Abstract: Objective To estimate the feasibility and safety of monitored anethesia using target controlled infusion of remifentanil in patients undergoing cystoscopy. Methods Thirty patients〔American Society of Anesthesiologists(ASA)Ⅰ~Ⅱ grade〕, scheduled for cystoscope, were randomly allocated into two groups. All the patients were treated with target controlled infusion of remifentanil. The target concentrations were 3 μg/L in group L(n=15) and 4 μg/L in group H(n=15) respectively. Operations began as soon as the effective concentration reached preconcerted value. Bispectral index(BIS) was applied in both groups. When patients’ actions appeared that disturbed the operation, higher level of remifentanil could be administered. Oxygen was given by mask routinely and to make breath manually when pulse oxygen saturation(SpO₂)<90%. Blood pressure, heart rate, SpO₂ and BIS value were monitored. Other parameters such as visual analgesia score(VAS), complications, dosage and frequency of remifentanil injection were also analyzed. Results BIS value of the two groups were 89±10 and 86±13 respectively,and the average VAS were 4.8 and 3.3 respectively, which showed good analgesic effects and were not significantly different. Manually assisted respiration was applied in 2/15 cases in group L and in 8/15 cases in group H(P=0.02), respectively; the incidence of body action were 5/15 in group L and 1/15 in group H(P=0.08) respectively; total dosage of propofol given was(125.5±77.7)μg in group L and (242.5±72.6)μg in group H; all of the 5 parameters mentioned above were significantly different between the two groups. Conclusion The schemes of MAC in two groups are in enough depth of anesthesia in patients undergoing cystoscope. The concentration of 2~4 μg/L for remifentanil is considered as safe and effective, with less adverse effects.

Key words: remifentanil, target-controlled infusion, monitored anesthesia care(MAC), cystoscope