The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest

Introduction: Partial pressure of end-tidal carbon dioxide (PetCO2) during cardiopulmonary resuscitation (CPR) correlates with cardiac output and consequently has a prognostic value in CPR. In our previous study we confirmed that initial PetCO2 value was significantly higher in asphyxial arrest than in ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) cardiac arrest. In this study we sought to evaluate the pattern of PetCO2 changes in cardiac arrest caused by VF/VT and asphyxial cardiac arrest in patients who were resuscitated according to new 2005 Guidelines. Methods: The study included two cohorts of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity (PEA), and cardiac arrest due to arrhythmia with initial rhythm VF or pulseless VT. PetCO2 was measured for both groups immediately after intubation and repeatedly every minute, both for patients with or without return of spontaneous circulation (ROSC). We compared the dynamic pattern of PetCO2 between groups. Results: Between June 2006 and June 2009 resuscitation was attempted in 325 patients and in this study we included 51 patients with asphyxial cardiac arrest and 63 patients with VF/VT cardiac arrest. The initial values of PetCO2 were significantly higher in the group with asphyxial cardiac arrest (6.74 +/- 4.22 kPa versus 4.51 +/- 2.47 kPaP = 0.004). In the group with asphyxial cardiac arrest, the initial values of PetCO2 did not show a significant difference when we compared patients with and without ROSC (6.96 +/- 3.63 kPa versus 5.77 +/- 4.64 kPaP = 0.313). We confirmed significantly higher initial PetCO2 values for those with ROSC in the group with primary cardiac arrest (4.62 +/- 2.46 kPa versus 3.29 +/- 1.76 kPaP = 0.041). A significant difference in PetCO2 values for those with and without ROSC was achieved after five minutes of CPR in both groups. In all patients with ROSC the initial PetCO2 was again higher than 1.33 kPa. Conclusions: The dynamic pattern of PetCO2 values during out-of-hospital CPR showed higher values of PetCO2 in the first two minutes of CPR in asphyxia, and a prognostic value of initial PetCO2 only in primary VF/VT cardiac arrest. A prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until final values. This difference seems to be a useful criterion in prehospital diagnostic procedures and attendance of cardiac arrest

Prehospital monitoring in resuscitation : today and the future

There is growing evidence that early detection and response to physiological deterioration can improve outcome for patients. Working out-of-hospital, we often find ourselves in diagnostic dilemmas, thus more reliable data could change our actions as well as give better assessment of patient\u27s condition. Therefore, we are always exploring new perspectives that could be transferred from experimental laboratory settings to our primary working area in the field to help us improve decision-making leading to better outcome. In the following sections, we represent our previous studies about the utility of continuous capnometry and the importance of point-of-care ultrasound in cardiopulmonary resuscitation (CPR), and discuss about the possible future use of transthoracic and transesophageal ultrasound, point-of-care biochemical monitoring, tissue oxygen saturation, pupillometry, and mixed and central venous oxygen saturation monitoring in the prehospital setting

Decision Support Based on Bio-PEPA Modeling and Decision Tree Induction: A New Approach, Applied to a Tuberculosis Case Study

The problem of selecting determinant features generating appropriate model structure is a challenge in epidemiological modelling. Disease spread is highly complex, and experts develop their understanding of its dynamic over years. There is an increasing variety and volume of epidemiological data which adds to the potential confusion. We propose here to make use of that data to better understand disease systems. Decision tree techniques have been extensively used to extract pertinent information and improve decision making. In this paper, we propose an innovative structured approach combining decision tree induction with Bio-PEPA computational modelling, and illustrate the approach through application to tuberculosis. By using decision tree induction, the enhanced Bio-PEPA model shows considerable improvement over the initial model with regard to the simulated results matching observed data. The key finding is that the developer expresses a realistic predictive model using relevant features, thus considering this approach as decision support, empowers the epidemiologist in his policy decision making

Preparing for out of hospital cardiac arrests (OHCA) in Riyadh, Saudi Arabia: A GIS scenario-modeling approach

This study employed location-allocation modeling and a geographic information system (GIS) to study the current placement of automated external defibrillators (AEDs) in relationship to neighborhoods in Riyadh City, Saudi Arabia, and to determine the optimal locations for additional AEDs in the city. Using GIS to mathematically locate additional healthcare facilities for the placement of AEDs is more reliable than to select them using informed guesses. The objective of this research was to elaborate a mathematical and GIS model for placing AED devices so that people who need to use these devices in the City of Riyadh, Saudi Arabia, can access them within a time frame of three minutes or less, which is the international standard for such accessibility. The research employed street blocks as demand points; existing healthcare facilities, mosques, and schools as supply points; and the maximum coverage algorithm to model optimal locations for AED devices. Models were run for both vehicle and pedestrian travel times. Model results of current conditions indicated that 75% of household blocks were covered when vehicles were used to access AED sites, as compared to 9% of people when pedestrian travel to an AED is considered. Introduction of 1,371 mosques and 34 community colleges and universities as additional supply points for AEDs improved coverage to 94% for vehicular access, but only 34% for pedestrian traffic. Although mosques are considered to be focus points for Muslim communities, other facilities including, but not limited to, police stations, malls, primary and secondary schools, and playgrounds should be used to gain wider coverage. In addition, cluster analysis should be employed to avoid selecting AED supply points that are too close to each other and which are unlikely to improve accessibility. The study succeeded in elaborating a framework for conceptualizing the relationship between vehicular and pedestrian access to AEDs. It also demonstrates how GIS-based location-allocation modeling can be used for efficient placement of AEDs. The broad conceptual framework for AED placement used in this study has applicability to other countries in the Middle East