Impact of Endotracheal Tube Size on Performance of Continuous Laryngeal Adductor Reflex Monitoring

Abstract

Introduction: Laryngeal adductor reflex-continuous intraoperative nerve monitoring (LAR-CIONM) decreased Recurrent Laryngeal nerve (RLN) injury as it provides real-time updates about functional integrity of the RLN intraoperatively. However, intraoperative loss of signal (LOS) does not necessarily imply nerve injury. we thought to investigate the false-positive rates of LOS of LAR intraoperatively, and to investigate the predictors of false-positive LOS. Methods: In this prospective cohort study, we investigated statistical measures of LAR-CIONM during anterior neck surgeries. SPSS v26.0 was used to calculate the rates of false positive LOS of RLN and investigate the predictors of false positive LOS. Results: A total of 101 patients with a mean age of 56.59±12.83 years were included. The endotracheal tubes (ETT) size was determined according to gender, BMI, and height. A total of 23 patients (22.7%) exhibited false positive LOS. False LOS occurred more frequently in patients who had a small ETT size for BMI, small ETT size for gender, and small ETT size for height (N = 12, 63.16%, N = 12, 66.67%, and N = 12, 66.67%), compared with patients who received appropriate ETT size for their BMI, appropriate ETT for gender, and appropriate ETT for height (N = 11, 13.41%, N = 11, 13.25%, and N = 12, 66.67%), p < 0.001 respectively. Patients with small-sized ETT for height had higher odds of false LOS (OR=1.93, 95%CI:1.25-2.97, p < 0.001). Conclusion: Smaller ETT is associated with increased rates of false LOS. Surgeons should have full knowledge of the effect ETT size on false LOS to better interpret the intraoperative signaling, and subsequently surgical decisions.