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

Abstract

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 (N2O)/oxygen (O2) inspired mixture on the appearance time of the ISP (TISP) via the modified inflation‐deflation method. Methods A total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N2O (n = 24), 50% N2O (n = 23) or 0% N2O (n = 18). The 75% N2O group received a gas mixture of N2O/O2 (Fio2 = 0.25), the 50% N2O group received N2O/O2 (Fio2 = 0.5), and the 0% N2O 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 TISP was significantly shorter in the 75% N2O group (320.2 ± 65.9 s) compared with that of the 50% N2O group (552.4 ± 88.9 s, p < 0.001) and the 0% N2O group (968.3 ± 85.5 s, p < 0.001), while the 50% N2O group was shorter than that of the 0% N2O group (p < 0.001). Arterial oxygenation was significantly improved in the 0% N2O group only after lung expansion, before which there were no differences in mean PaO2 values among groups. Conclusions The use of N2O 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.

Comparison of bronchial methylene blue staining and modified inflation-deflation method in identifying the intersegmental plane during lung segmentectomy

“…However, with the modified inflation-deflation method, we had to wait for a period of time before the ISP could be visualized. This wait time is about 15 minutes, which is also similar to previous reports ( 12 , 25 ). This was not the case with the bronchial methylene blue method, where the ISP could be visualized during methylene blue injection, thus reducing the anesthesia time and surgical duration.…”

“…The inclusion criteria were as follows: (I) peripheral nodules ≤2 cm in diameter, together with at least one of the following factors: pathological confirmation of adenocarcinoma in situ (AIS), nodules with ≥50% ground-glass appearance on CT, or a tumor doubling time of ≥400 days according to radiologic surveillance; (II) no evidence of lymph nodes or distant metastases; (III) marginal cardiopulmonary reserve or multiple comorbidities limiting the option of lobectomy ( 12 ). Exclusion criteria included the presence of other metastatic disease, comorbidities in cardiovascular, lung, kidney and other important organ that cannot tolerate surgery.…”

Intraoperative Identification of the Intersegmental Plane: From the Beginning to the Future

“…Yang replaced the pure oxygen (O 2 ), the conventional gas for inflation, with mixed nitrous oxide (75% N 2 O with 25% O 2 or 50% N 2 O with 50% O 2 ). The time for intersegmental plane emergence was significantly shorter in the 75% N 2 O group without additional complications, despite a lower level of arterial oxygenation after lung expansion (8). The third limitation exists in patients with chronic obstructive pulmonary diseases (COPDs), who lost their normal pulmonary function of contraction and expansion.…”

Precise identification of the intersegmental plane for lung cancer segmentectomy

“…Conversely, the gas in the adjacent segment is absorbed by the artery, so the adjacent segment is collapsed. This difference in inflation state allows visualization of the intersegmental plane (14,15). This method does not require special equipment, is simple, and can accurately and stably delineate the intersegmental plane.…”