| ObjectiveWith social development, the aging of society has become more obvious. The number of the elderly population suffering from surgical diseases who need surgical treatment is increasing. However, the elderly whose whole organ and tissue cell degenerative changes lead to changes in the in physiological and pathological of anesthetic and cause resistance to anesthesia and surgery. So how to improve the quality of anesthesia, keep safety through the perioperative period and reduce complications and mortality for the elderly is an important focus.Sufentanil, as a popular new type of opioid analgesics, is more suitable for the elderly with nice cardiovascular stability, little respiratory depression,no histamine release, nausea,vomiting and other side effects than other opioids. Propofol, as a short-acting powerful sedative-hypnotics,can rapid distribution to the central ner-vous system and peripheral tissue after administration from the blood. As a suitable d rug for target-controlled infusion(TCI), propofol has a negative inotropic effects, w hich can reduce sympathetic vasoconstrictor nerve activity role in a common cause of decreased blood pressure. The rate of decline is related to dose, infusion rate, age, A SA physical status and drugs used in combination. With the development of TCI techn ology,TCI model of propofol and sufentanil provide a new method to to maintain a stable plasma concentration and a stable depth of anesthesia for us. Combined with pr opofol and sufentanil used in tracheal intubation of anesthesia induction in elderly pat ients. It is rarely reported to choose the appropriate concentration of propofol inhibiti ng the noxious stimuli in elderly patients of different ages used the different target co ncentration of sufentanil.This study is a prospective, randomized, double-blind study designed to investigate the median effective plasma concentration (Cp50) of propofol blunting cardiovascular responses to tracheal intubation with sufentanil at different targeted concentrations during anesthesia induction in elderly patients. After this, we can provide a basis for guiding clinical tracheal intubation reasonable application of sufentanil and propofol.MethodsAfter obtaining the approval of our institutional ethics committee and written informed consent, we enrolled ninety-four ASA physical status Ⅰ-Ⅲ patients who were60-79years old and scheduled for general anesthesia under tracheal intubation. Exclusion criteria: body mass index>30kg/m2or<18kg/m2,without the laws of the treatment of poorly controlled hypertension (≥2, preoperative systolic blood pressure>160mmHg or diastolic blood pressure>110mmHg), hepatic insufficiency, renal insufficiency, cerebrovascular diseases, diabetes, asthma, chronic obstructive pulmonary disease, psychiatric disorders or cognitive dysfunction, long-term administration of sedatives, theMallampati airway classification grade Ⅲ-Ⅳ or limited mouth opening suggestive of a difficult intubation, and refused to participate in the researcher.Patients were randomly allocated into four groups according to the old stage and which sufentanil concentration they received. The patients in Group A and Group B (60-69years) and the ones in Group C and Group D (70～79years) received sufentanil with a target effect concentration of0.2ng/ml,0.3ng/ml,respectively.Upon arrival in the operating room, a20G venous cannula was sited with5ml/kg lactated Ringer’s solution and5ml/kg colloid was infused. Subsequently, Ringer’s solution was infused at a rate of100ml/h. The infusion port for propofol and sufentanil was connected as close as possible to the intravenous catheter to minimize dead space. Standard monitoring included electrocardiogram, oxyhaemoglobin saturation, noninvasive arterial blood pressure and the depth of anesthesia monitored using the bispectral index monitor. We used the Schnider pharmacokinetic model for propofol, in which the plasma-effect-site equilibration rate constant is0.46/min. Also,we used the Gepts pharmacokinetic model for sufentanil.All patients were pre-oxygenated using100%oxygen with a normal tidal volume for3min. Induction of anesthesia was initiated by TCI sufentanil at target effect-site concentration and the target effect-site concentration of sufentanil was maintained stable before administration of propofol determined by up and down sequential test. At the moment of loss of consciousness, cis-atracurium0.2mg/kg was administered. Intubation was performed for3min later. The plasma-site concentration of propofol used for each patient was determined by the response of the previously tested patient using a modified up-and-down sequential allocation technique.The first patient received a plasma-site concentration of propofol of2.5μg/ml. The response of each patient determined the plasma-site concentration of propofol of the next patient. If the tracheal intubation is effectively suppressed, then the target plasma-site concentration of propofol was decreased by a step of0.5μg/ml.. If the tracheal intubation is a failure, the target plasma-site concentration of propofol was increased by the same dose. According to the modified up-and-down method, the first stage consisted of an up-and-down sequence of steps of0.5μg/ml. until three changes of response type were observed. After the first three such "negative-positive" up-and-down crossovers, the step change of dose was reduced to0.2μg/ml. When the the second six such "negative-positive" up-and-down crossovers appeared, the trial was ended. Mean arterial pressure increased lower than20percent of the basic value or the heart rate lower than15percent of the basic value, that was classified as a success of intubation response.Hypotention was defined as a decrease of>30%form the baseline value that persisted for more than1min and was treated by an incremental bolus of intravaneous ephedrine0.1mg/kg. A heart rate of<50bpm from the baseline value lasting more than1min was defined as bradycardia and treated with0.05mg/kg of intravenous atropine.The patient’s SBP, MAP, HR, BIS score of OAA/S and the dosage of sufentanil were recorded immediately at TO (baseline), T1(sufentanil plasma and effect-site concentration reached a balance), T2(loss of conscious), T3(immediately before intubation), T4(1minute after intubation), T5(2minute after intubation), T6(5minute after intubation). All patients were interviewed in the postoperative anaethesia care unit to access memory recall and the next day after surgery.Statistical analysis was performed using the Statistical Package for Social Science software (SPSS13.0for windows). The plasma-site concentration of propofol required for inhibition of tracheal intubation in50%of patients (Cp50) was determined by calculating the mean of the midpoint concentration of all independent pairs of patients who manifested a crossover from a negative response to a positive one. Cp50with95%confidence interval (CI) was determined by a probit analysis. Haemodynamic data were analysed with repeated measures of ANOVA. A p value<0.05was considered statistically significant.ResultsEighty-nine old patients were finished this study,25cases of whom in Group A,24cases in Group B,21cases in Group C and19cases in Group D. No significant difference was found among the four groups concerning sex ratio, body mass index, ASA physical status, age between Group A and Group B, Group C and Group D and the number of cases with hypertension (P>0.05).The Cp50of propofol were3.60±0.24μg/ml with95%confidence interval (CI) of3.34-3.86μg/ml in Group A,2.03±0.16μg/ml with95%CI ofl.86～2.20μg/ml in Group B,2.70±0.13μg/ml with95%CI of2.56～2.84μg/ml in Group C,1.97±0.10μg/ml with95%CI of1.86-2.08μg/ml in Group D, respectively.There was1case in Group A,2cases in Group B,1case in Group C and1case in Group D of hypotension in the negative group at T3, and1case of bradycardia in the positive group at T3. There was no significant difference. None of the four groups occurred chest wall rigidity, cough during intubation and other adverse reactions. In Group A, total doses of sufentanil was13.6±1.2μg(0.242±0.044μg/kg), Group B was22.4±1.5μg (0.397±0.051μg/kg), Group C13.4±0.8μg (0.237±0.037μg/kg),Group D21.8±1.2μg (0.394±0.058μg/kg). In Group A, total doses of propofol was115±19mg (2.04±0.37mg/kg), Group B was79±11mg (1.41±0.20mg/kg), Group C89±7mg (1.56±0.16mg/kg), Group D was74±14mg (1.31±0.18mg/kg).The total induction time of the four groups were:Group A (16.22±1.34) min, Group B (16.70±1.25) min, Group C (16.35±1.21) min, Group B (16.48±1.67) min, respectively. There were no significant difference among the four groups.ConclusionWith the concentrations of sufentanil or age increased, the Cp50of propofol decreased in elderly patients. Sufentanli combined with propofol TCI provides a stable hemadynamics during the induction of the elderly patients. |
PDF Full Text Request