Índices de desmame: o que devemos saber? Weaning indexes: what do we need to know?

The article discusses the evaluation and recommendations for the use of mechanical ventilation weaning indexes, as well as their applicability, limitations, and accuracy. The use of a spontaneous breathing trial (SBT) prior to weaning is recommended, and clinical judgment plays an important role. However, these cannot, either alone or in combination, accurately predict weaning outcomes. Although the great majority of weaning indexes are inaccurate, at least five should be considered to evaluate their prognosis. The most widely used weaning index is the respiratory rate to tidal volume ratio, also known as the rapid shallow breathing index. Other recommended indices include respiratory rate, maximal inspiratory pressure, tidal volume, and vital capacity. In Brazil, we have the new integrative weaning index that has proven highly accurate in heterogeneous populations. The main limitations of the weaning indexes are related to their use in specific populations, the use of different thresholds, and variations in the methods of measurement. Because clinical judgment and SBT do not present 100% accuracy, weaning indexes can be useful, mainly in difficult decision making situations for discontinuation from mechanical ventilation.