Prediction of the level of consciousness using pupillometer measurements in patients with impaired consciousness brought to the emergency and critical care center

Aim We investigated whether the level of consciousness can be predicted using pupillometer measurements in patients with severe disturbance of consciousness. Methods Patients with a Glasgow Coma Scale (GCS) of 3–8, except for those after cardiac arrest, were included. Pupillary contraction rate and contraction velocity were each measured using a pupillometer. Results Thirty‐five patients were analyzed. At the time of discharge or changing hospitals, 16 patients had a GCS score of 3–13 and 19 patients had a GCS score of 14–15. In the non‐sedative group at about the time of arrival at our hospital, average pupillary contraction rates were 18.36% in the GCS 3–13 group and 19.67% in the GCS 14–15 group ( P  = 0.739), and average pupillary contraction velocities were 1.02 and 1.48, respectively ( P  = 0.182). Approximately 48 h after arrival, average pupillary contraction rates were 21.18% and 29.27%, respectively ( P  = 0.058), and average pupillary contraction velocities were 1.37 and 1.91, respectively ( P  = 0.172). Among the sedative group, at about the time of arrival, average pupillary contraction rates were 8.75% in the GCS 3–13 group and 19.75% in the GCS 14–15 group ( P  = 0.032). Average pupillary contraction velocities were 0.34 and 1.48, respectively ( P  = 0.001). Approximately 48 h after arrival, average pupillary contraction rates were 13.50% and 13.50%, respectively ( P  = 1.00), and average pupillary contraction velocities were 0.80 and 0.82, respectively ( P  = 0.93). Conclusions Pupillometer measurements could predict level of consciousness of patients with severe consciousness disorder.