The Effect of Laterality in Modified Radical Neck Dissection on the Risk of Intraoperative Bradycardia: A Retrospective Cohort Study.

Background Intraoperative bradycardia is a hardly studied complication of modified radical neck dissection (MRND). Methods Using convenient sampling, we retrospectively studied a cohort (n = 159) of patients who underwent MRND at Papanikolaou General Hospital, Thessaloniki, Greece between 2019 and 2020 to investigate whether MRND laterality (bilateral vs. unilateral) affects the occurrence of intraoperative bradycardia (a pulse rate lower than 50 bpm). Results Roughly two-thirds of the patients underwent unilateral MRND, and the rest underwent bilateral MRND. Bradycardia was observed in 25.8% of the cohort. We used logistic regression and investigated several potential confounding factors. Unilateral MRND was associated with a lower risk of intraoperative bradycardia compared to bilateral MRND in the simple regression model (relative risk (RR): 0.555, 95% confidence interval (CI): 0.331-0.932, p = 0.027). MRND laterality was not significantly associated with intraoperative bradycardia (p = 0.082) in the multiple regression model, whereas an American Society of Anesthesiologists physical status (ASA-PS) score of 3 vs. 4 (adjusted odds ratio (aOR) = 0.125, 95% CI: 0.0340-0.457, p = 0.002), the presence of atrial fibrillation (aOR = 11.4, 95% CI: 4.10-31.8, p < 0.001) and induction of anesthesia with dexmedetomidine (aOR = 4.57, 95% CI: 1.34-15.6, p = 0.015) were significantly associated with intraoperative bradycardia. Conclusions MRND laterality was close to statistical significance. Bigger sample sizes may provide more definitive information since the effect of MRND laterality on intraoperative bradycardia remains unclear. Our findings can inform clinical practice so that clinicians know when to expect bradycardia and are better prepared to manage it.