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Pulmonary aspiration in mechanical ventilation occurs despite appropriate inflation of the tracheal tube cuff. After anaesthesiath is can causep ostoperative and, in critically ill patients, ventilator-associated pneumonia. Cuff over-inflation exerts excessive pressure on the tracheal mucosa causing injury. High volume low pressure (HVLP) cuffs permit wall pressure control as the intracuff pressure (CP) is the tracheal wall pressure (TWP). Unfortunately, at the cuff wall, folds and channels and, therefore, fluid leakage occur. Low volume high pressure (LVHP) cuffs develop neither folds nor associated leakage, but TWP is not easily inferred from CP and excessive pressures can result in tracheal injury. This thesis examines the problem of aspiration in a model, in anaesthetised patients and in the critically ill. In the model, protection against leakage resulted from positive end-expiratory pressure and cuff lubrication. Two tracheal cuff prototypes are introduced. Firstly, the compliant HVLP cuff is one with a tapered shape made of highly compliant material. Within the model this produced a circumferential band at the cuff wall without folds thus effectively eliminating channels and leakage. Secondly, the prototype pressure limited cuff (PLC) is a latex LVHP cuff with inflation characteristics such that TWP can be inferred from CP and maintained at an acceptable level. Within the model the PLC prevented leakage at acceptable TWPs. For clinical use a constant pressure inflation device is required to provide uninterrupted protection, although notably HVLP cuffs allow leakage despite this. The PLC prevented dye aspiration in 100% of tracheally intubated critically ill patients compared with 13% of the control HVLP group (p<0.01). A silicone cuff with similar inflation characteristics, yet improved biocompatability and shelf life, prevented dye aspiration in 100% of patients with tracheostomies compared to 0% of the HVLP control group (p=0.001). HVLP cuff lubrication delayed dye aspiration for 1 to 5 days (p<0.05).

Orientador: Antonio José Maria / Resumo: Justificativa: as lesões da mucosa traqueal em contato com o balonete do tubo traqueal são proporcionais à pressão exercida pelo balonete e ao tempo de exposição. Objetivo: estudar as eventuais lesões da mucosa do segmento traqueal em contato com o balonete do tubo traqueal insuflado com volume de ar suficiente para se obter a pressão de "selo" para impedir vazamento durante ventilação artificial, ou com a pressão "crítica" de 25 cm H2O. Método: dezesseis cães foram submetidos à anestesia venosa com pentobarbital sódico e ventilação com fluxo total de gases frescos de 2 L.min-1. Os cães foram distribuídos aleatoriamente em dois grupos de acordo com a pressão no balonete de grande volume do tubo traqueal (Portex Blue-Line, Inglaterra): G1 (n=8) balonete insuflado até a obtenção da pressão mínima de "selo" necessária para impedir vazamento de ar durante a respiração artificial; G2 (n=8) balonete insuflado até atingir a pressão de 25 cm de H20. A medida da pressão do balonete foi realizada por meio de manômetro digital (Mallinckrodt, EUA) no início do experimento (controle) e após 60, 120 e 180 minutos. Após osacrifício dos cães, foram feitas biópsias nas áreas traqueais adjacente ao tubo traqueal para análise à microscopia óptica (MO) e microscopia eletrônica de varredura (MEV). Resultados: à MO, evidenciaram-se mínimas alterações em ambos os grupos, mais significantemente em G1, em duas áreas da parede anterior da traquéia: uma em contato com o balonete (BB1) e outra abaixo do tubo traqueal (BP1) (p=0,002). À MEV as alterações não foram significantemente diferente nos grupos (p>0,30), mas ocorreram lesões mais intensas nas áreas de contato com o balonete nos dois grupos (p<0,05). Conclusões: no cão, nas condições experimentais empregadas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: The lesions of the tracheal mucosa in contact with the endotracheal tube cuff are proportionally related to the intracuff pressure and to the time of exposition. Objective: the aim of this work was to study the development lesions of tracheal mucosa in contact with the endotracheal tube cuff inflated to reach the "sealing" pressure in order to avoid leaking during the artificial ventilation or with the "peak" inflation pressure of 25 cm H2O. Methods: sixteen dogs were submitted to intravenous anesthesia with pentobarbital sodium and ventilation with total flow of fresh gases of 2 L.min-1. The dogs were randomly distribuited into two experimental groups according to the pressure in the high volume cuff of the endotracheal tube (Portex Blue Line, Inglaterra): G1 (n=8) the cuff was inflated in order to reach the sealing minimum pressure to avoid air leaking during the artificial respiration; G2 (n=8) the cuff was inflated to reach the pressure of 25 cm H2O. The intracuff pressure was measured with a digital manometer (Mallinckrodt, EUA) at the beginning of the experiment (control) and after 60, 120 and 180 minutes. The animals were sacrificied and biopsies were perfomed from the areas of the trachea adjacent the endotracheal tube to be analysed by light microscopy (LM) and scanning electronic microscopy (SEM). Results: The light microscopy showed mild and similar alterations in both groups. However G1 revealed alterations most frequently in two different areas of trachea anterior wall: one lesion in direct contact with the cuff (BB1) and the other lesion just below the tracheal tube (BP1) (p=0.002). The scanning electronic microscopy also showed similar alterations in both groups (P>0.30), with more. Conclusions: In the dog, considering the experimental conditions used... (Complete abstract, click electronic address below) / Doutor

Rhythmic collapse and reinflation of tracheal tubes is a form of active ventilation that augments convective gas exchange in multiple orders of insects. The underlying mechanism driving this phenomenon is not known. Among other things, tracheal tube collapse could be caused by either direct impingement of trachea or by a difference of pressure gradients between the intra-tracheal air and the surrounding hemolymph. To determine the relationship between hemolymph pressure and tracheal tube collapse in the ground beetle (Pterostichus commutabulis), we performed direct measurements of hemolymph pressure inside the beetle's prothorax while simultaneously using synchrotron phase contrast imaging to observe morphological changes in the trachea. We observed that a pressure pulse co-occurred with every tube compression observed throughout the body, suggesting that pulses in hemolymph pressure are responsible for tracheal collapse. To assess the effects of the experimental x-ray conditions imposed on the subjects during imaging, hemolymph pressure was also directly measured in the prothorax of beetles less restricted in non-x-ray trials. To compare the pressure patterns in the two experiments, a novel method of identifying and analyzing pressure pulses was developed and applied to the data sets. The comparison provides the first quantitative characterization of a directly measured hemolymph pressure environment, and demonstrates strong similarities in the pressure patterns recorded in both tests. However, pulses occurring during the x-ray experiments exhibited larger average magnitudes. Further video analysis however shows that collapse of the primary tracheal tubes was observed to occur even in the presence of the smallest simultaneously measured pressure pulse (1.01 kPa), suggesting that collapse of the primary tracheal tubes. / Master of Science

Made available in DSpace on 2014-06-11T19:30:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2002Bitstream added on 2014-06-13T19:19:33Z : No. of bitstreams: 1 castilho_ec_dr_botfm.pdf: 693976 bytes, checksum: bbfa4da3f523001acac2d23b6b1ac73b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Justificativa: as lesões da mucosa traqueal em contato com o balonete do tubo traqueal são proporcionais à pressão exercida pelo balonete e ao tempo de exposição. Objetivo: estudar as eventuais lesões da mucosa do segmento traqueal em contato com o balonete do tubo traqueal insuflado com volume de ar suficiente para se obter a pressão de “selo” para impedir vazamento durante ventilação artificial, ou com a pressão “crítica” de 25 cm H2O. Método: dezesseis cães foram submetidos à anestesia venosa com pentobarbital sódico e ventilação com fluxo total de gases frescos de 2 L.min-1. Os cães foram distribuídos aleatoriamente em dois grupos de acordo com a pressão no balonete de grande volume do tubo traqueal (Portex Blue-Line, Inglaterra): G1 (n=8) balonete insuflado até a obtenção da pressão mínima de “selo” necessária para impedir vazamento de ar durante a respiração artificial; G2 (n=8) balonete insuflado até atingir a pressão de 25 cm de H20. A medida da pressão do balonete foi realizada por meio de manômetro digital (Mallinckrodt, EUA) no início do experimento (controle) e após 60, 120 e 180 minutos. Após osacrifício dos cães, foram feitas biópsias nas áreas traqueais adjacente ao tubo traqueal para análise à microscopia óptica (MO) e microscopia eletrônica de varredura (MEV). Resultados: à MO, evidenciaram-se mínimas alterações em ambos os grupos, mais significantemente em G1, em duas áreas da parede anterior da traquéia: uma em contato com o balonete (BB1) e outra abaixo do tubo traqueal (BP1) (p=0,002). À MEV as alterações não foram significantemente diferente nos grupos (p>0,30), mas ocorreram lesões mais intensas nas áreas de contato com o balonete nos dois grupos (p<0,05). Conclusões: no cão, nas condições experimentais empregadas... / Background: The lesions of the tracheal mucosa in contact with the endotracheal tube cuff are proportionally related to the intracuff pressure and to the time of exposition. Objective: the aim of this work was to study the development lesions of tracheal mucosa in contact with the endotracheal tube cuff inflated to reach the “sealing” pressure in order to avoid leaking during the artificial ventilation or with the “peak” inflation pressure of 25 cm H2O. Methods: sixteen dogs were submitted to intravenous anesthesia with pentobarbital sodium and ventilation with total flow of fresh gases of 2 L.min-1. The dogs were randomly distribuited into two experimental groups according to the pressure in the high volume cuff of the endotracheal tube (Portex Blue Line, Inglaterra): G1 (n=8) the cuff was inflated in order to reach the sealing minimum pressure to avoid air leaking during the artificial respiration; G2 (n=8) the cuff was inflated to reach the pressure of 25 cm H2O. The intracuff pressure was measured with a digital manometer (Mallinckrodt, EUA) at the beginning of the experiment (control) and after 60, 120 and 180 minutes. The animals were sacrificied and biopsies were perfomed from the areas of the trachea adjacent the endotracheal tube to be analysed by light microscopy (LM) and scanning electronic microscopy (SEM). Results: The light microscopy showed mild and similar alterations in both groups. However G1 revealed alterations most frequently in two different areas of trachea anterior wall: one lesion in direct contact with the cuff (BB1) and the other lesion just below the tracheal tube (BP1) (p=0.002). The scanning electronic microscopy also showed similar alterations in both groups (P>0.30), with more. Conclusions: In the dog, considering the experimental conditions used... (Complete abstract, click electronic address below)

A laringoscopia e a intubação traqueal produzem intensa resposta de estresse. Este estudo comparou o efeito da administração intratecal de 10 µg, 1,0 µg/Kg e 2,0 µg/Kg na resposta de estresse induzida pela intubação. Os pacientes foram casualizados em três grupos distintos, de acordo com a quantidade de sufentanil administrada pela via intratecal. Após administração de 0,05 mg/Kg de midazolam pela via venosa, todos os pacientes receberam sufentanilintratecal na quantidade determinada por um sorteio prévio. Aguardou-se o tempo de 10 minutos, nos quais os pacientes foram mantidos sob observação e, em seguida, a anestesia geral foi induzida com propofol (2,5 mg/Kg) e vecurônio (0,1 mg/Kg). Após ventilação sob máscara durante quatro minutos, os pacientes foram intubados mediante uma única tentativa, com laringoscopia de no máximo 20 segundos. A observação dos pacientes ocorreu em dois períodos distintos: um que contemplou o período compreendido entre a administração do sufentanil pela via subaracnóidea até imediatamente antes da indução anestésica e outro que compreendeu o período após a indução anestésica até seis minutos após a intubação orotraqueal. No primeiro período, avaliou-se o impacto do sufentanil subaracnóideo no comportamento hemodinâmico, no grau de sedação e no grau de ventilação. No segundoperíodo foi avaliado o comportamento hemodinâmico dos pacientes após a indução anestésica e a intubação traqueal. A glicemia foi quantificada nos dois períodos e serviu como parâmetro da resposta de estresse. Os pacientes foram avaliados em 15 momentos distintos (M1 - antes da punção venosa, M2 - um minuto após a administração do midazolam, M3 - imediatamente após a punção subaracnóidea, M4 - 2 minutos após a administração do sufentanil, M5 - 4 minutos após o sufentanil, M6 - 6 minutos após, M7 - 8 minutos após, M8 - 10 minutos após, M9 - 2 minutos após a indução anestésica, M10 - 4 minutos após, M11 - 30 segundos após a intubação, M12 - 1 minuto após, M13 - 2 minutos após, M14 - 4 minutos após e M15 - 6 minutos após). No primeiro período de observação, o comportamento hemodinâmico entre os três grupos foi semelhante. Houve diminuição da pressão arterial diastólica, pressão arterial média e da frequência cardíaca após administração do sufentanil, mas a pressão arterial sistólica manteve-se inalterada, exceto no grupo que recebeu 2,0 µg/Kg. Este grupo apresentou maior porcentagem de pacientes com depressão do grau de consciência e ventilação. Após intubação traqueal, o comportamento da frequência cardíaca foi semelhante nos três grupos e não houve aumento da pressão arterial sistólica, diastólica ou média no grupo que recebeu 2,0 µg/Kg. Somente este grupo teve diferença significativa da glicemia entre M1 e M15. Dentre as doses testadas, somente a de 2,0 µg/Kg atenua a resposta de estresse após intubação orotraqueal. / Laryngoscopy and orotracheal intubation produce intense stress response. This study compared the effect of intrathecal administration of 10 µg, 1,0 µg/Kg and 2,0 µg/Kg on stress response induced by intubation. Patients were assigned into three groups, according to the amount of sufentanil administered intrathecally. After administration of 0,05 mg/Kg intravenous midazolam, all patients received the previous selected dose of intrathecal sufentanil. Patients were kept under observation for the next ten minutes, and then general anesthesia was induced with propofol (2,5 mg/Kg) and vecuronium (0,1 mg/Kg). After being ventilated under facial mask for four minutes, patients were intubated on a first attempt basis, with laryngoscopy duration of 20 seconds maximum. Observation period was divided into twodistinct phases: the first one comprised the interval between intrathecal injection of sufentanil and general anesthesia induction, and the second one unrolled from anesthesia induction until six minutes after orotracheal intubation. Throughoutthe first phase, intrathecal sufentanil impact on haemodynamics, sedation and respiration was analized. During the second phase, the haemodynamic behavior after general anesthesia induction and orotracheal intubation was assessed. Glucose levels were measured on both phases and worked as a stress response parameter. Patients were evaluated at 15 predetermined moments (M1 - before venous cannulation, M2 - one minute after administration of midazolam, M3 - immediately after intrathecal injection of sufentanil, M4 - 2 minutes after intrathecal injection of sufentanil, M5 - 4 minutes after intrathecal injection of sufentanil , M6 - 6 minutes after intrathecal injection of sufentanil, M7 - 8 minutes after intrathecal injection of sufentanil, M8 - 10 minutes after intrathecal injection of sufentanil, M9 - 2 minutes after anesthesia induction, M10 - 4 minutes after anesthesia induction, M11 - 30 seconds after intubation, M12 - 1 minute after intubation, M13 - 2 minutes after intubation, M14 - 4 minutes after intubation e M15 - 6 minutes after intubation). At the first period of observation, haemodynamic profile between all three groups was similar. Diastolic arterial pressure levels, mean arterial pressure levels and heart rate decreased after intrathecal administration of sufentanil and sistolic arterial pressure levels remained the same, except in the 2,0 µg/Kg group. This group had the highest incidence of patients undergoing sedation and respiratory depression. After orotracheal intubation, heart rate was similar in all three groups, and there was no increase of SAP, DAP and MAP levels in the 2,0 µg/Kg group. Glucose levels presented significant differences between M1 and M15 only in the 2,0 µg/Kg group. Among all tested doses, the 2,0 µg/Kg dose was the only to attenuate stress response to tracheal intubation.

A laringoscopia e a intubação traqueal produzem intensa resposta de estresse. Este estudo comparou o efeito da administração intratecal de 10 µg, 1,0 µg/Kg e 2,0 µg/Kg na resposta de estresse induzida pela intubação. Os pacientes foram casualizados em três grupos distintos, de acordo com a quantidade de sufentanil administrada pela via intratecal. Após administração de 0,05 mg/Kg de midazolam pela via venosa, todos os pacientes receberam sufentanilintratecal na quantidade determinada por um sorteio prévio. Aguardou-se o tempo de 10 minutos, nos quais os pacientes foram mantidos sob observação e, em seguida, a anestesia geral foi induzida com propofol (2,5 mg/Kg) e vecurônio (0,1 mg/Kg). Após ventilação sob máscara durante quatro minutos, os pacientes foram intubados mediante uma única tentativa, com laringoscopia de no máximo 20 segundos. A observação dos pacientes ocorreu em dois períodos distintos: um que contemplou o período compreendido entre a administração do sufentanil pela via subaracnóidea até imediatamente antes da indução anestésica e outro que compreendeu o período após a indução anestésica até seis minutos após a intubação orotraqueal. No primeiro período, avaliou-se o impacto do sufentanil subaracnóideo no comportamento hemodinâmico, no grau de sedação e no grau de ventilação. No segundoperíodo foi avaliado o comportamento hemodinâmico dos pacientes após a indução anestésica e a intubação traqueal. A glicemia foi quantificada nos dois períodos e serviu como parâmetro da resposta de estresse. Os pacientes foram avaliados em 15 momentos distintos (M1 - antes da punção venosa, M2 - um minuto após a administração do midazolam, M3 - imediatamente após a punção subaracnóidea, M4 - 2 minutos após a administração do sufentanil, M5 - 4 minutos após o sufentanil, M6 - 6 minutos após, M7 - 8 minutos após, M8 - 10 minutos após, M9 - 2 minutos após a indução anestésica, M10 - 4 minutos após, M11 - 30 segundos após a intubação, M12 - 1 minuto após, M13 - 2 minutos após, M14 - 4 minutos após e M15 - 6 minutos após). No primeiro período de observação, o comportamento hemodinâmico entre os três grupos foi semelhante. Houve diminuição da pressão arterial diastólica, pressão arterial média e da frequência cardíaca após administração do sufentanil, mas a pressão arterial sistólica manteve-se inalterada, exceto no grupo que recebeu 2,0 µg/Kg. Este grupo apresentou maior porcentagem de pacientes com depressão do grau de consciência e ventilação. Após intubação traqueal, o comportamento da frequência cardíaca foi semelhante nos três grupos e não houve aumento da pressão arterial sistólica, diastólica ou média no grupo que recebeu 2,0 µg/Kg. Somente este grupo teve diferença significativa da glicemia entre M1 e M15. Dentre as doses testadas, somente a de 2,0 µg/Kg atenua a resposta de estresse após intubação orotraqueal. / Laryngoscopy and orotracheal intubation produce intense stress response. This study compared the effect of intrathecal administration of 10 µg, 1,0 µg/Kg and 2,0 µg/Kg on stress response induced by intubation. Patients were assigned into three groups, according to the amount of sufentanil administered intrathecally. After administration of 0,05 mg/Kg intravenous midazolam, all patients received the previous selected dose of intrathecal sufentanil. Patients were kept under observation for the next ten minutes, and then general anesthesia was induced with propofol (2,5 mg/Kg) and vecuronium (0,1 mg/Kg). After being ventilated under facial mask for four minutes, patients were intubated on a first attempt basis, with laryngoscopy duration of 20 seconds maximum. Observation period was divided into twodistinct phases: the first one comprised the interval between intrathecal injection of sufentanil and general anesthesia induction, and the second one unrolled from anesthesia induction until six minutes after orotracheal intubation. Throughoutthe first phase, intrathecal sufentanil impact on haemodynamics, sedation and respiration was analized. During the second phase, the haemodynamic behavior after general anesthesia induction and orotracheal intubation was assessed. Glucose levels were measured on both phases and worked as a stress response parameter. Patients were evaluated at 15 predetermined moments (M1 - before venous cannulation, M2 - one minute after administration of midazolam, M3 - immediately after intrathecal injection of sufentanil, M4 - 2 minutes after intrathecal injection of sufentanil, M5 - 4 minutes after intrathecal injection of sufentanil , M6 - 6 minutes after intrathecal injection of sufentanil, M7 - 8 minutes after intrathecal injection of sufentanil, M8 - 10 minutes after intrathecal injection of sufentanil, M9 - 2 minutes after anesthesia induction, M10 - 4 minutes after anesthesia induction, M11 - 30 seconds after intubation, M12 - 1 minute after intubation, M13 - 2 minutes after intubation, M14 - 4 minutes after intubation e M15 - 6 minutes after intubation). At the first period of observation, haemodynamic profile between all three groups was similar. Diastolic arterial pressure levels, mean arterial pressure levels and heart rate decreased after intrathecal administration of sufentanil and sistolic arterial pressure levels remained the same, except in the 2,0 µg/Kg group. This group had the highest incidence of patients undergoing sedation and respiratory depression. After orotracheal intubation, heart rate was similar in all three groups, and there was no increase of SAP, DAP and MAP levels in the 2,0 µg/Kg group. Glucose levels presented significant differences between M1 and M15 only in the 2,0 µg/Kg group. Among all tested doses, the 2,0 µg/Kg dose was the only to attenuate stress response to tracheal intubation.

In surgery for airway obstruction, the anesthetist and the ear-nose-throat surgeon share the approach to the airway and jet ventilation (JV) is a mutually convenient ventilation technique for both parties. As a consequence of the open system jet ventilation is applied in, bedside measurements of lung volumes are cumbersome to perform and thus, there is a lack of studies comparing different modes of JV or investigating the influence of ventilator settings on lung volumes and gas exchange. In this thesis, single frequency jet ventilation and superimposed high frequency jet ventilation (SHFJV) at different frequencies are systematically compared with respect to lung volume changes, underlying airway pressure variations and the resulting gas exchange. We compared three single-frequency JV modalities with SHFJV in patients. Moreover, we performed a systematic investigation of single frequency JV and SHFJV in a porcine model. Single frequency JV and SHFJV were compared frequency-wise in intact airways and in a newly developed model of tracheal obstruction. This model was also used to assess the influence of variable airway diameter on ventilation effectiveness during SHFJV. We measured chest wall volume variations with opto-electronic plethysmography and obtained airway pressures as well as gas exchange parameters. In unobstructed airways, both single-frequency JV and SHFJV provided adequate oxygenation, despite differences in lung volumes. Carbon dioxide removal was most effective using single frequency JV at a frequency of 150 min-1. During SHFJV, for both intact and obstructed airways, the choice of frequency for the high frequency component had little influence on lung volumes, airway pressures and gas exchange. With decreasing airway diameter and SHFJV, we observed air trapping and lower tidal volumes and acceptable oxygenation. Carbon dioxide removal, however, was insufficient at the narrowest airway diameter. In single frequency JV, very high frequencies resulted in negligible tidal volume and inacceptable gas exchange. Airway obstruction potentiated this frequency dependence. In conclusion, in intact airways, single frequency JV at sufficiently low frequencies provided adequate oxygenation and better CO2 removal than SHFJV. With decreasing airway diameter, SHFJV provided better oxygenation and CO2 removal and may therefore be the mode of choice in more complicated cases.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21343号 / 医博第4401号 / 新制||医||1031(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 平井 豊博, 教授 松田 秀一, 教授 別所 和久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM