A Device Performing a New Method of Cardiopulmonary Resuscitation: A Preliminary Report

BACKGROUND: There have been many efforts to augment blood flow during cardiopulmonary resuscitation. These efforts have focused on maximizing the effect of cardiac pump or thoracic pump alone. However, considering that the heart is the biggest blood reservoir and increase of intrathoracic pressure can generate blood flow, simultaneous exploitation of both mechanisms may have synergistic effect. We hypothesized that simultaneous chest constriction in addition to sternal compression by standard CPR may have additive hemodynamic effects by preventing deformation of the chest and increase of intrathoracic pressure. METHODS AND RESULTS: we built a new mechanical device to perform compression and thoracic constriction simultaneously. The device consists of two main elements. Piston in the center is to depress the sternum. Strap is to constrict the thorax circumferentially. Strap is attached to both sides of the piston. When the piston is pushed down, it depresses the sternum and pulls on the thoracic strap. To detemine sump width to produce optimal hemodynamic effect, we measured hemodynamic parameters with variable widths of sump in two dogs after induction of ventricular fibrillation. Result of the experiment showed that 10 cm wide strap was determined to be most effective. We also determined optimal depth of compression to produce maximal hemodynamic effect with animal experiments using two dogs. Animal experiments showed that the highest aortic pressure could be generated when the sternum was depressed to 5 cm. Cardiopulmonary resuscitation using a new device could generate higher systolic aortic pressure, coronary perfusion pressure and end-tidal carbon dioxide tension in comparison with standard cardiopulmonary resuscitation in a pilot animal Study Using two dogs. CONCLUSION: New cardiopulmonary resuscitation method using a mechanical device designed by us could perform sternal compression and simultaneous thoracic constriction, and generate better hemodynamic effects than standard cardiopulmonary resuscitation in pilot animal experiments.

Developing of Systemic Inflammatory Response Syndrome and Serum TNF-alpha Level in Multiple Trauma Patients

BACKGROUND AND PURPOSE: The systemic inflammatory response syndrome(SIRS), as defied recently by critical-care specialists, may result from various etiologies including infection, bum, or trauma. The purpose of this study was to determine whether TNF- alpha is associated with the development of systemic inflammatory response syndrome caused by multiple trauma. METHODS: The study population consisted of 21 patients with multiple trauma presented emergency department within 2 hours after insult were enrolled in this study Multiple blood samples were serially drawn to measure seam TNF-alpha level on admission, 12 hours, 24 hours, and every day until 5 days after injury. Serum TNF-alpha was measured by ELISA ("Sandwich type"). Blood samples of fifteen volunteers were used as a reference value far serum TNF-alpha. RESULTS: Serum TNF-alpha. levels of SIRS group were persistency elevated above reference value until 3 days after on admission. Peak seam TNF-alpha level at 12 hours after admission was higher in SIRS group than non-SIRS group(p< 0.05). There was no significant correlation between injury severity score and TNF-alpha levels on regression analysis, all patients with ISS higher than 16 had SIRS. No one had SIRS among patients with ISS less than 16. CONCLUSION: the result of this study suggests that persistent elevation of TNF-alpha and degree of injury severity are associated with the development of systemic inflammatory response syndrome in multiple trauma.

Role of Transesophageal Echocardiography in Differential Diagnosis of The Cause of Cardiac Arrest During The Secondary Survey of Advanced Cardiac Life Support

BACKGROUND: During the secondary survey of advanced cardiac life support (ACLS), differential diagnosis to seek the cause of cardiac arrest is an important step in patient who failed to restore spontaneous circulation after the primary survey and resuscitation. This study was to evaluate the role of transesophageal echocardiography (TEE) for assessing the cause of cardiac arrest during the secondary survey of ACLS. METHOD: We performed biplane TEE during cardiopulmonary resuscitation (CPR) in 52 consecutive patients (31 male, 21 female, mean age: 58 years old) with cardiac arrest who failed to restore spontaneous circulation after the primary survey and resuscitation attempt. Initial presenting ECG rhythm was ventricular fibrillation in 7, asystole in 25, and pulseless electrical activity in 20 patients. TEE was performed immediately if spontaneous circulation was not restored after the primary survey and resuscitation. Possible causes of cardiac arrest were detected in 23 patients (44%) by TEE. Positive findings were observed in 3 (43%) of 7 patients with ventricular fibrillation, 12 (48%) of 25 patients with asystole, and 8 (40%) of 20 patients with pulseless electrical activity. TEE findings were as followings : pericardial effusion in 10, aortic dissection in 5, occlusion of mitral orifice by a thrombus or a mass in 2, main pulmonary artery thrombus in 2, thrombotic occlusion of the prosthetic valve in 1, hypertrophic cardiomyopathy in 1, and aortic stenosis in 1. Interventions including pericardiocentesis (n=10) and emergency thoracotomy (n=1) were attempted during resuscitation. Spontaneous circulation was restored in 16 patients (31%). One patient was discharged alive. CONCLUSION: TEE is an useful diagnostic tool to identify the cause of cardiac arrest during the secondary survey of ACLS.