Evaluation of bed vacancy and occupancy times as governance parameters in patients admitted to a public intensive care unit

Abstract Objective: To evaluate the vacancy and occupancy times of intensive care unit beds; to analyze differences in these times between the day and night shifts and weekdays, weekends, and holidays; and to identify predictors of vacancy and occupancy times. Methods: This was a cross-sectional, observational, descriptive, analytical, inferential study. A total of 700 vacancy-to-occupancy records from 54 beds of an adult intensive care unit of a public hospital in Sergipe, Brazil, dated between January and December 2018 were analyzed. The nonparametric Mann-Whitney test was used for comparisons between groups. Several predictive models of length of stay were constructed. The incidence rate ratio was used to estimate the effect size. Results: During the study period, there were 13,477 requests for the 54 intensive care unit beds, and only 5% (700 patients) were granted. The vacancy-to-occupancy times were shorter when beds were occupied at night (incidence rate ratio of 0.658; 95%CI 0.550 - 0.787; p < 0.0001) or on weekends (incidence rate ratio of 0.566; 95%CI 0.382 - 0.838; p = 0.004). Female sex (incidence rate ratio of 0.749; 95%CI 0.657 - 0.856; p < 0.0001) was a predictor of shorter vacancy-to-occupancy time. This time tended to increase with patient age (incidence rate ratio of 1.006; 95% CI 1.003 - 1.009; p < 0.0001). Conclusion: Disparities in the waiting time for intensive care unit beds were identified, as the time was greater in the daytime and on weekdays, and women and younger patients experienced shorter vacancy-to-occupancy times.

摘要
研究目的：评估重症监护病房（Intensive Care Unit, ICU）床位的空置与占用时长；分析日间、夜间班次以及工作日、周末与节假日期间，上述时长的差异；并明确影响床位空置至占用时长的预测因素。
研究方法：本研究为横断面、观察性、描述性、分析性与推断性研究。纳入巴西塞尔希培州一所公立医院成人重症监护病房54张床位在2018年1月至12月期间的700条床位空置至占用记录。组间比较采用非参数曼-惠特尼（Mann-Whitney）检验；构建了多套住院时长预测模型；采用发生率比（Incidence Rate Ratio, IRR）估算效应量。
研究结果：研究期间，该54张重症监护病房床位累计收到13477次床位使用申请，仅5%（700例患者）的申请获得批准。当床位在夜间被占用时，其空置至占用时长更短（发生率比=0.658；95%置信区间0.550~0.787；p<0.0001）；在周末占用时，该时长同样更短（发生率比=0.566；95%置信区间0.382~0.838；p=0.004）。女性性别（发生率比=0.749；95%置信区间0.657~0.856；p<0.0001）为床位空置至占用时长更短的预测因素；而该时长随患者年龄增长呈延长趋势（发生率比=1.006；95%置信区间1.003~1.009；p<0.0001）。
研究结论：本研究证实重症监护病房床位等待时长存在显著差异：日间与工作日的等待时长更长，女性及年轻患者的床位空置至占用时长更短。