Transition in eye gaze as a predictor of emergence from general anesthesia in children and adults: a prospective observational study

BACKGROUND: It is useful to monitor eye movements during general anesthesia, but few studies have examined neurological finding of the eyes during emergence from general anesthesia maintained with short-acting opioids and volatile anesthetics. METHODS: Thirty children aged 1–6 years and 30 adults aged 20–79 years were enrolled. Patients received general anesthesia maintained with sevoflurane and remifentanil. The timing of three physical-behavioral responses—eye-gaze transition (the cycle from conjugate to disconjugate and back to conjugate), resumption of somatic movement (limbs or body), and resumption of respiration—were recorded until spontaneous awakening. The primary outcome measure was the timing of the physical-behavioral responses. Secondary outcome measures were the incidence of eye-gaze transition, and the bispectral index, concentration of end-tidal sevoflurane, and heart rate at the timing of eye-gaze transition. RESULTS: Eye-gaze transition was evident in 29 children (96.7%; 95% confidence interval, 82.8–99.9). After the end of surgery, eye-gaze transition was observed significantly earlier than resumption of somatic movement or respiration (472 [standard deviation 219] s, 723 [235] s, and 754 [232] s, respectively; p < 0.001). In adults, 3 cases (10%; 95% CI, 0.2–26.5) showed eye-gaze transition during emergence from anesthesia. The incidence of eye-gaze transition was significantly lower in adults than in children (p < 0.001). CONCLUSION: In children, eye-gaze transition was observed significantly earlier than other physical-behavioral responses during emergence from general anesthesia and seemed to reflect emergence from anesthesia. In contrast, observation of eye gaze was not a useful indicator of emergence from anesthesia in adults. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12871-022-01867-3.