The Effects of Topical Anesthetic on Swallowing During Nasoendoscopy

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1 The Laryngoscope VC 2013 The American Laryngological, Rhinological and Otological Society, Inc. The Effects of Topical Anesthetic on Swallowing During Nasoendoscopy Scott Lester, BS; Susan E. Langmore, PhD; Catherine R. Lintzenich, MD; S. Carter Wright, MD; Karen Grace-Martin, MA; Tim Fife, MD; Susan G. Butler, PhD Objectives/Hypothesis: To assess the effects of a typical otolaryngologic dose of 1 ml of 4% lidocaine on penetration aspiration scale scores and participant discomfort during flexible endoscopic evaluation of swallowing. Study Design: A prospective pilot study. Methods: Twenty healthy participants consumed 12 swallows consisting of graduated volumes of milk, water, pudding, and cracker in anesthetized and nonanesthetized conditions. Each participant was randomly selected to begin with the anesthetized or nonanesthetized condition. Each participant returned within 7 days to repeat the study in the other condition. Digital recordings of their evaluations were scored via the penetration-aspiration scale in a blinded fashion. Participants recorded their discomfort and tolerance of each flexible endoscopic evaluation of swallowing. Results: The anesthetized condition yielded significantly worse swallowing function (P ¼.001) than the nonanesthetized condition. The nonanesthetized condition yielded greater discomfort and pain during the procedure (P ¼.006,.018), greater pain during insertion and removal of the endoscope (P ¼.002,.003) and less overall tolerance (P ¼.016) than the anesthetized condition. Conclusions: A typical otolaryngologic anesthetic dose of 1 ml of 4% lidocaine during flexible endoscopic evaluation of swallowing predisposed healthy young adults to higher penetration aspiration scale scores (less safe swallowing) than the nonanesthetized condition; however, the anesthetic reduced discomfort and provided better overall tolerance. Future studies need to evaluate the effects of lower doses of lidocaine (0.2 and 0.5 ml) on swallowing function and comfort. Key Words: Swallowing, aspiration, flexible endoscopic evaluation of swallowing, anesthesia, discomfort, nasoendoscopy. Level of Evidence: 4 Laryngoscope, 123: , 2013 From the Department of Otolaryngology (C.R.L., C.W., T.F., S.G.B.), Wake Forest University School of Medicine (S.L.), Winston-Salem, North Carolina; Department of Otolaryngology (S.E.L.), Boston University Medical Center, Boston, Massachusetts; and The Analysis Factor (K.G.-M.), Brooktondale, New York, U.S.A.. Editor s Note: This Manuscript was accepted for publication October 31, This work was supported by an NIDCD grant (R03 DC009875; PI, Butler). The authors have no other funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Susan G. Butler, PhD, Associate Professor, Wake Forest University School of Medicine, Department of Otolaryngology, Medical Center Boulevard, Winston-Salem, NC sbutler@wfubmc.edu DOI: /lary INTRODUCTION Flexible endoscopic evaluation of swallowing (FEES) was first introduced into the literature to assess dysphagia in It has since been shown to be as or more sensitive in detection of aspiration than the modified barium swallow, the original gold standard for assessing dysphagia. 2 5 FEES requires the insertion of a flexible endoscope transnasally to observe the hypopharynx and larynx/upper trachea and to assess swallowing physiology. FEES is typically done without application of topical anesthetic to the nares for concern that the anesthetic may enter into the hypopharynx and negatively alter swallowing function. In contrast, the majority of otolaryngologists prefer to administer a topical anesthetic to the nares to limit patient discomfort during transnasal endoscopies. 6 However if a topical anesthetic could be used during FEES to improve patient comfort without potentially negatively affecting the exam, that would be desirable. To date, the literature on the effects of topical anesthetic during FEES is equivocal. There are two issues as to whether or not topical anesthetic should be applied transnasally prior to FEES. The first is that the topical anesthetic must not alter swallowing function. The second is that the topical anesthetic must improve patient comfort/tolerance to justify the risk of the potential side effects, although rare, associated with topical anesthesia. To the first issue, Johnson et al. administered 0.05% oxymetazoline, 4% cocaine, or saline to the nares to compare their effects on laryngopharyngeal sensation using flexible endoscopic evaluation of swallowing with sensory testing. They applied two sprays to each nare of 1 second duration each. They found no significant difference in laryngopharyngeal sensation between the three agents and concluded if anesthesia is used judiciously, physicians and speech pathologists do not need to worry about the effects of anesthesia on laryngopharyngeal

2 sensory testing. 7 However, the authors only tested sensation via a reflex (the laryngeal adductor reflex) and did not assess the effects of the study anesthetics on swallowing function. Shaker et al. also assessed the effects of a reflex, the pharyngo-upper esophageal sphincter contractile reflex, in the anesthetized and nonanesthetized conditions. They applied 4% aquase Xylocaine (APP Pharmaceuticals, LLC, Schaumburg, IL) to the pharynx and 2% Xylocaine to the nare. They found that the reflex was present in the nonanesthetized condition, but absent in the presence of anesthesia and attributed the loss of reflex due to an anesthetic-induced loss of pharyngeal sensation. 8 Thus, the literature provides two opposing conclusions relative to the effects of topical anesthesia on deglutitive/airway reflexes. Bastian and Riggs compared swallowing function in the anesthetized and nonanesthetized states among 13 healthy adults. They applied six sprays of 10% lidocaine to the oral cavity, and 4% lidocaine directly to the larynx (3 ml). They concluded that normal swallowing can take place in the presence of anesthesia, but 10 of 13 participants in their study demonstrated abnormal swallowing while anesthetized. 9 Of those abnormal swallows in the anesthetized condition, four of their participants demonstrated early spillage of liquid, and five participants demonstrated trace aspiration of liquids. Significant aspiration and penetration occurred one time each in their study. The lack of generalization to clinical practice from this article lies in the large amounts of anesthetic applied to both the oral and hypopharyngeal regions. 7 There has also been some discordance in previous reports as to the efficacy of 4% lidocaine and other anesthetics in limiting pain and discomfort during transnasal endoscopy Given the sparsity of literature in this area and the above dissenting findings, we aimed to determine the effects of a typical otolaryngologic dose of anesthesia (1 ml) on swallowing function in healthy adults. We hypothesized that swallowing in the anesthetized condition would result in worse penetration-aspiration scale (PAS) scores 14 but improved tolerance scores compared to the nonanesthetized condition. MATERIALS AND METHODS Participants Twenty adults volunteered (mean age, years; range, years) to participate in the study. Participants reported no history of swallowing, speech, and voice problems and no known neurologic or otolaryngologic disorders. Participants were recruited by electronic communication. Informed consent was obtained. Each participant served as his or her own control. All participants completed two rounds of FEES, one in the anesthetized condition and one in the nonanesthetized condition. Participants were randomized as to the order of the condition, and instructed after the first FEES session to return within 7 days for the second FEES in the remaining condition. Apparatus A KayPENTAX Swallowing Workstation (KayPENTAX, Inc., Lincoln Park, NJ) with a PENTAX VNL 1070 STK Swallowing Status TABLE I. Penetration-Aspiration Scale 14 Categorized According to Swallowing Status. PAS Score Description No penetration 1 Material does not enter the airway or aspiration Penetration 2 Material enters the airway, remains above the vocal folds, and is ejected from the airway 3 Material enters the airway, remains above the vocal folds, and is not ejected from the airway 4 Material enters the airway, contacts the vocal folds, and is ejected from the airway 5 Material enters the airway, contacts the vocal folds, and is not ejected from the airway Aspiration 6 Material enters the airway, passes below the vocal folds, and is ejected into the larynx or out of the airway 7 Material enters the airway, passes below the vocal folds, and is not ejected from the trachea despite effort 8 Material enters the airway, passes below the vocal folds, and no effort is made to eject PAS ¼ penetration-aspiration scale. naso-pharyngo-laryngoscope and PENTAX EPK-1000 Digital Color Video Processors were utilized for conducting the FEES. Procedure Participants underwent FEES while sitting in the upright position. A 3.1-mm digital flexible endoscope was lubricated with Surgilube (Altana Inc., Melville, NY) and passed transnasally, typically on the floor of the nose, by the first author to obtain a superior view of the hypopharynx. The endoscope was moved throughout the study between the swallow and postswallow positions to collect the data. Two minutes prior to the insertion of the endoscope, 1 ml of lidocaine was applied to one nare of each participant with a controlled-volume syringe atomizer. The endoscope was inserted transnasally and advanced to swallowing position. Swallowing position required that the distal end of the endoscope was just above the top of the epiglottis so that the entire base of tongue, the tip of the epiglottis, posterior pharyngeal wall, lateral pharyngeal walls (e.g., lateral channels), and laryngeal vestibule were visualized prior to bolus administration. The endoscope was maintained in the swallowing position throughout bolus administration and was only advanced to the postswallow position following a bolus presentation. To obtain the postswallow position, the distal end of the scope was advanced lower into the pharynx, past the tip of the epiglottis, and into the upper portion of the laryngeal vestibule where the glottis and trachea could be well visualized. Postswallow position was only held long enough to allow for determination of the PAS score (Table I), 14 and then the scope was pulled back into the swallow position. Four boluses of water and four boluses of 2% milk were administered at volumes of 5, 10, 15, and 20 ml each. Participants were instructed to swallow each volume in one swallow by drinking directly from 30 ml plastic cups. All liquid boluses 1705

3 were taken from the refrigerator simultaneously approximately 5 to 10 minutes prior to administration, and were dyed with green food coloring to improve endoscopic visualization. Approximately 1 ml of green food coloring was added per 150 ml of liquid. Two boluses of vanilla pudding with volumes of 5 and 10 ml each and two boluses of graham cracker of 2 and 4 g each were also administered. The pudding was dyed with green food coloring and given to the participants on a plastic spoon. All liquid and solid boluses were randomly presented to each participant in one data collection session of approximately 5 minutes. Swallows were reviewed in real time, slow motion, and frame by frame to assign the corresponding PAS score in accordance with previously published methods. 6 The rater performed all PAS ratings blinded to condition. However, the reviewer could often distinguish between the two conditions because residual lidocaine was often visible in the nare and occasionally in the hypopharynx. A PAS score of 1 indicates a swallow with no penetration or aspiration (i.e., no material in the airway), scores between 2 and 5 indicate that material entered the laryngeal vestibule (i.e., penetration), and scores of 6 to 8 indicate that material passed below the vocal cords into the trachea (i.e., aspiration). Prior to insertion of the endoscope in both the anesthetized and nonanesthetized conditions, participants were asked to rate their anxiety on a scale of 0 to 10. To appropriately assess the impact of local anesthesia on prescope anxiety, participants were not blinded to their condition. After the endoscope was removed, participants recorded via questionnaire their pain and discomfort at three separate times: during insertion, during the procedure, and during removal of the endoscope. Their responses were 0 to 10 on pain and discomfort scales. Zero represented no discomfort or pain, whereas 10 represented severe discomfort and pain. Participants rated overall tolerance on a 0 to 10 scale, where 0 indicated complete tolerance and 10 indicated poor tolerance. Data Analysis A total of 473 data points were available for statistical analyses. All swallows were originally scored with the eightpoint PAS, but only a very small minority of swallows scored above a 1 (bolus entry into the laryngeal vestibule or below) on the original PAS; therefore, responses were collapsed into no penetration or aspiration (0) and penetration or aspiration (1) categories. A binary logistic regression generalized estimating equations model compared the odds of a swallow demonstrating penetration or aspiration under anesthetized and nonanesthetized conditions, controlling for repeated measures. Differences in pain, discomfort, and tolerance between the conditions were evaluated using Wilcoxon signed rank tests, as all these measures were non-normally distributed. All analyses were performed using IBM SPSS version 19 (IBM SPSS, Armonk, NY), and a level of.05 was set for statistical significance. RESULTS Differences in PAS Between Anesthetized and Nonanesthetized Conditions The number of PAS events by bolus and anesthesia condition is provided in Table II. The mean PAS scores for the anesthetized and nonanesthetized conditions were 1.21 (standard deviation [SD] ¼ 0.70) and 1.05 (SD ¼ 0.28), respectively. PAS scores equal to 1 versus >1 TABLE II. Penetration Aspiration Scale Scores as a Function of Anesthetized and Nonanesthetized Conditions. No. of Events (No. of Participants) Anesthetized Nonanesthetized Thin liquids PAS (20) 154 (20) PAS (11) 5 (5) PAS PAS PAS PAS (1) 0 (0) PAS PAS PAS Mean PAS Puree PAS 1 31 (19) 39 (20) PAS (6) 1 (1) PAS PAS PAS PAS (0) 0 (0) Mean PAS Solid PAS 1 40 (20) 39 (20) PAS (0) 1 (1) PAS PAS PAS PAS (0) 0 (0) Mean PAS The total number of events for thin liquids (water and milk), puree, and solids were 314, 79, and 80, respectively. PAS ¼ penetration-aspiration scale score. differed significantly by anesthetic condition (P ¼.001). PAS scores >1 were significantly more likely to occur in the anesthetized condition (10.7%) as compared to the nonanesthetized condition (3.3%). Of the participants, seven and five had at least one swallow with a PAS score >1 in the anesthetized condition and nonanesthetized condition, respectively. Differences in Pain, Discomfort, and Overall Tolerance as a Function of Anesthetized and Nonanesthetized Conditions Participant pain, discomfort, and overall tolerance as a function of anesthesia are presented in Table III. Participants reported less discomfort and pain and a greater overall tolerance of the procedure in the anesthetized condition. Specifically, participants reported a significant reduction in pain during insertion, the 1706

4 TABLE III. Participant Pain, Discomfort, and Tolerance Ratings as a Function of Anesthetized and Nonanesthetized Conditions. Condition Anesthetized Nonanesthetized Pain during insertion 1 (0 5) 4 (0 7) Pain during procedure 1 (0 2) 3 (0 5) Pain during removal 1 (0 3) 2 (0 5) Discomfort during insertion 0 (0 10) 1 (1 8) Discomfort during procedure 0 (0 6) 1 (0 5) Discomfort during removal 0 (0 7) 1 (0 7) Overall tolerance of the procedure 1 (0 7) 1 (0 7) Responses were on a 1 to 10 scale, with 1 being less pain/discomfort and greater overall tolerance and 10 being more pain/discomfort and less overall tolerance. Median values are listed with range denoted in parentheses. procedure, and removal (P ¼.002,.018,.003, respectively). Participants also reported less discomfort during the procedure (P ¼.006) and greater overall tolerance (P ¼.016) of the procedure in the anesthetized condition. DISCUSSION Swallowing function of healthy adults was evaluated in the anesthetized and nonanesthetized conditions. The administration of anesthesia resulted in a statistically significant increase in the number of swallows with a PAS >1 (10.7%) as compared to nonanesthetized condition (3.3%). Out of 20 participants, seven and five demonstrated at least one swallow with a PAS >1 in the anesthetized and nonanesthetized conditions, respectively. Of those swallows, the most concerning PAS score (i.e., the furthest score from PAS of 1) in the nonanesthetized condition was 3, whereas at least three different participants recorded PAS scores of 4 or greater in the anesthetized condition. This implies that the anesthesia predisposed participants to more penetration and aspiration events, and those events were likely to be more severe (worse on the PAS scale) when compared to the nonanesthetized condition. Swallowing of thin liquids and pureed thick foods was affected, whereas swallowing of solid foods was not. While anesthetized eleven participants demonstrated penetration (PAS 2-5) when swallowing thin liquids compared to five participants in the nonanesthetized condition. The only aspiration event (PAS score above 5) was observed as a participant swallowed 20 ml of water (the largest volume studied) while anesthetized. Six participants demonstrated penetration when swallowing pudding (puree thickness) in the anesthetized condition, whereas only one participant demonstrated penetration in the nonanesthetized condition. Anesthesia did not statistically or clinically alter swallowing of solid foods. Our results on swallowing function are similar to previous findings. Bastian and Riggs used a much larger dose of anesthetic than in the current study and compared swallowing function in the anesthetized and nonanesthetized states among 13 healthy adults. They concluded that normal swallowing can take place in the presence of anesthesia, but 10 of 13 participants in their study demonstrated abnormal swallowing while anesthetized. 9 In the present study, the majority of participants maintained unaffected swallowing function in the anesthetized condition; however, the fact that the anesthetic bore any effect indicates that, at least at a dose of 1 ml, it should be avoided so as to avoid negatively altering swallowing test results. Also, our results specifically identify adverse effects of anesthesia on swallowing function when ingesting thin liquids and pureed foods, but not when swallowing solid foods. The difference may be explained in their varying stimulation of the mechanoreceptors of the oropharyngeal fields. The heavy rougher texture of the solid boluses versus the smooth consistency of the liquid and pureed boluses may have overcome the anesthetic effects of the 1 ml of lidocaine used in this study. Also, the additional mastication required with the solid boluses may have provided longer oral phase sensory input for a more normalized sensorimotor response. A second component of deciding whether to pursue the use of topical anesthetic during FEES is whether or not it improves patient tolerance of the endoscopy. Participants in the anesthetized condition reported a statistically significant decrease in pain and discomfort during the procedure as well as a decrease in pain during insertion and removal of the endoscope. Furthermore, participants reported a statistically significant greater overall tolerance of the procedure when given anesthetic prior to transnasal endoscopy. Several prior studies have attempted to determine and quantify the efficacy of anesthesia on limiting patient discomfort. Singh et al. tested the effects of anesthesia on discomfort by administering 4% cocaine to one nostril, saline to the other, and then performing a transnasal flexible endoscopy (TFL) through each nostril. The patients rated their discomfort for each nostril, which revealed no statistically detectable difference between cocaine and saline. 10 Johnson et al. performed a similar study with 15 participants who received either 4% cocaine, 0.05% oxymetazoline, or saline on three separate occasions prior to TFL. They found that 4% cocaine was more effective at reducing discomfort than saline or 0.05% oxymetazoline. 11 In similar fashion, Sadek et al. compared 5% lidocaine, 10% Xylocaine, and 0.1% Otrivin, a vasoconstrictor, to nothing and found that vasoconstriction led to a significant reduction in discomfort, but anesthetics had no detectable effect. 10 Leder et al. also compared patient comfort during TFL after administering topical anesthesia, a vasoconstrictor, or a placebo. The results were not statistically significant, but revealed a trend toward anesthesia being the most effective agent at reducing discomfort. 12 Swallowing tests are an important aspect in patient care providing insight into individual risk for aspiration pneumonia and malnourishment. It is important that the test be tolerable to patients to ensure compliance with repeated evaluations over time to determine changes in swallowing function. Our findings indicate that administration of anesthesia prior to transnasal endoscopy provides a significant benefit to normal, healthy, 1707

5 young subjects in terms of limiting discomfort and pain and increasing overall tolerance. The varying outcomes on this aspect of the role of anesthesia continue to encourage additional and repeated studies to better determine and quantify the efficacy of anesthesia in reducing patient discomfort and pain, and improving overall tolerance of FEES. Administration of topical anesthesia requires time, comes at a financial cost to the patient, and poses a slight, but serious risk of a hypersensitive reaction. For anesthesia to be utilized in the clinical setting of swallowing tests, the benefits it provides for the patient must be significant to merit its application. Our findings affirm the present consensus that topical anesthesia can alter swallowing and obscure tests of swallowing function particularly when assessing swallowing of thin liquids and pureed foods. Our findings also demonstrate that anesthesia can improve overall patient tolerance of FEES. These findings taken together suggest that it is and will continue to be important for health care providers to carefully evaluate the decision to use topical anesthesia in the setting of swallowing evaluations. It is important to note that our findings are specific to a typical otolaryngologic dose (1 ml) of 4% lidocaine. Future studies will be needed to evaluate the efficacy of a reduced volume of 4% lidocaine (e.g., 0.5 and/or 0.2 ml) and a decongestant only (i.e., no anesthetic) prior to FEES. A smaller volume of lidocaine or a decongestant alone may provide the benefits of limiting pain and discomfort, without affecting swallowing function. A limitation of this study is that participants were not blinded to the anesthetized condition. This was necessary to accurately assess the potential benefits of anesthesia on prescope anxiety. It will be important for future studies to evaluate patients who are blinded to their condition with respect to local anesthesia to determine if the placebo effect is present in this setting, and if so to what extent it characterizes a patient s experience with FEES. However, it is doubtful that a lack of participant blinding affected swallowing physiology. The pharyngeal phase of swallowing is entirely reflexive. Still, future studies that analyze the effects of swallowing physiology only and not the effects of anesthesia on participant prescope anxiety levels may easily control for this by applying a saline versus anesthetic to the nares in blinded fashion. Another limitation of this study was that the infrequency of swallows demonstrating penetration or aspiration in this population of healthy adults rendered subanalysis of the corresponding sensorimotor response versus absence of response not feasible with this sample size. A larger sample size of healthy adults could be examined or the methodology of this study could be reproduced with a population of participants with preexisting dysphagia. It is anticipated that swallows demonstrating penetration or aspiration will occur more frequently in a dysphagic population, and enable statistical subanalysis of sensorimotor manifestations. CONCLUSION We found that a typical otolaryngologic dose of topical anesthesia applied to the nares prior to transnasal endoscopy significantly increased the likelihood of penetration when swallowing thin liquids and pureed foods. We also found that the use of anesthesia prior to FEES limited patient discomfort, pain, and increased overall tolerance of the procedure. These findings indicate the importance of carefully weighing the benefits of tolerance and improving comfort with the risk of obscuring an evaluation of swallowing. BIBLIOGRAPHY 1. Langmore SE, Schatz K, Olsen N. 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