Effect Of TAES Of Neiguan On HRV In Elderly Patients Undergoing Colonoscopy Under Anesthesia

Objectives:To explore the difference of autonomic nerve function between the elderly and the young during colonoscopy under anesthesia,and to explore the effect of transcutaneous acupoint electrical stimulation(TAES)at Neiguan(PC6)on autonomic nerve function,whether PC6 improve HRV and respiratory function of elderly patients during colonoscopy under anesthesia by regulating plasma catecholamine level and improving autonomic nerve function.Methods:This trial was divided into two parts.Part 1:To compare the changes and differences of autonomic nerve function between the elderly and young adults undergoing colonoscopy under intravenous anesthesia,and to explore that the decline of autonomic nerve regulation function in elderly patients is one of the important reasons that lead to the inhibition of respiratory and circulatory function more than that in young patients.There were 44 ASA Ⅰ-Ⅱ patients aged 18-59 years old and aged over 60 years old who were scheduled to receive colonoscopy under intervenous anesthesia(informed consent was signed before the trial),and were devided into 2 groups,Group Ⅰ:young,group Ⅱ:elderly.there were 22 patients in each group.After entering operating room,the patient was lying on the left side,connected to the monitor,and delivered oxygen(2 L/min)through the nasal catheter.The patient was calm for 5 minutes.Sufentanil and propofol was delivered by venous.Colonoscopy was started when the observer’s assessment of alertness/sedation scale(OAA/S)was below 3.The indexes were monitored and recorded at the three time points:before performance,during performance,and waking up.1)Main outcome measures:Heart rate variability(HRV):low frequency(LF),high frequency(HF),LF/HF,and total power(TP),and the change rate of these indicators in the process were calculated.2)Secondary outcome measures:Respiratory function:respiratory rate(RR);Circulation function:mean arterial pressure(MAP),heart rate(HR);Peripheral oxygen saturation(SpO2);Anesthesia depth(value of Narcotrend,NT).At the same time,the number of cases requiring respiratory support during test,the time required for consultation and the number of cases requiring ephedrine or atropine treatment during operation were recorded.The changes of HRV indexes before performance,during performance,and waking up were compared between the 2 groups.At the same time,the respiratory support ratio and other indicators were compared between the 2 groups.Part 2:To observe the effect of TAES Neiguan point on HRV and plasma catecholamine levels in elderly patients under anesthesia and to explore the possible mechanism of TAES.138 elderly patients with age ≥60 were selected according to age stratification(60～69,70～79,or≥80 years old).According to age stratification the patients were also assigned randomly to the control group and the treatment group receiving the "TAES":the control group(Ⅰc:60～69 years old;Ⅱc:70～79 years old and Ⅲc:≥80 years old)and the treatment group(Ⅰt:60～69 years old;Ⅱt:70～79 years old and Ⅲt:≥80 years old).The number of cases in each group was 23.After entering the operating room,the patient was connected with the monitor,and the left side was in a quiet position for 5 minutes.The patients in the treatment group were given TAES at 2 Hz and 6 mA on point PC 6 with Han’s nerve stimulator for 20 minutes.The control group performed the same procedure,but the frequency and intensity were zero.Intravenous anesthesia were given immediately after 20 minutes of " TAES”.The following indexes were measured at 8 time points:T1,when entering the left lying position of the clinic for 5min(basic value);T2,20 minutes after simulating or real TAES;T3,colonoscopy enters anus when patient’s OAA/S scale dropped to 3;T4,5 minutes after performance;T5,10 minutes after performance;T6,colonoscopy is finished and when it exits the anus;T7,operation is over,OAA/S recovery to 4;T8,the patient left the operating room.The airway support,drug therapy and HRV collection were the same as the part 1.1)Main outcome measures:The ECG records were respectively collected for 5 minutes from the time point T1(before perfomance),T4(during performance)and T7(waking up),and the HRV indexes were obtained:LF,HF,LF/HF and TP.2)Secondary outcome measures:The following indicators were measured at 8 time points,from T1 to T8:RR;Systolic pressure(SBP),diastolic pressure(DBP),heart rate(HR);SpO2;NT.Meanwhile,the plasma concentration of dopamine,noradrenaline,adrenaline and glucose were measured by peripheral blood of subjects at T1,T4 and T7,and the change rate of plasma catecholamine in the process was calculated also.The respiratory support ratio during test,the time needed for the performance and the number of cases requiring ephedrine or atropine treatment during the operation were recorded also.The HRV indexes,change of plasma catecholamine and ratio of SpO2 decreased by more than 4%during test were compared.The change degree of plasma catecholamine is expressed by the change rate of plasma catecholamine level at T1,T4 and T7..Results:The results of part 1 are as follows:Compared with before performance,LF,HF and TP in the young group decreased significantly(P<0.05),and LF/HF tended to increase.In the elderly group,LF,HF and TP were significantly lower than those before performance(P<0.05),and LF/HF increased significantly(P<0.05);after waking up,HF and TP decreased significantly without change.During performance,the LF2 change rate of the elderly group was higher than that of the young group,while the HF2 change rate was significantly higher than that of the young group(P<0.05),which means that the decrease percentage of HF value of the elderly group was significantly higher than that of the young group,and the decrease rate of LF value was greater than that of the young group;during performance,the LF/HF2 change rate of the elderly group was significantly lower than that of the young group(P<0.05),which means that the LF/HF value of the elderly group increased significantly than that of young group during performance.The respiratory support ratio was 9/22,40.9%in the elderly group and 4/22,18.9%in the young group.In terms of airway support ratio,the elderly group was significantly higher than the adult group(P<0.05).The results of part 2 are as follows:60～69 years old:During performance,the LF,HF and TP values of the control group were significantly lower than those before performance(P<0.05),and the decrease of TP value continued until the patients were awake;the LF,HF and TP values of the treatment group also showed a significant downward trend during performance(P<0.05),and continued until the patients were awake.The LF,HF and TP values of the treatment group were significantly higher than those of the control group(P<0.05).During performance,the change rate of dopamine in the treatment group was significantly higher than that in the control group,and the change rate of norepinephrine was significantly lower(P<0.05).In the treatment group,the percentage of patients whose SpO2 decreased by more than 4%from baseline was significantly lower than that in the control group(3/23,13.0%,9/23,39.1%,χ 2=10.522,P=0.001).70～79 years old:During performance,the LF,HF and TP values of the control group were significantly lower than those before performance(P<0.05),and the TP value continued to decline until waking up;the HF and TP values of the treatment group were significantly decreased(P<0.05).HF in the treatment group was significantly higher than that in the control group(P<0.05).During performance,the change rate of dopamine in the treatment group was significantly higher than that in the control group(P<0.05),and the change rate of plasma norepinephrine was significantly lower than that in the control group(P<0.05).In the treatment group,the percentage of patients whose SpO2 decreased by more than 4%from baseline was significantly lower than that in the control group(4/23,17.3%,12/23,52.1%,χ2=4.261,P=0.039).Patients over 80 years old:During performance,the LF and HF values of the control group were significantly lower than the base line(P<0.05);the LF,HF,LF/HF and TP values of the treatment group showed a generally significant downward trend(P<0.05).However,there was no significant difference in each index between the treatment group and the control group before performance,during performance and after waking up.There was no significant difference in plasma catecholamines between the two groups,and no significant difference between the treatment group and the control group(8/23,34.8%,9/23,39.1%,χ2=1.391,P=0.238)on the percentage of patients whose SpO2 decreased by more than 4%from base line.Conclusion:Compared with young adults,the value of LF,HF and TP in the elderly patients undergoing colonoscopy under anesthesia was significantly reduced,and more respiratory support was needed.The application of TAES at 2 Hz and 6mA can improve the HRV related indexes of the elderly patients aged 60～79 years old during colonoscopy,regulate the plasma catecholamine level and reduce the incidence of hypoxia.