A Clinical Study On The Prevention Of Hypotension In Elderly Patients During General Anesthesia By Bispectral Index Monitoring

ObjectiveTo compare the incidence of intraoperative hypotension in elderly patients with general anesthesia,two intraoperative management methods,BIS guided anesthesia depth and experience guided anesthesia depth,were used.Methods80 patients with ASA grade I ~ III,aged between 65-80 years old,who underwent selective noncardiac and non neurosurgical operations in our hospital from April 2018 to January 2019 and whose operation duration is expected to exceed 2 hours were selected.The patients were randomly divided into two groups by the central random system,40 in the experience group(maintaining the depth of anesthesia according to clinical experience),and 40 in the BIS group(keeping the BIS value in the range of 45-60 as much as possible during the anesthesia maintenance).The BIS value was monitored in both the experience group and the BIS group.In the experimental group,the BIS value was occluded during the whole operation.The anesthesia induction time,operation start time,suture end time,anesthesia stop time and extubation time were recorded.After the operation,the patient's blood pressure,BIS value and other information were immediately exported from the Mindray monitor(model beneview T8),and the occurrence times,duration and cumulative time of intraoperative hypotension and low BIS were recorded,including the occurrence time of double low,the occurrence time of low BIS caused by hypotension,and the occurrence time of hypotension caused by low BIS.Refer to the standard version of digital hospital information management system(version iMedical 8.0)of Donghua to record the patient's hospitalization time and expenses after surgery.Results(1)In the experience group,the incidence of hypotension was 216%,the incidence of double low was 152%,and the incidence of low BIS was 219%;in the BIS group,the incidence of hypotension was 190%,the incidence of double low was 54%,and the incidence of low BIS was 103%.(2)There was statistics difference in the constituent ratio of double low,simple low BIS and simple low hypotension between the two groups(P < 0.05).The proportion of patients with double low and simple low BIS in experience group was higher than that in the BIS group,and the proportion of patients with simple hypotension(normal BIS)in the experience group was lower than that in the BIS group.(3)Hypotension caused by low BIS(hypotension caused by too deep anesthesia)and low BIS caused by hypotension(hypotension followed by low bis)as a percentage of total hypotension in the experience group respectly were higher than the above two cases as a percentage of total hypotension in the BIS group respectly,and the difference between the two groups was statistically significant(P < 0.05).(4)In the case of hypotension caused by low BIS,the time needed for hypotension(within 20min)was positively correlated with the percentage of decrease of blood pressure(within 30% ~ 40%)compared with that of basic blood pressure(P < 0.05,correlation coefficient r = 0.517);In the case of low BIS caused by hypotension,the decrease percentage of blood pressure(30% ~ 44%)was negatively correlated with the time needed for the occurrence of low BIS(within 12 minutes),P < 0.05,correlation coefficient r =-0.634;In the case of low BIS caused by hypotension,there was a positive correlation between the change of blood pressure(within 35% ~ 60%)and the change of bis(within 60%)from baseline,P < 0.05,and the correlation coefficient was r = 0.665.(5)The duration,cumulative time of hypotension,duration and cumulative time of low BIS in the experience group were longer than those in the BIS group,and the difference between the two groups was statistically significant(P < 0.05).(6)The time of extubation in the experience group was longer than that in the BIS group,the difference was statistically significant(P < 0.05);there was no significant difference between the experience group and the BIS group in the post hospital day and the cost of hospitalization,P > 0.05.Conclusion(1)In the elderly patients anesthesia,BIS guidance of anesthesia depth can prevent excessive anesthesia,reduce the incidence of intraoperative hypotension,and accelerate the recovery of patients.(2)Intraoperative hypotension can lead to a low BIS that is not related to the depth of anesthesia,indicating the lack of cerebral perfusion and the resulting brain dysfunction.