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Objective:To evaluate the dose-response relationship of alfentanil inhibiting gag reflex when combined with propofol in elderly patients undergoing painless gastroscopy.Methods:Patients of American Society of Anesthesiologists physical statusⅠor Ⅱ, aged ≥60 yr, scheduled for elective painless gastroscopy, were selected. Propofol 1.5 mg/kg combined with alfentanil was given intravenously in all the patients. The dose of alfentanil was determined by the Dixon up-and-down method. The initial dose of alfentanil was set at 5 μg/kg. The dose of alfentanil in the next patient was determined according to the development of gag reflex, and the ratio between the two successive doses was 1.1. The median effective dose (ED 50) and 95% confidence interval of alfentanil-induced inhibition of gag reflex when combined with propofol in elderly patients undergoing painless gastroscopy were calculated using the by up-and-down sequential allocation. Results:The ED 50 (95% confidence interval) of alfentanil-induced inhibition of gag reflex when combined with propofol 1.5 mg/kg was 2.8 (2.4-3.2) μg/kg in elderly patients undergoing painless gastroscopy. Conclusion:When combined with propofol 1.5 mg/kg, the ED 50 of alfentanil inhibiting gag reflex is 2.8 μg/kg in elderly patients undergoing painless gastroscopy.
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Objective:To evaluate the relationship between postoperative acute kidney injury (AKI) and preoperative dehydration in the patients undergoing surgery for gastrointestinal tumor.Methods:A total of 231 patients, of American Society of Anesthesiologists physical statusⅠ or Ⅱ, aged≥18 yr, undergoing elective surgery for gastrointestinal tumor with general anesthesia, were enrolled.Preoperative dehydration index was calculated according to preoperative urine color, specific gravity, osmotic pressure and creatinine.Preoperative dehydration was defined as dehydration index≥3.5.AKI was defined according to the Kidney Disease Improving Global Outcomes criteria.Logistic regression analysis was conducted to assess the association between preoperative dehydration and postoperative AKI.Results:Of the 231 patients who met our inclusion criteria, 27 (11.7%) developed postoperative AKI, and 13 patients (48.1%) had preoperative dehydration among the patients developed postoperative AKI.The results of logistic analysis showed that preoperative dehydration was an independent risk factor for postoperative AKI in the patients undergoing surgery for gastrointestinal tumor ( OR=4.03, 95% confidence interval 1.72-9.39). Conclusion:Preoperative dehydration is an independent risk factor for postoperative AKI in the patients undergoing surgery for gastrointestinal tumor.
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Objective To evaluate the effects of different doses of dexmedetomidine on propofol-induced inhibition of responses to laryngeal mask airway (LMA) insertion when combined with fentanyl in patients undergoing gynecological operation.Methods One hundred and twenty-five ASA Ⅰ-Ⅱ female patients,aged 20-60 yr,scheduled for elective short-time surgery,were randomly divided into 5 groups (n =25 each):normal saline group (group NS) and different doses of dexmedetomidne groups (groups D1-4).Normal saline 40 ml and dexmedetomidne 0.4,0.6,0.8,1.0 μg/kg (in 40 ml of normal saline) were infused over 10 min in groups NS and D1-4,respectively.1％ propofol was then given by target-controlled infusion.The concentration of propofol was determined by using modified Dixon's up-and-down method.The initial plasma concentration of propofol was 3.0 μg/ml and the ratio between the 2 successive concentrations was 1.1.Fentanyl 1.5 μg/kg was injected intravenously when the effect-site concentration of propofol reached the preset plasma concentration.LMA was inserted 4 min later.When LMA insertion was successful,the concentration of propofol was decreased in the next patient and when LMA insertion failed,the concentration of propofol was increased in the next patient.Failure of LMA insertion was defined as difficulty in inserting LMA or body movement,corner of mouth movement,biting LMA,swallowing and/or lacrimation during insertion.The median effective target effect-site concentration and 95％ confidence interval of propofol blunting responses to LMA insertion when combined with fentanyl were calculated.Results The median effective target effect-site concentration (95％ confidence interval) of propofol blunting responses to LMA insertion when combined with fentanyl were 3.09 (2.83-3.36),2.48 (2.26-2.73),2.29 (2.18-2.41),2.04 (1.95-2.12) and 1.67 (1.55-1.81) μg/ml in groups NS and D1 4,respectively.Conclusion Dexmedetomidine can enhance propofol-induced inhibition of responses to LMA insertion when combined with fentanyl in dose-dependent manner in patients undergoing gynecological operation.
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Objective To evaluate the effect of epidural block on postoperative cognitive dysfunction in elderly patients undergoing laparoscopic radical operation for gastric cancer under general anesthesia.Methods Sixty ASA physical status Ⅰ or Ⅱ patients,aged 65-75 yr,with preoperative Mini-Mental State Examination (MMSE) score ＞ 23,scheduled for elective laparoscopic radical operation for gastric cancer under general anesthesia,were randomized into epidural block group (group E,n =30) and control group (group C,n =30) using a random number table.Epidural block was performed at T8,9 interspace before induction of anesthesia.Anesthesia was induced with iv injection of midazolam 0.03 mg/kg,propofol 1.0-1.5 mg/kg,fentanyl 3-4 μg/kg and rocuronium 0.9 mg/kg.The patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with iv infusion of remifentanil 0.15-0.25 μg· kg-1· min 1 and propofol target-controlled infusion (target plasma concentration 2.5-3.0μg/ml).In group E,10 ml of mixture of 0.25％ ropivacaine and 0.04 mg/ml butorphanol was injected via the epidural catheter at 30 min before skin incision.In the two groups,the mixture 10 ml mentioned above was administered via the epidural catheter at 10 min before the end of operation followed by patientcontrolled epidural analgesia.The development of postoperative cognitive dysfunction (MMSE score ＜ 21) was recorded within 72 h after operation.Blood samples were collected from the internal jugular vein to detect the concentration of serum protein S-100β.Results The concentration of serum protein S-100β was significantly lower at 6,12 and 24 h after operation,and the incidence of postoperative cognitive dysfunction within 72 h after operation was lower in group E than in group C (P ＜ 0.05).Conclusion Epidural block can decrease the development of postoperative cognitive dysfunction in elderly patients undergoing laparoscopic radical operation for gastric cancer under general anesthesia.