Frank Archer

Sensitivity and Specificity of the Medical Priority Dispatch System in Detecting Cardiac Arrest Emergency Calls in Melbourne

INTRODUCTIONnIn Australia, cardiac arrest kills 142 out of every 100,000 people each year; with only 3-4% of out-of-hospital patients with cardiac arrest in Melbourne surviving to hospital discharge. Prompt initiation of cardiopulmonary resuscitation (CPR), defibrillation, and advanced cardiac care greatly improves the chances of survival from cardiac arrest. A critical step in survival is identifying by the emergency ambulance dispatcher potential of the probability that the person is in cardiac arrest. The Melbourne Metropolitan Ambulance Service (MAS) uses the computerized call-taking system, Medical Priority Dispatch System (MPDS), to triage incoming, emergency, requests for ambulance responses. The MPDS is used in many emergency medical systems around the world, however, there is little published evidence of the systems efficacy.nnnOBJECTIVEnThis study attempts to undertake a sensitivity/specificity analysis to determine the ability of MPDS to detect cardiac arrest.nnnMETHODSnEmergency ambulance dispatch records of all cases identified as suspected cardiac arrest by MPDS were matched with ambulance, patient-care records and records from the Victorian Ambulance Cardiac Arrest Registry to determine the number of correctly identified cardiac arrests. Additionally, cases that had cardiac arrests, but were not identified correctly at the point of call-taking, were examined. All data were collected retrospectively for a three-month period (01 January through 31 March 2003).nnnRESULTSnThe sensitivity of MPDS in detecting cardiac arrest was 76.7% (95% confidence interval (CI): 73.6%-79.8%) and specificity was 99.2% (95% CI: 99.1-99.3%). These results indicate that cardiac arrests are correctly identified in 76.7% of cases.nnnCONCLUSIONnAlthough the system correctly identified 76.7% of cardiac arrest cases, the number of false negatives suggests that there is room for improvement in recognition by MPDS to maximize chances for survival in out-of-hospital cardiac arrest. This study provides an objective and comprehensive measurement of the accuracy of MPDS cardiac-arrest detection in Melbourne, as well as providing a baseline for comparison with subsequent changes to the MPDS.

Is Mechanism of Injury a Useful Predictor in Prehospital Trauma Triage

s 14th World Congress on Disaster and Emergency Medicine sl47 Materials and Methods: The medical charts of 16 patients who underwent DCS from October 2000-April 2004 were reviewed retrospectively. All of the patients were classified into one of two groups: (1) Survived (Group A: 11 cases); and (2) Expired (Group B: 5 cases). The number of patients who underwent DCS, and met the following criteria were evaluated: (1) systolic blood pressure <90 mmHg; body temperature <35C; and (3) pH <7.3. Results: The aims of the DCS were hemorrhage control for massive hepatic injury in 12 cases (Group A: 7, Group B: 5) or severe pancreatic injury in four cases (all in Group A). The response pattern of the circulation from initial fluid resuscitation revealed transient responders (six cases) or non-responders (10 cases). The severity of injury was greater in B group (ISS of 39.4 and p = 0.47) comparing with Group A (ISS of 31.3 and p = 0.729). A matching number of these DCS criteria in Group A were 0 (3 cases), 1 (3 cases), 2 (5 cases) and 3 (1 case). On the other hand, all cases matched 3 (full scores) in Group B. The time from admission to fulfill these three criteria between both groups was 40.7 minutes. Conclusion: Although further investigation is needed, the revised DCS decision criteria seems to be useful, and DCS should be performed before the abdominal trauma patient fulfills these three criteria.