BACKGROUND Anesthesia staffing models rely on predictable surgical case volumes. Previous studies have found no relationship between month of the year and surgical volume. However, seasonal events and greater use of high-deductible health insurance plans may cause U.S. patients to schedule elective surgery later in the calendar year. The hypothesis was that elective anesthesia caseloads would be higher in December than in other months. METHODS This review analyzed yearly adult case data in Florida and Texas locations of a multistate anesthesia practice from 2017 to 2019. To focus on elective caseload, the study excluded obstetric, weekend, and holiday cases. Time trend decomposition analysis was used with seasonal variation to assess differences between December and other months in daily caseload and their relationship to age and insurance subgroups. RESULTS A total of 3,504,394 adult cases were included in the analyses. Overall, daily caseloads increased by 2.5 ± 0.1 cases per day across the 3-yr data set. After adjusting for time trends, the average daily December caseload in 2017 was 5,039 cases (95% CI, 4,900 to 5,177), a 20% increase over the January-to-November baseline (4,196 cases; 95% CI, 4,158 to 4,235; P < 0.0001). This increase was replicated in 2018: 5,567 cases in December (95% CI, 5,434 to 5,700) versus 4,589 cases at baseline (95% CI, 4,538 to 4,641), a 21.3% increase; and in 2019: 6,103 cases in December (95% CI, 5,871 to 6,334) versus 5,045 cases at baseline (95% CI, 4,984 to 5,107), a 21% increase (both P < 0.001). The proportion of commercially insured patients and those aged 18 to 64 yr was also higher in December than in other months. CONCLUSIONS In this 3-yr retrospective analysis, it was observed that, after accounting for time trends, elective anesthesia caseloads were higher in December than in other months of the year. Proportions of commercially insured and younger patients were also higher in December. When compared to previous studies finding no increase, this pattern suggests a recent shift in elective surgical scheduling behavior. EDITOR’S PERSPECTIVE

中文翻译：

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十二月即将到来：佛罗里达州和得克萨斯州一家大型多州诊所成人选择性麻醉病例月度变化的时间趋势分析。

背景麻醉人员配备模型依赖于可预测的手术病例量。以前的研究发现一年中的月份与手术量之间没有关系。然而，季节性事件和高免赔额健康保险计划的更多使用可能会导致美国患者在日历年晚些时候安排择期手术。假设是 12 月的选择性麻醉病例数会高于其他月份。方法 本综述分析了 2017 年至 2019 年佛罗里达州和德克萨斯州多州麻醉实践地点的年度成人病例数据。为了关注选择性病例量，该研究排除了产科、周末和假期病例。时间趋势分解分析与季节性变化一起使用，以评估 12 月和其他月份在每日案件量方面的差异及其与年龄和保险亚组的关系。结果 共有 3,504,394 例成人病例被纳入分析。总体而言，在 3 年的数据集中，每天的工作量增加了 2.5 ± 0.1 例。调整时间趋势后，2017 年 12 月的平均每日工作量为 5,039 例（95% CI，4,900 至 5,177），比 1 月至 11 月的基线（4,196 例；95% CI，4,158 至 4,235； P < 0.0001）。2018 年也出现了这种增长：12 月为 5,567 例（95% CI，5,434 至 5,700），而基线时为 4,589 例（95% CI，4,538 至 4,641），增加了 21.3%；2019 年：12 月为 6,103 例（95% CI，5,871 至 6,334），基线时为 5,045 例（95% CI，4,984 至 5，107)，增加了 21%（均 P < 0.001）。商业保险患者和 18 至 64 岁患者的比例在 12 月也高于其他月份。结论 在这项为期 3 年的回顾性分析中，观察到在考虑时间趋势后，12 月的择期麻醉病例数高于一年中的其他月份。12 月，商业保险和年轻患者的比例也更高。与之前没有发现增加的研究相比，这种模式表明最近择期手术安排行为发生了变化。编辑的观点 考虑到时间趋势后，12 月的择期麻醉病例数高于一年中的其他月份。12 月，商业保险和年轻患者的比例也更高。与之前没有发现增加的研究相比，这种模式表明最近择期手术安排行为发生了变化。编辑的观点 考虑到时间趋势后，12 月的择期麻醉病例数高于一年中的其他月份。12 月，商业保险和年轻患者的比例也更高。与之前没有发现增加的研究相比，这种模式表明最近择期手术安排行为发生了变化。编辑的观点