Objective To investigate the isoflurane consumption during LFCCA. Methods Thirty-five patients with ASA of grade Ⅰ～Ⅲ underwent the elective surgery lasting longer than 2 hours under general anesthesia through the tracheae. No massive hemorrhage occurred during the operations in all the patients. The patients continuously received transtracheally isoflurane by the infusion pump after the endotracheal intubation. Results The isoflurane consumption within the first an hour was 9.68 ml±1.78 ml, which was significantly more than that within other any an hour (P<0.01). In the second an hour it was 7.49 ml±1.59 ml, which was significantly more than that 5.79 ml±1.16 ml in the third an hour and that 5.72 ml±1.28 ml in the fourth an hour (P<0.01). The isoflurane consumption had no significant difference between the third and fourth an hour. Conclusion The present data provided a reference index for an anesthesiologist estimating the isoflurane consumption during LFCCA.