Application Of Heart Rate Variability In Prevention And Treatment Of Postoperative Nausea And Vomiting In Patients With Cesarean Section Under Spinal Anesthesia

Objective: Different degrees of sympathetic block and parasympathetic block after spinal anesthesia disrupt the balance in the autonomic nervous system.Coupled with the impact of supine hypotensive syndrome,patients with cesarean section under spinal anesthesia are prone to hypotension,and sudden decrease in cerebral blood supply excites the vomiting center,leading to postoperative nausea and vomiting.Heart rate variability can monitor the homeostasis of the autonomic nervous system.This study aims to investigate the heart rate variability’s practical value in the prevention and treatment of postoperative nausea and vomiting for patients with cesarean section under spinal anesthesia by monitoring their heart rate variability and vital signs.It will provide a new idea for the prevention and treatment of postoperative nausea and vomiting,guide the rational use of medicines in clinic,and help accelerate the postoperative recovery of women.Methods: In this study,200 patients with elective cesarean section were selected from the First Affiliated Hospital of Wannan Medical College from October 2018 to January2020.All cesarean section patients who met the inclusion criteria were opereated with the spinal anesthesia uniformly,among which failure cases were eliminated and re-recorded.Changes in vital signs,indexes of heart rate variability,and postoperative follow-up indicators of all cesarean patients during surgery were recorded.All patients were divided into hypotension group and non-hypotension group.Statistical analysiswas performed on indicators including general information,intraoperative blood pressure,heart rate,heart rate variability(LF,HF,LF / HF),postoperative nausea and vomiting,etc..Also,statistical analysis of heart rate variability was applied to patients with nausea and vomiting and those who without nausea and vomiting.Results: 1.This study showed that the incidence of hypotension after spinal anesthesia during cesarean section was as high as 49.5%,and the total incidence of postoperative nausea and vomiting was 16.5%.2.The fetal delivery time and operation time of patients with hypotension were longer than those with non-hypotension,and the former needed more fluid replacement volume(P <0.05).3.LF at T1(P <0.05),LF at T2(P<0.05),and LF,HF,LF / HF(P <0.05)at T3 of patients with hypotension were statistically significant compared with that of non-hypotension patients.4.At T3,the area under the ROC curve of LF / HF and hypotension was 0.61(95% CI: 0.532,0.688),and the best diagnosis point of LF / HF was 1.95(sensitivity: 51.5%,specificity: 69.3%).5.The incidence of postoperative nausea and vomiting in patients with hypotension was22.2%,and that in non-hypotension patients was 10.9%.The comparison of incidence of postoperative nausea and vomiting was statistically significant in both groups(P<0.05).6.The comparison of LF at T5 between non-nausea and non-vomiting patients and those who with nausea and vomiting was statistically significant(P <0.05).The area under the ROC curve of LF and non-PONV at T5 was 0.625(95% CI: 0.518,0.733),with the best diagnosis point 852.95(sensitivity was 69.7%,specificity was54.5%).Conclusions: 1.Delivery women with hypotension after spinal anesthesia are more likely to suffer from PONV.2.As a quantitative method for monitoring the function of the autonomic nervous system,HRV can feedback the risk of hypotension with cesarean section under spinal anesthesia when the body is in the compensatory stage,and can indirectly prevent PONV in such patients.3.LF,as the intraoperative HRV index,can identify non-PONV patients and PONV patients,avoid drug abuse,and has certainapplication value for the prevention and treatment of PONV in spinal anesthesia patients.