Base teórica: Muitos pacientes internados em Unidade de Terapia Intensiva (UTI) necessitam da instituição da ventilação mecânica invasiva (VM). Porém esta pode trazer efeitos deletérios como: alteração na higiene brônquica e pneumonia associada à ventilação mecânica (PAV). Devido a isso, faz-se necessária avaliação de técnicas de higiene brônquicas eficazes e o menos deletérias possíveis. Objetivos: Comparar a eficácia das técnicas em estudo: vibrocompressão (VB) (G1), hiperinsuflação com o ventilador mecânico (HMV) (G2) VB + HMV (G3) na quantidade de secreção aspirada (SEC), no tempo de VM, na incidência de PAV, na reintubação orotraqueal (Re-IoT) e na mortalidade de pacientes em VM. Método: Ensaio clínico randomizado, realizado no Centro de Terapia Intensiva do Hospital de Clínicas de Porto Alegre (HCPA). Foram incluídos no estudo 93 pacientes (29 G1, 32 G2 e 32 G3) em VM por mais de 24 horas. Foram aplicadas as seguintes técnicas: aspiração isolada (ASP), VB, HMV e VB + HMV. Foram medidas as seguintes variáveis: frequência cardíaca (FC), frequência respiratória (FR), pressão arterial média (PAM), saturação arterial periférica de oxigênio (SpO2), pressão inspiratória de pico (PIP), volume corrente (VC), complacência dinâmica (Cdyn), peso da SEC; tempo de VM, Re-IoT, incidência de PAV e mortalidade na VM. Conclusão: O grupo 3 foi o único que apresentou aumento significativo da SEC, quando comparado à ASP (0,7 g (0,1-2,5) vs 0,2 g (0,0-0,6) – p = 0,006). Em comparação com os demais grupos, o grupo 2 apresentou aumento significativo na incidência de PAV (22% - p = 0,003) e Re-IoT (21,9% - p = 0,048), demonstrando assim, na amostra estudada, que VB + HMV é mais eficaz quanto à quantidade de SEC e exerce efeito protetor, juntamente com a VB, na incidência de PAV e Re-IoT. / Background: Many patients admitted to the Intensive Care Unit (ICU) require the institution of invasive Mechanical Ventilation (MV). However, this can bring harmful effects such as changes in mucociliary transport and cough capacity, leading to bronchial obstruction and Ventilator Associated-Pneumonia (VAP). Objective: To compare the efficacy of the techniques: Vibrocompression (G1), Hyperinflation with Mechanical Ventilation (G2) Vibrocompression + Hyperinflation with Mechanical Ventilation (G3) in the amount of Aspirated Secretions (AS), MV time, the incidence of VAP, Re-intubation tracheal (Re-IoT) and mortality of patients on MV. Method: Randomized clinical trial, conducted at the Intensive Care Unit, of the Hospital de Clinicas de Porto Alegre (HCPA). 93 patients were included in the study (29 G1, 32 G2 and 32 G3) in mechanical ventilation for more than 24 hours. The following techniques were applied: Isolated Aspiration (ASP), Vibrocompression (VB), Hyperinflation with Mechanical Ventilation (HMV) Vibrocompression + Hyperinflation with Mechanical Ventilation (HMV + VB). The following variables were measured: Heart Rate (HR), Respiratory Rate (RR), Mean Arterial Pressure (MAP), Peripheral Arterial Oxygen Saturation (SpO2); Peak Inspiratory Pressure (PIP), Tidal Volume (TV); Dynamic Compliance (Cdyn); weight of the AS; VM time; Re-IoT; VAP incidence and mortality in the VM. Conclusion: The HMV + VB (G3) was the only group that showed significant increase in the AS (0.7 g (0.1-2.5) vs 0.2 g (0.0-0.6) – p = 0.006) when compared to ASP. Compared with the other groups G2 showed a significant increase in the incidence of VAP (22% - p = 0.003) and Re-IoT (21.9% - p = 0.048). Thus demonstrating in the sample, which HMV + VB is more effective as the amount of secretion aspirated and has a protective effect, along with the VB, the incidence of VAP and Re-IoT.

A hiperinsuflação dinâmica (HD) é considerada um importante contribuinte para a sensação de dispnéia e interrupção do esforço físico em pacientes portadores de doença pulmonar obstrutiva crônica (DPOC). Diversas estratégias são testadas para tentar amenizar a HD e, frequentemente, utiliza-se a capacidade inspiratória (CI) para avaliar esse efeito. Os objetivos deste estudo foram verificar a presença de HD através da pletismografia logo após a suspensão do exercício e avaliar os efeitos da pressão expiratória positiva em via aérea (EPAP) na HD em pacientes portadores de DPOC submetidos ao exercício. Foram incluídos portadores de DPOC moderada a muito grave, de ambos os sexos, considerados capazes de realizarem o teste de esforço. Todos os participantes submeteram-se à mensuração de fluxos expiratórios, volumes e capacidades pulmonares, além da análise de difusão dos gases através da pletismografia. Essas medidas foram feitas antes e após o uso do broncodilatador. A seguir utilizou-se um protocolo de exercício submáximo e nova prova de função pulmonar era realizada imediatamente após o esforço físico para avaliar a presença de hiperinsuflação, ainda sob efeito do broncodilatador. Os pacientes que apresentaram sinal de HD na pletismografia foram convidados a retornar após 48 horas para repetir o mesmo protocolo de estudo, porém com uso de máscara de EPAP durante o exercício. Os parâmetros de função pulmonar foram analisados e comparados nos diferentes momentos e entre os protocolos. A amostra foi composta inicialmente por 46 pacientes, com média de idade de 65±8,5 anos, sendo 32 (70%) do sexo masculino, 25 (54%) com doença em estágio IV. Do total, 17(37%) apresentaram HD na pletismografia realizada após o teste de exercício. Após o exercício, observou-se diferença significativa entre pacientes com e sem HD apenas nas variáveis: CI (p<0,0001), CI/CPT (p=0,001), CRF/CPT (p=0,002). O uso da EPAP durante o exercício aplicado em 17 pacientes com HD não alterou de maneira significativa a capacidade pulmonar total (CPT; p=0,64), a capacidade residual funcional (CRF; p=0,09) e o volume residual (VR; p=0,10) quando comparado aos valores obtidos após exercício sem EPAP. Entretanto na comparação da CI observou-se uma menor perda de CI (p=0,02) com o uso da máscara. Verificou-se diferença significativa na comparação da relação CI/CPT antes e após o exercício em cada protocolo, ambos apresentando uma queda do valor com o exercício. Na comparação entre protocolos observou-se diferença significativa (p=0,01), representado uma queda menor da relação CI/CPT no protocolo com EPAP. Também se observaram relações VR/CPT e CRF/CPT significativamente menores (p=0,03) após o exercício com EPAP em relação ao exercício isolado. Conclui-se que 37% dos 46 pacientes apresentaram HD, detectada através da redução da CI e da sua relação com a CPT, quando avaliados imediatamente após o teste de exercício através da pletismografia. O uso da EPAP através de máscara facial reduziu a HD em teste de exercício submáximo, observado através da redução significativa da queda da CI e da relação CI/CPT, e pela menor alteração das relações VR/CPT e CRF/CPT. / Dynamic hyperinflation (DH) contributes substantially to the sensation of dyspnea and the interruption of physical exercise in patients with chronic obstructive pulmonary disease (COPD). Several strategies have been tested to mitigate DH, and inspiratory capacity (IC) is often used to measure it. The purpose of this study was investigate the presence of DH immediately after exercise interruption using plethysmography and to evaluate the effects of expiratory positive airway pressure (EPAP) on DH of patients with COPD that underwent a exercise test. The study enrolled men and women with moderate to very severe COPD who were able to perform a exercise test. All participants underwent measurement of expiratory flows, volumes and lung capacities, and gas diffusion using plethysmography before and after the use of bronchodilators. A submaximal exercise test and repeated pulmonary function tests were conducted immediately after physical exercise to evaluate hyperinflation, still under the effect of the bronchodilator. The patients with DH according to plethysmography were invited to return 48 hours later to repeat the same protocol using an EPAP mask during exercise test. Pulmonary function parameters were analyzed and compared at the different time points and between the two tests. The sample consisted of 46 patients whose mean age was 65±8.5 years; 32 (70%) were men, and 25 (54%) had stage IV disease. Plethysmography performed after the exercise test revealed DH in 17 (37%) participants. After exercise, there was a significant difference between patients with and without DH only in IC (p<0.0001), IC/TLC (p=0.001), and FRC/TLC (p=0.002). The use of EPAP during exercise in 17 patients with DH did not significantly change total lung capacity (TLC; p=0.64), functional residual capacity (FRC; p=0.09), or residual volume (RV; p=0.10) when compared with the values obtained after exercise without EPAP. However, there was a lower loss of IC (p=0.02) in the EPAP mask group. There was a significant difference in IC/TLC before and after the exercise in each test, and both groups had a decrease in this value after exercise. The comparison between groups revealed a significant difference (p=0.01) and a smaller decrease in the IC/TLC ratio in the EPAP group. Moreover, significantly lower RV/TLC and FRC/TLC (p=0.03) were found after exercise with EPAP than after exercise alone. Of the 46 study patients, 37% developed DH, detected by a reduction in IC and in IC/TLC when evaluated immediately after exercise test using plethysmography. The use of EPAP delivered by face mask reduced DH in submaximal exercise tests, indicated by a significant reduction in IC and IC/TLC decreases and smaller changes in RV/TLC and FRC/TLC.

Introdução: A hiperinsuflação manual (HM) é uma técnica comum para facilitar a remoção de secreção traqueal de pacientes em UTI, e teoricamente, deveria ser realizada com uma insuflação lenta. Muitos fisioterapeutas não realizam a manobra com a insuflação lenta e os reanimadores manuais (RM) fabricados no Brasil possuem válvula de alívio de pressão, que não pode ser fechada na grande maioria desses dispositivos. Objetivos: Avaliar, em modelo mecânico, a influência da manobra de HM no volume corrente, picos de fluxo inspiratório e expiratório, e pressões alveolar e proximal por oito fisioterapeutas brasileiros, utilizando dois tipos de RM (com e sem válvula reguladora de pressão), de acordo com duas situações [conforme a prática clínica (PC) e após orientação de realizar a HM com a insuflação lenta, chamada de recomendada pela literatura (RL)], e em três cenários clínicos simulados (paciente normal, restritivo e obstrutivo). Resultados: Seis dos 8 fisioterapeutas realizaram a técnica com mais de duas insuflações; as pressões proximais geradas na situação RL foram menores devido aos menores picos de fluxo inspiratório. Os valores de pressões alveolares foram menores que 42,5 cmH2O (mediana = 13,9; intervalo interquartil:10,2-20,3) mesmo com altas pressões proximais (máximo 96,6 cmH2O, mediana 31,4; 19,2-44,8). Os volumes correntes foram menores do que os encontrados na literatura pesquisada (mediana = 514mL; 410-641). Os picos de fluxo inspiratórios (1,32; 0,92- 1,80) foram maiores que os expiratórios (0,88; 0,54-1,13) em quase todas as medidas. O pico de fluxo expiratório se correlacionou com o volume corrente: em cada cenário, os menores picos de fluxo expiratórios estavam correlacionados com baixos volumes correntes. Pressões, volumes e fluxos foram mais baixos com o RM com válvula reguladora de pressão. Conclusão: A manobra de HM foi realizada de forma diferente da preconizada na literatura; o RM com válvula reguladora de pressão gerou menores volumes, pressões e fluxos na maior parte dos cenários; as pressões proximais geradas não determinam, necessariamente, risco para o paciente, pois as pressões alveolares se mantiveram baixas / Background: Manual hyperinflation (MH) is a common technique used for removing pulmonary secretions in ICU and theoretically should be performed with a slow inflation. Many Brazilian respiratory therapists do not perform the maneuver with a slow inflation and manual resuscitators (MR) made in Brazil have pressure relief valve (PRV) which in many of them cannot be closed to perform MH. Objectives: evaluate, in a lung model, the influence on tidal volume, inspiratory and expiratory peak flow, proximal and alveolar pressures of MH performed by eight Brazilian respiratory therapists using two types of MR (with and without pressure relief valve), in two manners [like clinical practice (CP) and after orientation to perform MH with a slow inflation, named literature recommended (LR)] and in three clinical simulated scenarios (normal, restrictive and obstructive patient). Results: Six of 8 respiratory therapists performed MH with two or more inflation. After instruction proximal pressure generated was lower because of the slower inspiratory peak flow. The alveolar pressure values were lesser than 42.5 cmH2O (median = 13.9; interquartile range: 10.2-20.3), despite of high proximal pressure (max 96.6 cmH2O, median 31.4; 19.2-44.8). Inspiratory tidal volume were smaller than other reports (median=514mL; 410-641). Inspiratory peak flow (1.32; 0.92- 1.80) were higher than expiratory (0.88; 0.54-1.13) in almost all measurement. Expiratory peak flow was correlated with tidal volume: for each scenario, the low expiratory peak flow was mainly generated by small tidal volume. Pressures, volumes and flows were lower with MR that uses PRV. Conclusion: In this small sample of respiratory therapists, MH was done different that literature recommends; MR whit pressure limiting system generate lower tidal volume, pressures and peak pressures in most scenarios; proximal pressure generated not determine, necessarily, risk for patient, because alveolar pressure was maintained low

The primary aim of this thesis was to develop a better understanding of the physiology and perceptual responses associated with the performance of continuous (CE) and intermittent exercise (IE) in patients with moderate chronic obstructive pulmonary disease (COPD). A secondary aim was to examine factors that could potentially limit exercise tolerance in COPD patients, particularly in relation to the dynamics of the cardiovascular system and muscle metabolism. The results of the four studies conducted to achieve these aims are presented in this thesis. In Study 1, the physiological, metabolic and perceptual responses to an acute bout of IE and CE were examined in 10 individuals with moderate COPD. Each subject completed an incremental exercise test to exhaustion on a cycle ergometer. Subjects then performed IE (1 min exercise: 1 min rest ratio) and CE tests at 70% of peak power in random order on separate days. Gas exchange, heart rate, plasma lactate concentration, ratings of breathlessness, inspiratory capacity and the total amount of work completed were measured during each exercise test. Subjects were able to complete a significantly greater amount of work during IE (71 ± 32 kJ) compared with CE (31 ± 24 kJ). Intermittent exercise was associated with significantly lower values for oxygen uptake, expired ventilation and plasma lactate concentration when compared with CE. Subjects also reported a significantly lower rating of breathlessness during IE compared to CE. The degree of dynamic lung hyperinflation (change in end-expiratory lung volume) was lower during IE (0.23 ± 0.07 L) than during CE (0.52 ± 0.13 L). The results suggest that IE may be superior to CE as a mode of training for patients with COPD. The greater amount of total work performed and the lower measured physiological responses attained with intermittent exercise could potentially allow greater training adaptations to be achieved in individuals with more limited lung function. The purpose of Study 2 was to compare the adaptations to 8 wk of supervised intermittent and continuous cycle ergometry training, performed at the same relative intensity and matched for total work completed, in patients with COPD. Nineteen subjects with moderate COPD were stratified according to age, gender, and pulmonary function, and then randomly assigned to either an IE (1 min exercise: 1 min rest ratio) or CE training group. Subjects trained 3 d per week for 8 wk and completed 30 min of exercise. Initial training intensity, i.e., the power output applied during the CE bouts and during the exercise interval of the IE bouts, was determined as 50% of the peak power output achieved during incremental exercise and was increased by 5% each week after 2 wk of training. The total amount of work performed was not significantly different (P=0.74) between the CE (750 ± 90 kJ) and IE (707 ± 92 kJ) groups. The subjects who performed IE (N=9) experienced significantly lower levels of perceived breathlessness and lower limb fatigue during the exercise-training bouts than the group who performed CE (N=10). However, exercise capacity (peak oxygen uptake) and exercise tolerance (peak power output and 6-min walk distance) improved to a similar extent in both training groups. During submaximal constant-load exercise, the improved (faster) phase II oxygen uptake kinetic response with training was independent of exercise mode. Furthermore, training-induced reductions in submaximal exercise heart rate, carbon dioxide output, expired ventilation and blood lactate concentrations were not different between the two training modes. Exercise training also resulted in an equivalent reduction for both training modes in the degree of dynamic hyperinflation observed during incremental exercise. Thus, when total work performed and relative intensity were the same for both training modes, 8 wk of CE or IE training resulted in similar functional improvements and physiological adaptations in patients with moderate COPD. Study 3 examined the relationship between exercise capacity (peak oxygen uptake) and lower limb vasodilatory capacity in 9 patients with moderate COPD and 9 healthy age-matched control subjects. While peak oxygen uptake was significantly lower in the COPD patients (15.8 ± 3.5 mL·min-1·kg-1) compared to the control subjects (25.2 ± 3.5 mL·kg-1·min-1), there were no significant differences between groups in peak calf blood flow or peak calf conductance measured 7 s post-ischemia. Peak oxygen uptake was significantly correlated with peak calf blood flow and peak conductance in the control group, whereas there was no significant relationship found between these variables in the COPD group. However, the rate of decay in blood flow following ischemia was significantly slower (p less than 0.05) for the COPD group (-0.036 ± 0.005 mL·100 mL-1·min-1·s-1) when compared to the control group (-0.048 ± 0.015 mL·100 mL-1·min-1·s-1). The results of this study suggest that the lower peak exercise capacity in patients with moderate COPD is not related to a loss in leg vasodilatory capacity. Study 4 examined the dynamics of oxygen uptake kinetics during high-intensity constant-load cycling performed at 70% of the peak power attained during an incremental exercise test in 7 patients with moderate COPD and 7 healthy age-matched controls. The time constant of the primary component (phase II) of oxygen uptake was significantly slower in the COPD patients (82 ± 8 s) when compared to healthy control subjects (44 ± 4 s). Moreover, the oxygen cost per unit increment in power output for the primary component and the overall response were significantly higher in patients with COPD than in healthy control subjects. A slow component was observed in 5 of the 7 patients with COPD (49 ± 11 mL·min-1), whereas all of the control subjects demonstrated a slow component of oxygen uptake (213 ± 35 mL·min-1). The slow component comprised a significantly greater proportion of the total oxygen uptake response in the healthy control group (18 ± 2%) than in the COPD group (10 ± 2%). In the COPD patients, the slow component amplitude was significantly correlated with the decrease in inspiratory capacity (r = -0.88, P less than 0.05; N=5), indicating that the magnitude of the slow component was larger in individuals who experienced a greater degree of dynamic hyperinflation. This study demonstrated that most patients with moderate COPD are able to exercise at intensities high enough to elicit a slow component of oxygen uptake during constant-load exercise. The significant correlation observed between the slow component amplitude and the degree of dynamic hyperinflation suggests that the work of breathing may contribute to the slow component in patients with COPD.

Maschinelle Beatmung kann neben den gewünschten Effekten eine vorbestehende Lungenerkrankung weiter aggravieren und sogar das Lungenparenchym zuvor lungengesunder Patienten schädigen. Mit Hilfe der quantitativen Computertomographie (qCT) können pathologische Belüftungszustände und gegebenenfalls durch maschinelle Beatmung verursachte Schäden analysiert werden. Solche auf der qCT basierende Analysen der Lungenbelüftung werden jedoch potentiell durch CT-Akquisitions- und Bildrekonstruktionsparameter beeinflusst. Um die Ergebnisse vor allem von Analysen des überbelüfteten Lungenvolumens richtig bewerten zu können, müssen solche Einflüsse untersucht werden. Bei 10 Versuchstieren (Schweine) wurden bei einem konstanten Atemwegsdruck von 25 cm H2O zuerst bei gesunder Lunge und dann erneut nach experimenteller Lungenschädigung CT-Bildserien mit zwei unterschiedlichen Strahlendosen angefertigt. Von diesen Rohdaten wurden Bildserien mit unterschiedlichen Rekonstruktionsparametern angefertigt und in jeder dieser Bildserien das überbelüftete Lungenvolumen bestimmt. Sowohl die Schichtdicke, der Filter als auch die Stromstärke hatten einen signifikanten Einfluss auf das eigentlich konstante überbelüftete Lungenvolumen, der jedoch nur teilweise klinisch relevant war. Bei der Interpretation von Messungen des überbelüfteten Lungenvolumens sollten dennoch die Einflüsse der genannten Parameter beachtet und für Vergleichsuntersuchungen gleiche Parametereinstellungen verwendet werden. Eine Dosisreduktion scheint dabei für Messungen des überbelüfteten Lungenvolumens praktikabel.

Orientador: Ana Lúcia dos Anjos Ferreira / Banca: Victor Zuniga Dourado / Banca: Luis Cuadrado Martin / Resumo: Apesar da fisioterapia respiratória aparentemente beneficiar pacientes sob ventilação mecânica, não há evidências suficientes para sua recomendação. Usando associação das manobras compressão torácica (CT) e hiperinsuflação manual (HM), prévio estudo de nosso grupo identificou significante redução no período de ventilação mecânica (VM), no período de internação e melhora da extensão de lesão pulmonar (Murray) em pacientes sob VM. Contudo, é desconhecido o papel isolado de cada manobra nos benefícios encontrados. Portanto, o objetivo deste estudo foi comparar prospectivamente o efeito isolado e associado das manobras CT e HM no período de internação e de VM em pacientes sob VM. O estudo foi conduzido por 13 meses na UTI (Pronto-Socorro do Hospital das Clínicas, UNESP, Botucatu, SP, Brasil) de um hospital universitário terciário. Foi também avaliada a interferência das manobras nos seguintes parâmetros: índice prognóstico (APACHE-II), Murray, oxigenação (PaO2/FiO2), mecânica respiratória, repercussões hemodinâmicas e saturação periférica de oxigênio (SpO2). A análise estatística utilizou o teste de Goodman para contrastes entre e dentro de populações multinomiais, qui-quadrado, análise de variância e análise de variância para o modelo de medidas repetidas em grupos independentes. Dos 204 pacientes que preencheram os critérios de inclusão e exclusão e foram admitidos no estudo, 20 pacientes foram alocados no grupo CT, 20 no grupo HM e 20 no grupo CT+HM de acordo com o processo de sistematização. Diversas causas levaram à exclusão de alguns pacientes durante o estudo e cada grupo passou a ser constituído por 15 pacientes. O grupo CT recebeu compressão torácica, o grupo HM recebeu hiperinsuflação manual e o grupo CT+HM recebeu a associação de ambas as manobras duas vezes ao dia durante cinco... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: There is no evidence to support the recommendation of chest physiotherapy on mechanically ventilated (MV) patients, although this procedure apparently improves those patients. Using association of thoracic compression (TC) and manual hyperinflation (MH), our previous study identified significant reduction in duration of weaning from ventilation, discharge from intensive care unit (ICU) and extent of lung damage index (Murray). However, it is unknown the individual role of each maneuver on those benefits. Therefore, the aim of the study was evaluate the isolated and associated effect of TC and MH on the mechanical ventilation period and length of stay in mechanically ventilated patients. Secondarily, outcomes of interest were the effect of physiotherapy on Murray, severity score and on hemodynamics, gas exchange, and respiratory mechanics. It was conducted at ICU of the Emergency Room (ER) at Hospital das Clínicas of São Paulo State University (UNESP-HC) (Botucatu, SP, Brazil) for 13 consecutive months. The significance of differences between groups was accessed by Goodman test, chi-squared analysis, ANOVA and a nonparametric repeated measures ANOVA. The present study was a three-group (TC, MH, and TC+MH), prospective and systematized clinical study lasting 5 days. Of the 204 patients who fulfilled all the inclusion criteria and were enrolled in the study, 20 patients were allocated into TC group, 20 into MH group or 20 into TC+HM group. The TC group received expiratory chest compression, the MH group received manual hyperinflation and the TC+HM received manual hyperinflation combined with expiratory chest compression twice a day for 5 days. Five patients from TC, 5 from MH and 5 from TC+HM were withdrawn during the study period due to several reasons and therefore, 15 patients remained in each group. The 3 groups... (Complete abstract click electronic access below) / Mestre

No description available.

Introdução: A atelectasia intraoperatória ocorre imediatamente após a indução anestésica e pode ser detectada por ultrassom pulmonar (LUS). No entanto, até o momento o LUS não é utilizado para avaliar a hiperdistensão pulmonar. Neste estudo, descreveu-se um método para detectar hiperdistensão pulmonar usando LUS. A tomografia de impedância elétrica (TIE) foi a referência para comparação dos métodos. Métodos: Dezoito (18) pacientes, com 63 ± 6 anos de idade, com pulmões normais, submetidos à cirurgia abdominal inferior. O TIE foi calibrado, realizada a indução anestésica, intubação e ventilação mecânica. Para reverter a atelectasia posterior, realizou-se uma manobra de recrutamento alveolar com o uso de pressão expiratória final positiva (PEEP) 20 cmH20 e pressão aérea do platô 40 cmH2O durante 120 segundos. A titulação PEEP foi então obtida com valores descendentes: 20, 18, 16, 14,12,10, 8, 6 e 4 cmH2O. Os dados de ultrassom e TIE foram coletados em cada nível PEEP e interpretados por dois observadores independentes. O número de linhas H foi contado usando um filtro especial. O teste de correlação de Spearman e a curva ROC foram utilizados para comparar os dados do LUS e TIE. Resultados: O número de linhas H aumentou linearmente com PEEP: de 3 em PEEP 4 cmH2O a 10 em PEEP 20 cmH2O. Cinco linhas H foram o limiar para a detecção de hiperdistensão pulmonar, definida como hiperdistensão na TIE >= 24,5%. A área sob a curva ROC foi 0,947 (IC 95% 0.901-0.976). Conclusão: O LUS intraoperatório detectou hiperdistensão pulmonar em valores descendentes de PEEP. A presença de cinco ou mais linhas H podem ser consideradas como indicando hiperdistensão pulmonar / Purpose: Intraoperative atelectasis occurs immediately after anaesthetic induction and can be detected by lung ultrasound (LUS). However, LUS is considered as unable to assess pulmonary hyperinflation. In this study, we propose a method to detect pulmonary hyperinflation using LUS. Electrical impedance tomography (EIT) was the reference method. Methods: We included 18 patients, 63 ± 6-year old, with normal lungs, undergoing lower abdominal surgery. The following protocol was used: EIT was calibrated, followed by anaesthetic induction, intubation and mechanical ventilation. To reverse posterior atelectasis, a recruitment maneuver - positive end-expiratory pressure (PEEP) 20 cmH20 and plateau airway pressure 40 cmH2O during 120 sec was performed. PEEP titration was then obtained during a descending trial: 20, 18, 16, 14,12,10, 8, 6 and 4 cmH2O. Ultrasound and EIT data were collected at each PEEP level and analyzed by two independent observers. The number of H lines was counted using a special filter. Spearman correlation test and ROC curve were used to compare LUS and EIT data. Results: The number of H lines increased linearly with PEEP: from 3 at PEEP 4 cmH2O to 10 at PEEP 20 cmH2O. Five H lines was the threshold for detecting pulmonary hyperinflation, defined as a mean decrease in maximum EIT compliance >= 24,5 %. The area under the ROC curve was 0.947 (CI 95% 0.901-0.976). Conclusion: Intraoperative transthoracic LUS can detect pulmonary hyperinflation during a PEEP descending trial. Five or more H lines can be considered as indicating pulmonary hyperinflation in normally aerated lung regions

Introdução: A atelectasia intraoperatória ocorre imediatamente após a indução anestésica e pode ser detectada por ultrassom pulmonar (LUS). No entanto, até o momento o LUS não é utilizado para avaliar a hiperdistensão pulmonar. Neste estudo, descreveu-se um método para detectar hiperdistensão pulmonar usando LUS. A tomografia de impedância elétrica (TIE) foi a referência para comparação dos métodos. Métodos: Dezoito (18) pacientes, com 63 ± 6 anos de idade, com pulmões normais, submetidos à cirurgia abdominal inferior. O TIE foi calibrado, realizada a indução anestésica, intubação e ventilação mecânica. Para reverter a atelectasia posterior, realizou-se uma manobra de recrutamento alveolar com o uso de pressão expiratória final positiva (PEEP) 20 cmH20 e pressão aérea do platô 40 cmH2O durante 120 segundos. A titulação PEEP foi então obtida com valores descendentes: 20, 18, 16, 14,12,10, 8, 6 e 4 cmH2O. Os dados de ultrassom e TIE foram coletados em cada nível PEEP e interpretados por dois observadores independentes. O número de linhas H foi contado usando um filtro especial. O teste de correlação de Spearman e a curva ROC foram utilizados para comparar os dados do LUS e TIE. Resultados: O número de linhas H aumentou linearmente com PEEP: de 3 em PEEP 4 cmH2O a 10 em PEEP 20 cmH2O. Cinco linhas H foram o limiar para a detecção de hiperdistensão pulmonar, definida como hiperdistensão na TIE >= 24,5%. A área sob a curva ROC foi 0,947 (IC 95% 0.901-0.976). Conclusão: O LUS intraoperatório detectou hiperdistensão pulmonar em valores descendentes de PEEP. A presença de cinco ou mais linhas H podem ser consideradas como indicando hiperdistensão pulmonar / Purpose: Intraoperative atelectasis occurs immediately after anaesthetic induction and can be detected by lung ultrasound (LUS). However, LUS is considered as unable to assess pulmonary hyperinflation. In this study, we propose a method to detect pulmonary hyperinflation using LUS. Electrical impedance tomography (EIT) was the reference method. Methods: We included 18 patients, 63 ± 6-year old, with normal lungs, undergoing lower abdominal surgery. The following protocol was used: EIT was calibrated, followed by anaesthetic induction, intubation and mechanical ventilation. To reverse posterior atelectasis, a recruitment maneuver - positive end-expiratory pressure (PEEP) 20 cmH20 and plateau airway pressure 40 cmH2O during 120 sec was performed. PEEP titration was then obtained during a descending trial: 20, 18, 16, 14,12,10, 8, 6 and 4 cmH2O. Ultrasound and EIT data were collected at each PEEP level and analyzed by two independent observers. The number of H lines was counted using a special filter. Spearman correlation test and ROC curve were used to compare LUS and EIT data. Results: The number of H lines increased linearly with PEEP: from 3 at PEEP 4 cmH2O to 10 at PEEP 20 cmH2O. Five H lines was the threshold for detecting pulmonary hyperinflation, defined as a mean decrease in maximum EIT compliance >= 24,5 %. The area under the ROC curve was 0.947 (CI 95% 0.901-0.976). Conclusion: Intraoperative transthoracic LUS can detect pulmonary hyperinflation during a PEEP descending trial. Five or more H lines can be considered as indicating pulmonary hyperinflation in normally aerated lung regions

Maschinelle Beatmung kann neben den gewünschten Effekten eine vorbestehende Lungenerkrankung weiter aggravieren und sogar das Lungenparenchym zuvor lungengesunder Patienten schädigen. Mit Hilfe der quantitativen Computertomographie (qCT) können pathologische Belüftungszustände und gegebenenfalls durch maschinelle Beatmung verursachte Schäden analysiert werden. Solche auf der qCT basierende Analysen der Lungenbelüftung werden jedoch potentiell durch CT-Akquisitions- und Bildrekonstruktionsparameter beeinflusst. Um die Ergebnisse vor allem von Analysen des überbelüfteten Lungenvolumens richtig bewerten zu können, müssen solche Einflüsse untersucht werden. Bei 10 Versuchstieren (Schweine) wurden bei einem konstanten Atemwegsdruck von 25 cm H2O zuerst bei gesunder Lunge und dann erneut nach experimenteller Lungenschädigung CT-Bildserien mit zwei unterschiedlichen Strahlendosen angefertigt. Von diesen Rohdaten wurden Bildserien mit unterschiedlichen Rekonstruktionsparametern angefertigt und in jeder dieser Bildserien das überbelüftete Lungenvolumen bestimmt. Sowohl die Schichtdicke, der Filter als auch die Stromstärke hatten einen signifikanten Einfluss auf das eigentlich konstante überbelüftete Lungenvolumen, der jedoch nur teilweise klinisch relevant war. Bei der Interpretation von Messungen des überbelüfteten Lungenvolumens sollten dennoch die Einflüsse der genannten Parameter beachtet und für Vergleichsuntersuchungen gleiche Parametereinstellungen verwendet werden. Eine Dosisreduktion scheint dabei für Messungen des überbelüfteten Lungenvolumens praktikabel.:Inhaltsverzeichnis 0 Abkürzungsverzeichnis 1 1 Einleitung 3 1.1 Ventilator-associated Lung Injury (VALI) 3 1.2 Computertomographie und Diagnostik von Lungenerkrankungen 5 1.3 Spiral-CT 9 1.4 Datenerfassung und Bildrekonstruktion 10 1.5 Grundlagen zur Dichtemessung 12 1.6 Einfluss von Filter und Schichtdicke auf das Bild 13 1.7 Einfluss von Filter und Schichtdicke auf die Analyse der pulmonalen Überbelüftung 15 1.8 Zielstellung 17 2 Materialien und Methodik 18 2.1 Versuchstiere 18 2.2 Überblick über den Versuchsablauf 18 2.2.1 Prämedikation und Narkoseführung 18 2.2.2 Induktion des Lungenschadens 20 2.2.3 CT-Scans und Bildrekonstruktionen 21 2.3 Segmentierung und volumetrische Analyse 22 2.4 Statistische Analyse 24 3 Ergebnisse 26 3.1 Einfluss von Schichtdicke, Filter und Stromstärke auf normale Lungen 26 3.2 Einfluss von Schichtdicke, Filter und Stromstärke auf geschädigte Lungen 34 3.3 Vergleich der automatischen und manuellen Segmentierung 38 4 Diskussion 40 4.1 Einfluss von Schichtdicke und Filter 42 4.2 Einfluss der Stromstärke 49 4.3 Einfluss der experimentell induzierten Lungenschädigung 53 4.4 Vergleich der Segmentierungssoftware 55 4.5 Diskussion der Methodik 55 4.6 Schlussfolgerung 58 5 Zusammenfassung der Arbeit 60 6 Literaturverzeichnis 63 7 Danksagung 77 8 Erklärung über die eigenständige Abfassung der Arbeit 78