A Clinical Comparison of Two New Bronchial Blockers vs. Double Lumen Tubes in One Lung Ventilation

Overview

Patients undergoing thoracic surgery require selective ventilation of one lung, which allows surgery to proceed on the operative lung that is deflated, and no longer moving. One-lung ventilation (OLV) may be achieved by the use of a double lumen endotracheal tube (DLT) or the placement of a bronchial blocker (BB) via a single lumen endotracheal tube, both of which are in routine clinical use at University Health Network. Recently, the Endobronchial Blocker (EZ blocker) has been marketed, with a forked tip design and two balloons, one of which is designed to fall into each of the right and left sides, it may require less repositioning. Initial clinical experience with the EZ Blocker suggests that it may be less likely than other blockers to become malpositioned during surgery. This study will compare the EZ blocker to the Fuji blocker, the most frequently used blocker at this institution, and to double-lumen tubes, the most commonly used devices to provide lung isolation, with respect to intra-operative malpositioning and the speed of lung separation and efficacy of lung collapse during thoracic surgery. Patients will be randomly assigned, to one of the three study groups: EZ Blocker, Fuji, or left-sided DLT, immediately prior to induction of anesthesia. The primary end points of time to lung isolation and number of required repositioning maneuvers.

STUDY END POINTS The time required to achieve lung separation, from beginning of laryngoscopy to lung isolation (inflation of the bronchial cuff or blocker), will be recorded. The thoracic surgeons, using a verbal analogue scale, will assess the lung collapse(lung collapse scores-LCS, 0=no collapse, to 10=complete collapse). The LCS will be assessed and recorded as they open the pleura during the procedure (LCS 0), and at 10 min., (LCS 10), and 20 min. (LCS 20) after opening the pleura. The surgeons will be blinded to the lung isolation device used in the patient. If the lung collapse is not satisfactory, the FOB will be passed to assess the lung isolation, and if necessary reposition the device. A malposition will be defined as a clinically obvious relocation of the devise in the trachea or bronchus and a loss of lung isolation interfering with surgery. The number of repositions of the lung isolation device after initial supine placement, airway pressures, tidal volumes, duration of surgery, and the arterial blood gases 20 minutes after pleural opening will be noted. In addition to the primary end points of time to lung isolation and number of required repositioning maneuvers, the following variables will be recorded: Age, gender, weight, height, BMI, ASA, airway Mallampati score, pulmonary spirometry (if clinically performed: TLC, FEV1, FVC, DLCO), LCS 0/10/20, ventilatory parameters on OLV (airway pressure, tidal volume, respiratory rate, compliance, duration of OLV and surgery, arterial blood gas 20 minutes after opening the pleura (pH, paO2, pCO2 bicarbonate, base excess, oxygen saturation), and finally the dimensions of the left main bronchus (LMB) and the right main bronchus (RMB) using the on-screen program of the radiology server on the pre-operative chest imaging, by the anesthesiologist.