Introduction: Overcrowd of emergency rooms affects efficiency and quality of medical care.
Objectives: To describe the mathematical-computational system modified overcrowd index which measures in real time and in four levels of warnings (non crowded, crowded, overcrowded and extreme overcrowded) emergency room saturation in a network of hospitals, from only seven simple variables (number of available beds, physicians and nurses, number of patients in the waiting room, in medical consultation and admitted for further evaluation, as well as number of critically ill patients admitted).
Materials and methods: The modified overcrowd index was exhaustively tested with 245,280 virtual transactions from seven hospitals in an uninterrupted schedule basis simulating hourly surveillance for four years.
Results: From 224 episodes of overcrowd, 216 (97%) where correctly identified and verified by the network of hospitals warnings, its time series also provided useful information about available personnel and resource distribution within the hospital network.
Conclusions: Modified overcrowd index is an efficient tool detecting emergency room overcrowd outbreaks in a network of hospitals.