Two-minute disconnection technique with a double-lumen tube to speed the collapse of the non-ventilated lung for one-lung ventilation in thoracoscopic surgery

Abstract

BackgroundThoracic surgery requires the effective collapse of the non-ventilated lung. In the majority of cases, we accomplished, accelerated lung collapse using a double-lumen tube (DLT). We hypothesized that using the two-minute disconnection technique with a DLT would improve lung collapse during subsequent one-lung ventilation.MethodsFifty patients undergoing thoracoscopic surgery with physical classification I or II according to the American Society of Anesthesiologists were randomly divided into two groups for respiratory management of one-lung ventilation (OLV). In group N, OLV was initiated after the DLT was disconnected for 2 min; the initiation time began when the surgeon made the skin incision. In group C, OLV was initiated when the surgeon commenced the skin incision and scored the quality of lung collapse (using a four-point ordinal scale). The surgeon’s satisfaction or comfort with the surgical conditions was assessed using a visual analogue scale. rSO2 level, mean arterial pressure, pulse oxygen saturation, arterial blood gas analysis, intraoperative hypoxaemia, intraoperative use of CPAP during OLV, and awakening time were determined in patients at the following time points: while inhaling air (T0), after anaesthesia induction andinhaling 100% oxygen in the supine position under double lung ventilation for five mins (T1), at two mins after skin incision (T2), at ten mins after skin incision (T3), and after the lung recruitment manoeuvres and inhaling 50% oxygen for five mins (T4).ResultsThe two-minute disconnection technique was associated with a significantly shorter time to total lung collapse compared to that of the conventional OLV ventilation method (15 mins vs 22 mins, respectively; P < 0.001), and the overall surgeon’s satisfaction was higher (9 vs 7, respectively; P < 0.001). At T2, the PaCO2, left rSO2 and right rSO2 were higher in group N than in group C. There were no statistically significant differences between the incidence of intraoperative hypoxaemia and intraoperative use of CPAP during OLV (10% vs 5%, respectively; P = 1.000), duration of awakening (18 mins vs 19 mins, respectively; P = 0.616).ConclusionsA two-minute disconnection technique using a double-lumen tube was used to speed the collapse of the non-ventilated lung during one-lung ventilation for thoracoscopic surgery. The surgeon was satisfied with the surgical conditions.Trial registrationChinese Clinical Trial Registry number, ChiCTR-IPR-17010352. Registered on Jan, 7, 2017.

Preemptive one lung ventilation enhances lung collapse during thoracoscopic surgery: A randomized controlled trial

“…However, in routine practice, the distal port of the DLT lumen to the non‐ventilated lung is opened to the atmosphere immediately after being clamped; as a result, air could enter the non‐ventilated lung due to the tidal movement caused by the ventilated lung and delay lung collapse . Previous studies used the time needed for complete lung collapse as the primary end point whereas the present study uses the duration of time from pleural incision to satisfactory lung collapse (collapse score of 8) as complete lung collapse is not always achievable in every patient.…”

“…Since there was no data reporting the duration to collapse with a score of 8, we calculated the sample size based on a previous report of duration to complete lung collapse (score of 10). A power analysis indicated a minimum of 23 subjects are needed in each group based on the following assumptions: (i) α at 0.05; (ii) 1‐β at 0.9; (iii) the primary end point measure (duration to lung collapse score of 10) in the conventional OLV group at 22 ± 3.6 minutes; and (iv) clinically meaningful 3.5‐minutes reduction of the primary end point measure in the preemptive OLV group. Considering possible attrition (due to lung adhesion or intubation failure) and the primary measure of collapse at a score of 8, rather than score of 10, we expanded the sample size calculation by a factor of 1.65, and planned to enroll a total of 76 subjects.…”

“…Pure oxygen has been shown to be superior to the mixture of oxygen and air in speeding phase II lung collapse when used for two lung ventilation before OLV as it is more easily absorbed into the blood . Other methods for accelerating lung collapse include ventilation with nitrous oxide and use of the disconnection technique …”

“…8 Other methods for accelerating lung collapse include ventilation with nitrous oxide 9 and use of the disconnection technique. 10,11 A previous study 12 showed that at an inspired alveolar ventilation/perfusion ratio of 0.001, it requires no more than six minutes for a lung unit to collapse with a fraction of inspired oxygen of 1.0. We therefore speculated that initiating OLV at least six minutes prior to pleural opening to create a confined space to the non-ventilated lung when inhaling pure oxygen could expedite lung collapse.…”

The fraction of Nitrous Oxide in oxygen for facilitating Lung collapse During One-Lung Ventilation with double lumen tube

“…Then, a verbal rating scale [7,8], scored from 0 (no lung de ation) to 10 (maximal lung collapse), was used by the surgeon to score the patient's lung collapse condition. Other studies [13,14] have also used a four-point ordinal scale (1, extremely poor to no collapse of the lung; 2, poor partial collapse with interference with surgical exposure; 3, good total collapse, but the lung still contained residual air; and 4, excellent to complete collapse with perfect surgical exposure). To evaluate the condition of the lung, however, de ning a "success" and "fail" condition is a necessary step for determining EC 50 using the up-and-down method.…”