BACKGROUND: It is still unknown whether newborn infant parasympathetic evaluation (NIPE), based on heart rate variability (HRV) as a reflection of parasympathetic nerve tone, can predict the hemodynamic response to a nociception stimulus in children less than 2 years old. METHODS: Fifty-five children undergoing elective surgery were analyzed in this prospective observational study. Noninvasive mean blood pressure (MBP), heart rate (HR) and NIPE values were recorded just before and 1 min after general anesthesia with endotracheal intubation as well as skin incision. The predictive performance of NIPE was evaluated by receiver-operating characteristic (ROC) curve analysis. A significant hemodynamic response was defined by a > 20% increase in HR and/or MBP. RESULTS: Endotracheal intubation and skin incision caused HR increases of 22.2% (95% confidence interval [CI] 17.5-26.9%) and 3.8% (2.1-5.5%), MBP increases of 18.2% (12.0-24.4%) and 10.6% (7.7-13.4%), and conversely, NIPE decreases of 9.9% (5.3-14.4%) and 5.6% (2.1-9.1%), respectively (all P < 0.01 vs. pre-event value). Positive hemodynamic responses were observed in 32 patients (62.7%) during tracheal intubation and 13 patients (23.6%) during skin incision. The area under the ROC curve values for the ability of NIPE to predict positive hemodynamic responses at endotracheal intubation and skin incision were 0.65 (0.50-0.78) and 0.58 (0.44-0.71), respectively. CONCLUSIONS: NIPE reflected nociceptive events as well as anesthestic induction in children less than 2 years undergoing general anaesthetia. Nevertheless, NIPE may not serve as a sensitive and specific predictor to changes in hemodynamics. TRIAL REGISTRATION: This study was registered on May 3, 2018 in the Chinese Clinical Trail Registry; the registration number is ( ChiCTR1800015973 ).