Cantwell Kate, Morgans Amee, Smith Karen, Livingston Michael, Dietze Paul
Centre for Population Health, Burnet Institute , Melbourne , Australia .
Chronobiol Int. 2015;32(6):731-8. doi: 10.3109/07420528.2015.1041600. Epub 2015 Jun 10.
Diagnosed cardiovascular disease has well-reported temporal patterns, with demand distribution peaks in the late morning and greater case numbers on Mondays and in winter. We aimed to report temporal patterns of presumptive cardiovascular disease cases as determined after emergency medical services (EMS) assessment and to characterize the demand distribution by day of the week. We conducted a secondary analysis of all Ambulance Victoria cases in metropolitan Melbourne (Victoria, Australia) between January 2008 and December 2011. Analyzed data included time of call, incident mechanism, location type, final assessment (paramedic "diagnosis") and patient age. We employed Poisson's regression to analyze case numbers and trigonometric regression to quantify distribution patterns. The 182 983 cases of presumptive cardiovascular disease observed during the study period constituted 15.2% of total demand. The median age of persons attended was 72 (IQR 57-82) and there was an almost even split between genders (51% female). Peak numbers of most cardiovascular case types occurred between 09:00 and 11:00; the only exception was acute pulmonary edema, which had peak case numbers at 06:00. Trigonometric regression showed distinct time of day distribution patterns, which did not alter by season. Although weekend day demand was lower than on Mondays, due to a different distribution pattern, these differences were not constant over the 24-hour period. There were up to 27% fewer cases at 09:00 and up to 2.8% more cases at 01:00 on weekends compared to Mondays. We have shown that examination of presumptive cardiovascular disease using not only case counts but also demand distribution patterns allows for a greater understanding of ambulance demand. Monday might be the most frequent day for cardiovascular cases but different patterns of demand occur on weekends. Increased knowledge of when different types of cases are most likely to occur will help inform EMS planning, including paramedic capacity and resources.
已确诊的心血管疾病具有充分报道的时间模式，需求分布高峰出现在上午晚些时候，周一和冬季的病例数更多。我们旨在报告经紧急医疗服务（EMS）评估后确定的疑似心血管疾病病例的时间模式，并按星期几来描述需求分布特征。我们对2008年1月至2011年12月期间澳大利亚维多利亚州墨尔本大都市地区所有维多利亚救护车服务病例进行了二次分析。分析的数据包括呼叫时间、事件机制、地点类型、最终评估（护理人员“诊断”）和患者年龄。我们采用泊松回归分析病例数，并采用三角回归来量化分布模式。在研究期间观察到的182983例疑似心血管疾病病例占总需求的15.2%。就诊人员的年龄中位数为72岁（四分位距57 - 82岁），性别分布几乎均匀（女性占51%）。大多数心血管病例类型的高峰数出现在09:00至11:00之间；唯一的例外是急性肺水肿，其病例数高峰出现在06:00。三角回归显示了明显的每日时间分布模式，且不随季节变化。虽然周末的需求低于周一，但由于分布模式不同，这些差异在24小时内并不恒定。与周一相比，周末09:00时的病例数减少多达27%，01:00时的病例数增加多达2.8%。我们已经表明，不仅使用病例数而且使用需求分布模式来检查疑似心血管疾病，有助于更好地理解救护车需求。周一可能是心血管病例最常见的日子，但周末会出现不同的需求模式。更多地了解不同类型病例最可能出现的时间，将有助于为EMS规划提供信息，包括护理人员的能力和资源。
