In Reply:-We thank Dr. Cheng for his comments about our study. Dr. Cheng speculates that intentionally not correcting a distally malpositioned double lumen tube after intubation may lead to less proximally malpositioned tubes after patient positioning and may obliviate the use of fiberoptic bronchoscopy in most cases. Although we agree that proximal malposition predominates after patient positioning, some points, however, must be kept in mind. First, one would still need a fiberoptic bronchoscope to intentionally but safely insert the tube deeper. Placing a tube intentionally too deep without a bronchoscope may cause serious injuries. Sakuragi et al. report of a rupture of the left main-stem bronchus after the insertion of a left-sided double-lumen endobronchial tube in a 76-yr-old woman in which a fiberoptic bronchoscope was not used. Second, not only proximal, but also distal malpositions, occur after patient positioning. [1,3,4]Because the very same tubes that are malpositioned distally after intubation are not necessarily those predestined to be malpositioned proximally after patient positioning, a distal malpositioning left undisturbed may predispose the patient to serious injuries if it moves distally during patient positioning.
Dr. Cheng also maintains that, based on his experience of many thousand patients, fiberoptic bronchoscopy is seldom necessary if continuous vigilance is given to bilateral auscultation, cuff palpation, and changes in airway pressure. Our study, and surprisingly, some points of his own study point to the contrary. Auscultation may be practically impossible after the patient is washed and draped; cuff palpation cannot be performed during video-assisted surgery or in cases in which the nonoperated lung is intubated, and airway pressure may also increase because of other reasons (secretions, blood, surgical manipulation). Fiberoptic monitoring of double lumen tubes, similar to most monitoring measures in medicine, is performed in a majority of patients to avoid mishaps in a small minority. Positive experience in many patients may not be predictive of a negative outcome in the individual patient.
Uwe Klein, M.D.
Professor of Anesthesiology
Waheedullah Karzai, M.D.
Staff Anesthesiologist; Department of Anesthesiology and Intensive Care Medicine; University Hospital; Friedrich-Schiller-University Jena; Jena, Germany;email@example.com
(Accepted for publication July 7, 1998.)