To the Editor:—
I read with interest the report by Campos et al. 1This article reported 39% and 36% incidences of failure of proper placement of lung isolation devices by faculty and senior residents, respectively. All participating anesthesiologists did not regularly practice thoracic anesthesia. The authors stated that one-lung ventilation is primarily provided by either a double-lumen tube, the Univent® torque control blocker (Vitaid Ltd., Lewiston, NY), or the Arndt® blocker (Cook Critical Care, Bloomington, IN). However, an additional blocker that was not mentioned is the Cohen blocker (Cook Critical Care). This commonly used blocker has a wheel at the operator end that, when turned, flexes the tip and gives the anesthesiologist the ability to direct the blocker to the appropriate bronchus.
This is an important article that highlights the difficulties for anesthesiologists who need to provide one-lung ventilation on an occasional basis. There is a learning curve with all of these techniques. I agree with the authors that the successful practice of thoracic anesthesia requires familiarity with the devices, skill in fiberoptic bronchoscopy, and knowledge of the tracheobronchial anatomy. Residents learning thoracic anesthesia should learn all three of these types of skills before graduation, and these should be specific goals in residency programs.
The authors stated that the preoperative instruction included the fiberoptic views that constituted correct positioning of the device. When checking the position of the lung isolating device, it is also important to identify the right upper lobe, the characteristic D-shaped opening to the middle lobe, and the basilar and superior segments of the lower lobe. The left mainstem bronchus is identified, as well as the left upper and left lower lobes. The views of just the double-lumen tube or blocker balloon are not adequate for establishing correct positioning, which could account for some of the malpositions reported in the study. If a simplified instruction is given, it is most important to identify the right upper lobe. It would be helpful to know exactly which views were included in the tutorial.
It would be interesting to repeat the study, with more training, to achieve a higher success rate. Anesthesiologists who may have to provide one-lung ventilation on occasion should become familiar with the devices, learn the tracheobronchial anatomy, and practice fiberoptic bronchoscopy. There are hands-on workshops that are given at the annual meetings of the American Society of Anesthesiologists and the International Anesthesia Research Society and at the PostGraduate Assembly in Anesthesiology.
When choosing a lung isolation technique, there are other issues to consider besides the initial placement. Blockers, especially when used on the right side, are more easily dislodged than double-lumen tubes. It is also easier to suction and apply oxygen via a double-lumen tube, compared with a blocker. The main advantage of the blocker is in the patient with the difficult airway, which was excluded in the study. It is essential to be knowledgeable of possible complications. For example, a blocker may become dislocated into the trachea and block ventilation completely. Techniques for prevention and treatment of hypoxemia must be understood.
There is more to practicing thoracic anesthesia than just the initial placement of the lung isolation device.
The most important teaching message from this study is that practitioners who may have to provide one-lung ventilation on an occasional basis need to do continuing medical education. Development of a tutorial and/or attending a hands-on workshop might be beneficial.
The Mount Sinai Medical Center, New York, New York. steve.neustein@msnyuhealth.org
