| ObjectiveDexmedetomidine is often used in clinical anesthesia because of its sedative,analgesic and sympathetic excitatory suppressing effects.It is often used during general anesthesia for radical gastrectomy of gastrointestinal malignancy due to long operation time,heavy trauma and strong stress response.Prolonged use of dexmedetomidine is associated with a risk of prolonging the QT interval and causing the incidence of tip torsion ventricular tachycardia.Perioperative hypokalemia is easy to occur during gastrointestinal surgery.Hypokalemia may affect myocardial repolarization and increase the risk of tip torsion ventricular tachycardia.This study used dexmedetomidine during general anesthesia for patients undergoing gastrointestinal malignant tumor resection.The primary aim is to observe the effects of long-term use of dexmedetomidine on electrolytes such as serum potassium concentration and rehabilitation.The second aim is to explore the optimal dose of dexmedetomidine with the least effect on serum potassium concentration in gastrointestinal malignant tumor resection.This study will provide a theoretical basis for rational application of dexmedetomidine in clinical use.MethodsA total of 120 patients undergoing elective radical resection gastrointestinal malignant tumor were randomly divided into 4 groups(n=30):groups D1,D2 and D3 received dexmedetomidine loading dose 1,1 and 0.5 μg/kg,which was infused intravenously for 10 min,and maintenance dose 0.25,0.5 and 0.5 μg·kg-1·h-1,respectively;group C received normal saline 50 ml/h for 10 min and maintenance dose 10 ml/h.Dexmedetomidine and normal saline maintenance doses were continued until approximately 30 min before the completion of surgery.For all patients,general anesthesia was induced with midazolam 0.05 mg/kg,propofol 1.0-1.5 mg/kg,and sufentanil 0.2-0.4 μg/kg.Cisatracurium 0.15 mg/kg was administered to provide proper relaxation of the muscles.After that,trachea intubation was manipulated and mechanical ventilation initiated.The total sufentanil dose was controlled at 0.6 μg/kg.Propofol and remifentanil were intravenously infused,and sevoflurane 1 MAC was inhaled to maintain the general anesthesia for all patients.Cisatracurium 0.1-0.15 mg·kg-1·h-1 was infused to maintain muscle relaxation during general anesthesia.Heart rate and arterial blood pressure were recorded at 5 min after arteriovenous puncture(T1),dexmedetomidine loading dose finish(T2),surgery beginning(T3),5 min(T4),10 min(T5)and 1 h(T6)after surgery beginning,surgery ending(T7),extubation(T8),5 min after extubation(T9)and 1 h into the post-anesthesia care unit(PACU)(T10).Electrolyte concentrations and blood gas changes were recorded at T1,T6,T7 and T10.Electrolytes were also examined at 48 h postoperatively(T11).The duration of surgery,duration of anesthesia(from dexmedetomidine iniation to general anesthetics stopping),extubation time(from surgery ending to endotracheal extubation),propofol and remifentanil total doses,total fluid intake,urine volume,blood loss,and use of vasoactive drugs during intraoperative and PACU were recorded.Liver and kidney function at 24 h postoperatively,and urine volume and intraperitoneal drainage volume at 48 h postoperatively were recorded.Length of hospital stay and postoperative complications such as pulmonary infection were recorded.Results(1)There were no significant differences of the demographics(age,sex,body mass index[BMI]and ASA status)among the four groups(P>0.05).Compared with group C,the urine volume increased significantly in groups D2 and D3(P<0.05).There were no significant differences of perioperative indicators(surgery time,anesthesia time,extubation time,the total fluid infusion and blood loss during surgery and in the PACU)among the four groups(P>0.05).(2)Changes of electrolytes and internal environment in four groupsCompared with the serum potassium basic values,the concentrations at T11 increased significantly in groups D1,D2 and C(P<0.01),while increased significantly at T7,T10 and T11 in group D3(P<0.05).Compared with group C,the serum potassium concentration at T11 decreased significantly in group D2(P<0.05).Compared with group D2,the serum potassium concentration at T7 increased significantly in group D3(P<0.05).Compared with the serum sodium basic value,the concentrations decreased significantly at T11 in groups D1,D2 and C(P<0.01).Compared with group C,the serum sodium concentration increased significantly at T11 in groups D1 and D3(P<0.05).Compared with the serum calcium basic value,the concentrations increased significantly at T11 in groups D1,D2 and C(P<0.001),while increased significantly at T10 and T11 in group D3(P<0.01).Compared with group C,the serum calcium concentration increased significantly at T10 in group D3(P<0.01).Compared with group D2,the serum calcium concentration increased significantly at T10 in group D3(P<0.05).Compared with the lactic acid(Lac)basic value,the concentrations decreased significantly at T6 in groups D2 and D3(P<0.01).Compared with group D2,the Lac in group D3 decreased significantly at T10(P<0.05).Compared with the base excess(BE)basic value,the concentration decreased significantly at T6 in group D2(P<0.05).Compared with group C,the BE in groups D1,D2 and D3 showed no significant changes(P>0.05).There were no significant changes in BE between groups D2 and D3(P>0.05).Compared with the pH basic value,the concentrations decreased significantly at T6 in the groups D2 and C(P<0.05).Compared with group C,the BE in groups Di,D2 and D3 showed no significant changes(P>0.05).There were no significant changes in BE between groups D2 and D3(P>0.05).(3)Changes of hemodynamics in the four groupsCompared with heart rate(HR)basic value,HR decreased significantly at T2,T3,T4,T5,T6 and T7 in group D1(P<0.05),at T3,T4,T5,T6,T7,T8,T9 and T10 in group D2(P<0.05),at T2,T3,T4,T5,T6,T7,T8,T9 and T10 in group D3(P<0.05),and at T4 in group C(P<0.05).Compared with group C,HR decreased significantly at T5,T7,T8,T9 and T10 in groups D2 and D3(P<0.05).Compared with the systolic blood pressure(SBP)basic value,SBP decreased significantly at T3,T4,T5,and T6 in group D1(P<0.05),at T6 and T10 in group D2(P<0.05),and at T6 in group D3(P<0.05),while decreased significantly at T3 and T6(P<0.01)and increased significantly at T8 in group C(P<0.01).Compared with group C,SBP decreased significantly at T8 in group D1(P<0.01),at T8 and T10 in groups D2(P<0.01)and D3(P<0.05).Compared with the diastolic blood pressure(DBP)basic value,DBP decreased significantly at T2,T3,T4,T6 and T7 in group D1(P<0.05),at T3,T6,T7,and T10 in group D3(P<0.05)and at T3 and T6 in group C(P<0.05).Compared with group C,DBP decreased significantly at T8 in group D2(P<0.05).Compared with the mean arterial pressure(MAP)basic value,MAP at T4,T5,T6,T7,T8 and T9 decreased significantly in group D1(P<0.05),at T10 in group D2(P<0.05),and at T6 and T10 in group D3(P<0.01),while decreased significantly at T3,and T6(P<0.01)and increased significantly at T8(P<0.05)in group C.Compared with group C,MAP increased significantly at T2(P<0.05)and decreased significantly at T5,T7,T8 and T9(P<0.05)in group D1,decreased significantly at T8,T9 and T10 in group D2(P<0.05)and at T8 and T9 in group D3(P<0.05).(4)Postoperative rehabilitation of the four groupsThe concentrations of alanine aminotransferase at 24 h postoperatively were significantly higher than before surgery in all the four groups(P<0.05).The concentrations of aspartate aminotransferase at 24 h postoperatively were significantly higher than that before surgery in groups D2,D3 and C(P<0.05).Blood urea nitrogen at 24 h postoperatively was significantly higher than preoperatively in group D1(P<0.05).There were no significant differences in length of hospital stay,and intraperitoneal drainage volume and pulmonary infection incidence at 48 h postoperatively among the four groups(P>0.05).ConclusionIn our study,dexmedetomidine did not decrease perioperative potassium concentrations in patients undergoing radical resection of gastrointestinal malignancy.While its loading dose 0.5 μg/kg and maintenance dose 0.5 μg·kg-1·h-1 can elevate potassium concentration slightly,reduce lactic acid,remifentanil use significantly,relieve perioperative hemodynamic fluctuations,and have no adverse effect on postoperative rehabilitation. |
