Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.

Cricoid pressure is a widely accepted, yet highly questionable maneuver employed by airway management specialists. The function of cricoid pressure is to help prevent gastric regurgitation and pulmonary aspiration when intubating high-risk patients. Although initially well-received by the medical community, the status of cricoid pressure as a standard of care has been challenged by arguments that this procedure is ineffective, unsafe, and generally unfit for clinical practice. Moreover, the lack of a standardized protocol has contributed to significant discrepancies in the way cricoid pressure is applied. A literature analysis reveals insufficient data to determine whether or not cricoid pressure decreases the risk of regurgitation. However, the maneuver can still be deemed effective because of its anatomical basis. Advanced imaging studies affirm the ability of cricoid pressure to occlude the lumen of the postcricoid hypopharynx, physically impeding passage of gastric or esophageal content through the point of compression. An evaluation of cricoid pressure protocol is done in an effort to establish a standardized set of guidelines. Although a general consensus has been reached regarding certain aspects of the maneuver, such as force and timing, further research is required to thoroughly understand its additional intricacies. In the meantime, a cautious approach to applying cricoid pressure is strongly advised.

No description available.

The esophageal sphincters constitute the anatomical protection against pulmonary aspiration. The aim of this thesis was to study the esophageal sphincters and how they are affected by different components of emergency anesthesia using high-resolution solid-state manometry. The effect of propofol (0.3 mg/kg) was studied in young and elderly volunteers. Propofol can be given as an anxiolytic agent for manometric studies of the lower esophageal sphincter (LES) without affecting the results. However, propofol is not recommended for studies of the upper esophageal sphincter (UES). The effects of cricoid pressure (CP) and peripheral pain were studied in awake volunteers, with and without remifentanil infusion (5 ng/ml). Pain did not affect pressure in the LES, but CP or remifentanil induced a significant decrease in LES pressure. However, neither CP nor remifentanil affected the barrier pressure (LES-intra gastric pressure). When CP was applied during ongoing remifentanil infusion, no further decrease in LES pressure was measured. CP induced high pressures in the area of the UES independent of remifentanil infusion, indicating that CP is effective in preventing gastroesophageal regurgitation. Barrier pressure was also studied in anesthetized patients after rocuronium (0.6 mg/kg) administration and no decrease was measured. In addition, alfentanil (20 μ/kg) added during anesthesia induction with propofol did not decrease the barrier pressure. In conclusion, CP seems to be effective in preventing regurgitation and does not affect barrier pressure. Muscle relaxation with rocuronium does not risk gastro-esophageal integrity. In addition, opioids can be integrated, even during emergency anethesia, without increasing the risk for pulmonary aspiration.

A aproximação cricotireóidea simula a contração do músculo cricotireóideo, aproximando as cartilagens cricóidea e tireóidea anteriormente. Distende e tensiona as pregas vocais, elevando a freqüência fundamental da voz. É indicada em pacientes que apresentam voz grave em conseqüência da paralisia do nervo laríngeo superior ou por doenças endócrinas e reumatológicas no sexo feminino. Com o objetivo de estudar os efeitos da aproximação cricotireóidea sobre a vibração das pregas vocais em ambos sexos, foram avaliadas 30 laringes excisadas de cadáveres humanos frescos pré e pós aproximação cricotireóidea. Esse trabalho experimental permitiu excluir as interferências dos mecanismos compensatórios da fonação presentes em um estudo 'in vivo'. As cartilagens aritenóideas foram aproximadas por sutura, fechando a glote. Um fluxo de ar comprimido umedecido foi injetado no interior da traquéia, e ao passar pela glote promoveu a vibração das pregas vocais. Foi então realizada a aproximação cricotireóidea através de suturas, aproximando as cartilagens tireóidea e cricóidea. O comprimento da porção membranosa das pregas vocais foi obtido através de um paquímetro. A vibração das pregas vocais foi gravada pré e pós a aproximação cricotireóidea utilizando-se uma câmera de videoquimografia. Após digitalização e análise quadro a quadro das imagens documentadas, foram realizadas medidas da freqüência fundamental, da amplitude de vibração das pregas vocais, do ciclo vibratório e suas fases (aberta, fechada, de abertura e fechamento) pré e pós aproximação cricotireóidea. Foram também calculados e analisados índices que correlacionam a duração das diferentes fases do ciclo vibratório, como o quociente de abertura, de fechamento e o quociente de velocidade. Estas variáveis foram analisadas estatisticamente pela técnica multivariada de análise de perfil e correlacionadas entre si. Observamos que houve alongamento significante das pregas vocais após a aproximação cricotireóidea, sendo mais evidente no sexo feminino. Ocorreu elevação significante da freqüência fundamental, mas esta não se correlacionou com o alongamento das pregas vocais. A amplitude de vibração diminuiu de forma significante, assim como a duração do ciclo vibratório e suas fases, correlacionando-se diretamente com o aumento da freqüência fundamental. A redução da fase de abertura foi significantemente maior no sexo masculino. Concluindo, a aproximação cricotireóidea provocou alongamento da prega vocal, redução da amplitude e duração do ciclo vibratório e suas fases, existindo correlação inversa com o aumento da freqüência de vibração. Embora as pregas vocais de laringes femininas tenham apresentado maior alongamento, e as masculinas maior redução da fase de abertura, não houve diferença significante do efeito da aproximação cricotireóidea sobre a freqüência vocal entre os sexos. / The cricothyroid approximation simulates the cricothyroid muscle contraction by approximating the cricoid and thyroid cartilage’s. By this surgery, the vocal folds are lengthened. Consequently, the fundamental frequency of the voice is increased. The main indications for this procedure are patients presenting voice hoarseness due to superior laryngeal nerve palsy or to rheumatoid and endocrinological diseases in women. Thirty fresh cadaver’s larynges were used for the purpose of studying the effects of the cricothyroid approximation on the vocal folds vibration in both genders. Ideally, this experiment would allow exclusion of the diverse phonation compensatory factors that can possible compromise the accuracy of an “in vivo" study. The surgical procedure was performed in the excised larynges. Initially, the arytenoids cartilages were approximated by suturing both together, closing the glottis. Humidified compressed air was injected inside of the tracheal tube, causing vocal folds vibration. The cricothyroid approximation was performed by sutures placed in the cricoid and thyroid cartilages. Calipers were used to measure the length of the membranous portion of the vocal folds. Pre and post cricothyroid approximation. Vocal folds vibration was recorded by a portable camera specific for videokymographic studies. After digitalizing the recorded images, each one of them was carefully evaluated. The fundamental voice frequency, the vocal folds vibratory amplitude, and the vibratory cycle with its phases (opened, closed, opening and closing phases) were measured pre and post operatively. Indexes related to the duration of the different phases of the vibratory cycle, such as open quotient, closed quotient and speed quotient were then calculated and analyzed. Multivariate statistical analysis and profile analysis were used for correlation and understanding of the results. There was a statistically significant lengthen of the vocal folds after cricothyroid approximation, more noticeable in female laryngeal specimens. The fundamental voice frequency was increased, but no relation with the increased length of the vocal cords could be observed. The vibratory amplitude was significantly reduced, as was the vibratory cycle duration. The latter was directly correlated with the increase of fundamental voice frequency. The male laryngeal specimens presented a significant higher reduction of the opening phase of the vibratory cycle. In this study, the cricothyroid approximation caused lengthening of the vocal folds. The vibratory cycle and its phases were also altered, presenting a reduced duration. An inverse correlation between these variables and the increase of the vibratory frequency was noted. Although the female laryngeal specimens had shown a longer length when compared with the male, and the male specimens had a higher decrease of the opening phase of the vibratory cycle, there was no statistically significant difference in the cricothyroid approximation effect on the vocal frequency according to gender.

A aproximação cricotireóidea simula a contração do músculo cricotireóideo, aproximando as cartilagens cricóidea e tireóidea anteriormente. Distende e tensiona as pregas vocais, elevando a freqüência fundamental da voz. É indicada em pacientes que apresentam voz grave em conseqüência da paralisia do nervo laríngeo superior ou por doenças endócrinas e reumatológicas no sexo feminino. Com o objetivo de estudar os efeitos da aproximação cricotireóidea sobre a vibração das pregas vocais em ambos sexos, foram avaliadas 30 laringes excisadas de cadáveres humanos frescos pré e pós aproximação cricotireóidea. Esse trabalho experimental permitiu excluir as interferências dos mecanismos compensatórios da fonação presentes em um estudo 'in vivo'. As cartilagens aritenóideas foram aproximadas por sutura, fechando a glote. Um fluxo de ar comprimido umedecido foi injetado no interior da traquéia, e ao passar pela glote promoveu a vibração das pregas vocais. Foi então realizada a aproximação cricotireóidea através de suturas, aproximando as cartilagens tireóidea e cricóidea. O comprimento da porção membranosa das pregas vocais foi obtido através de um paquímetro. A vibração das pregas vocais foi gravada pré e pós a aproximação cricotireóidea utilizando-se uma câmera de videoquimografia. Após digitalização e análise quadro a quadro das imagens documentadas, foram realizadas medidas da freqüência fundamental, da amplitude de vibração das pregas vocais, do ciclo vibratório e suas fases (aberta, fechada, de abertura e fechamento) pré e pós aproximação cricotireóidea. Foram também calculados e analisados índices que correlacionam a duração das diferentes fases do ciclo vibratório, como o quociente de abertura, de fechamento e o quociente de velocidade. Estas variáveis foram analisadas estatisticamente pela técnica multivariada de análise de perfil e correlacionadas entre si. Observamos que houve alongamento significante das pregas vocais após a aproximação cricotireóidea, sendo mais evidente no sexo feminino. Ocorreu elevação significante da freqüência fundamental, mas esta não se correlacionou com o alongamento das pregas vocais. A amplitude de vibração diminuiu de forma significante, assim como a duração do ciclo vibratório e suas fases, correlacionando-se diretamente com o aumento da freqüência fundamental. A redução da fase de abertura foi significantemente maior no sexo masculino. Concluindo, a aproximação cricotireóidea provocou alongamento da prega vocal, redução da amplitude e duração do ciclo vibratório e suas fases, existindo correlação inversa com o aumento da freqüência de vibração. Embora as pregas vocais de laringes femininas tenham apresentado maior alongamento, e as masculinas maior redução da fase de abertura, não houve diferença significante do efeito da aproximação cricotireóidea sobre a freqüência vocal entre os sexos. / The cricothyroid approximation simulates the cricothyroid muscle contraction by approximating the cricoid and thyroid cartilage’s. By this surgery, the vocal folds are lengthened. Consequently, the fundamental frequency of the voice is increased. The main indications for this procedure are patients presenting voice hoarseness due to superior laryngeal nerve palsy or to rheumatoid and endocrinological diseases in women. Thirty fresh cadaver’s larynges were used for the purpose of studying the effects of the cricothyroid approximation on the vocal folds vibration in both genders. Ideally, this experiment would allow exclusion of the diverse phonation compensatory factors that can possible compromise the accuracy of an “in vivo” study. The surgical procedure was performed in the excised larynges. Initially, the arytenoids cartilages were approximated by suturing both together, closing the glottis. Humidified compressed air was injected inside of the tracheal tube, causing vocal folds vibration. The cricothyroid approximation was performed by sutures placed in the cricoid and thyroid cartilages. Calipers were used to measure the length of the membranous portion of the vocal folds. Pre and post cricothyroid approximation. Vocal folds vibration was recorded by a portable camera specific for videokymographic studies. After digitalizing the recorded images, each one of them was carefully evaluated. The fundamental voice frequency, the vocal folds vibratory amplitude, and the vibratory cycle with its phases (opened, closed, opening and closing phases) were measured pre and post operatively. Indexes related to the duration of the different phases of the vibratory cycle, such as open quotient, closed quotient and speed quotient were then calculated and analyzed. Multivariate statistical analysis and profile analysis were used for correlation and understanding of the results. There was a statistically significant lengthen of the vocal folds after cricothyroid approximation, more noticeable in female laryngeal specimens. The fundamental voice frequency was increased, but no relation with the increased length of the vocal cords could be observed. The vibratory amplitude was significantly reduced, as was the vibratory cycle duration. The latter was directly correlated with the increase of fundamental voice frequency. The male laryngeal specimens presented a significant higher reduction of the opening phase of the vibratory cycle. In this study, the cricothyroid approximation caused lengthening of the vocal folds. The vibratory cycle and its phases were also altered, presenting a reduced duration. An inverse correlation between these variables and the increase of the vibratory frequency was noted. Although the female laryngeal specimens had shown a longer length when compared with the male, and the male specimens had a higher decrease of the opening phase of the vibratory cycle, there was no statistically significant difference in the cricothyroid approximation effect on the vocal frequency according to gender.