Determination of the minimum alveolar concentration of sevoflurane in patients diagnosed as gastric car-cinoma and treated with neoadjuvant chemotherapy / 临床麻醉学杂志

ABSTRACT

Objective To determine the minimum alveolar concentration (MAC)of sevoflurane for blunting the responses to surgical incision in 50% adult patients diagnosed as gastric carcinoma and treated with neoadjuvant chemotherapy.Methods Twenty-five ASA physical statusⅠor Ⅱ,and aged 30-50 years patients (14 males and 11 females)diagnosed with gastric carcinoma were enrolled.At least 1 month before the operation,all these patients received 2 cycles (1 chemotherapy cycle was 14 days)of chemotherapy including oxaliplatin and tegafur.At first,the anesthesia induc-tion was started by inhaling 6% sevoflurane.After the patient lost consciousness,the endotracheal in-tubation was performed.And then,the end tidal sevoflurane concentration was adjusted to the target concentration and maintained stable for 15 min.After that,the surgical incision was executed.The Dixon's up-and-down method was used to calculate the MAC.The initial end tidal sevoflurane con-centration was 2.2% and it was increased or decreased by 0.2% in the next patient according to the surgical incision response.If the surgical incision response was positive,the end tidal sevoflurane con-centration was increased;if the surgical incision response was negative,the end tidal sevoflurane con-centration was decreased.The midpoint from negative response to positive response was set as the balance point and the mean value of the concentrations of sevoflurane at all the balance points were calculated as MAC.Results Minor physical activity occurred when the surgical incision started.No body twisting,eye opening or intraoperative awareness occurred.Body moving occurred in 11 patients (44%)when the surgical incision started.The end tidal sevoflurane concentration for blunting the re-sponses to surgical incision in 50% adult patients diagnosed as gastric carcinoma and treated with neo-adjuvant chemotherapy was 1.52%,and the 95% CI was 1.37%-1.65%.Conclusion The MAC of sevoflurane for blunting the responses to surgical incision in 50% adult patients diagnosed as gastric carcinoma and treated with neoadjuvant chemotherapy is 1.52%.