Optimal Respiratory Rate for Low-Tidal Volume and Two-Lung Ventilation in Thoracoscopic Bleb Resection

Objectives One-lung ventilation is considered to be mandatory in video-assisted thoracoscopic surgery. However, the authors showed in a previous report that two-lung ventilation with low tidal volume is feasible in thoracoscopic bleb resection (TBR). In this study, they evaluated optimal respiratory rate during TBR under two-lung ventilation with low-tidal volume anesthesia. Design A prospective, randomized, single-blinded intervention study. Setting An operating room in a teaching hospital. Participants Forty-eight patients who underwent scheduled TBR under general anesthesia. Interventions TBR was performed under low-tidal-volume (5 mL/kg), two-lung ventilation. Respiratory rate (RR) varied according to the protocol: 15 (group I), 18 (group II), and 22 cycles/min (group III). Using block randomization method, 16 patients were assigned to each of 3 groups. Measurements and Main Results Minute ventilation of group I was lowered significantly compared with the other groups (p<0.001). The results of arterial blood gas analysis were in the physiologic range in all patients. Surgery and anesthetic times and number of endostaples used were not significantly different among the 3 groups. Conclusions The RR of 15 cycles/min with low-tidal volume (5 mL/kg) and two-lung ventilation did not produce abnormal physiologic changes including arterial pH, partial arterial oxygen pressure, and partial pressure of carbon dioxide and guaranteed an optimal surgical field. Therefore, these setting are considered acceptable for two-lung ventilation during TBR.