Combination of nitrous oxide and the modified inflation-deflation method for identifying the intersegmental plane in segmentectomy: A randomized controlled trial.

BACKGROUND

During thoracoscopic segmentectomy, accurately and rapidly identifying the intersegmental plane (ISP) is of great importance. This study aimed to investigate the effect and safety of a nitrous oxide (N O)/oxygen (O ) inspired mixture on the appearance time of the ISP (T ) via the modified inflation-deflation method.

METHODS

A total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N O (n = 24), 50% N O (n = 23) or 0% N O (n = 18). The 75% N O group received a gas mixture of N O/O (Fio = 0.25), the 50% N O group received N O/O (Fio = 0.5), and the 0% N O group received 100% oxygen during lung expansion. The appearance time of satisfactory and ideal planes was recorded. Furthermore, arterial blood gas at breathing room air, one-lung ventilation (OLV) before lung expansion, 5 and 15 min after lung expansion were also recorded.

RESULTS

T was significantly shorter in the 75% N O group (320.2 ± 65.9 s) compared with that of the 50% N O group (552.4 ± 88.9 s, p < 0.001) and the 0% N O group (968.3 ± 85.5 s, p < 0.001), while the 50% N O group was shorter than that of the 0% N O group (p < 0.001). Arterial oxygenation was significantly improved in the 0% N O group only after lung expansion, before which there were no differences in mean PaO values among groups.

CONCLUSIONS

The use of N O in the inspired gas mixture during lung expansion is an applicable strategy to rapidly identify the ISP via the modified inflation-deflation method without any adverse effect on OLV related arterial oxygenation during segmentectomy.