PubMed Health⌕ Search

Biomedical subjects

G Nichol

Publications and source records attributed to G Nichol.

At least 19 recordsLinked to original sources
PubMed2005

International Resuscitation Network Registry: design, rationale and preliminary results.

There is a lack of high-quality information about the effectiveness of resuscitation interventions and international differences in structure, process and outcome after out-of-hospital cardiac arrest and cardiopulmonary resuscitation because data are not collected uniformly. An internet-based international registry could make such evaluations possible, and enable the conduct of large randomized controlled trials of resuscitation therapies. A prospective international cohort study was performed that included 571 infants, children and adults (a) who experienced cardiac arrest requiring chest compressions or external defibrillation, (b) outside the hospital in the study communities and (c) upon whom resuscitation was attempted by EMS personnel. Cardiac arrest was defined as lack of responsiveness, breathing or movement in individuals for whom the EMS system is activated for whom an arrest record is completed. All data were collated via a secure and confidential web-based method by using automated forms processing software with appropriate variable range checks, logic checks and skip rules. Median number of missing responses for each variable was 0 (interquartile range 0, 0). Twenty-seven percent of the patients had a first recorded rhythm of ventricular fibrillation or ventricular tachycardia, 60% had a witnessed arrest, and 34% received bystander CPR. Mean time from call to arrival on scene was 7.1+/-5.1 min. Six percent of the patients survived to hospital discharge. The resuscitation process was highly variable across centers, and survival and neurological outcome were also significantly and independently different across centers. This study shows that it is possible to collect data prospectively describing the structure, process and outcome associated with cardiac arrest in multiple international sites via the internet. Therefore, it is feasible to conduct adequately powered randomized trials of resuscitation therapies in international settings.

Adolescent↗
PubMed2004

Impact of informed consent requirements on cardiac arrest research in the United States: exception from consent or from research?

INTRODUCTION: Research in patients with life-threatening illness such as cardiac arrest is challenging since they can not consent. The Food and Drug Administration addressed research under emergency conditions by publishing new criteria for exception from informed consent in 1996. We systematically reviewed randomized trials over a 10-year period to assess the impact of these regulations. METHODS: Case-control study of published trials for cardiac arrest (cases) and atrial fibrillation (controls.) Studies were identified by using structured searches of MEDLINE and EMBASE from 1992 to 2002. Included were studies using random allocation in humans with cardiac arrest or atrial fibrillation prior to enrollment. Excluded were duplicate publications. Number of American trials, foreign trials and proportion of trials of American origin were compared by using regression analysis. Changes in cardiac arrest versus atrial fibrillation trials were calculated as risk differences. RESULTS: Of 4982 identified cardiac arrest studies, 57 (1.1%) were randomized trials. The number of American cardiac arrest trials decreased by 15% (95% CI: 8, 22%) annually (P = 0.05). The proportion of cardiac arrest trials of American origin decreased by 16% (95% CI: 10, 22%) annually (P = 0.006). Of 5596 identified atrial fibrillation studies, 197 trials (3.5%) were randomized trials. The risk difference between cardiac arrest versus atrial fibrillation trials being of American origin decreased significantly (annual difference -5.8% (95% CI: -10, -0.1%), P = 0.03). INTERPRETATION: Fewer American cardiac arrest trials were published during the last decade, when federal consent requirements changed. Regulatory requirements for clinical trials may inhibit improvements in care and threaten public health.

Atrial Fibrillation↗
PubMed2003

Cost effectiveness of defibrillation by targeted responders in public settings.

BACKGROUND: Out-of-hospital cardiac arrest is frequent and has poor outcomes. Defibrillation by trained targeted nontraditional responders improves survival versus historical controls, but it is unclear whether such defibrillation is a good value for the money. Therefore, this study estimated the incremental cost effectiveness of defibrillation by targeted nontraditional responders in public settings by using decision analysis. METHODS AND RESULTS: A Markov model evaluated the potential cost effectiveness of standard emergency medical services (EMS) versus targeted nontraditional responders. Standard EMS included first-responder defibrillation followed by advanced life support. Targeted nontraditional responders included standard EMS supplemented by defibrillation by trained lay responders. The analysis adopted a US societal perspective. Input data were derived from published or publicly available data. Future costs and effects were discounted at 3%. Monte Carlo simulation and sensitivity analyses assessed the robustness of results. Standard EMS had a median of 0.47 (interquartile range [IQR]=0.32 to 0.69) quality-adjusted life years and a median of 14 100 dollars (IQR=8600 dollars to 21 900 dollars) costs per arrest. Targeted nontraditional responders in casinos had an incremental cost of a median 56 700 dollars (IQR=44 100 dollars to 77 200 dollars) per additional quality-adjusted life year. The results were sensitive to changes in time to defibrillation, incidence of arrest, and number of devices required to implement rapid defibrillation. CONCLUSIONS: Where cardiac arrest is frequent and response time intervals are short, rapid defibrillation by targeted nontraditional responders may be a good value for the money compared with standard EMS. The incidence of arrest should be considered when choosing locations to implement public access defibrillation.

Adult↗
PubMed2003

Variation in outcome in studies of out-of-hospital cardiac arrest: a review of studies conforming to the Utstein guidelines.

The objective of this study was to systematically review studies on out-of-hospital cardiac arrest published according to the Utstein guidelines to describe the variability in factors of resuscitation and outcome. Articles that reported primary data on survival after out-of-hospital cardiac arrest in the Utstein style were included. Forty-seven articles were identified using Medline. Fourteen studies met our criteria for inclusion. The number of patients in whom resuscitation was attempted varied between 78 and 3,243. The proportion of bystander-witnessed cases varied between 38% and 89%; bystander CPR was performed in 21% to 56% of the cases. Patients with a bystander-witnessed cardiac arrest of cardiac etiology were discharged alive in 2% to 49% of the cases. Even when data are reported in a uniform way as suggested by the Utstein template, there is a tremendous variability in outcome. This did not appear to be entirely explained by variability in the traditional risk factors for a low chance of survival. One cannot exclude the possibility of other factors being of ultimate importance for the outcome.

Cardiopulmonary Resuscitation↗
PubMed2002

Meta-analysis of randomised controlled trials of the effectiveness of antiarrhythmic agents at promoting sinus rhythm in patients with atrial fibrillation.

OBJECTIVE: To conduct a meta-analysis of randomised controlled trials to estimate the effectiveness of antiarrhythmic drugs at promoting sinus rhythm in patients with atrial fibrillation. DESIGN: Articles were identified by using a comprehensive search of English language papers indexed in Medline from 1966 to August 2001. For the outcomes of sinus rhythm and death, a random effects model was used to model repeated assessments within a study at different time points. SETTING: Emergency departments and ambulatory clinics. PATIENTS: Patients with atrial fibrillation. INTERVENTIONS: Antiarrhythmic agents grouped according to their Vaughan-Williams class. MAIN OUTCOME MEASURES: Sinus rhythm and mortality. RESULTS: 91 articles met a priori criteria for inclusion in the analysis. Median duration of follow up was one day (range 0.04-1096, mean (SD) 46 (136) days). The median proportion of patients in sinus rhythm at follow up was 55% (range 0-100%) and 32% (range 0-90%) receiving active treatment and placebo, respectively. Median survival was 99% (range 55-100%) and 99% (range 55-100%). Compared with placebo, the following drug classes were associated with increased sinus rhythm at follow up: IA (treatment difference 21.5%, 95% confidence interval (CI) 16.3% to 26.8%); IC (treatment difference 33.1%, 95% CI 23.3% to 42.9%); and III (treatment difference 17.4%, 95% CI 11.5% to 23.3%). Class IC drugs were associated with increased sinus rhythm at follow up compared with class IV drugs (treatment difference 43.2%, 95% CI 11.5% to 75.0%). There was no significant difference in mortality between any drug classes. CONCLUSIONS: Class IA, IC, and III drugs are associated with increased sinus rhythm at follow up compared with placebo. It is unclear whether any antiarrhythmic drug class is associated with increased or decreased mortality.

Anti-Arrhythmia Agents↗
PubMed2001

Stenting versus thrombolysis in acute myocardial infarction trial (STAT).

OBJECTIVES: We sought to directly compare primary stenting with accelerated tissue plasminogen activator (t-PA) in patients presenting with acute ST-elevation myocardial infarction (AMI). BACKGROUND: Thrombolysis remains the standard therapy for AMI. However, at some institutions primary angioplasty is favored. Randomized trials have shown that primary angioplasty is equal or superior to thrombolysis, while recent studies demonstrate that stent implantation improves the results of primary angioplasty. METHODS: Patients presenting with AMI were randomly assigned to primary stenting (n = 62) or accelerated t-PA (n = 61). The primary end point was the composite of death, reinfarction, stroke or repeat target vessel revascularization (TVR) for ischemia at six months. RESULTS: The primary end point was significantly reduced in the stent group compared with the accelerated t-PA group, 24.2% versus 55.7% (p < 0.001). The event rates for other outcomes in the stent group versus the t-PA group were as follows: mortality: 4.8% versus 3.3% (p = 1.00); reinfarction: 6.5% versus 16.4% (p = 0.096); stroke: 1.6% versus 4.9% (p = 0.36); recurrent unstable ischemia: 9.7% versus 26.2% (p = 0.03) and repeat TVR for ischemia: 14.5% versus 49.2% (p < 0.001). The median length of the initial hospitalization was four days in the stent group and seven days in the t-PA group (p < 0.001). CONCLUSIONS: Compared with accelerated t-PA, primary stenting reduces death, reinfarction, stroke or repeat TVR for ischemia. In centers where facilities and experienced interventionists are available, primary stenting offers an attractive alternative to thrombolysis.

Aged↗
PubMed2001

The chain of survival.

Explore the source record for details and available documents.

Advanced Cardiac Life Support↗
PubMed2001

The effect of perioperative aspirin therapy in peripheral vascular surgery: a decision analysis.

Patients who undergo infrainguinal revascularization surgery are at increased risk for perioperative thrombotic complications. Aspirin decreases thrombotic events in the nonoperative setting; however, aspirin is often discontinued to avoid perioperative hemorrhagic complications. We used a decision analysis to determine whether aspirin should be discontinued before infrainguinal revascularization surgery. Two strategies were compared: aspirin cessation 2 wk before surgery and aspirin continuation throughout the perioperative period. Clinical events examined included myocardial infarction, thrombotic cerebrovascular accident, hemorrhagic cerebrovascular accident, gastrointestinal hemorrhage, and incisional hemorrhagic complications. Event rates and effect of aspirin were obtained by using MEDLINE. The outcomes were perioperative mortality, life expectancy, and quality-adjusted life expectancy. According to the model, continued aspirin use decreased perioperative mortality rates from 2.78% to 2.05%. Continued aspirin use increased life expectancy from 14.83 to 14.89 yr and increased quality-adjusted life expectancy from 14.72 to 14.79 yr. Aspirin increased the number of hemorrhagic complications by 2.46%, primarily because of an increased incidence of non-life-threatening complications.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos.

BACKGROUND: The use of automated external defibrillators by persons other than paramedics and emergency medical technicians is advocated by the American Heart Association and other organizations. However, there are few data on the outcomes when the devices are used by nonmedical personnel for out-of-hospital cardiac arrest. METHODS: We studied a prospective series of cases of sudden cardiac arrest in casinos. Casino security officers were instructed in the use of automated external defibrillators. The locations where the defibrillators were stored in the casinos were chosen to make possible a target interval of three minutes or less from collapse to the first defibrillation. Our protocol called for a defibrillation first (if feasible), followed by manual cardiopulmonary resuscitation. The primary outcome was survival to discharge from the hospital. RESULTS: Automated external defibrillators were used, 105 patients whose initial cardiac rhythm was ventricular fibrillation. Fifty-six of the patients 153 percent) survived to discharge from the hospital. Among the 90 patients whose collapse was witnessed (86 percent), the clinically relevant time intervals were a mean (+/-SD) of 3.5+/-2.9 minutes from collapse to attachment of the defibrillator, 4.4+/-2.9 minutes from collapse to the delivery of the first defibrillation shock, and 9.8+/-4.3 minutes from collapse to The arrival of the paramedics. The survival rate was 74 percent for those who received their first defibrillation no later than three minutes after a witnessed collapse and 49 percent for those who received their first defibrillation after more than three minutes. CONCLUSIONS: Rapid defibrillation by nonmedical personnel using an automated external defibrillator can improve survival after out-of-hospital cardiac arrest due to ventricular fibrillation. Intervals of no more than three minutes from collapse to defibrillation are necessary to achieve the highest survival rates.

Aged↗
PubMed1999

Choosing antithrombotic therapy for elderly patients with atrial fibrillation who are at risk for falls.

OBJECTIVE: To determine whether the risk of falling (with a possible increased chance of subdural hematoma) should influence the choice of antithrombotic therapy in elderly patients with atrial fibrillation. DESIGN: A Markov decision analytic model was used to determine the preferred treatment strategy (no antithrombotic therapy, long-term aspirin use, or long-term warfarin use) for patients with atrial fibrillation who are 65 years of age and older, are at risk for falling, and have no other contraindications to antithrombotic therapy. Input data were obtained by systematic review of MEDLINE. Outcomes were expressed as quality-adjusted life-years. RESULTS: For patients with average risks of stroke and falling, warfarin therapy was associated with 12.90 quality-adjusted life-years per patient; aspirin therapy, 11.17 quality-adjusted life-years; and no antithrombotic therapy, 10.15 quality-adjusted life-years. Sensitivity analysis demonstrated that, regardless of the patients' age or baseline risk of stroke, the risk of falling was not an important factor in determining their optimal antithrombotic therapy. CONCLUSIONS: For elderly patients with atrial fibrillation, the choice of optimal therapy to prevent stroke depends on many clinical factors, especially their baseline risk of stroke. However, patients' propensity to fall is not an important factor in this decision.

Accidental Falls↗
PubMed1999

The Ontario Prehospital Advanced Life Support (OPALS) study Part II: Rationale and methodology for trauma and respiratory distress patients. OPALS Study Group.

The Ontario Prehospital Advanced Life Support (OPALS) Study represents the largest prehospital study yet conducted, worldwide. This study will involve more than 25,000 cardiac arrest, trauma, and critically ill patients over an 8-year period (1994-2002). The current article, Part II, describes in detail the rationale and methodology for major trauma and respiratory distress patients and for an economic evaluation of Advanced Life Support (ALS) programs in the OPALS Study. The OPALS Study, using a rigorous controlled methodology and a large sample size, should clearly indicate the benefit in trauma and respiratory distress patient survival and morbidity that results from the widespread introduction of prehospital ALS programs to communities of many different sizes. [Stiell IG, Wells GA, Spaite DW, Nichol G, O'Brien B, Munkley DP, Field BJ, Lyver MB, Luinstra LG, Dagnone E, Campeau T, Ward R, Anderson S, for the OPALS Study Group: The Ontario Prehospital Advanced Life Support (OPALS) Study Part II: Rationale and methodology for trauma and respiratory distress patients.

Emergency Medical Services↗