The different stages of Covid-19 pandemic can be described by two key-variables: ICU patients and deaths in hospitals. We propose simple models that can be used by medical doctors and decision makers to predict the trends on both short-term and long-term horizons. Daily updates of the models with real data allow forecasting some key indicators for decision-making (an Excel file in the Supplemental material allows computing them). These are beds allocation, residence time, doubling time, rate of renewal, maximum daily rate of change (positive/negative), halfway points, maximum plateaus, asymptotic conditions, and dates and time intervals when some key thresholds are overtaken.

Doubling time of ICU beds for Covid-19 emergency can be as low as 2-3 days at the outbreak of the pandemic. The models allow identifying the possible departure of the phenomenon from the predicted trend and thus can play the role of early warning systems and describe further outbreaks.

Covid-19大流行的不同阶段可以通过两个关键变量来描述：ICU患者和医院死亡。我们提出了可供医生和决策者使用的简单模型，以预测短期和长期前景的趋势。每天使用真实数据更新模型可以预测决策的一些关键指标（补充材料中的Excel文件允许计算这些指标）。这些是床位分配，停留时间，加倍时间，更新率，最大每日变化率（正/负），中途点，最大平稳期，渐近条件，以及超过某些关键阈值的日期和时间间隔。

在大流行爆发时，用于Covid-19紧急情况的ICU病床时间加倍可低至2-3天。这些模型可以识别现象与预测趋势的可能偏离，从而可以发挥预警系统的作用并描述进一步的爆发。