INTRODUCTIONPre-hospital ambulance calls are not random events, but occur in patterns and trends that are related to movement patterns of people, as well as the geographical epidemiology of the population. This study describes the geographic-time epidemiology of ambulance calls in a large urban city and conducts a time demand analysis. This will facilitate a Systems Status Plan for the deployment of ambulances based on the most cost effective deployment strategy.

MATERIALS AND METHODSAn observational prospective study looking at the geographic-time epidemiology of all ambulance calls in Singapore. Locations of ambulance calls were spot mapped using Geographic Information Systems (GIS) technology. Ambulance response times were mapped and a demand analysis conducted by postal districts.

RESULTSBetween 1 January 2006 and 31 May 2006, 31,896 patients were enrolled into the study. Mean age of patients was 51.6 years (S.D. 23.0) with 60.0% male. Race distribution was 62.5% Chinese, 19.4% Malay, 12.9% Indian and 5.2% others. Trauma consisted 31.2% of calls and medical 68.8%. 9.7% of cases were priority 1 (most severe) and 70.1% priority 2 (moderate severity). Mean call receipt to arrival at scene was 8.0 min (S.D. 4.8). Call volumes in the day were almost twice those at night, with the most calls on Mondays. We found a definite geographical distribution pattern with heavier call volumes in the suburban town centres in the Eastern and Southern part of the country. We characterised the top 35 districts with the highest call volumes by time periods, which will form the basis for ambulance deployment plans.

CONCLUSIONWe found a definite geographical distribution pattern of ambulance calls. This study demonstrates the utility of GIS with despatch demand analysis and has implications for maximising the effectiveness of ambulance deployment.

Ambulances ; utilization ; Geographic Information Systems ; Singapore

INTRODUCTIONThe aim of the study is to investigate the effect of using Automated External Defibrillator (AED) audiovisual feedback on the quality of cardiopulmonary resuscitation (CPR) in a manikin training setting.

MATERIALS AND METHODSFive cycles of 30 chest compressions were performed on a manikin without CPR prompts. After an interval of at least 5 minutes, the participants performed another 5 cycles with the use of real time audiovisual feedback via the ZOLL E-Series defibrillator. Performance data were obtained and analysed.

RESULTSA total of 209 dialysis centre staff participated in the study. Using a feedback system resulted in a statistically significant improvement from 39.57% to 46.94% (P=0.009) of the participants being within the target compression depth of 4 cm to 5 cm and a reduction in those below target from 16.45% to 11.05% (P=0.004). The use of feedback also produced a significant improvement in achieving the target for rate of chest compression (90 to 110 compressions per minute) from 41.27% to 53.49%; (P<0.001). The mean depth of chest compressions was 4.85 cm (SD=0.79) without audiovisual feedback and 4.91 (SD=0.69) with feedback. For rate of chest compressions, it was 104.89 (SD=13.74) vs 101.65 (SD=10.21) respectively. The mean depth of chest compression was less in males than in females (4.61 cm vs 4.93 cm, P=0.011), and this trend was reversed with the use of feedback.

CONCLUSIONIn conclusion, the use of feedback devices helps to improve the quality of CPR during training. However more studies involving cardiac arrest patients requiring CPR need to be done to determine if these devices improve survival.

Adult ; Audiovisual Aids ; Cardiopulmonary Resuscitation ; instrumentation ; methods ; Defibrillators ; Feedback ; Female ; Humans ; Male ; Manikins ; Middle Aged ; Pressure ; Prospective Studies ; Thorax ; Young Adult