Strategies for lung isolation: to block or not to block?

Abstract

In this issue of the Journal, Bussières et al.1 report their findings of a randomized-controlled trial evaluating the use of a bronchial blocker (BB) vs a left-sided double-lumen endotracheal tube (DL-ETT) during video-assisted thoracoscopic surgery (VATS). The focus of their study was on the quality of lung collapse and the time to achieve optimal lung deflation.The authors studied 40 patients requiring one-lung ventilation (OLV) and randomized to receive a BB or a left-sided DL-ETT. The time from opening the pleura until complete lung collapse as well as the quality of lung collapse (graded from 1-3) were evaluated in real time by the surgeons who were blinded to the method used to achieve lung separation. The time to lung collapse and the quality of the collapse were also graded offline by independent observers -i.e., two thoracic surgeons and an anesthesiologist who reviewed video recordings of the VATS procedures. Finally, the operating surgeons were asked to guess which device was used for lung isolation.The findings of the study showed that the time to complete lung collapse in patients having elective VATS was significantly faster with a BB than with a left-sided DL-ETT. The scores of the quality of lung deflation at 5, 10, and 20 min following opening of the pleura were also better in the BB group than in the DL-ETT group, in both real-time and offline assessments. Finally, when the surgeons were asked to guess which method was being used for lung isolation, they were correct only 37% of the time. This outcome would suggest that the two devices could be used interchangeably without the surgeon noticing any differences.As DL-ETTs are considered the ''gold standard'' for lung separation, they are the most widely used devices for performing this procedure. They have been used for more than 50 years, and as a result, most anesthesiologists and surgeons are familiar with them and are comfortable with their use. [2][3][4][5][6] The decision whether to use a DL-ETT or BB depends on three factors: patient safety, the anesthesiologist's comfort with the selected device, and the surgeon's preference. Unfortunately, there are sometimes situations where these three factors cannot coincide. As with many devices, correct use of a BB involves a significant learning curve, and most anesthesiologists are unfamiliar with the device and inexperienced in its use. As a result, a thoracic surgeon who is not accustomed to having a BB used for OLV may be reluctant to accept this new technique.The study by Bussières et al. 1 addresses some of the myths surrounding the use of a BB. Indeed, there may be a bias against its use and an impression amongst surgeons (and some anesthesiologists) that a BB fails to provide optimal lung separation.7 These myths regarding the BB include the view that the quality of lung collapse is inferior to that with the DLT; that it would take more time to achieve adequate lung deflation than with the DL-ETT; and that it takes less time to insert and position a DL-ETT than to perform the same procedure...

One-lung Ventilation for Thoracic Surgery: Current Perspectives

“…Probably The most important thing is to know which is the best practice in each condition, taking into account the safety of the patient, the need for surgical exposure and the comfort of the anesthesiologist (10). The use of DLT is mandatory in lung isolation and in lung resections involving the main bronchus, while BB is recommended in case of difficult airway management (2, 11), rapid sequence induction, OLV in children, and when postoperative ventilatory support is needed (10). The correct size of the left DLT can easily be derived from the measurement of the left bronchus on CT scan (12).…”

“…Therefore the division into absolute and relative indications for OLV as has been used to date no longer makes sense; moreover, it is also unpredictable given that a relative indication may become absolute (2,3). In addition to intraoperative hypoxemia, there are other problems that may occur during OLV, which include the mechanical ventila-main bronchus, while BB is recommended in case of difficult airway management (2,11), rapid sequence induction, OLV in children, and when postoperative ventilatory support is needed (10). The correct size of the left DLT can easily be derived from the measurement of the left bronchus on CT scan (12).…”

Atelectasis in one lung ventilation: the good, the bad, and the ugly: a narrative review

“…We would like to share the experience of our research program on lung collapse during OLV to address this lack in literature. Unlike other studies, our research group has obtained faster lung collapse using BB than DLT, especially when the internal channel of the BB was occluded (9,10). Based on those findings, we (11) demonstrated that a negative pressure develops in the non-ventilated surgical lung after OLV initiation and before pleural opening with both devices.…”

The Evidence Base Surrounding Lung Isolation Often Is Wider Than Described

“…Although we particularly appreciated the history and anatomy sections, we were somewhat disappointed by the sections describing the different techniques that have been used for lung isolation. It seems to us that many other important aspects of lung isolation were omitted from this review, including some studies on alternative lung isolation devices and double lumen endotracheal tubes (DL-ETTs) 2,3 and some of our own work to improve the use of left and right DL-ETTs. 4 For example, in 2001, we published a randomized study challenging the classic technique 5 of positioning left-sided DL-ETTs and proposed a new position and landmark technique based on directly visualizing the carina through the left endobronchial lumen of the DL-ETT.…”

“…(3) the long-term patency of this arteriovenous graft could be equivalent to that of totally arterial grafts thanks to the action onto the intimal layer of the venous component of relaxing factors such as nitric oxide, which are derived from the endothelial cells of the right IMA stump. 3 The need for a good match (size, thickness, and quality of the wall) between the right IMA stump and saphenous vein graft, a higher risk Letter to the Editor / Journal of Cardiothoracic and Vascular Anesthesia 32 (2018) e1-e34 e13…”