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Effect of neoadjuvant chemotherapy on sevoflurane MAC-BAR value of patients undergoing radical stomach carcinoma surgery.

OBJECTIVE
To determine the minimum alveolar concentration (MAC) of sevoflurane required for 50% blockade of the adrenergic response (BAR) to surgical incision in patients treated with neoadjuvant chemotherapy prior to radical gastrectomy.


PATIENTS AND DESIGN
Forty-four patients were selected for this study. Patients with preoperative neoadjuvant chemotherapy comprised the NC group (n = 22) and patients without preoperative neoadjuvant chemotherapy were included as the C group (n = 22). Patients in the NC group were treated with two cycles of 14-day neoadjuvant chemotherapy with combination of oxaliplatin and Gio, and underwent surgery 3 weeks later. Patients in the C group received no chemotherapy prior to surgery. A sequential allocation method was employed to determine the MAC-BAR for each group. The initial end-tidal concentration of sevoflurane was set as 3% for both the NC and C groups. Sympathetic responses to surgical incision were evaluated 6 times by measuring the heart rate (HR) and mean arterial blood pressure (MAP) at 1 min intervals before (T1, T2, T3) and after (T4, T5, T6) skin incision, and used to adjust the end-tidal sevoflurane concentrations for each patient. More than a 15% increase in MAP or HR after incision was scored as a positive response.


MAIN RESULTS
The HR and MAP levels measured pre- (T1) and post-incision (T6) were significantly lower than base line values at admission in both groups, but without statistical difference between the groups. The MAC-BAR value of sevoflurane was 2.2% in the NC group and 3.0% in the C group (P < 0.05).


CONCLUSIONS
Neoadjuvant chemotherapy reduced the MAC-BAR value of sevoflurane in gastric cancer patients by enhancing the inhibitory effect of sevoflurane on the stress response.