Resuscitation Outcomes and Clinical Characteristics of Non-traumatic Out-of-Hospital Geriatric Cardiac Arrest

PURPOSE: This study was to investigate the resuscitation outcomes and the clinical characteristics of geriatric nontraumatic out-of-hospital cardiac arrest by analyzing data from a single institution's registry. METHODS: We conducted a retrospective study of 804 patients who came to the emergency department with nontraumatic out-of-hospital cardiac arrest during the period 1991-2002. Only patients over 18 years of age were included. Clinical characteristics, variables associated with cardiac arrest, and data during resuscitation were obtained from our cardiac arrest database. Patients were divided into two age groups: less than 65 years of age (non-geriatric group, n=530), and over 65 years of age (geriatric group, n=274). RESULTS: The proportion of cardiac etiology was higher with the geriatric group than with the non-geriatric group (48% vs 39%, chi-square=0.013). A lower incidence of ventricular arrhythmia was observed in the geriatric group (8% vs 13%, chi-square= 0.037). The arrest time, the CPR time, the witnessed arrest, the epinephrine doses, and total defibrillation energy were not different between two groups. Spontaneous circulation was restored in 127 (46%) patients in the geriatric group and in 255 (48%) patients in the non-geriatric group (chi-square=0.382). The patients discharged alive numbered were 33 (6%) in the non-geriatric group and 10 (4%) in the geriatric group (chi-square=0.138). CONCLUSION: Cardiac etiology was predominant in geriatric cardiac arrest and a lower incidence of ventricular arrhythmia was observed. An older age (over 65 years) did not affect the resuscitation outcome.

Effect of Standard Cardiopulmonary Resuscitation on Cerebral Blood Flow and Coronary Perfusion Pressure in the Canine Model of Simulated Ventricular Tachycardia

PURPOSE: The purpose of this study was to evaluate the hemodynamic effects of external chest compression in state of the heart's beating. METHODS: Ten mongrel dogs were used in this study. Ventricular tachycardia was simulated by using a rapid ventricular pacing and ventricular rate was adjusted and maintained at the rate necessary to achieve a 50-mmHg fall in the baseline systolic aortic pressure. External chest compression was initiated after 4 minutes of simulated ventricular tachycardia and was continued for 4 minutes. Hemodynamic measurements, including the systolic and the diastolic aortic pressure, the right atrial pressure, the carotid blood flow, and the end tidal CO2 tension, were done at baseline, during the simulated ventricular tachycardia (VT), and during the simulated ventricular tachycardia with external chest compression (VT+ECC). RESULTS: The systolic aortic pressure, the diastolic aortic pressure, and the mean right atrial pressure were higher during VT+ECC than during VT (99+/-12 vs 92+/-8 mmHg, p=0.157, 59+/-8 vs 55+/-12 mmHg, p=0.140, and 23+/-8 vs 8+/-2 mmHg, p<0.001, respectively). The carotid blood flow was higher during VT+ECC than during VT (273+/-203 vs 136+/-76 mL/min., p=0.011). The calculated coronary perfusion pressure was lower during VT+ECC than during VT ( 26+/-8 vs 40+/-9 mmHg, p<0.001). The end tidal CO2 tension was not different between VT+ECC and VT. CONCLUSION: In the canine model of simulated ventricular tachycardia, external chest compression had a contradictory hemodynamic effect, including an increase in the cerebral blood flow and a decrease in the coronary perfusion pressure.

B-type Natriuretic Peptide in Differentiating Acute Dyspnea

PURPOSE: This study was to test the diagnostic value of Btype natriuretic peptide (BNP) for differentiating between the causes of acute dyspnea. METHODS: We conducted a prospective study of 41 patients who came to the emergency department with acute dyspnea between August 1, 2002, and October 31, 2002. Plasma BNP was measured for a bedside assay. We excluded patients who suffered from dyspnea due to airway obstruction, hyperventilation syndrome, psychiatric causes, drug intoxication, and chronic renal failure or from dyspnea of neuromuscular origin. The clinical diagnosis of congestive heart failure was adjudicated by echocardiographic findings. Two emergency physicians, who were blinded to the results of the BNP assay and the echocardiographic findings, determined the cause of dyspnea as regard to the Framingham criteria. RESULTS: The final diagnosis of dyspnea was due to a cardiogenic origin in 29 patients (71%), and due to a noncardiogenic origin in 12 patients (29%). The plasma BNP levels in themselves were more specific and sensitive in diagnosing cardiogenic dyspnea than was a clinical decision based on the authority of the Framingham criteria. In the echocardiographic findings, the left-ventricular end-systolic dimension and the left- ventricular end-diastolic dimension were positively correlated with the plasma BNP levels(R=0.44, p=0.002 and R=0.40, p=0.005), the ejection fraction was negatively correlated (R=-0.46, p=0.001). In the multiple logistic-regression analysis, measurements of the plasma BNP level added significant independent predictive power to other clinical variables in the models. CONCLUSION: The assay of plasma BNP in the emergency department was useful method for differentiating acute dyspnea based on its cause, and the plasma BNP level was corresponded to the degree of left ventricular dysfunction.