Effect of lidocaine combined with atropine on heart rate variability in elderly patients with elective surgery under general anesthesia

Objective To study the effect of intravenous injection of lidocaine combined with atropine on heart rate variability in elderly patients with elective surgery under general anesthesia. Methods Sixty patients with class Ⅱ or Ⅲ of American Society of Anesthesiologists(ASA)were randomly assigned into three groups: lidocaine combined with atropine group(LA group), atropine group(A group)and normal saline control group(S group), with 20 cases in each group. Group LA was given 2% of lidocaine for 1.5 mL/kg before anesthesia induction, groups A and S were given the same volume of saline. After insertion of laryngeal mask for 5 minutes, group LA and A were given 0.5 mg of atropine, while group S was given same volume of saline. Change of heart rate variability was recorded before induction(T₀), at 1 min(T₁)and 3 min(T₂)after induction, and at 1 min(T₃)and 3 min(T₄)after intravenous infusion of atropine or saline. Results Compared with T₀, the low frequency band(LF), high frequency band(HF)and total power band(TP)at T₁ and T₂ were significantly decreased in three groups(P<0.05), the LF to HF ratios(LF/HF)in groups A and S were significantly decreased at T₁ and T₂(P<0.05). The HF of group LA was significantly higher than group A and S, but the LF was significantly lower than group A and S(P<0.05). Compared with T₂, the LF and TP at T₃ and T₄ of all three groups were significantly increased(P<0.05), the LF/HF - of groups LA and S showed no significant difference(P>0.05), while was significantly increased in group A at T₃ and T₄(P<0.05). Compared with T₂, the increase of the LF and TP and the decrease of the HF in group LA were significantly less than those in group A(P<0.05), but were significantly higher than that in group S. Conclusion Intravenous injection of lidocaine can significantly inhibit the excitement of sympathetic nervous. Lidocaine combined with atropine can decrease the effect on the heart rate variability in elderly patients, and maintain the balance between the autonomic nerve.