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Biomedical subjects

J P Ornato

Publications and source records attributed to J P Ornato.

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

Public-access defibrillation and survival after out-of-hospital cardiac arrest.

BACKGROUND: The rate of survival after out-of-hospital cardiac arrest is low. It is not known whether this rate will increase if laypersons are trained to attempt defibrillation with the use of automated external defibrillators (AEDs). METHODS: We conducted a prospective, community-based, multicenter clinical trial in which we randomly assigned community units (e.g., shopping malls and apartment complexes) to a structured and monitored emergency-response system involving lay volunteers trained in cardiopulmonary resuscitation (CPR) alone or in CPR and the use of AEDs. The primary outcome was survival to hospital discharge. RESULTS: More than 19,000 volunteer responders from 993 community units in 24 North American regions participated. The two study groups had similar unit and volunteer characteristics. Patients with treated out-of-hospital cardiac arrest in the two groups were similar in age (mean, 69.8 years), proportion of men (67 percent), rate of cardiac arrest in a public location (70 percent), and rate of witnessed cardiac arrest (72 percent). No inappropriate shocks were delivered. There were more survivors to hospital discharge in the units assigned to have volunteers trained in CPR plus the use of AEDs (30 survivors among 128 arrests) than there were in the units assigned to have volunteers trained only in CPR (15 among 107; P=0.03; relative risk, 2.0; 95 percent confidence interval, 1.07 to 3.77); there were only 2 survivors in residential complexes. Functional status at hospital discharge did not differ between the two groups. CONCLUSIONS: Training and equipping volunteers to attempt early defibrillation within a structured response system can increase the number of survivors to hospital discharge after out-of-hospital cardiac arrest in public locations. Trained laypersons can use AEDs safely and effectively.

Adolescent↗
PubMed2001

Simultaneous sternothoracic cardiopulmonary resuscitation: a new method of cardiopulmonary resuscitation.

No existing device for cardiopulmonary resuscitation (CPR) is designed to exploit both the "cardiac pump" and the "thoracic pump" effect simultaneously. The purpose of this study was to measure the haemodynamic effect of a new simultaneous sternothoracic cardiopulmonary resuscitation (SST-CPR) device that could compress the sternum and constrict the thoracic cavity simultaneously in a canine cardiac arrest model. After 4 min of ventricular fibrillation, 24 mongrel dogs were randomized to receive standard CPR (n=12) or SST-CPR (n=12). SST-CPR generated a new pattern of the aortic pressure curve presumed to be the result of both sternal compression and thoracic constriction. SST-CPR resulted in significantly higher mean arterial pressure than standard CPR (68.9+/-16.1 vs. 30.5+/-10.0 mmHg, P<0.01). SST-CPR generated higher coronary perfusion pressure than standard CPR (47.0+/-11.4 vs. 17.3+/-8.9 mmHg, P<0.01). End tidal CO(2) tension was also higher during SST-CPR than standard CPR (11.6+/-6.1 vs. 2.17+/-3.3 mmHg, P<0.01). In this preliminary animal model study, simultaneous sternothoracic cardiopulmonary resuscitation generated better haemodynamic effects than standard, closed chest cardiopulmonary resuscitation.

Animals↗
PubMed2001

Factors associated with the occurrence of cardiac arrest during hospitalization for acute myocardial infarction in the second national registry of myocardial infarction in the US.

Cardiac arrest can occur as a complication of acute myocardial infarction (AMI). To date, few studies have described factors associated with cardiac arrest occurrence and survival during hospitalization for treatment of AMI. We used data from a large national registry of hospitalized AMI patients to identify these factors. Data were collected from 1073 participating institutions, representing 14.4% of US hospitals. Hospital site coordinators conducted periodic chart reviews for AMI patients and data were submitted to an independent center for periodic review. Univariate analysis and multivariate logistic regression were used to identify factors associated with cardiac arrest. We found that cardiac arrest occurred in 4.8% (14,725/305,812) of hospitalized AMI patients. The survival rate to hospital discharge for these individuals was 29.4%. Sustained ventricular tachycardia or fibrillation (VT/VF) was present in 34.7% and was associated with a higher rate of survival to hospital discharge compared to cardiac arrest patients without a ventricular tachyarrhythmia (47.5 vs. 19.8%, P < 0.00001). Hypotension (initial systolic BP < 90 mmHg), q-wave AMI, old age, heart failure and initial heart rate abnormalities (bradycardia or tachycardia) were associated with a higher prevalence of cardiac arrest. A higher percentage of women compared to men experienced cardiac arrest (6.0 vs. 4.41%, P < 0.0001). Cardiac arrest prevalence was lower in patients with inferior wall infarction than in other types of ST-elevation infarction. Use of reperfusion therapy (PTCA or tPA) was associated with improved survival compared to hospitalized AMI patients who did not receive such therapy.

Age Distribution↗
PubMed2001

Prediction of lidocaine tissue concentrations following different dose regimes during cardiac arrest using a physiologically based pharmacokinetic model.

BACKGROUND: The purpose of our study was to develop a physiologically based pharmacokinetic (PBPK) model describing the behavior of lidocaine in humans by scaling up physiological variables from animal models of cardiac arrest. We attempted to identify the optimal dose regime for lidocaine during cardiac arrest using this model. METHODS AND RESULTS: We designed a flow-dependent PBPK model representing nine body tissues for lidocaine. Physiological organ flow rates, tissue volumes, and plasma-tissue partition parameters for lidocaine in humans were taken from the literature. Data from published animal studies were used to estimate loss of organ blood flow during cardiac arrest and lidocaine tissue partition coefficients. The model assumed a 70 kg cardiac arrest patient. The following five lidocaine dose regimes were simulated: (1) 4 mg/kg i.v. push (IVP) (2) 1.5 mg/kg IVP then 1.5 mg/kg IVP in 4 min, (3) 3 mg/kg IVP, (4) 2 mg/kg IVP, and (5) 1.5 mg/kg IVP. A simulation of Regimen 2, which is the current American Heart Association (AHA) recommendation, suggests that the concentration of lidocaine is suboptimal at the decision point (3-5 min) to administer another dose. Regimen 4 offers a slightly more rapid progress towards optimal cardiac concentrations and more acceptable brain concentrations compared to regimes 1-3. CONCLUSION: Simulations from our PBPK model suggest that the current AHA lidocaine dose regime for cardiac arrest may not result in optimal lidocaine concentrations in the heart and brain. Simulations suggest that 2 mg/kg IVP may be the most acceptable lidocaine dose regime during cardiac arrest.

Algorithms↗
PubMed2001

Critical decision making in the management of patients with acute myocardial infarction and other acute coronary syndromes.

The decision-making process for emergency physicians in managing patients with signs or symptoms of AMI or unstable angina is quite different than that used by other specialists who might evaluate such patients in a less critical setting (e.g., a cardiologist seeing a private patient in an office or outpatient clinic environment). The emergency physician's evaluation must be highly focused and follow established principles of emergency medicine (Fig. 2). Although the evaluation and treatment of all patients must be individualized to some degree, increasing experience at high-volume centers nationally indicates that well-constructed institutional strategies, protocols, and critical pathways can help emergency physicians to provide consistent, cost-effective management of such patients.

Algorithms↗
PubMed2001

Can myocardial infarction be rapidly identified in emergency department patients who have left bundle-branch block?

STUDY OBJECTIVES: Fibrinolytic therapy is recommended for patients who have chest pain and left bundle-branch block (LBBB). However, the presence of baseline ECG abnormalities makes early accurate identification of acute myocardial infarction (AMI) difficult. The predictive ability of clinical and ECG variables for identifying patients with LBBB and AMI has not been well studied. We sought to determine the prevalence and predictors of myocardial infarction among patients presenting to the emergency department with LBBB on the initial ECG who were evaluated for myocardial infarction. METHODS: All patients presenting to the ED were prospectively risk stratified on the basis of clinical and historical variables. ECGs from patients with LBBB were compared retrospectively with previously published criteria for identification of AMI. The ability of a new LBBB to predict AMI was also determined. RESULTS: Twenty-four (13%) of the 182 patients with LBBB had AMI. Clinical and historical variables were similar in patients with and without AMI. A new LBBB had a sensitivity of 42% and a specificity of 65%. The presence of concordant ST-segment elevation or depression had specificities and positive predictive values of 100%; however, sensitivities were only 8% and 17%, respectively. The best diagnostic criterion was the presence of concordant ST-segment elevation or depression on the ECG or an initially elevated creatine kinase MB (sensitivity, 63%; specificity, 99%). CONCLUSION: ECG criteria for identifying patients with AMI and LBBB identify only a small minority of patients with AMI. Treating all patients with LBBB and chest pain with fibrinolytics would result in treatment of a significant number of patients without AMI.

Aged↗
PubMed2001

A nonischemic electrocardiogram does not always predict a small myocardial infarction: results with acute myocardial perfusion imaging.

BACKGROUND: A nonischemic electrocardiogram (ECG) in association with myocardial infarction (MI) indicates a small MI in some but not all cases. Myocardial perfusion imaging using technetium-99m sestamibi offers the ability to better characterize these "electrically silent" infarctions. METHODS: Patients considered low risk for myocardial infarction with a normal or nonischemic ECG (no significant ST elevation, ST depression, ischemic T-wave inversion, or left bundle branch block) underwent early emergency department perfusion imaging, followed by serial myocardial marker sampling. Risk area (defect size) was quantitated by use of a 50% threshold from multiple short-axis slices. RESULTS: A total of 87 patients with nonischemic ECGs had myocardial infarction (mean peak creatine kinase [CK] 710 +/- 720 U/L, range 111-3196 U/L). Peak CKs were lower in the 7 patients with negative perfusion imaging (420 +/- 290 U/L vs 730 +/- 740 U/L, P =.06). Mean risk area was 18% +/- 11% of the left ventricle (range 0%-62%) and was not significantly different among the different infarct-related arteries. Patients with normal ECGs had a similar risk area compared with other patients (16% +/- 12% vs 19 +/- 12%, P =.25). Coronary angiography was performed in 81 patients, with significant stenoses in 74 (91%) (37 one-vessel, 19 two-vessel, 18 three-vessel), with the infarct related artery most commonly the left circumflex (n = 32 [38%]). CONCLUSIONS: The ischemic risk area in patients with a nonischemic ECG was comparable to patients with inferior ST-elevation myocardial infarction found in previous studies. A nonischemic ECG does not predict a small ischemic risk area.

Coronary Angiography↗