Abstract: Embodiments herein relate to systems, devices, and methods for assessing hemorrhage and other conditions and treating patients suffering from the same. In an embodiment, a method for detecting hemorrhage in a patient is included. The method can include obtaining a breath sample from the subject and contacting it with a chemical sensor element, the chemical sensor element including a plurality of discrete graphene varactors; sensing and storing capacitance of the discrete graphene varactors to obtain a sample data set; and classifying the sample data set into one or more preestablished hemorrhage classifications. Other embodiments are included herein.