 7 seconds). Adjustment for covariates did not alter the survival association. CONCLUSIONS: These results suggest the new resuscitation guidelines will alter the interface between defibrillation and cardiopulmonary resuscitation and in turn may improve outcomes.

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PubMed2006

Increasing first responder CPR during resuscitation of out-of-hospital cardiac arrest using automated external defibrillators.

OBJECTIVE: Evidence supports that increasing the balance of "hands-on" CPR may improve survival in ventricular fibrillation out-of-hospital cardiac arrest (OHCA). We assessed whether training and/or AED reconfiguration was associated with an increase in the proportion of time during which CPR was performed between first and second stacks of shocks. METHODS: The investigation was a cohort study of 291 persons who suffered ventricular fibrillation OHCA and were treated with at least two stacks of AED shocks by emergency medical services (EMS) first-tier responders. In January 2003, first-tier providers were retrained regarding the importance of CPR. In addition, a subset of AEDs was reconfigured to remove continuous fibrillation detection and its associated voice prompts as to be comparable with other AED models. The amount of time spent on CPR was assessed through review of AED electronic and audio recordings to compare the pre-intervention (n = 241) and post-intervention periods (n = 50). RESULTS: The proportion of time spent performing hands-on CPR between first and second stacks of shocks was 0.40 in the pre-intervention period compared to 0.51 in the post-intervention period (p = 0.001). The difference was greatest for AEDs where EMS was retrained and the AED reconfigured (0.33 versus 0.50, p = 0.01). No difference in survival was detected between the pre- and post-intervention periods (24.9% versus 28.0%, p = 0.65). CONCLUSIONS: An intervention consisting of retraining and AED reconfiguration was associated with an increase in the proportion of time spent performing CPR between first and second stacks of shocks by first-tier EMS. Whether this increase improves patient outcomes requires additional study.

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PubMed2006

Plasma phospholipid trans fatty acids, fatal ischemic heart disease, and sudden cardiac death in older adults: the cardiovascular health study.

BACKGROUND: Intake of trans fatty acids is associated with increased risk of coronary heart disease. Whether different classes of trans fatty acids show similar associations is unclear. We previously reported an association of sudden cardiac death with red cell membrane trans-18:2 but not trans-18:1 fatty acids. To extend these findings, we investigated the associations of plasma phospholipid trans fatty acids with fatal ischemic heart disease (IHD) and sudden cardiac death. METHODS AND RESULTS: We conducted a case-control study nested in the Cardiovascular Health Study. We identified 214 cases of fatal IHD (fatal myocardial infarction and coronary heart disease death) between 1992 and 1998. We randomly selected 214 controls, matched to cases on demographics, prevalent cardiovascular disease, and timing of blood draw. Plasma phospholipid fatty acids were assessed in blood samples collected earlier. Higher levels of plasma phospholipid trans-18:2 fatty acids were associated with higher risk of fatal IHD (odds ratio [OR] for interquintile range 1.68, 95% confidence interval [CI] 1.21 to 2.33) after adjustment for risk factors and trans-18:1 levels. Trans-18:1 levels above the 20th percentile were associated with lower risk (OR 0.34, 95% CI 0.18 to 0.63). In analyses limited to cases of sudden cardiac death (n=95), higher levels of trans-18:2 fatty acids were associated with higher risk (OR 2.34, 95% CI 1.27 to 4.31) and higher trans-18:1 with lower risk (OR 0.18, 95% CI 0.06 to 0.54). CONCLUSIONS: Higher levels of trans-18:2 and lower levels of trans-18:1 fatty acids are associated with higher risks of fatal IHD and sudden cardiac death. If confirmed, these findings suggest that current efforts at decreasing trans fatty acid intake in foods should take into consideration the trans-18:2 content.

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PubMed2006

Three-phase model of cardiac arrest: time-dependent benefit of bystander cardiopulmonary resuscitation.

Evidence has suggested that the pathophysiology of ventricular fibrillation cardiac arrest may consist of 3 time-sensitive phases: electrical, circulatory, and metabolic. We performed a retrospective cohort study of adults in a metropolitan county who had had witnessed ventricular fibrillation arrest before emergency medical services were undertaken to investigate this 3-phase model with regard to bystander cardiopulmonary resuscitation (CPR). We hypothesized that the survival benefit from bystander CPR depends on the collapse-to-shock interval, with the highest benefit occurring during the circulatory phase. The collapse-to-shock interval was a priori grouped into 4 categories: 1 to 5, 6 to 7, 8 to 10, and > or = 11 minutes. We used logistic regression analysis to assess whether the association between CPR and survival to hospital discharge depended on the collapse-to-shock interval category. Of the 2,193 events meeting the inclusion criteria, 67.0% had received bystander CPR. The average collapse-to-shock interval was 8.2 +/- 2.8 minutes. The survival rate was 33.4%. A higher likelihood of survival was associated with bystander CPR (odds ratio [OR] 1.41, 95% confidence interval [CI] 1.15 to 1.73) and a shorter collapse-to-shock interval (OR -1.84, 95% CI 1.62 to 2.10, for each additional SD of 2.8 minutes less) after adjustment. The beneficial association of CPR increased as the collapse-to-shock interval increased (p = 0.05 for interaction). The bystander CPR was associated with an OR of survival of 0.96 (95% CI 0.64 to 1.46) for a 1- to 5-minute collapse-to shock interval, OR of 1.25 (95% CI 1.00 to 1.58) for a 6- to 7-minute interval, OR of 1.62 (95% CI 1.25 to 2.11) for an 8- to 10-minute interval, and OR of 2.11 (95% CI 1.32 to 3.37) for an > or = 11-minute interval. The results of this investigation support a phased model of ventricular fibrillation arrest. The findings suggest that the transition from the electrical to circulatory phase may occur at about 5 minutes, and the circulatory phase may extend to 15 minutes.

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PubMed2006

Manual chest compression vs use of an automated chest compression device during resuscitation following out-of-hospital cardiac arrest: a randomized trial.

CONTEXT: High-quality cardiopulmonary resuscitation (CPR) may improve both cardiac and brain resuscitation following cardiac arrest. Compared with manual chest compression, an automated load-distributing band (LDB) chest compression device produces greater blood flow to vital organs and may improve resuscitation outcomes. OBJECTIVE: To compare resuscitation outcomes following out-of-hospital cardiac arrest when an automated LDB-CPR device was added to standard emergency medical services (EMS) care with manual CPR. DESIGN, SETTING, AND PATIENTS: Multicenter, randomized trial of patients experiencing out-of-hospital cardiac arrest in the United States and Canada. The a priori primary population was patients with cardiac arrest that was presumed to be of cardiac origin and that had occurred prior to the arrival of EMS personnel. Initial study enrollment varied by site, ranging from late July to mid November 2004; all sites halted study enrollment on March 31, 2005. INTERVENTION: Standard EMS care for cardiac arrest with an LDB-CPR device (n = 554) or manual CPR (n = 517). MAIN OUTCOME MEASURES: The primary end point was survival to 4 hours after the 911 call. Secondary end points were survival to hospital discharge and neurological status among survivors. RESULTS: Following the first planned interim monitoring conducted by an independent data and safety monitoring board, study enrollment was terminated. No difference existed in the primary end point of survival to 4 hours between the manual CPR group and the LDB-CPR group overall (N = 1071; 29.5% vs 28.5%; P = .74) or among the primary study population (n = 767; 24.7% vs 26.4%, respectively; P = .62). However, among the primary population, survival to hospital discharge was 9.9% in the manual CPR group and 5.8% in the LDB-CPR group (P = .06, adjusted for covariates and clustering). A cerebral performance category of 1 or 2 at hospital discharge was recorded in 7.5% of patients in the manual CPR group and in 3.1% of the LDB-CPR group (P = .006). CONCLUSIONS: Use of an automated LDB-CPR device as implemented in this study was associated with worse neurological outcomes and a trend toward worse survival than manual CPR. Device design or implementation strategies require further evaluation. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00120965.

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PubMed2006

Energy doses for treatment of out-of-hospital pediatric ventricular fibrillation.

AIM: To investigate the energy dose used to treat out-of-hospital pediatric ventricular fibrillation and the survival rates of these patients. METHODS: We reviewed three emergency medical systems (EMS) for their reports of patients under 1 month to 18 years who received shocks for ventricular fibrillation to determine the energy of each shock as well as other patient and care characteristics. Each patient's weight was estimated at the age-appropriate 50th and 95th percentiles. Patients were then grouped as receiving recommended energy doses (2 to < or = 4 J/kg), moderately high energy doses (> 4-6 J/kg), and high energy doses (> 6 J/kg). RESULTS: Of 57 patients identified, 54% were male, with a mean age of 11 years, range 2 months to 17 years. Ventricular fibrillation was the initial rhythm in 80% (43/54) of patients. The mean number of shocks delivered was 3, with < or = 2 shocks delivered to 28 (49%) and > or = 5 shocks delivered to 10 (18%) patients. When evaluating all 185 shocks using the 50th percentile estimated weight, 45 (24%) shocks were at recommended doses, 56 (30%) were at moderately high energy doses, and 84 (45%) were high energy doses. Elevated energy dose was associated with an increasing number of shocks and lack of bystander CPR (p < .05). Nineteen (33%) patients survived to hospital discharge having received total doses up to 73 J/kg. Energy dose was not related to survival. CONCLUSION: In this observational, multicenter out of hospital experience, children received a wide range of defibrillation doses, often exceeding recommended doses and equivalent to adult energy levels. Survival occurred at low and very high energy doses.

Adolescent↗

PubMed2006

Withholding resuscitation: a new approach to prehospital end-of-life decisions.

BACKGROUND: Emergency medical services (EMS) personnel often are not permitted to honor requests to withhold resuscitation at the end of life, particularly if there is no written do-not-resuscitate (DNR) order. OBJECTIVE: To determine whether EMS personnel from agencies implementing new guidelines would be more likely to withhold resuscitation from persons having out-of-hospital cardiac arrests than would personnel from agencies that did not implement the guidelines. DESIGN: Observational study in which 16 of 35 local EMS agencies volunteered to implement new guidelines for withholding resuscitation. SETTING: King County, Washington. PATIENTS: 2770 patients with EMS-attended cardiac arrest. INTERVENTION: New guidelines adopted by participating agencies permitted EMS personnel to withhold resuscitation if the patient had a terminal condition and if the patient, family, or caregivers indicated, in writing or verbally, that no resuscitation was desired. MEASUREMENTS: Proportion of resuscitations withheld in agencies that implemented new guidelines compared with those that did not. RESULTS: Emergency medical services personnel from agencies implementing new guidelines withheld resuscitation in 11.8% of patients (99 of 841 patients) having cardiac arrests, compared with an average of 5.3% (range, 4.2% to 5.9%) of patients (103 of 1929 patients) in 3 historical and contemporary control groups. Honoring verbal requests alone accounted for 53% of withheld resuscitations in the intervention group (52 of 99 patients) compared with an average of 8% (range, 7% to 9%) in the control groups (8 of 103 patients). LIMITATIONS: The study was not a randomized, controlled trial; individual agencies chose whether to implement the guidelines. CONCLUSIONS: Implementation of new guidelines was associated with an increase in the number of resuscitations withheld by EMS personnel. This increase was primarily due to honoring verbal requests.

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PubMed2006

Beta2-adrenergic receptor genetic variants and risk of sudden cardiac death.

BACKGROUND: Sympathetic activation influences the risk of ventricular arrhythmias and sudden cardiac death (SCD), mediated in part by the beta2-adrenergic receptor (B2AR). We investigated whether variation in the B2AR gene is associated with SCD risk. METHODS AND RESULTS: In this study, 4441 white and 808 black Cardiovascular Health Study (CHS) participants were followed up prospectively for SCD and genotyped for B2AR Gly16Arg and Gln27Glu polymorphisms. The study was replicated in 155 case and 144 control white subjects in a population-based case-control study of SCD, the Cardiac Arrest Blood Study (CABS). In CHS, Gly16 and Gln27 allele frequencies were 62.4% and 57.1% among white and 50.1% and 81.4% among black participants. Over a median follow-up of 11.1 years, 156 and 39 SCD events occurred in white and black participants, respectively. The Gln27Glu variant was associated with SCD risk (P=0.008 for general model). SCD risk was higher in Gln27 homozygous participants than in Glu27 carriers (ethnicity-adjusted hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.17 to 2.09; P=0.003). The increased risk did not differ significantly between white (HR, 1.62; 95% CI, 1.18 to 2.23) and black (HR, 1.23; 95% CI, 0.61 to 2.48) participants, although the confidence interval was wide in blacks. In the CABS replication study, Gln27 homozygous participants similarly had higher SCD risk than Glu27 carriers (odds ratio, 1.64; 95% CI, 1.02 to 2.63; P=0.040). Gly16Arg was not associated with SCD risk in either study. CONCLUSIONS: Gln27 homozygous individuals have an increased risk of SCD in 2 study populations. Our findings suggest that B2AR plays a role in SCD in humans. Study of genetic variation within the B2AR gene may help identify those at increased SCD risk.

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PubMed2005

Diabetes, glucose level, and risk of sudden cardiac death.

AIMS: The prevalence of diabetes mellitus in industrialized countries is rapidly increasing, and diabetes is suspected to carry a particular high risk for sudden cardiac death (SCD). METHODS AND RESULTS: We conducted a population-based case-control study at Group Health Cooperative. Cases (n=2040) experienced out-of-hospital cardiac arrest due to heart disease between 1980 and 1994. Controls (n=3800) were a stratified random sample of enrollees. Diabetes status was classified into four exclusive groups: (i) no diabetes, (ii) borderline, (iii) diabetes without microvascular disease (retinopathy or proteinuria), and (iv) diabetes with microvascular disease. When compared with no diabetes, we observed progressively higher risk of SCD associated with borderline diabetes [Odds ratio (OR)=1.24 (0.98-1.57)], diabetes without microvascular disease [OR=1.73 (1.28-2.34)], and diabetes with microvascular disease [OR=2.66 (1.84-3.85)], after adjustment for potential confounders (P-value for trend <0.001). Higher glucose levels were also associated with the risk of SCD both in the absence and in the presence of microvascular disease. However, subjects with microvascular complications but with glucose level <7.7 mmol/L were not at significant increased risk of SCD. CONCLUSION: These results emphasize the role of diabetes as a strong risk factor for SCD and outline the importance of glucose level at every stage of diabetes severity.

Adult↗

PubMed2005

Congestive heart failure incidence and prognosis: case identification using central adjudication versus hospital discharge diagnoses.

PURPOSE: We compared hospitalized congestive heart failure (CHF) incidence and prognosis estimates using hospital discharge diagnoses or central adjudication. METHODS: We used the Cardiovascular Health Study (CHS), a population-based cohort study of 5888 elderly adults. A physician committee adjudicated potential CHF events, confirmed by signs, symptoms, clinical tests, and/or medical therapy. A CHF discharge diagnosis included any of these ICD-9 codes in any position: 428, 425, 398.91, 402.01, 402.11, 402.91, and 997.1. We constructed an inception cohort of 1209 hospitalized, nonfatal, incident CHF cases, identified by discharge diagnosis, adjudication, or both. RESULTS: Incidence rates for hospitalized CHF were 24.6 per 1000 person-years using discharge diagnoses and 17.1 per 1000 person-years using central adjudication. Compared to the group identified as having CHF by both methods, the group with only a discharge diagnosis (hazard ratio=0.77, 95% confidence interval=0.65-0.91) and the group with central adjudication only (hazard ratio=0.72, 95% confidence interval=0.55-0.94) had lower mortality rates. CONCLUSIONS: In the elderly, studies using only discharge diagnoses, as compared to central adjudication, may estimate higher rates of incident hospitalized CHF. Mortality following CHF onset may be similar for these methods and higher if both methods are used together.

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PubMed2005

Statin use and the risk of incident dementia: the Cardiovascular Health Study.

BACKGROUND: Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) reduce cardiovascular risk through mechanisms that might affect the development of dementia. OBJECTIVE: To evaluate whether statin use is associated with a lower risk of dementia compared with never use of lipid-lowering agents (LLAs). DESIGN: Cohort study of community-dwelling adults 65 years and older. The analysis included 2798 participants free of dementia at baseline. MAIN OUTCOME MEASURES: Using Cox proportional hazards regression analysis, we estimated the risk of incident all-cause and type-specific dementia associated with time-dependent statin therapy compared with never use of LLAs. The primary analyses incorporated a 1-year lag between exposure and outcome. Secondary analyses included the final year of exposure and modeled statin use as current use vs nonuse to simulate a case-control approach. RESULTS: Compared with never use of LLAs, ever use of statins was not associated with the risk of all-cause dementia (multivariable-adjusted hazard ratio [HR], 1.08; 95% confidence interval [CI], 0.77-1.52), Alzheimer disease alone (HR, 1.21; 95% CI, 0.76-1.91), mixed Alzheimer disease and vascular dementia (HR, 0.87; 95% CI, 0.44-1.72), or vascular dementia alone (HR, 1.36; 95% CI, 0.61-3.06). In contrast, in secondary analyses, current use of statins compared with nonuse of LLAs was associated with HRs of 0.69 (95% CI, 0.46-1.02) for all-cause dementia and 0.56 (95% CI, 0.35-0.92) for any Alzheimer disease. CONCLUSIONS: In this cohort study, statin therapy was not associated with a decreased risk of dementia. Methodological differences may explain why results of this cohort investigation differ from those of prior case-control studies. Additional investigation is needed to determine whether and for whom statin use may affect dementia risk.

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PubMed2005

Association of beta-blocker use with mortality among patients with congestive heart failure in the Cardiovascular Health Study (CHS).

BACKGROUND: In clinical trials, beta-blocker therapy reduces all-cause mortality among people with congestive heart failure (CHF) characterized by depressed systolic function, but few trials included large numbers of elderly participants. This study assessed the association between beta-blocker therapy and mortality among community-dwelling older adults with CHF. METHODS: The Cardiovascular Health Study (CHS) is a longitudinal, population-based study of adults aged > or = 65 years. Recruitment began in 1989 with follow-up extending through June 2000 or death. Cox proportional hazard regression models were used to assess the association between beta-blocker therapy and all-cause mortality among 950 participants who developed new-onset CHF. RESULTS: beta-Blocker users (n = 157) were more likely than nonusers (n = 793) to have treated hypertension, clinical coronary artery disease, and valvular disease at the time of CHF diagnosis. Death occurred in 67 users and 446 nonusers during a median follow-up of 2.3 years. Compared with nonuse, use of beta-blockers was associated with a multivariable adjusted hazard ratio (HR) of 0.74 (95% CI 0.56-0.98) for all-cause mortality. Among the 520 participants who had left ventricular ejection fraction assessed within 90 days after CHF diagnosis, the risk for all cause mortality associated with beta-blocker use did not differ significantly between those with ejection fraction of < 40% and those with ejection fraction of > or = 40% (HR 0.56, 95% CI 0.27-1.13; HR 0.82, 95% CI 0.56-1.22, respectively; interaction P = .34). CONCLUSIONS: This observational study suggests that beta-blocker treatment is associated with a reduced risk of all-cause mortality among community-dwelling older adults with CHF.

Adrenergic beta-Antagonists↗

PubMed2005

Automated external defibrillators: to what extent does the algorithm delay CPR?

STUDY OBJECTIVE: Maximizing cardiopulmonary resuscitation (CPR) during resuscitation may improve survival. Resuscitation protocols stack up to 3 shocks to achieve defibrillation, followed by an immediate postdefibrillation pulse check. The purpose of this study is to evaluate outcomes of rhythm reanalyses immediately after shock, stacked shocks, and initial postshock pulse checks in relation to achieving a pulse and initiating CPR. METHODS: We conducted an observational study of patients with ventricular fibrillation treated by first-tier emergency medical services (EMS). We collected data from EMS, dispatch, and hospital records. Additionally, we analyzed automatic external defibrillator recordings to determine the proportion of cardiac arrest victims who were defibrillated and achieved a pulse according to shock number (single versus stacked shock), proportion of victims with a pulse during the initial postdefibrillation pulse check, and interval from initial shock to CPR. RESULTS: The study included 481 cardiac arrest subjects. Automatic external defibrillators terminated ventricular fibrillation with the initial shock in 83.6% (n=402) of cases. A second shock terminated ventricular fibrillation in an additional 7.5% (n=36) of cases, and a third shock terminated ventricular fibrillation in 4.8% (n=23) of cases. The initial sequence of 3 shocks failed to terminate ventricular fibrillation in 4.1% (n=20) of cases. In total, automatic external defibrillators performed 560 rhythm reanalyses during the initial shock sequence and delivered 122 "stacked" shocks. Termination of ventricular fibrillation was not synonymous with return of a pulse. The initial shock produced a pulse that was eventually detected in 21.8% (105/481) of cases. Stacked shocks produced a pulse in 10.7% (13/122) of cases. For the 24.5 % (n=118) of cases in which a pulse returned, the pulse was detected during the initial postshock pulse check only 12 times, or 2.5% of all cases. The median interval from initial shock until CPR was 29 (23,41) seconds. CONCLUSION: Rhythm reanalyses, stacked shocks, and postshock pulse checks had low yield for achieving or detecting return of a pulse. CPR was not initiated until 29 seconds after the initial shock.

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PubMed2005

Incidence of EMS-treated out-of-hospital cardiac arrest in Europe.

BACKGROUND: The potential impact of efforts in Europe to improve survival from out-of-hospital cardiac arrest is unclear, in part, because estimates of incidence and survival are uncertain. The aim of the investigation was to determine a representative European incidence and survival from cardiac arrest in all-rhythms and in ventricular fibrillation treated by the emergency medical services (EMS). METHODS AND RESULTS: We used Medline to identify peer-reviewed articles published between 1 January 1980 and 30 June 2004 that reported a European community's EMS cardiac arrest experience. Inclusion criteria required the study to include at least 25 cases, report of the total number of all-rhythm and/or ventricular fibrillation arrests, and information about population size and study duration. The incidence was computed by dividing the total number of events by the product of the community's population and the study duration. Reports from 37 communities met the inclusion criteria. A total of 18,105 all-rhythm EMS-treated cardiac arrests occurred during 48 million person-years of observation, resulting in an overall incidence for all-rhythm arrests of 37.72 per 100,000 person-years. Incidence of ventricular fibrillation arrest was 16.84 per 100,000 person-years. Survival was 10.7% for all-rhythm and 21.2% for ventricular fibrillation cardiac arrest. Applying these results to the European population, approximately, 275,000 persons would experience, all-rhythm cardiac arrest treated by the EMS with 29,000 persons surviving to hospital discharge. CONCLUSION: The results provide a framework to assess opportunities and limitations of EMS care with regard to the public health burden of cardiac arrest in Europe.

Cardiopulmonary Resuscitation↗

PubMed2005

Agonal respirations during cardiac arrest.

PURPOSE OF REVIEW: This review examines the physiologic understanding and clinical implications of agonal respirations during cardiac arrest. RECENT FINDINGS: Agonal respirations originate from lower brainstem neurons as higher centers become increasingly hypoxic during cardiac arrest. No single layperson descriptor consistently identifies agonal respirations; rather, laypersons use a collection of terms to describe the abnormal breathing of agonal respirations. Animal studies demonstrate that agonal respirations can produce clinically important ventilation, oxygenation, and circulation. In human studies, agonal respirations are apparent in 40% of persons suffering out-of-hospital cardiac arrest. Agonal respirations are associated with witnessed events, ventricular fibrillation, and survival, suggesting that agonal respirations are a marker of an arrest's early phase and may potentially directly affect cardiopulmonary function. Although agonal respirations appear to exert favorable cardiopulmonary effects, they may paradoxically inhibit rescue efforts by preventing arrest recognition. A standardized dispatch approach can help dispatchers identify agonal respirations by distinguishing normal and abnormal breathing in the unconscious patient. Future study should consider how information about agonal respirations might be integrated into the resuscitation to optimize outcomes. SUMMARY: Agonal respirations have physiologic and care implications. Efforts to identify agonal respirations and integrate this information into resuscitation care may improve outcome from cardiac arrest.

Cardiopulmonary Resuscitation↗

PubMed2005

Weight loss, muscle strength, and angiotensin-converting enzyme inhibitors in older adults with congestive heart failure or hypertension.

OBJECTIVES: To determine whether angiotensin-converting enzyme (ACE) inhibitor use may be associated with weight maintenance and sustained muscle strength (measured by grip strength) in older adults. DESIGN: Data from the Cardiovascular Health Study (CHS), a community-based prospective cohort study of 5,888 older adults, were used. SETTING: Subjects were recruited from four U.S. sites beginning in 1989; this analysis included data through 2001. PARTICIPANTS: CHS participants with congestive heart failure (CHF) or treated hypertension. MEASUREMENTS: The exposure, current ACE inhibitor use, was ascertained by medication inventory at annual clinic visits; the outcomes were weight change and grip-strength change during the following year. Multivariate linear regression was used, accounting for correlations between observations on the same participant over time. RESULTS: The average annual weight change was -0.38 kg in 2,834 participants (14,443 person-years) with treated hypertension and -0.62 kg in 342 participants (980 person-years) with CHF. ACE inhibitor use was associated with less annual weight loss after adjustment for potential confounders: a difference of 0.17 kg (95% confidence interval (CI)=0.05-0.29) in those with treated hypertension and 0.29 kg (95% CI=-0.25-0.83) in those with CHF. There was no evidence of association between ACE inhibitor use and grip-strength change. CONCLUSION: ACE inhibitor use may be associated with weight maintenance, but not maintenance of muscle strength, in older adults with treated hypertension.

Aged↗

PubMed2005

Socioeconomic status and survival from out-of-hospital cardiac arrest.

BACKGROUND: Socioeconomic status (SES) has been linked to heart disease, but its influence on outcome from out-of-hospital cardiac arrest (OHCA) is not well understood. OBJECTIVES: The authors hypothesized that higher levels of SES would be associated with better survival, potentially through demographic, circumstance, or care factors. METHODS: A cohort investigation of OHCA due to heart disease treated by emergency medical services between January 1, 1999, and December 31, 2003, was conducted in the study county. Socioeconomic status was assessed using two different measures: an individual-level measure, tax-assessed property value per unit, and a geography-based measure, median household income from the 2000 Census. The authors used logistic regression to evaluate the association between survival to hospital discharge and quartile of SES. Models systematically adjusted for demographic, circumstance, and care factors that could potentially confound the association. RESULTS: Socioeconomic status as measured by value per unit was associated with survival in unadjusted models (odds ratio [OR] = 1.21; 95% confidence interval [95% CI] = 1.05 to 1.36, for each successive increase in value-per-unit quartile). Adjustment for demographic, circumstance, and care factors altered the association only slightly (fully adjusted OR = 1.23; 95% CI = 1.08 to 1.39). In contrast, SES as measured by median household income was not associated with survival. The study could not investigate all potentially explanatory factors. The findings may not be generalizable to persons or communities that differ from the current investigation. CONCLUSIONS: An individual-level, but not an area-level, measure of SES predicted survival following OHCA independent of demographic, circumstance, or care factors. Future research should continue to investigate mechanisms through which SES is associated with OHCA survival.

Age Distribution↗

PubMed2004

Survival associated with two sets of diagnostic criteria for congestive heart failure.

Congestive heart failure (CHF) definitions vary across epidemiologic studies. The Framingham Heart Study criteria include CHF signs and symptoms assessed by a physician panel. In the Cardiovascular Health Study, a committee of physicians adjudicated CHF diagnoses, confirmed by signs, symptoms, clinical tests, and/or medical therapy. The authors used data from the Cardiovascular Health Study, a population-based cohort study of 5,888 elderly US adults, to compare CHF incidence and survival patterns following onset of CHF as defined by Framingham and/or Cardiovascular Health Study criteria. They constructed an inception cohort of nonfatal, hospitalized CHF patients. Of 875 participants who had qualifying CHF hospitalizations between 1989 and 2000, 54% experienced a first CHF event that fulfilled both sets of diagnostic criteria (concordant), 31% fulfilled only the Framingham criteria (Framingham only), and 15% fulfilled only the Cardiovascular Health Study criteria (Cardiovascular Health Study only). No significant survival difference was found between the Framingham-only group (hazard ratio = 0.87, 95% confidence interval: 0.71, 1.07) or the Cardiovascular Health Study-only group (hazard ratio = 0.89, 95% confidence interval: 0.68, 1.15) and the concordant group (referent). Compared with Cardiovascular Health Study central adjudication, Framingham criteria for CHF identified a larger group of participants with incident CHF, but all-cause mortality rates were similar across these diagnostic classifications.

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