To the Editor:—
In the study entitled “Gum Elastic Bougie–guided Insertion of the ProSeal™
Laryngeal Mask Airway is Superior to the Digital and Introducer Tool Techniques,” Brimacombe et al.1
reported an overall airway morbidity consisting of sore throat (14.6%), dysphagia (10.4%), and dysphonia (7.1%). The authors classified two sore throats, three dysphagias, and two dysphonias as severe at 18–24 h postoperatively. Any sore throat that did not produce “constant pain, independent of swallowing” was excluded from their data. The unusual nature of the reported morbidity associated with the ProSeal™
laryngeal mask airway (PLMA; Laryngeal Mask Company North America, San Diego, CA) deserves attention for a multitude of reasons.
Practice Guidelines for Management of the Difficult Airway2
established by a Task Force of the American Society of Anesthesiologists state that the anesthesiologist should follow and evaluate patients with signs and symptoms such as sore throat and difficulty swallowing because these symptoms could indicate bleeding, edema, or more serious complications such as perforation of the esophagus or trachea. The report also instructs the anesthesiologist to enter a written report in the medical chart and appropriately advise the patient. Dysphonia, which occurred in 17 of 240 patients in the study of Brimacombe et al.
, is not listed as a complication of any of the other methods for managing a difficult airway,2
nor is it listed as a complication of airway management in standard texts of anesthesiology.3,4
Regarding the sign of dysphonia, is this the same form of morbidity that Howarth et al.5
referred to as dysarthria
(1%) in a previous PLMA report? Dysarthria
describes imperfect articulation, whereas dysphonia
is any impairment of voice. Clarification of this point is essential so that PLMA providers and patients will know what to expect postoperatively. Did any of the patients have a perforation, permanent dysphonia, or dysphagia? The reported morbidity associated with the PLMA becomes less acceptable when one considers that patients known or predicted to have a difficult airway, a mouth opening less than 2.5 cm, or a body mass index greater than 35 kg/m2
or those at risk for aspiration were excluded from the study. Normally, a group of patients selected by these criteria would have minimal if any morbidity regardless of the method of airway management, i.e.
, facial mask and airway or even orotracheal intubation. Complications of the frequency and magnitude reported require elucidation and moreover a solution if the technique is to achieve maximum utility in anesthesia practice. There are at least three factors to be considered. Mucosal abrasion as manifested by both visual and occult blood is an obvious factor that could be worsened by pressure ischemia resulting from cuff inflation to 60 cm H2
O. Silent regurgitation of gastric acid either during the procedure or in the perioperative period either alone or in conjunction with mucosal abrasions and impaired tissue perfusion could further complicate the process. Proper laryngeal mask airway selection (size) and placement along with periodic cuff deflation should be considered. Both cimetidine and metoclopramide, useful in patients with gastroesophageal reflux disease, might be effective in removing gastric acid from the triad of potential factors.
The role of the PLMA in managing the emergent airway is problematic. Based on the data of Brimacombe et al., the overall insertion time and large SD (digital, 33 ± 19 s; IT, 37 ± 25 s; gum elastic bougie [GEB], 25 ± 14 s) suggests that although some PLMAs were quickly inserted, others were not (> 60 s), even when performed by an experienced provider in a highly selected patient population. The oropharyngeal leak pressures recorded (digital, 31 ± 8; IT, 30 ± 9; GEB, 31 ± 8) are of greater concern because the majority of emergency airway patients have noncompliant airways related to bronchospasm, laryngospasm, obesity, and obstructive airway disease and thus require high, sometimes sustained, peak airway pressures to achieve adequate ventilation. Therefore, replacing a facemask and airway with a leak pressure of greater than 40 with a PLMA with an oropharyngeal leak pressure of less than 25 could prove fatal. Here again, the authors should provide raw data; specifically how many patients had oropharyngeal leak pressures of less than 20–25? The SD of 8–9 suggests a significant number.
The authors, in referring to the GEB PLMA technique, state, “another potential advantage of the technique is that routine use of the laryngoscope may help maintain intubation skills and provide information about the ease of intubation.” The GEB PLMA technique had other objective advantages over the blind insertion groups (digital and introducer tool). The incidence of visible blood was 2.5% in the GEB group and 4.4% in the combined groups in which blind insertion was used. This difference suggests that laryngoscopy (partial) reduces airway morbidity and is further supported by a lower incidence of morbidity 18–24 h postoperatively; the authors reported a combined (digital, introducer tool) airway morbidity of 33.5%, compared with 28% with the GEB method.
summarizes the authors’ results in 240 selected patients treated with the PLMA1
compared with a group of unselected patients managed by facial mask and airway or orotracheal intubation. The authors caution that their results may not necessarily apply to less experienced personnel, further supporting the choice of facial mask and airway or orotracheal intubation over laryngeal mask airway. Why then would an anesthetist insert a GEB PLMA when a conventional endotracheal tube could be placed in less time, without an assistant? Additional benefits of orotracheal intubation include absolute airway control and relative freedom from morbidity—bleeding, dysphagia, dysphonia, dysarthria, severe sore throat, and nerve injury.1,4,5
Charles E. Reier M.D.
Ohio State University, Columbus, Ohio, and Jay County Hospital, Portland, Indiana. firstname.lastname@example.org
1. Brimacombe J, Keller C, Vosoba D: Gum elastic bougie–guided insertion of the ProSeal™ laryngeal mask airway is superior to the digital and introducer tool techniques. Anesthesiology 2004; 100:25–9
2. American Society of Anesthesiologists Task Force on Management of the Difficult Airway: Practice guidelines for management of the difficult airway: An updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2003; 98:1269–77
3. Pollard BJ, Norton ML. Principles of airway management, Wylie and Churchill-Davidson’s A Practice of Anesthesia, 7th edition. By Healy T, Knight P. London, Arnold, 2003, pp 443–64
4. Barash P, Cullen B, Stoelting R: Airway management, Handbook of Clinical Anesthesia, 4th edition. Philadelphia, Lippincott Williams & Wilkins, 2001, pp 295–308
5. Howarth A, Brimacombe J, Keller C: Gum elastic bougie-guided insertion of the ProSeal laryngeal mask airway: A new technique. Anesth Intensive Care 2002; 30:624–7
© 2004 American Society of Anesthesiologists, Inc.