Regarding Fiberoptic Intubation and Laryngeal Morbidity

Abstract

University of Texas Health Science Center, Houston, Texas. charles.e.cowles@uth.tmc.eduI read with interest the article “Fiberoptic Intubation and Laryngeal Morbidity” by Heidegger et al. 1The authors’ purpose was to demonstrate that the frequency of vocal cord sequelae (VCS) after fiberoptic tracheal intubation without neuromuscular blockade (NMB) was less than 25% when compared to VCS with NMB. I believe their study fell short of the model for evidence-based medicine.The study group and the control group were managed so differently that comparison of the frequency of VCS in either group cannot be reasonably compared. Along with objective assessment of the patients, the patients were asked to subjectively assess hoarseness and discomfort with introduction of potential bias. Using subjective assessment tools dependent on the patient’s own feelings, one must consider and attempt to eliminate distracting factors that could significantly impact the objectivity of the assessment.To truly control for fiberoptic technique and NMB, the two groups could have easily been standardized by the following:Another concern is the selection of patients undergoing surgery to eye, ear, and salivary glands, which could affect subjective discomfort associated with VCS.Finally, the assessment of the vocal cords was performed by an ear, nose, and throat surgeon blinded to patient group assignment. It is difficult to believe that an experienced ear, nose, and throat surgeon could not recognize that a patient underwent recent nasal intubation. Even with the best of conditions, minor traumatic injury is often noted along the path of a nasotracheal intubation.The authors did design the study to compare with the trial of Mencke et al. ,2which used a silicone ETT for fiberoptic cases and polyvinyl chloride for direct laryngoscopy cases, and acknowledge that future study is needed to assess silicone tubes and VCS in oral direct laryngoscopy ETT placement. With respect to anesthetic agents and ETT assignment, the authors state that the goal was to compare two established techniques and not to solely compare NMB versus no NMB. However, this is in contrast to the stated goal of the study and even to the title of the article itself.University of Texas Health Science Center, Houston, Texas. charles.e.cowles@uth.tmc.edu