Using a generalized neural network to identify airway obstructions in anesthetized patients postoperatively based on photoplethysmography.

Photoplethysmography has been recently studied asa non-invasive indicator of circulatory and respiratory function. In this study, photoplethysmographic (PPG) data were recorded from patients under the influence of anesthesia, but not intubated. Both time and frequency domain features were extracted from the PPG and used as inputs to a neural network classifier.

Heart rate variability during sleep and the early development of posttraumatic stress disorder.

Background: Noradrenergic function has been linked to posttraumatic stress disorder (PTSD) and might have a role in mediating sleep disturbances of the disorder. Our objective was to relate a peripheral manifestation of noradrenergic function, sympathetic nervous system activity as indexed by heart rate variability during sleep, to the development of PTSD in subjects with recent traumatic injuries.

Methods: Subjects who had recall of life-threatening experiences were recruited from one of two regional trauma centers.