Heat, Nurse Workload, and Patient Safety in Hot-Climate Hospitals: A Two-Month Time-Series Study (May–June 2025)

This study examined the relationship between environmental heat and hospital safety outcomes in hot-climate settings. Using a retrospective ecological time-series design, we analyzed data collected from May to June 2025 across multiple hospital units. Daily maximum heat index values were merged with nurse staffing rosters and patient safety incident logs. Nurse workload indicators included patients-per-nurse ratios, overtime minutes, and sick leave, while safety outcomes were captured as falls and medication errors per 1,000 patient-days. Advanced time-series models, specifically quasi-Poisson regression with distributed lags, were employed to capture short-term effects of heat exposure while adjusting for potential confounders such as day-of-week, hospital site, and unit type. Findings indicated that days with a heat index above 41 °C were associated with increased overtime, higher patient falls, and greater medication error rates. Mediation analyses further suggested that nurse workload partially explained the relationship between heat exposure and safety incidents. This study highlights the vulnerability of healthcare systems to environmental stressors and underscores the need for climate-adaptive staffing strategies and protective policies to ensure nurse well-being and patient safety.本研究针对炎热气候环境下环境高温与医院安全结局之间的关联展开了系统考察。本研究采用回顾性生态时间序列设计（retrospective ecological time-series design），对2025年5月至6月期间多家医院科室收集的相关数据进行了分析。研究将每日最高热指数（heat index）值与护士排班表、患者安全事件日志进行匹配整合。护士工作量指标涵盖护患比、加班时长及病假情况，安全结局则以每1000患者日的跌倒事件与用药错误数进行统计。 本研究采用高级时间序列模型，具体为带有分布滞后（distributed lags）的拟泊松回归（quasi-Poisson regression），以捕捉高温暴露的短期效应，同时对星期几、医院院区及科室类型等潜在混杂因素（confounder）进行了校正。 研究结果显示，热指数高于41℃的日期与加班时长增加、患者跌倒率上升及用药错误率升高存在显著关联。中介分析（mediation analyses）进一步表明，护士工作量部分介导了高温暴露与安全事件之间的关联。 本研究凸显了医疗系统对环境应激源的脆弱性，并强调亟需制定气候适应性人员配置策略与防护政策，以保障护士福祉与患者安全。