Objective To evaluate the accuracy of velocity time integral variation (△VTI) of the carotid artery for predicting volume responsiveness in patients mechanically ventilated at a low tidal volume. Methods A total of 50 patients, aged 50 to 70 years, American Society of Anesthesiologists (ASA) grade Ⅰ or Ⅱ, who underwent elective gastrointestinal surgery under general anesthesia were selected. All the patients were ventilated at a low tidal volume (tidal volume 7 ml/kg) after induction of tracheal intubation under general anesthesia. When the hemodynamics became stable [before the volume loading test (VE)], the velocity time integral (VTI) and peak velocity (Vpeak) were measured by a pulsed Doppler in the middle of the carotid. The tidal volume was then temporarily changed to 9 ml/kg and VE was conducted after connecting the Vigileo system. The stroke volume (SV) was recorded before and after VE, and the stroke volume variation (△SV) was calculated. According to △SV, the patients were divided into two groups: a response group (group R, △SV≥15%, n=27) and a non‑response group (group N, △SV<15%, n=23). Then, all the patients were ventilated at a low tidal volume (tidal volume 7 ml/kg), when the hemodynamics became stable (after VE), VTI and Vpeak were measured in the carotid. The △VTI and peak velocity variation (△Vpeak) were calculated. Furthermore, the mean arterial pressure (MAP), and heart rate were recorded before and after VE. A receiver operating characteristic (ROC) curve was plotted to analyze the △VTI and △Vpeak, while the cut‑off value, sensitivity, specificity, area under the curve (AUC) and 95% confidence interval (CI) were calculated at the optimal Youden index. The accuracy of △VTI and △Vpeak in predicting volume responsiveness in patients mechanically ventilated at a low tidal volume was evaluated. Results Compared with those before VE, both groups showed increases in MAP (all P<0.05), but decreases in heart rate, △VTI and △Vpeak after VE (all P<0.05). Compared with group N, group R presented decreases in MPA (P<0.05) and increases in heart rate, △VTI and △Vpeak before VE (P<0.05); and showed decreases in MAP (P<0.05), and increases in △VTI after VE (P<0.05), without statistical differences in heart rate and △Vpeak (all P>0.05). According to ROC analysis, the cut‑off value of △VTI in predicting volume responsiveness in patients mechanically ventilated at a low tidal volume was 12.35%, with a sensitivity of 74.1% and a specificity of 91.3%, and the AUC was 0.902 [(95%CI 0.820~0.984), P<0.05]. The cut‑off value of △Vpeak in predicting volume responsiveness in patients mechanically ventilated at a low tidal volume was 10.70%, with a sensitivity of 55.6% and a specificity of 95.7%, and the AUC was 0.873 [(95%CI 0.730, 0.943), P<0.05]. Conclusion △VTI can accurately predict volume responsiveness in patients mechanically ventilated at a low tidal volume.