Tonic down-rolling and eccentric down-positioning of eyes under general anaesthesia without non-depolarising muscle relaxant

Purpose: To describe and analyze the relationship between the downward eccentric eye movement/positioning encountered in patients undergoing ophthalmic surgeries under general anesthesia (GA) with fluctuation in the depth of anesthesia (DOA) Design: observational case-seriesMethods. Patients undergoing ophthalmic surgeries under GA without non-depolarizing muscle relaxant (NDMR) between January2018-August2021 who witnessed a sudden tonic downward movement of eyes were included. DOA at the time of eccentric movement were noted in terms of MAC (minimum alveolar concentration) with/without BIS (bispectral index).Results. A total of 12/249 patients (14 events) were enrolled in this study with a median (IQR) age of 1.05years (0.8-1.57). All cases were performed with sevoflurane as an inducing agent. Downward movement /down-positioning of eyes was seen before the start of surgery in 7, during surgery in 6, and end of surgery in 1 case. It was preceded by an eccentric upward drift of eyes in 6 cases. A strong negative correlation was seen between DOA and eccentric eye position (r=-0.77, p=0.000). Median (IQR) MAC and eye position/score in 14 events at the time of eccentric down-rolling was 1.55(1.40-1.83) and -3(-4 to -2.0) respectively while median (IQR) MAC at the time of centralized position was 1.25(1.18-1.40). BIS values were inconclusive in 2 cases but corroborated elevated and downward eye positions with lighter and deeper DOA respectively in 2 cases. Conclusions. Tonic-down-rolling/downward eccentric positioning of eyes is not an uncommon entity in children under GA without NDMR, and fluctuations in DOA should be avoided to circumvent inadvertent complications during ocular surgery.