Introdução: A presença de lesões agudas de laringe na criança, causadas pela intubação endotraqueal, pode levar ao desenvolvimento de lesões crônicas, principalmente de estenose subglótica (ESG). Não há consenso na literatura sobre qual a classificação de lesões agudas mais acurada para predizer essa evolução. Além disso, alguns fatores de risco que levam à formação de ESG ainda não foram completamente elucidados nessa população. Objetivos: Comparar a acurácia da Classificação de Lesões Agudas de Laringe (CLAL) com a das outras classificações disponíveis na literatura. Determinar, também, os fatores de risco para ESG na população pediátrica, principalmente a relação da sedação com o desenvolvimento dessa patologia. Delineamento: Estudo de coorte prospectivo. Materiais e Métodos: Todas as crianças intubadas pela primeira vez na Unidade de Terapia Intensiva Pediátrica foram incluídas e dados referentes aos possíveis fatores de risco para ESG foram coletados, incluindo escores da escala de sedação COMFORT-B durante todo o período de intubação. As crianças foram submetidas a fibronasolaringoscopia (FNL) em até oito horas após a extubação. As lesões encontradas foram classificadas de acordo com a CLAL e com outras disponíveis na literatura (Lindholm adaptada, Colice adaptada e Benjamin adaptada). As crianças foram acompanhadas a fim de se determinar quantas evoluiriam para ESG. Resultados: Para a análise das lesões agudas, foram incluídas 194 crianças. A sensibilidade e a especificidade da CLAL foram de 90% e 73%, respectivamente. A CLAL mostrou-se uma classificação com maior especificidade do que as classificações de Colice e Benjamin adaptadas (p<0,001 para ambas), e maior sensibilidade do que a de Lindholm adaptada (p<0,001). Para a análise dos fatores de risco, foram incluídas 226 crianças. A incidência de ESG foi de 10,17%. Os fatores de risco estatisticamente significativos foram tempo prolongado de intubação e doses adicionais de sedação. Do total, 36 crianças tinham escores de sedação coletados. As crianças com ESG apresentavam uma média de escores de COMFORT-B de 16.00 ± 1.76, enquanto a média dos escores de COMFORT-B naquelas que não desenvolveram ESG foi de 12.76 ± 2.13 (p = 0.006). Discussão: De acordo com a CLAL, 90% das crianças que desenvolveram ESG apresentaram inicialmente lesões moderadas ou graves na FNL. A CLAL inclui todos os tipos de lesões descritas por Benjamin, com o adicional de propor uma escala de gravidade para essas lesões, apresentando assim boa acurácia para o desenvolvimento de lesão crônica. Quanto aos fatores de risco, crianças mais agitadas provavelmente apresentam maior movimentação do tubo endotraqueal na via aérea e desenvolvem mais frequentemente ESG do que crianças mais sedadas. Conclusão: A CLAL mostrou-se uma classificação com alta acurácia para predizer evolução para ESG. As crianças que desenvolveram ESG estavam pouco sedadas durante o período em que permaneceram intubadas. / Introduction: The presence of post-intubation acute laryngeal injuries in children can predict the development of chronic lesions, particularly subglottic stenosis (SGS). Until now, no acute injury classification system had been validated. Furthermore, there are some risk factors for the development of SGS that are still not elucidated in children. Objectives: To compare the Classification of Acute Laryngeal Injuries (CALI) with other classifications available in the literature. Moreover, to analyze the risk factors for the development of SGS, especially the role of sedation during intubation. Design: Prospective cohort study. Materials and methods: Children who required intubation in the Pediatric Intensive Care Unit were included e data regarding possible risk factors for SGS were collected, including COMFORT-B sedation scores. Children underwent flexible fiber-optic laryngoscopy (FFL) in the first 8 h after extubation. Injuries were categorized using CALI, as well as adapted classifications from Lindholm, Colice and Benjamin. The children were followed up to determine who developed subglottic stenosis. Results: For the acute lesions analysis, 194 children were included. The sensitivity and specificity of CALI were 90% and 73%, respectively. CALI showed greater specificity than the adapted classifications from Colice and Benjamin (p < 0.001 for both), and greater sensitivity than adapted classification from Lindholm (p < 0.001). For the risk factors analysis, 226 children were included. Incidence of SGS was 10.17%. Statistically significant risk factors were prolonged intubation and requirement of additional sedative doses. The 36 children most recently included in the cohort had COMFORT-B scores. The children with SGS had average COMFORT-B scores of 16.00 ± 1.76, while the mean COMFORT-B score of those who did not develop ESG was 12.76 ± 2.13 (p = 0.006). Discussion: Based on CALI, 90% of children who developed subglottic stenosis had moderate to severe injuries on the initial FFL. CALI includes all injury types described by Benjamin, as well as a proposed severity scale for these lesions, which showed good accuracy for predicting development of chronic injury. Regarding risk factors, undersedated children probably underwent more airway trauma caused by the endotracheal tube and developed more frequently SGS than children oversedated. Conclusion: CALI showed good accuracy for predicting development of SGS. Children who developed SGS were undersedated throughout the intubation period.

Introdução: A presença de lesões agudas de laringe na criança, causadas pela intubação endotraqueal, pode levar ao desenvolvimento de lesões crônicas, principalmente de estenose subglótica (ESG). Não há consenso na literatura sobre qual a classificação de lesões agudas mais acurada para predizer essa evolução. Além disso, alguns fatores de risco que levam à formação de ESG ainda não foram completamente elucidados nessa população. Objetivos: Comparar a acurácia da Classificação de Lesões Agudas de Laringe (CLAL) com a das outras classificações disponíveis na literatura. Determinar, também, os fatores de risco para ESG na população pediátrica, principalmente a relação da sedação com o desenvolvimento dessa patologia. Delineamento: Estudo de coorte prospectivo. Materiais e Métodos: Todas as crianças intubadas pela primeira vez na Unidade de Terapia Intensiva Pediátrica foram incluídas e dados referentes aos possíveis fatores de risco para ESG foram coletados, incluindo escores da escala de sedação COMFORT-B durante todo o período de intubação. As crianças foram submetidas a fibronasolaringoscopia (FNL) em até oito horas após a extubação. As lesões encontradas foram classificadas de acordo com a CLAL e com outras disponíveis na literatura (Lindholm adaptada, Colice adaptada e Benjamin adaptada). As crianças foram acompanhadas a fim de se determinar quantas evoluiriam para ESG. Resultados: Para a análise das lesões agudas, foram incluídas 194 crianças. A sensibilidade e a especificidade da CLAL foram de 90% e 73%, respectivamente. A CLAL mostrou-se uma classificação com maior especificidade do que as classificações de Colice e Benjamin adaptadas (p<0,001 para ambas), e maior sensibilidade do que a de Lindholm adaptada (p<0,001). Para a análise dos fatores de risco, foram incluídas 226 crianças. A incidência de ESG foi de 10,17%. Os fatores de risco estatisticamente significativos foram tempo prolongado de intubação e doses adicionais de sedação. Do total, 36 crianças tinham escores de sedação coletados. As crianças com ESG apresentavam uma média de escores de COMFORT-B de 16.00 ± 1.76, enquanto a média dos escores de COMFORT-B naquelas que não desenvolveram ESG foi de 12.76 ± 2.13 (p = 0.006). Discussão: De acordo com a CLAL, 90% das crianças que desenvolveram ESG apresentaram inicialmente lesões moderadas ou graves na FNL. A CLAL inclui todos os tipos de lesões descritas por Benjamin, com o adicional de propor uma escala de gravidade para essas lesões, apresentando assim boa acurácia para o desenvolvimento de lesão crônica. Quanto aos fatores de risco, crianças mais agitadas provavelmente apresentam maior movimentação do tubo endotraqueal na via aérea e desenvolvem mais frequentemente ESG do que crianças mais sedadas. Conclusão: A CLAL mostrou-se uma classificação com alta acurácia para predizer evolução para ESG. As crianças que desenvolveram ESG estavam pouco sedadas durante o período em que permaneceram intubadas. / Introduction: The presence of post-intubation acute laryngeal injuries in children can predict the development of chronic lesions, particularly subglottic stenosis (SGS). Until now, no acute injury classification system had been validated. Furthermore, there are some risk factors for the development of SGS that are still not elucidated in children. Objectives: To compare the Classification of Acute Laryngeal Injuries (CALI) with other classifications available in the literature. Moreover, to analyze the risk factors for the development of SGS, especially the role of sedation during intubation. Design: Prospective cohort study. Materials and methods: Children who required intubation in the Pediatric Intensive Care Unit were included e data regarding possible risk factors for SGS were collected, including COMFORT-B sedation scores. Children underwent flexible fiber-optic laryngoscopy (FFL) in the first 8 h after extubation. Injuries were categorized using CALI, as well as adapted classifications from Lindholm, Colice and Benjamin. The children were followed up to determine who developed subglottic stenosis. Results: For the acute lesions analysis, 194 children were included. The sensitivity and specificity of CALI were 90% and 73%, respectively. CALI showed greater specificity than the adapted classifications from Colice and Benjamin (p < 0.001 for both), and greater sensitivity than adapted classification from Lindholm (p < 0.001). For the risk factors analysis, 226 children were included. Incidence of SGS was 10.17%. Statistically significant risk factors were prolonged intubation and requirement of additional sedative doses. The 36 children most recently included in the cohort had COMFORT-B scores. The children with SGS had average COMFORT-B scores of 16.00 ± 1.76, while the mean COMFORT-B score of those who did not develop ESG was 12.76 ± 2.13 (p = 0.006). Discussion: Based on CALI, 90% of children who developed subglottic stenosis had moderate to severe injuries on the initial FFL. CALI includes all injury types described by Benjamin, as well as a proposed severity scale for these lesions, which showed good accuracy for predicting development of chronic injury. Regarding risk factors, undersedated children probably underwent more airway trauma caused by the endotracheal tube and developed more frequently SGS than children oversedated. Conclusion: CALI showed good accuracy for predicting development of SGS. Children who developed SGS were undersedated throughout the intubation period.

Introdução. A bronquiolite viral aguda é uma doença de evolução geralmente benigna, mas algumas crianças desenvolvem disfunção respiratória grave a ponto de requererem intubação e ventilação mecânica. Com a necessidade de intubação, surgem as eventuais complicações desta, sendo a estenose subglótica a mais grave. O objetivo desse trabalho é o de avaliar a incidência de estenose subglótica em crianças submetidas a intubação endotraqueal por bronquiolite viral aguda e seus possíveis fatores de risco. Métodos. Foram elegíveis todas as crianças internadas na Unidade de Terapia Intensiva Pediátrica do Hospital de Clínicas de Porto Alegre que necessitaram de intubação endotraqueal por mais de 24 horas. Foram excluídas crianças com história de intubação, patologia laríngea prévia, presença de traqueostomia atual ou no passado e pacientes considerados terminais pela equipe assistente. As crianças foram acompanhadas diariamente e, após a extubação, foram submetidas a fibronasolaringoscopia. Na primeira avaliação foram divididas em dois grupos: Grupo NA - alterações laríngeas leves ou exame normal, Grupo AA - alterações laríngeas moderadas a graves. As crianças do Grupo NA que desenvolveram sintomas durante o acompanhamento pós-internação e todas as do Grupo AA foram submetidas a novo exame em 7-10 dias. Nessa segunda avaliação foram, então, classificadas em Grupo NC - sem alterações crônicas e ESG - com estenose subglótica. Resultados. Foram incluídas 58 crianças entre novembro de 2005 e agosto de 2008. A incidência de estenose subglótica foi de 10,34% (2,51 - 18,18%). Todas as crianças que desenvolveram estenose subglótica apresentaram exame com alterações moderadas a graves logo após a extubação. O número de dias intubado, o número de reintubações, o número de dias em que o tubo foi mobilizado e o número de dias com sedação extra não foram estatisticamente diferentes entre os dois grupos. As crianças que desenvolveram estenose subglótica, porém, necessitaram de mais doses de sedação extra do que aquelas que não desenvolveram. Conclusão. Encontramos uma incidência de estenose subglótica de quase 11%. A necessidade de doses extras de sedação, possivelmente associada ao nível de agitação do paciente durante o período de intubação, parece ser um fato crucial para o desenvolvimento de estenose subglótica. / Introduction. Acute viral bronchiolitis is usually benign, but some children develop severe respiratory failure and require intubation and mechanical ventilation. Intubation may cause complications, of which subglottic stenosis is the most severe. The objective is to evaluate the incidence and risk factors of subglottic stenosis in children who underwent endotracheal intubation because of acute viral bronchiolitis. Methods. Children in the Pediatric Intensive Care Unit (PICU) of Hospital de Clínicas de Porto Alegre were eligible if they had endotracheal intubation for a period longer than 24 hours. Children were excluded if they had a history of intubation, previous laryngeal disease, current or past tracheostomy, or were classified as terminal by the healthcare team. Children were followed up daily and underwent flexible fiber-optic nasolaryngoscopy after extubation. In the first evaluation they were divided into two groups: NA group - mild laryngeal alterations or normal findings; AA group - moderate to severe laryngeal alterations. Children in the NA group developed symptoms during follow-up after PICU discharge, and all children in the AA group underwent another laryngoscopy 7-10 days later. After this second exam, children were classified into two other groups: NC - no chronic changes; and SGS - subglottic stenosis. Results: Fifty-eight children were included in the study from November 2005 to August 2008. The incidence of subglottic stenosis was 10.34% (2,51-18,18%). All children who developed subglottic stenosis had moderate to severe alterations immediately after extubation. The number of intubation days, tube reinsertions, days when tube maintenance was performed, and days with extra sedation were not statistically different between groups. Children that developed subglottic stenosis, however, had needed extra doses of sedation. Conclusion: We found a subglottic stenosis incidence of almost 11%. Extra doses of sedation, probably in association with patient agitation during intubation, seemed to be a crucial factor in the development of subglottic stenosis.

There are many conditions and diseases that affect voice production. One of these, subglottic stenosis (SGS), is characterized by a narrowing of the trachea near the cricotracheal junction. SGS causes dyspnea (labored breathing) and frequently surgery is necessary to eliminate the airway obstruction. SGS is also believed to adversely affect voice quality. While significant research has been conducted to study the effect of SGS on breathing, relatively few studies concerning its effect on voice production have been performed. The purpose of this research was to provide quantitative results concerning the predicted effects of SGS on vocal fold (VF) vibration and resulting sound production, and to provide tools for more extensive research involving synthetic VF models in the future. This was achieved through an experimental procedure in which a device simulating SGS was coupled with synthetic VF models and acoustic, aerodynamic, and vibratory measurements were acquired. Additionally, a device was developed and tested to study the effects of VF posturing using synthetic VF models. The design of the device is anticipated to serve as a useful tool in future experiments.The device simulating SGS was capable of creating an artificial stenosis of adjustable severity. The device was designed so that synthetic VF models inserted into rigid plates could be placed on top of the device, downstream of the stenosis. An experiment was conducted with the SGS device in conjunction with synthetic four-layer VF models in which flow and pressure were measured, radiated sound data were recorded, and visual data from a high-speed camera were captured as the percent obstruction was changed. The effects of subglottic stenosis were quantified using metrics such as onset pressure, glottal area, smoothed cepstral peak prominence (CPPS), harmonic-to-noise ratio (HNR), acoustic spectra, air flow, and pressure below and above the stenosis. The results show that the glottal area was not noticeably affected by the stenosis until 80% or 90% obstruction, and flow resistance through the stenosis was not significantly affected until 85% obstruction. However, changes in acoustics occurred as low as 65% or 70% obstruction.An MRI-compatible posturing device was developed which was capable of causing abduction/adduction and elongation in synthetic VF models. The device was used to adduct synthetic VF models from an abducted position into a pre-determined final phonatory posture as high-speed video and pressure data were collected. The device adducted to final phonatory posture in 500 ms, and phonation was initiated 680 ms later. In addition, the elongation of the synthetic models was varied as high-speed data were collected. The frequency of vibration of the four-layer models was found to not vary significantly when the models were elongated.

Ventilator associated pneumonia (VAP) is a nosocomial infection that is acquired in critically ill patients 48 hours or more after intubation. Many interventions have been studied to reduce or prevent patients from acquiring VAP. This integrated literature review examines empirical evidence related to suctioning techniques that reduce or prevent the acquisition of VAP. Oral and subglottic secretion suctioning were examined in depth. It is concluded that the intervention of oral and subglottic secretion suctioning was shown to reduce the incidence of VAP in adult patients.

The purpose of this thesis is to investigate the reversibility of the adverse effects of combination inhaled corticosteroids (ICs) on vocal fold health as part of a five-year study. This pilot study tested the hypothesis that the adverse effects of ICs may be induced and then reversed, using a benchtop model and rabbit larynges measuring sustained subglottic pressure and airflow. Eighteen rabbits were assigned randomly to 5 subgroups, including baseline, induction experimental, induction control, reversibility experimental, and reversibility control. Baseline rabbits did not receive any treatment. Both experimental groups, induction and reversibility, were administered Advair until visual-perceptual ratings were noted. Their paired control groups were administered nebulized saline in the same dosage levels. Induction groups were immediately sacrificed, while reversibility groups entered a withdrawal phase until visual-perceptual ratings showed a return to baseline. Larynges were dissected and mounted on a benchtop model for phonation trials. Dependent variables included sustained phonatory pressure (cm/H2O) and sustained phonatory airflow (L/min). The results of phonation trials indicate that sustained pressure and flow were higher for both induction and reversibility experimental groups when compared to baseline and control groups. The reversibility experimental group had lower sustained pressure and flow than the induction experimental group. These results indicate a reduction of signs after a period of rest. These findings suggest that voice symptoms may be reversible to a degree after combination IC use. These are important preliminary data that support future studies with larger sample sizes to confirm findings.

The voice plays a vital role in human communication. The purpose of voice research is to advance the understanding of voice production physics, with the ultimate goal of leading to improved voice care. In this research computational and synthetic vocal fold models were used to explore the role of subglottal geometry in vocal fold vibration. Three specific studies were performed. First, the effect of the inferior vocal fold surface angle on voice production was investigated using a two-dimensional self-oscillating finite element vocal fold model. Varying the inferior angle resulted in significant changes to model vibratory motion, glottal width, flow rate, and energy transfer. The changes were attributed primarily to changes in structural, rather than aerodynamic, factors. Second, subglottic stenosis (SGS) was introduced and parametrically varied in a similar computational model to determine the influence of SGS on vocal fold vibration. High severities of SGS influenced several factors related to vibration, including glottal width, flow rate, flow resistance, and vibration frequency. Subglottal pressure distributions and flow patterns were also affected. Third, the response of a self-oscillating silicone vocal fold model to varying degrees of SGS in an experimental setup was studied. Consistent with the computational SGS study, SGS had an effect on the synthetic model response at high severities. Changes were seen particularly in subglottal pressure and radiated acoustic sound, and consequently glottal efficiency, which may have important implications regarding the effect of SGS on the human voice.

Subglottic stenosis (SGS) is an abnormal narrowing of the airway at the level of the cricoid cartilage, above the first tracheal ring and immediately beneath the vocal folds. Individuals with SGS experience a reduction in their ability to breathe as well as adverse effects on voice function. SGS can result from a variety of causes with the type of treatment depending on stenosis severity. Surgical techniques such as laryngotracheal and cricotracheal reconstruction are beneficial for airway maintenance; however, these procedures have resulted in negative effects on voice production. On the other hand, there are patients with SGS who do not require surgery and still experience voice problems. The purpose of this study was to quantify the effects of SGS on vocal fold vibration using an excised larynx benchtop mechanical model. Using a within-subjects repeated measures design, nine porcine larynges underwent experimental conditions including 0% (i.e., normal airway), 50% and 75% stenosed. The primary outcome measure was phonation threshold flow (PTF), which is the rate of flow observed at the onset of phonation. For all larynges, the normal and stenosed conditions were sampled three times each and averaged. Analysis of the results revealed no statistically significant differences in PTF; however, descriptive data showed decreases in PTF and increased variability in PTF values as percent stenosis increased. These findings lay important groundwork for future research in SGS, specifically those that employ ex vivo methodologies. PTF has emerged as a promising means of quantifying voice function in addition to the traditional onset pressure measures. Future studies should examine a broader range of stenosis conditions with a larger sample size to promote generalization to clinical populations including individuals with SGS.

Subglottic stenosis (SGS) is a narrowing of the airway below the vocal folds and above the trachea. This narrowing may be idiopathic or caused by scarring in the airway due to prolonged endotracheal intubation, radiation therapy, trauma, or gastroesophageal reflux disease. People who present with SGS often experience respiratory difficulty both at rest and during exertion. Breathing difficulty increases with stenosis severity. SGS is also associated with voice problems. Research has identified relationships among stenosis severity, voice function and certain types of surgical management; however, many aspects of these relationships are not fully understood due to the complexities of studying human phonation in this population. The purpose of the present study was to examine the effects of SGS on aerodynamic features of voice function using an excised larynx benchtop mechanical model. Specifically, this research involved the comparison of excised porcine vocal fold vibration at baseline and under experimental conditions of 50% and 75% stenosed. The dependent variable was phonation threshold pressure (PTP), the minimum pressure needed to initiate and maintain vocal fold vibration. PTP was analyzed for nine excised porcine larynges, sampled three times each, at baseline and the two stenosis conditions. The results of this study revealed no differences in PTP based on within-subjects comparisons. Because airflow changes with airway narrowing, this finding might indicate that other factors are responsible for the voice problems associated with SGS that were not accounted for in the current mechanical model. Vocal fold tone is not easily simulated in a benchtop setup and might be an important consideration for future studies. The quantification and manipulation of vocal fold adduction, as well as the study of high-speed imaging, could be useful in future work involving excised larynx mechanical models for the study of SGS. The results from this pilot work represent an important step toward optimizing the experimental setup for studying aerodynamic features of SGS.

La collision entre les plis vocaux lors de la phonation, phénomène physiologique essentiel pour la synchronisation de la vibration des plis, est également une composante du phonotraumatisme. Le rôle du phonotraumatisme dans la physiopathologie des dysphonies est communément admis mais sa nature reste mal définie et sa quantification difficile. Ce travail propose d’aborder cette question au moyen d’approches in vivo sur des sujets sains et ex vivo sur des larynx humains excisés. L’objet de ce travail est l’étude du comportement laryngé lorsque le larynx est soumis à des conditions de pression sous-glottique extrêmement élevées. In vivo, l’étude de la voix criée reposait sur la mesure constante de la pression sous-glottique. Ex vivo, cette dernière était manipulée en dehors de toute modification des autres paramètres de contrôle. Le volet ex vivo a nécessité un développement méthodologique (modernisation et adaptation au larynx humain) du banc expérimental utilisé pour des larynx animaux. Les résultats ont montré l’existence chez les locuteurs sains d’un « plafonnement » dans l’intensité vocale et le signal électroglottographique pour les très hauts niveaux de pression sous-glottique. Les études sur larynx humains excisés mesuraient la force de collision entre les plis vocaux sous l’effet de la pression sous-glottique et ont mis en évidence l’existence, ici aussi, d’un « plafonnement » de cette force lorsque la pression sous-glottique est très élevée. Les observations rapportées par ce travail ont un intérêt clinique important même si les phénomènes physiques sous-jacents restent à préciser. / The collision between the vocal folds during phonation is a physiological phenomenon with a powerful role in the synchronization of their vibration. This collision is also a component of the phonotrauma. The role of phonotrauma in the pathophysiology of dysphonia is commonly accepted but its nature still unclear and its quantification remains difficult. This work proposes, an in vivo study in healthy subjects, and an ex vivo one on excised human larynges. The purpose of this work was to study of the laryngeal behavior when the larynx is subjected to extremely high subglottic pressure. In vivo, it is studying the shouted voice with constant measure of subglottal pressure. Ex vivo, the subglottic pressure is directly manipulated. The ex vivo study required a methodological development to modernize the experimental bench used for animal larynges studies and to adapt it to the human larynx. The results showed, in healthy speakers the existence of a "plateau" in the vocal intensity and in the electroglottographic signal for very high levels of subglottic pressure. The excised larynx studies measured the collision force between the vocal folds and its changes depending on other acoustic and electroglottographic parameters. They highlighted the existence, here too, of a "plateau" in the level of the collision force when the subglottic pressure was very high. The observations presented in this work are, to our knowledge, unprecedented. They have important clinical interest for understanding the concept of phonotrauma. Their interpretation in physical terms remains very incomplete.