Relationship Of Dexmedetomidine Applicated Intraoperativelly To Perioperative Circulation Depression:A Retrospective Study

Objective:Dexmedetomidine was a highly selective ?2 adrenergic receptor agonist.The clinical trials of dexmedetomidine were carried out in China in 2007.Dexmedetomidine was gradually applied to anesthesia or sedation for patients in ICU.It significantly reduced the dosage of anesthetic and opioid analgestic.It inhibited hemodynamic changes induced by tracheal intubation and surgical stimulation.It also reduced intraocular pressure and prevented the emergency agitation.Intraoperative application of dexmedetomidine increased the incidence of intraoperative hypotension and bradycardia.But it was still unclear whether dexmedetomidine influence the incidence of postoperative hypotension and bradycardia.We retrospectively analysed the clinical datas of patients undergone gastrointestinal surgery in our hospital between January 2012 and December 2013.We explored the relationship of dexmedetomidine and the incidences of perioperative hypotension and bradycardia.And the outcomes would help the anesthesiologist to applicate dexmedetomidine reasonably.Methods:Patients undergone gastrointestinal surgery in our hospital between January 2012 and December 2013 were included.Inclusion criteria were(1)Age ?18 years old.(2)the patient's BP and HR were monitored every 5 minutes intraoperation and in PACU,and at least per 2 hours postoperatively in the ward.(3)the operation time was not shorter than 60 minutes.Exclusion criteria were(1)the patient's basic HR<50 per minute or with serious heart block(greater than type ? degree ? atrioventricular block).(2)the patient accepted mechanical ventilation therapy within 12 hours after surgery.(3)nitroglycerin,esmolol or urapidil were used to decrease BP or HR.(4)the patient undergone two surgeries on the same day.Rates of perioperative circulation depression were observed.Circulatory depression was defined as patiens having any one of the following perioperatively:SBP decreased over 30%of the basic value or HR<40 per minute or using of any vasoactive drugs to raise blood pressure or heart rate.The rate of hypotension,bradycardia and the usage of vasoactive drug were recorded respectively.Database was established with Microsoft Office Excel and statistical analyses were performed using the SPSS 18.0 for Windows(SPSS Inc.).Normal distribution parametric datas were described as means and standard deviations,and were compared using independent t-tests.Non-normal distribution parametric datas were described as meadin and quartile,and were compared using Wilcoxon rank sum test.Pearson ?2 tests or Fisher exact tests for categorical variables were performed.Logistic regression was used for the risk factors of circulatory depression,hypotension or bradycardia respectively.A P-value<0.05 was considered to indicate a statistically significant difference.Results:A total of 825 patients' datas were collected,of which 121 patients were excluded(two patients with respiratory failure were accepted mechanical ventilation therapy in ICU within 12 hours after surgery,119 patients were given neostigmine and atropine to antagonize muscle relaxant).Then,the datas of 704 patients were included to be analysed.Rates of circulatory depression in dexmedetomidine group and non-dexmedetomidine group during surgry were 75.5%and 63.8%respectively(P<0.01),and which in PACU were 16.7%and 11.6%respectively(P<0.05).Rate of circulatory depression within 12 hours after surgery had no significant difference.Incidences of hypotension in dexmedetomidine group and non-dexmedetomidine group were 65.8%and 57.4%respectively(P<0.05),and which in PACU was 16.4%and 11.1%respectively(P<0.05).Incidences of hypotension and bradycardia within 12 hours after surgery in two groups had no significant difference.The usage of vasoactive drugs in two groups also had no signigicant difference.Multivariate analysis showed that general anesthesia compound with epidural anesthesia(X1),use of dexmedetomidine(X2),basic SBP(X3)and surgery time(X4)were the major risk factors for circulation depression during surgery.The established regression model was Logit P=-9.484+0.759 X1+0.679 X2+0.066 X3+0.004 X4.And the use of dexmedetomidine(X2),basic SBP(X3),midazolam(X7)were the major risk factors for circulation depression in PACU.The established regression model was Logit P=-11.799+0.505 X2+0.060 X3+0.871 X7.The major risk factors for circulation depression within 12 hours after surgery included basic SBP(X3)and no postoperative analgesia(X8).The established model was Logit P=-12.029+0.069 X3-1.007X8.Multivariate analysis showed that basic SBP(X3),surgery time(X4)and dexmedetomidine(X5)were the major factors for intraoperative hypotension.The established model was Logit P=-11.542+0.080 X3+0.005 X4+0.408 X5.Risk factor for bradycardia was loading dose of dexmedetomidine(X6).The established model was Logit P=-4.451+2,254 X6.Use of dexmedetomidine(X2)and basic SBP(X3)were the major factors for hypotension in PACU.The established model was Logit P=-11.846+0.512 X2+0.062 X3.Risk factors for hypotension within 12 hours after surgery included basic SBP(X3)and no postoperative analgesia(X8).The established model was Logit P=-12.232+0.070 X3-0.998 X8.Conclusion:(1)Dexmedetomidine used intraoperatively was associated with the circulation depression and hypotension during surgery and in PACU.(2)Loading dose of dexmedetomidine was significantly associated with bradycardia(HR?40 bpm)during surgery.(3)Circulation depression within 12 hours after surgery was not related to dexmedetomidine,but to postoperative analgesia.