Dai, X., Fu, C., Wang, C., Cai, Y., Zhang, S., Guo, W., & Kuang, D. (2015). The impact of tracheotomy on levels of procalcitonin in patients without sepsis: a prospective study . Clinics, 70(9), 612-617. https://doi.org/10.6061/clinics/2015(09)03