Objective To investigate the effects of mouse nerve growth factor on amikacin (AK)-induced ototoxicity in guinea pigs .Methods 45 guinea pigs were randomly divided into three groups with 15 guinea pigs in each group .The control group received no drug treatment ,the poisoning group received an intraperitoneal injection of AK (400 mg · kg -1 · d-1 ) for 10 days ,and the treatment group received an intraperitoneal injection of AK (400 mg · kg -1 · d-1 ) for 10 days and an intramuscular injection of NGF (1 500 AU · kg -1 · d-1 ) for 14 consecutive days .Auditory brainstem responses were tested on the day before administration ,the 10th day and 20th day after administration .All the guinea pigs were sacrificed when the last ABR test was finished on the 20th day whose Corti organs were observed as well .Results The ABR thresholds of each group showed no significant difference before administration .The ABR threshold of the treatment group was lower than that of the poisoning group .With light microscopy ,the hair cells with normal morphology were observed in the control group .However ,there was an ex-tensive loss of outer hair cell in the poisoning group .For the treatment group ,the miss rate of hair cell was lower compared with the poisoning group .Conclusion Our data shows that NGF has played a protective role on amikacin-induced ototoxicity .

Objective To determine the threshold of stroke volume variation (SVV) in determining the volume expansion responsiveness during fluid therapy in patients ventilated with different tidal volumes. Methods Fifty ASA Ⅰ or Ⅱ patients aged 20-75 yr undergoing elective gastrointestinal surgery under general anesthesia were randomly divided into 2 tidal volume groups (n = 25 each):group Ⅰ VT 8 ml/kg (group V1) and group ⅡVT 10 ml/kg (group V2). Radial artery was cannulated and connected to Vigelo monitor for continuous monitoring of cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI) and SVV. Internal jugular vein was cannulated for CVP monitoring. Anesthesia was induced with milazolam, propofol, fentanyl and rocuronium and maintained with intravenous propofol and remifentanil infusion. BIS was maintained at 40-50 during anesthesia. The patients were intubatel and mechanically ventilated (VT 8/10 ml/kg, RR 8-12 bpm, oxygen flow 2 L/min). 6％ HES 130/0.4 7 ml/kg was infused iv at a rate of 0.4 ml·kg-1 ·min-1 after induction of anesthesia. MAP, HR, CVP, CI, SVV, SVI and SVRI were recorded before and at 3 min after fluid therapy. The changing rate of SVV (△SVV) and CI (△CI) were calculated. The criterion for effective volume expansion was △CI 15%. The ROC curve for SVV in determring the volume expansion responsiveness was plotted and the diagnostic threshold was determined. Results ROC curve showed that the diagnostic threshold of SVV was 10.5 % in group V1 and 13.5% in group V2. The sensitivity and specificity in determining effective volume expansion were 93.3 % and 75.0 % in group V1 and 87.5 % and 85.7 % in group V2 respectively. The area under the curve for SVV and 95% confidence interval (CI) were 0.946 (0.860-1.031) in group V1 and 0.951 (0.868-1.034) in group V2. △SVV was negatively correlated with △CI in group V1 (=0.553) and V2 (= 0.602). Conclusion The threshold of SVV in determining the volume expansion responsiveness during fluid therapy is 10.5% and 13.5% in mechanically ventilated patients with tidal volume of 8 and 10 ml/kg respectively.

Objective To discuss the feasibility and safety of propofol used in senile patients undergoing minor surgery including gastroscopy and colonoscopy.Methods 40 patients aged 80-88 years old were randomly divided into two groups with 20 cases for each group.Group P received only propofol by intravenous injection in a speed of 1ml/s till eyelash response disappeared.In patients of group F fentanyl was first given at 0.5?g/kg,and 1 minute later,the patients were given propofol by intravenous injection in a same speed as in group P if there was no discomfort until eyelash response disappeared.MAP,HR,SpO2 and RR were determined before induction of anesthesia,beginning of operation,and 1st,3rd and 5th minute after operation.The onset time of anesthesia,total dosage of propofol used,time of palinesthesia and follow-up results were recorded.Results MAP was significantly decreased in both groups at the beginning of operation,and more stable in group F at the 3rd and 5th minute after operation.There were significant differences between two groups in amount of propofol used,and the dosage in group F was less than that used in group P(P