Background:
Over the last decade, utilization of robotically assisted thoracic operations have become more commonplace due to smaller incisions, improved postoperative pain control, quicker recovery, and ultimately, faster discharge of patients. However, given the bulkiness and space needed for the robotic equipment, providing good lung isolation and one lung ventilation can be challenging not only due to the size of the equipment, but also the unique positioning and limited airway access constraints. Hence, we conducted a randomized controlled trial that compared usage of both video double lumen tubes (VDLT) and conventional double lumen tubes (DLT) in thoracic surgery patients. 
Methods:
The study comprised of 80 patients who were 18 years or older requiring lung isolation for thoracic surgery. Of the 80 patients, 23 patients had surgery performed robotically. All 80 patients were randomized into either VDLT or DLT usage for their scheduled surgery. Attending anesthesiologists placed VDLT or DLT with conventional laryngoscopy or videolaryngoscopy, and then verified correct tube position through the view provided with either VDLT external monitor or fiberoptic bronchoscope (FOB). 

Results:
The result showed dislodgement requiring correction intervention occurred (7/23, 30.4%), of which (4/7, 57.1%) were in VDLT group and (3/7, 42.9%) were in the DLT group.  The anesthesiologist was able to forewarn dislodgement occurrence (2/4, 50%) in the VDLT group and 0/3, 0% in the DLT group.

Discussion:
Currently, placement of double lumen tubes (DLT) with fiberoptic bronchoscopy (FOB) confirmation is the standard of care in the United States. The positioning of the patient and robot, often make the airway inaccessible since the patient is in lateral position and the head may be turned 90-180 degrees away; making FOB challenging and awkward to perform.  Furthermore, following lateral repositioning or for evaluation of loss of lung isolation, the FOB is used to confirm and, if necessary, reacquire and maintain proper endobronchial tube placement. Unfortunately, many anesthesiologists lack the training and familiarity of tracheobronchial anatomy for adequate application of these techniques, leading to a high incidence (38%) of malposition. Technological advances in the miniaturization of video camera and light source offer a novel solution to the challenges faced by the anesthesiologist in these robotic cases.  Unlike the use of intermittent FOB visualization, the view provided by the VDLT allows for continuous real time visualization of the tracheal mucosa, primary carina, and proximal bronchial airways which facilitates rapid diagnosis and appropriate intervention; a critical factor in patients with low cardiopulmonary reserve in whom even transient disruption of ventilation may be detrimental. Although the study demonstrated that usage of VDLT can forewarn dislodgement during robotic thoracic surgery given the real-time continuous visualization rather than the intermittent view provided by the FOB, further larger studies are needed to better evaluate both devices in robotic surgery.  However, clinically the positioning of the robot, often make the airway inaccessible as the patient may be in the lateral position and the head may be turned 90-180 degrees away from the provider, thus making the FOB utilization awkward and challenging. Hence the VDLT offers a novel solution to the unique challenges faced by anesthesiologists in robotic cases. The continuous real-time view can facilitate rapid diagnosis and potentially quicker appropriate intervention without interrupting ventilation. Using this novel solution, the anesthesiologist is able to forewarn the surgical team when the tube may become malpositioned and not rely necessarily on desaturation, changes in airway pressures, or surgeon noting lung inflation in the surgical field. That may offer another measure of patient safety as the continuous visualization of the airway can reduce complications from adverse airway events.

04 / Video double lumen endobronchial tubes can forewarn dislodgement, thereby enhance patient safety in robotic thoracic surgery