INTRODUÇÃO E OBJETIVOS: A Circulação extracorpórea (CEC) é associada a ativação leucocitária, resposta inflamatória e disfunção pulmonar. Objetivou-se avaliar os efeitos da filtragem leucocitária sobre a resposta inflamatória e a função pulmonar em indivíduos submetidos à revascularização do miocárdio (RM) com CEC. MÉTODO: Após aprovação pelo Comitê de Ética Institucional e obtenção do consentimento informado dos indivíduos, foi realizado estudo prospectivo randomizado, para comparar indivíduos adultos submetidos à RM com CEC, utilizando-se filtragem leucocitária (n=09) ou filtro standard (n=11) durante a CEC. Tomografia computadorizada (CT) de tórax, espirometria, análise da oxigenação e hemograma foram realizados antes da cirurgia. A anestesia foi induzida por via venosa com etomidato (0,3 mg.kg-1), sufentanil (0,3 ug.kg-1), pancurônio (0,08 mg.kg-1) e mantida com isoflurano (0,5 - 1,0 CAM) e sufentanil (0,5 ug.kg-1.h-1). A ventilação mecânica utilizou volume corrente de 8 mL.kg-1, com FiO2 de 0,6 e PEEP de 5 cm H2O, exceto durante a CEC. No grupo Filtragem, durante a CEC, foi inserido um filtro de leucócitos na linha arterial do circuito (LG-6, Pall Biomedical Products) e, no grupo Controle, foi utilizado o filtro Standard. Contagem leucocitária foi realizada após a indução, aos 5, 25 e 50 min de CEC, ao final da cirurgia, com 12 e 24 h PO. Dados hemodinâmicos, PaO2/FiO2, fração de Shunt, interleucinas, elastase e mieloperoxidase foram colhidos antes e após a CEC, no final da cirurgia, com 6,12 e 24 h PO. Trinta minutos depois da indução, e trinta após a CEC, três amostras sequenciais de ar exalado foram colhidas para análise de óxido nítrico (NO), por quimiluminescência. Espirometria e CT de tórax foram realizadas no primeiro dia pós-operatório. Os dados foram analisados por meio de ANOVA de duplo fator para medidas repetidas. RESULTADOS: O tempo de CEC foi similar entre os grupos controle e filtragem (86,78 ± 19,58 versus 104,64 ± 27,76 min, p=0,161). O grupo Filtragem mostrou menor contagem leucocitária que o grupo Controle até 50 min de CEC (3384 ± 2025 versus 6478 ± 3582 U.mm-3 U.mm-3, p=0,036), menor fração de shunt até 6 h PO (10 ± 2% versus 16 ± 5%, p=0,040) e menores níveis de IL-10 até o final da cirurgia (1571 ± 1137 pg.mL-1 versus 3108 ± 1694 pg.mL-1, p=0,031). Não houve diferença estatisticamente significativa entre os grupos em relação ao restante dos parâmetros avaliados (p > 0,05). CONCLUSÕES: A filtragem leucocitária durante a CEC, quando comparada à utilização de filtro convencional, promove diminuição da contagem de neutrófilos até 50 minutos de CEC, menor liberação de IL-10 até o final da cirurgia e menor alteração da fração de shunt intrapulmonar até 6 h PO, protegendo os pulmões apenas temporariamente contra a injúria aguda relacionada / BACKGROUND AND OBJECTIVE: The Cardiopulmonary bypass (CPB) is related to leukocyte activation, inflammatory response and lung dysfunction. The aim of this study was to evaluate the effects of CPB-leukocyte filtration on the inflammatory response and lung function after coronary artery bypass grafting (CABG). METHODS: After approval by the institutional ethics committee and informed consent, a prospective randomized study was performed to compare CABG-patients undergoing CPB-leukocyte filtration (n=9) or standard CPB (n=11). Espirometry, chest computed tomography (CT), oxygenation analysis and leukocyte count were performed before surgery. Anesthesia induction was performed intravenously with etomidate (0,3 mg.kg-1), sufentanil (0,3 ug.kg-1), pancuronium bromide (0,08 mg.kg-1) e sustained with isoflurano (0,5 - 1,0 CAM) and sufentanil (0,5 ug.kg-1.h-1). The tidal volume used during mechanical ventilation was 8 mL.kg-1, the FiO2 0.6 and PEEP 5 cm H2O, except during CPB. In Filtered group, during CPB, was inserted a leukocyte filter in the arterial line of CPB circuit (LG-6, Pall Biomedical Products) and, in Control group, the Standard arterial line filter was utilized. Hemodynamic data, PaO2/FiO2, shunt fraction, interleukins, elastase and myeloperoxidase were evaluated before and after CPB, at the end of surgery, and 6, 12 and 24 h PO. Thirty minutes after induction, and Thirty after CPB, three sequential exhaled air samples were collected to perform analysis of nitric oxide (NO), by chemiluminescence technique. Espirometry and chest CT were performed on first PO. Data were analyzed using two-factor ANOVA for repeated measurements. RESULTS: Length of CPB was similar in the filtered and control groups (86.78 ± 19.58 versus 104.64 ± 27.76 min, p = 0.161). The filtered group showed lower neutrophil counts than the control group up to 50 minutes of CPB (3384 ± 2025 versus 6478 ± 3582 U/mm-3, p = 0.036), lower shunt fraction up to 6 hours after surgery (10 ± 2% versus 16 ± 5%, p = 0.040), and lower levels of IL-10 at the end of surgery (1571 ± 1137 pg.ml-1 versus 3108 ± 1694 pg.ml-1, p = 0.031). There were no significant differences between the groups with respect to rest of the parameters evaluated (p >u0,05). CONCLUSIONS: The leukocyte filtration during CPB, when compared to the use of conventional filter, promotes lower neutrophil counts up to 50 minutes of CPB, lower levels of IL-10 at the end of surgery and lower shunt fraction up to 6 hours after surgery, protecting the lungs only temporarily against the acute injury related Trial registration: Clinicaltrials.gov identifier: NCT01469676

<p>Obstructive sleep apnea (OSA) appears to affect up to 5% of the population. The extent to what pulmonary function awake and during sleep relates to obstructive breathing and hypoxemia during sleep in these patients is unclear. The aim of this study was to investigate respiratory function in patients with varying degree of snoring and OSA and to analyse regional lung aeration during sleep.</p><p>In all, 35 healthy subjects and 90 patients with snoring and OSA were studied. The ventilatory response to CO₂ (VRCO₂) was measured. Lung function tests were performed. A technique based on computed tomography was developed to study lung aeration during sleep.</p><p>Patients with OSA displayed a higher VRCO₂ in comparison to healthy subjects and snorers (p<0.01). Increased closing volume and reduced expiratory reserve volume (ERV) were found in patients with OSA (p<0.001). In a multiple regression analysis, ERV was an independent predictor of nocturnal apnea (R²=0.13; p=0.001) and desaturation frequency (R²=0.11; p<0.01). In both healthy subjects and OSA patients, lung aeration was reduced during sleep by 0.10 ml gas/g tissue in the dorsal lung region (p<0.05 and p<0.01). OSA patients had a significantly lower gas/tissue ratio in comparison to healthy subjects both awake (-23%; p<0.04) and during sleep (-25%; p<0.04). In a univariate analysis, functional residual capacity (FRC) correlated with the change in lung aeration from wakefulness to sleep (r=-0.78; p<0.001). In patients with OSA, ERV (r=-0.69; p<0.05) and sleep time (r=0.69; p<0.05) correlated with the fall in lung aeration. </p><p>In conclusion, patients with OSA display an increased ventilatory response to CO₂, reduced ERV and increased closing volume. ERV predicts nocturnal apnea and desaturation frequency to a similar extent as obesity. Lung aeration is reduced in the dorsal region during sleep and patients with OSA display a lower amount of gas in comparison to healthy subjects. Decrease in lung volumes, promoting airway closure, and loss of muscle tone contributed to the altered lung function during sleep.</p>

Obstructive sleep apnea (OSA) appears to affect up to 5% of the population. The extent to what pulmonary function awake and during sleep relates to obstructive breathing and hypoxemia during sleep in these patients is unclear. The aim of this study was to investigate respiratory function in patients with varying degree of snoring and OSA and to analyse regional lung aeration during sleep. In all, 35 healthy subjects and 90 patients with snoring and OSA were studied. The ventilatory response to CO2 (VRCO2) was measured. Lung function tests were performed. A technique based on computed tomography was developed to study lung aeration during sleep. Patients with OSA displayed a higher VRCO2 in comparison to healthy subjects and snorers (p&lt;0.01). Increased closing volume and reduced expiratory reserve volume (ERV) were found in patients with OSA (p&lt;0.001). In a multiple regression analysis, ERV was an independent predictor of nocturnal apnea (R2=0.13; p=0.001) and desaturation frequency (R2=0.11; p&lt;0.01). In both healthy subjects and OSA patients, lung aeration was reduced during sleep by 0.10 ml gas/g tissue in the dorsal lung region (p&lt;0.05 and p&lt;0.01). OSA patients had a significantly lower gas/tissue ratio in comparison to healthy subjects both awake (-23%; p&lt;0.04) and during sleep (-25%; p&lt;0.04). In a univariate analysis, functional residual capacity (FRC) correlated with the change in lung aeration from wakefulness to sleep (r=-0.78; p&lt;0.001). In patients with OSA, ERV (r=-0.69; p&lt;0.05) and sleep time (r=0.69; p&lt;0.05) correlated with the fall in lung aeration. In conclusion, patients with OSA display an increased ventilatory response to CO2, reduced ERV and increased closing volume. ERV predicts nocturnal apnea and desaturation frequency to a similar extent as obesity. Lung aeration is reduced in the dorsal region during sleep and patients with OSA display a lower amount of gas in comparison to healthy subjects. Decrease in lung volumes, promoting airway closure, and loss of muscle tone contributed to the altered lung function during sleep.

INTRODUÇÃO E OBJETIVOS: A Circulação extracorpórea (CEC) é associada a ativação leucocitária, resposta inflamatória e disfunção pulmonar. Objetivou-se avaliar os efeitos da filtragem leucocitária sobre a resposta inflamatória e a função pulmonar em indivíduos submetidos à revascularização do miocárdio (RM) com CEC. MÉTODO: Após aprovação pelo Comitê de Ética Institucional e obtenção do consentimento informado dos indivíduos, foi realizado estudo prospectivo randomizado, para comparar indivíduos adultos submetidos à RM com CEC, utilizando-se filtragem leucocitária (n=09) ou filtro standard (n=11) durante a CEC. Tomografia computadorizada (CT) de tórax, espirometria, análise da oxigenação e hemograma foram realizados antes da cirurgia. A anestesia foi induzida por via venosa com etomidato (0,3 mg.kg-1), sufentanil (0,3 ug.kg-1), pancurônio (0,08 mg.kg-1) e mantida com isoflurano (0,5 - 1,0 CAM) e sufentanil (0,5 ug.kg-1.h-1). A ventilação mecânica utilizou volume corrente de 8 mL.kg-1, com FiO2 de 0,6 e PEEP de 5 cm H2O, exceto durante a CEC. No grupo Filtragem, durante a CEC, foi inserido um filtro de leucócitos na linha arterial do circuito (LG-6, Pall Biomedical Products) e, no grupo Controle, foi utilizado o filtro Standard. Contagem leucocitária foi realizada após a indução, aos 5, 25 e 50 min de CEC, ao final da cirurgia, com 12 e 24 h PO. Dados hemodinâmicos, PaO2/FiO2, fração de Shunt, interleucinas, elastase e mieloperoxidase foram colhidos antes e após a CEC, no final da cirurgia, com 6,12 e 24 h PO. Trinta minutos depois da indução, e trinta após a CEC, três amostras sequenciais de ar exalado foram colhidas para análise de óxido nítrico (NO), por quimiluminescência. Espirometria e CT de tórax foram realizadas no primeiro dia pós-operatório. Os dados foram analisados por meio de ANOVA de duplo fator para medidas repetidas. RESULTADOS: O tempo de CEC foi similar entre os grupos controle e filtragem (86,78 ± 19,58 versus 104,64 ± 27,76 min, p=0,161). O grupo Filtragem mostrou menor contagem leucocitária que o grupo Controle até 50 min de CEC (3384 ± 2025 versus 6478 ± 3582 U.mm-3 U.mm-3, p=0,036), menor fração de shunt até 6 h PO (10 ± 2% versus 16 ± 5%, p=0,040) e menores níveis de IL-10 até o final da cirurgia (1571 ± 1137 pg.mL-1 versus 3108 ± 1694 pg.mL-1, p=0,031). Não houve diferença estatisticamente significativa entre os grupos em relação ao restante dos parâmetros avaliados (p > 0,05). CONCLUSÕES: A filtragem leucocitária durante a CEC, quando comparada à utilização de filtro convencional, promove diminuição da contagem de neutrófilos até 50 minutos de CEC, menor liberação de IL-10 até o final da cirurgia e menor alteração da fração de shunt intrapulmonar até 6 h PO, protegendo os pulmões apenas temporariamente contra a injúria aguda relacionada / BACKGROUND AND OBJECTIVE: The Cardiopulmonary bypass (CPB) is related to leukocyte activation, inflammatory response and lung dysfunction. The aim of this study was to evaluate the effects of CPB-leukocyte filtration on the inflammatory response and lung function after coronary artery bypass grafting (CABG). METHODS: After approval by the institutional ethics committee and informed consent, a prospective randomized study was performed to compare CABG-patients undergoing CPB-leukocyte filtration (n=9) or standard CPB (n=11). Espirometry, chest computed tomography (CT), oxygenation analysis and leukocyte count were performed before surgery. Anesthesia induction was performed intravenously with etomidate (0,3 mg.kg-1), sufentanil (0,3 ug.kg-1), pancuronium bromide (0,08 mg.kg-1) e sustained with isoflurano (0,5 - 1,0 CAM) and sufentanil (0,5 ug.kg-1.h-1). The tidal volume used during mechanical ventilation was 8 mL.kg-1, the FiO2 0.6 and PEEP 5 cm H2O, except during CPB. In Filtered group, during CPB, was inserted a leukocyte filter in the arterial line of CPB circuit (LG-6, Pall Biomedical Products) and, in Control group, the Standard arterial line filter was utilized. Hemodynamic data, PaO2/FiO2, shunt fraction, interleukins, elastase and myeloperoxidase were evaluated before and after CPB, at the end of surgery, and 6, 12 and 24 h PO. Thirty minutes after induction, and Thirty after CPB, three sequential exhaled air samples were collected to perform analysis of nitric oxide (NO), by chemiluminescence technique. Espirometry and chest CT were performed on first PO. Data were analyzed using two-factor ANOVA for repeated measurements. RESULTS: Length of CPB was similar in the filtered and control groups (86.78 ± 19.58 versus 104.64 ± 27.76 min, p = 0.161). The filtered group showed lower neutrophil counts than the control group up to 50 minutes of CPB (3384 ± 2025 versus 6478 ± 3582 U/mm-3, p = 0.036), lower shunt fraction up to 6 hours after surgery (10 ± 2% versus 16 ± 5%, p = 0.040), and lower levels of IL-10 at the end of surgery (1571 ± 1137 pg.ml-1 versus 3108 ± 1694 pg.ml-1, p = 0.031). There were no significant differences between the groups with respect to rest of the parameters evaluated (p >u0,05). CONCLUSIONS: The leukocyte filtration during CPB, when compared to the use of conventional filter, promotes lower neutrophil counts up to 50 minutes of CPB, lower levels of IL-10 at the end of surgery and lower shunt fraction up to 6 hours after surgery, protecting the lungs only temporarily against the acute injury related Trial registration: Clinicaltrials.gov identifier: NCT01469676

L’objectif de cette étude est de déterminer certains paramètres respiratoires et cardiovasculaires chez des sujets de tous âges pour utilisation, à titre d’intrants physiologiques, en modélisation toxicocinétique et en analyse du risque toxique. La base de données utilisée est tirée de la littérature. Il s’agit de mesures portant sur la dépense d’énergie quotidienne de base et la dépense d’énergie quotidienne de totale obtenues, l’une par calorimétrie indirecte, l’autre par double marquage isotopique des molécules d’eau. Selon le type d’unité retenu, les valeurs les plus élevées au 99e centile des taux quotidiens d’inhalation sont obtenues chez des adolescentes et des femmes âgées de 11 à 55 ans souffrant d’embonpoint ou d’obésité, durant leur 36e semaine de grossesse (47,31 m³/jour), ainsi que chez des garçons de poids corporel normal âgés de 2,6 à moins de 6 mois (1,138 m³/kg-jour) et de 10 à moins de 16,5 ans (22,29 m³/m²-jour). Chez les enfants et les adolescents de poids corporel normal âgés de 5 à moins de 16.5 ans, les valeurs pour l’écart entre le 2,5e au 99e centile sont généralement plus élevées que celles obtenues chez les sujets plus âgés : taux de ventilation minute, 0,132 à 0,774 L/kg-min ou 4,42 à 21,69 L/m²-min versus 0,076 à 0,461 L/kg-min ou 2,80 à 16,99 L/m²-min; taux de ventilation alvéolaire, 0,093 à 0,553 L/kg-min ou 3,09 à 15,53 L/m²-min versus 0,047 à 0,312 L/kg-min ou 1,73 à 11,63 L/m²-min; débit cardiaque, 0,065 à 0,330 L/kg-min ou 2,17 à 9,46 L/m²-min versus 0,045 à 0,201 L/kg-min ou 1,63 à 7,24 L/m²-min; ratio de ventilation-perfusion, 1,12 à 2,16 versus 0,78 à 2,40. Il faut conclure que les apports inhalés en polluants, exprimés en ug/kg-min ou ug/m²-min sont plus élevés chez les enfants que chez les sujets plus âgés pour des concentrations d’exposition comparables. D’autres données montrent qu’il en est de même pour les apports inhalés par unité de poids corporel chez les femmes enceintes et les femmes qui allaitent par rapport à des sujets males d’âge comparable. L’ensemble des résultats obtenus suggère notamment que les valeurs des NOAELH de Santé Canada pourraient être abaissées par un facteur de 2,6 par utilisation du 99e centile le plus élevé des taux quotidiens d’inhalation chez les enfants; le taux de ventilation minute de 20,83 L/min approximé pour une journée de travail de 8 heures peut être considéré comme étant conservateur ; par contre, l’utilisation du taux quotidien d’inhalation de 0,286 m³/kg-jour (c.-à-d. 20 m³/jour pour un adulte de poids corporel de 70 kg) est inappropriée en analyse et gestion du risque lorsqu’appliquée à l’ensemble de la population. / The aim of the present study is to determine some respiratory and cardiovascular parameters in subjects of all ages for use, as physiological inputs, in toxicokinetic simulations and toxic risk assessment. The database used is taken from the literature. Data of interest include basal energy expenditures and total daily energy expenditures obtained by indirect calorimetry and doubly labeled water measurements respectively. Depending upon the unit value chosen, the highest 99th percentiles for daily inhalation rates were found in overweight/obese females 11 to 55 years old during their 36th weeks of pregnancy (47.31 m³/day), as well as in normal-weight boys aged 2.6 to less than 6 months(1.138 m³/kg-day) and 10 to less than 16.5 years (22.29 m³/m²-day). Generally higher values for the 2.5th up to 99th percentile were found in normal-weight children and teenagers aged 5 to less than 16.5 years compared to those for older individuals: minute ventilation rate, 0.132 to 0.774 L/kg-min or 4.42 to 21.69 L/m²-min versus 0.076 to 0.461 L/kg-min or 2.80 to 16.99 L/m²-min; alveolar ventilation rate, 0.093 to 0.553 L/kg-min or 3.09 to 15.53 L/m²-min versus 0.047 to 0.312 L/kg-min or 1.73 to 11.63 L/m²-min; cardiac output, 0.065 to 0.330 L/kg-min or 2.17 to 9.46 L/m²-min versus 0.045 to 0.201 L/kg-min or 1.63 to 7.24 L/m²-min; ventilation-perfusion ratio, 1.12 to 2.16 versus 0.78 to 2.40. Higher intakes of air pollutants by the respiratory tract expressed in ug/kg-min or ug/m²-min are expected in children compared to older individuals for identical exposure concentrations.The same conclusion is reached in pregnant and lactating females compared to male subjects of same ages, for intakes expressed per unit of bodyweight. The aggregate results obtained notably suggests that NOAELH values from Health Canada could be decreased by a factor of 2.6 by the use of the highest 99th percentiles for daily inhalation rates found in children; the minute ventilation rate of 20.83 L/min approximated based on an 8-hour workday may be considered as being conservative; however, the use of the daily inhalation rate of 0.286 m³/kg-day (i.e. 20 m³/day for a 70-kg adult) is inappropriate in risk assessment and management when applied to the whole population.

L’objectif de cette étude est de déterminer certains paramètres respiratoires et cardiovasculaires chez des sujets de tous âges pour utilisation, à titre d’intrants physiologiques, en modélisation toxicocinétique et en analyse du risque toxique. La base de données utilisée est tirée de la littérature. Il s’agit de mesures portant sur la dépense d’énergie quotidienne de base et la dépense d’énergie quotidienne de totale obtenues, l’une par calorimétrie indirecte, l’autre par double marquage isotopique des molécules d’eau. Selon le type d’unité retenu, les valeurs les plus élevées au 99e centile des taux quotidiens d’inhalation sont obtenues chez des adolescentes et des femmes âgées de 11 à 55 ans souffrant d’embonpoint ou d’obésité, durant leur 36e semaine de grossesse (47,31 m³/jour), ainsi que chez des garçons de poids corporel normal âgés de 2,6 à moins de 6 mois (1,138 m³/kg-jour) et de 10 à moins de 16,5 ans (22,29 m³/m²-jour). Chez les enfants et les adolescents de poids corporel normal âgés de 5 à moins de 16.5 ans, les valeurs pour l’écart entre le 2,5e au 99e centile sont généralement plus élevées que celles obtenues chez les sujets plus âgés : taux de ventilation minute, 0,132 à 0,774 L/kg-min ou 4,42 à 21,69 L/m²-min versus 0,076 à 0,461 L/kg-min ou 2,80 à 16,99 L/m²-min; taux de ventilation alvéolaire, 0,093 à 0,553 L/kg-min ou 3,09 à 15,53 L/m²-min versus 0,047 à 0,312 L/kg-min ou 1,73 à 11,63 L/m²-min; débit cardiaque, 0,065 à 0,330 L/kg-min ou 2,17 à 9,46 L/m²-min versus 0,045 à 0,201 L/kg-min ou 1,63 à 7,24 L/m²-min; ratio de ventilation-perfusion, 1,12 à 2,16 versus 0,78 à 2,40. Il faut conclure que les apports inhalés en polluants, exprimés en ug/kg-min ou ug/m²-min sont plus élevés chez les enfants que chez les sujets plus âgés pour des concentrations d’exposition comparables. D’autres données montrent qu’il en est de même pour les apports inhalés par unité de poids corporel chez les femmes enceintes et les femmes qui allaitent par rapport à des sujets males d’âge comparable. L’ensemble des résultats obtenus suggère notamment que les valeurs des NOAELH de Santé Canada pourraient être abaissées par un facteur de 2,6 par utilisation du 99e centile le plus élevé des taux quotidiens d’inhalation chez les enfants; le taux de ventilation minute de 20,83 L/min approximé pour une journée de travail de 8 heures peut être considéré comme étant conservateur ; par contre, l’utilisation du taux quotidien d’inhalation de 0,286 m³/kg-jour (c.-à-d. 20 m³/jour pour un adulte de poids corporel de 70 kg) est inappropriée en analyse et gestion du risque lorsqu’appliquée à l’ensemble de la population. / The aim of the present study is to determine some respiratory and cardiovascular parameters in subjects of all ages for use, as physiological inputs, in toxicokinetic simulations and toxic risk assessment. The database used is taken from the literature. Data of interest include basal energy expenditures and total daily energy expenditures obtained by indirect calorimetry and doubly labeled water measurements respectively. Depending upon the unit value chosen, the highest 99th percentiles for daily inhalation rates were found in overweight/obese females 11 to 55 years old during their 36th weeks of pregnancy (47.31 m³/day), as well as in normal-weight boys aged 2.6 to less than 6 months(1.138 m³/kg-day) and 10 to less than 16.5 years (22.29 m³/m²-day). Generally higher values for the 2.5th up to 99th percentile were found in normal-weight children and teenagers aged 5 to less than 16.5 years compared to those for older individuals: minute ventilation rate, 0.132 to 0.774 L/kg-min or 4.42 to 21.69 L/m²-min versus 0.076 to 0.461 L/kg-min or 2.80 to 16.99 L/m²-min; alveolar ventilation rate, 0.093 to 0.553 L/kg-min or 3.09 to 15.53 L/m²-min versus 0.047 to 0.312 L/kg-min or 1.73 to 11.63 L/m²-min; cardiac output, 0.065 to 0.330 L/kg-min or 2.17 to 9.46 L/m²-min versus 0.045 to 0.201 L/kg-min or 1.63 to 7.24 L/m²-min; ventilation-perfusion ratio, 1.12 to 2.16 versus 0.78 to 2.40. Higher intakes of air pollutants by the respiratory tract expressed in ug/kg-min or ug/m²-min are expected in children compared to older individuals for identical exposure concentrations.The same conclusion is reached in pregnant and lactating females compared to male subjects of same ages, for intakes expressed per unit of bodyweight. The aggregate results obtained notably suggests that NOAELH values from Health Canada could be decreased by a factor of 2.6 by the use of the highest 99th percentiles for daily inhalation rates found in children; the minute ventilation rate of 20.83 L/min approximated based on an 8-hour workday may be considered as being conservative; however, the use of the daily inhalation rate of 0.286 m³/kg-day (i.e. 20 m³/day for a 70-kg adult) is inappropriate in risk assessment and management when applied to the whole population.

INTRODUÇÃO: A monitorização da ventilação em transplante pulmonar depende de medidas estáticas e globais a partir de testes de função pulmonar e tomografia computadorizada, o que não é suficiente para detectar alterações regionais no parênquima pulmonar, que podem ser relevantes na avaliação de diferentes causas de comprometimento funcional. Tomografia de Impedância Elétrica (TIE) é uma técnica não-invasiva e livre de radiação com base na medição do potencial elétrico na superfície da parede torácica. O comportamento dinâmico e as informações quantitativas extraídas de imagens da TIE tornam possível avaliar as diferenças regionais na ventilação pulmonar. OBJETIVOS: Avaliar a ventilação regional com a TIE, em pacientes submetidos a transplante pulmonar unilateral ou bilateral e avaliar as variações ventilatórias em várias posições diferentes. MÉTODOS: A TIE foi realizada em 18 pacientes transplantados de pulmão (7 pacientes com transplante de pulmão bilateral, 6 pacientes com transplante unilateral por enfisema e 5 pacientes com transplante unilateral por fibrose), nas posições: sentada, supina, prona e decúbitos lateral direito e esquerdo. Os pacientes foram orientados a realizar 30 ciclos de ventilação espontânea e, em seguida, uma manobra de capacidade vital lenta. RESULTADOS: A comparação entre os grupos mostrou que houve diferença entre porcentagem de ventilação referente ao melhor pulmão (nos unilaterais o melhor pulmão era o transplantado e nos bilaterais o pulmão com maior ventilação na posição sentada). Na ventilação espontânea os transplantes unilaterais por enfisema e fibrose tinham 79% e 83% da ventilação gerada pelo pulmão transplantado, enquanto para os bilaterais o melhor pulmão contribuía com 57% da ventilação. Houve redução significativa na desproporção da ventilação quando comparada a ventilação espontânea com a capacidade vital (p = 0,001). Na ventilação espontânea houve variação da ventilação de acordo com a posição analisada, o que não aconteceu na capacidade vital. A medida do ângulo de fase foi próxima a zero para os bilaterais, negativa para os unilaterais por enfisema e positiva para os unilaterais por fibrose, mostrando que nos bilaterais havia sincronia entre o esvaziamento dos dois pulmões e nos grupos unilaterais havia dissincronia (diferentes constantes de tempo). CONCLUSÃO: A TIE pode ser uma ferramenta útil para o estudo pacientes transplantados de pulmão, evidenciando diferenças ocultas na dinâmica ventilatória entre os pulmões nativos e os de pulmões transplantados. Como esperado, os pacientes de transplante de pulmão unilateral exibiram uma ventilação muito mais heterogênea regionalmente. O decúbito lateral e a ventilação espontânea amplificam tais diferenças. / INTRODUCTION: Ventilation monitoring in lung transplantation is still depending on static and global measurements from lung function testing and computed tomography, what is not enough to detect regional changes in lung parenchyma, which may be relevant in evaluating different causes of functional impairment. Electrical Impedance Tomography (EIT) is a noninvasive and radiation-free technique based on the measurement of electric potentials at the chest wall surface. The dynamic behavior and the quantitative information extracted from EIT images make it possible to assess regional differences in lung ventilation. OBJECTIVES: To assess regional ventilation with EIT, in patients who underwent single or bilateral lung transplantation and to evaluate ventilatory variations in several different body positions. METHODS: We performed the EIT in 18 lung transplanted patients (7 bilateral lung transplantation patients, 6 single lung transplantation patients with emphysema and 5 single lung transplantation patients with fibrosis), in seated, supine, right, left and ventral positions. Patients were asked to perform 30 cycles of spontaneous ventilation and then a slow vital capacity maneuver. RESULTS: The comparison between groups showed that there was difference between the percentage of ventilation related to the best lung (the best lung in single lung patients was the transplanted lung and in the bilateral patients was the lung with best ventilation in the sitting position). The ventilation generated by the transplanted lung on spontaneous ventilation in single lung patients for emphysema and fibrosis were 79% and 83% respectively, whereas for the bilateral group better lung contributed with 57% of ventilation. Significant reduction in the disparity of ventilation occurred comparing the spontaneous ventilation and the vital capacity maneuver (p = 0.001). Ventilation changed in accordance with the position analyzed in spontaneous ventilation, what did not happen in vital capacity. The measurement of phase angle was close to zero for the bilateral, negative for single lung emphysema group and positive for single lung fibrosis group, showing that we had synchronicity between the emptying of both lungs in the bilateral group and disynchronicity in the single lung groups (different time constants). CONCLUSION: EIT can be a useful tool to study lung transplant patients, evidencing occult differences in lung dynamics between the native and the transplanted lung. As expected, single lung transplant patients exhibited a much more disturbed regional ventilation. The lateral decubitus and the spontaneous ventilation amplified such differences

Made available in DSpace on 2016-01-26T12:51:53Z (GMT). No. of bitstreams: 1 maristeladeberaldini_dissert.pdf: 1301347 bytes, checksum: 7cac2aa1d04033762fd9af3c08299a4b (MD5) Previous issue date: 2006-08-25 / Hepatopulmonary syndrome (HPS) is a clinical triad characterized by the presence of intrapulmonary vascular dilation (IPVD) and arterial hypoxemia with hepatic disease. Liver transplantation constitutes the only cure for HPS; possibly providing a complete reversal of the symptoms. However, an association between HPS and adverse results has been reported with liver transplantation. Data on long-term survival of transplant patients with HPS are scarce. The objective of this study was to evaluate the short-term postoperative complications and short- and long-term survival in the postoperative period of transplant patients with and without HPS. Fifty-nine cirrhotic patients transplanted in the period from October 2001 to May 2004 were evaluated in this study. The patients were divided into two groups: with HPS (HPS Group n = 25) and without HPS (Control group n = 34). IPVD was diagnosed by echocardiogram contrasted using microbubbles. Hypoxemia was defined as D(A-a)O2 &#8805; 15 mmHg. The following variables were considered after liver transplantation: immediate survival (within the hospitalization period after transplantation), late survival (at 48 months), causes of death, time of hospital stay, time of ICU, time of ventilatory support, the necessity of re-intubation and complications. The results were analysed utilizing the following statistical tests: T-test to compare means, the non-parametric Mann-Whitney test to compare medians and ANOVA and chi-squared tests for qualitative variables. A level of significance of 0.05 for &#945; was adopted. The HPS and Control Groups were homogeneous in respect to age (p-value = 0.36; 43.8 ± 12.2 vs. 46.9 ± 13.5) and gender (p-value = 0.47), with a predominance of men in both groups (68 and 78%, respectively). They were also similar in respect to the severity of hepatic disease and the presence of ascitis. The PaO2 was significantly lower (74.9 ± 12.1 vs. 93 ± 6.4 mmHg; P-value < 0.001) and the D(A-a)O2 was significantly higher in the HPS Group compared to the Control Group. There were 10 patients with mild hypoxemia (40%), 11 with moderate hypoxemia (44%) and 4 with severe/very severe hypoxemia (16%) in the HPS Group. There were no significant differences between the groups with and without HPS in relation to early (68% vs. 77%; p-value = 0.27) and late (60% vs. 64%; p-value = 0.67) survival; time in ICU (median 7.0 vs. 5.5; p-value = 0.41); time on ventilatory support (median 38.0 vs. 27.5; p-value = 0.43); re-intubation rate (32.0% vs. 23.5%; p-value = 0.45) and complications (p-value = 0.72) in the immediate post-transplantation period. In conclusion, there were no significant differences in the results of liver transplantation of patients with and without HPS in respect to immediate morbidity or in relation to early and late survival 48 months after the procedure. The predominance of patients with mild and moderate HPS in the group may have influenced our results. / A síndrome hepatopulmonar (SHP) é uma tríade clínica caracterizada pela presença de dilatação vascular intrapulmonar (DVIP) e hipoxemia arterial [D(A-a)O2 &#8805; 15 mmHg] em portadores de doença hepática. O transplante de fígado constitui a única modalidade terapêutica para SHP podendo haver reversão completa do quadro. Porém, tem sido descrita associação entre SHP e resultados desfavoráveis do transplante de fígado. Dados sobre a sobrevida a longo prazo em transplantados com SHP são escassos. O objetivo deste estudo foi avaliar a morbidade pós-operatória precoce e a sobrevida precoce e tardia no período pós-operatório de pacientes transplantados com e sem SHP. Foram analisados, neste estudo transversal comparativo de amostras paralelas, 59 pacientes cirróticos transplantados no período de Outubro de 2001 a Maio de 2004, divididos em dois grupos: com SHP = grupo estudo (n=25) e sem SHP = grupo controle (n=34). A DVIP foi diagnosticada pelo exame ecocardiográfico contrastado com microbolhas. A hipoxemia foi definida como D(A-a)O2 &#8805; 15 mmHg. As seguintes variáveis após o transplante de fígado foram estudadas: sobrevida imediata (ocorrida no período da internação para o transplante), sobrevida tardia (48 meses), causas de óbito, tempo de permanência hospitalar, tempo de permanência em UTI e tempo de ventilação mecânica, necessidade de reentubação e complicações. Os resultados foram analisados utilizando os seguintes testes estatísticos: teste t para comparação de médias, teste não paramétrico de Mann-Whitney para comparação de medianas, ANOVA e teste qui-quadrado para variáveis qualitativas. O nível de significância adotado foi &#945;=0,05. Os grupos SHP e controle foram homogêneos quanto à idade (P=0,36) (43,8 ± 12,2 X 46,9 ± 13,5) e gênero (P=0,47), havendo predominância de homens nos dois grupos (68 e 78%, respectivamente). Foram também semelhantes quanto à causa e gravidade da doença hepática e quanto à presença de ascite. A PaO2 foi significativamente menor (74,9 ± 12,1 X 93 ± 6,4 mmHg; P<0,001) e a D(A-a)O2 foi significativamente maior (30,3 ± 10,6 X 11,0 ± 7,0; P<0,001) no grupo SHP em relação ao grupo controle. Houve 10 pacientes com hipoxemia leve (40%), 11 com hipoxemia moderada (44%) e 4 com hipoxemia grave/muito grave (16%) no grupo com SHP. Os resultados não mostraram evidência de diferença entre os grupos com e sem SHP quanto à sobrevida precoce (68% X 77%; P=0,27) e tardia (60% X 64%; P=0,67); quanto ao tempo de permanência em UTI (mediana 7,0 X 5,5; P=0,41); tempo de ventilação mecânica (mediana 38,0 X 27,5; P=0,43); taxa de reentubação (32,0% X 23,5%; P=0,45) e ocorrência de complicações (P=0,72), no período imediato após o transplante. Podemos concluir que não houve diferença no resultado do transplante de fígado de pacientes com e sem SHP, quanto à morbidade e complicações imediatas, e quanto à sobrevida precoce e aos 48 meses após o procedimento. O predomínio de pacientes com SHP leve e moderada no grupo SHP deve ter influenciado os nossos resultados.

Laparoscopic operations are a common and popular way for abdominal procedures. They are usually performed by insufflation of carbon dioxide (CO2) into the abdominal cavity. However, insufflation of CO2 may interfere with cardiac and circulatory as well as respiratory functions. The CO2-pneumoperitoneum (PP) may cause hypercarbia and acidosis. The direct effects of CO2 and acidosis lead to decreased cardiac contractility, sensitization of the myocardium to arrhythmogenic effects of catecholamines and systemic vasodilatation. There may even be long-lasting post-operative effects on breathing control. The pneumoperitoneum may also cause several respiratory changes, e.g. decreased functional residual capacity (FRC) and vital capacity (VC), formation of atelectasis, reduced respiratory compliance and increased airway pressure. Still, arterial oxygenation is mostly maintained or even improved during PP. In view of the apparently contradictory results in respiratory mechanics and gas exchange, the present studies were performed to evaluate respiratory changes on gas exchange and ventilation-perfusion distributions during PP in a porcine model. It was demonstrated that atelectasis during anaesthesia and PP may be estimated by an increased arterial to endtidal PCO2-gradient (study I). Perfusion was redistributed away from dorsal, collapsed lung regions when PP was established. This resulted in a better ventilation-perfusion match (study II). Increasing abdominal pressure shifted blood flow more and more away from collapsed lung tissue, decreased pulmonary shunt and improved oxygenation from 8 to 16 mmHg PP, despite an increase of atelectasis formation (study III). CO2-PP enhanced the shift of blood flow towards better ventilated parts of the lung compared to Air-PP. Moreover, sodium natriumprusside worsened the ventilation-perfusion match even more and blunted the effects previously seen with carbon dioxide. CO2 should therefore be the mediator of enhancing HPV during PP. In conclusion, pneumoperitoneum with CO2 causes atelectasis with elimination of ventilation in the dependent lung regions. However, an efficient shift of blood flow away from collapsed, non-ventilated regions results in a better ventilation-perfusion matching and better oxygenation of blood than without PP. A prerequisite for the beneficial effect is the use of carbon dioxide for the abdominal inflation, since it enhances HPV.

INTRODUÇÃO: A monitorização da ventilação em transplante pulmonar depende de medidas estáticas e globais a partir de testes de função pulmonar e tomografia computadorizada, o que não é suficiente para detectar alterações regionais no parênquima pulmonar, que podem ser relevantes na avaliação de diferentes causas de comprometimento funcional. Tomografia de Impedância Elétrica (TIE) é uma técnica não-invasiva e livre de radiação com base na medição do potencial elétrico na superfície da parede torácica. O comportamento dinâmico e as informações quantitativas extraídas de imagens da TIE tornam possível avaliar as diferenças regionais na ventilação pulmonar. OBJETIVOS: Avaliar a ventilação regional com a TIE, em pacientes submetidos a transplante pulmonar unilateral ou bilateral e avaliar as variações ventilatórias em várias posições diferentes. MÉTODOS: A TIE foi realizada em 18 pacientes transplantados de pulmão (7 pacientes com transplante de pulmão bilateral, 6 pacientes com transplante unilateral por enfisema e 5 pacientes com transplante unilateral por fibrose), nas posições: sentada, supina, prona e decúbitos lateral direito e esquerdo. Os pacientes foram orientados a realizar 30 ciclos de ventilação espontânea e, em seguida, uma manobra de capacidade vital lenta. RESULTADOS: A comparação entre os grupos mostrou que houve diferença entre porcentagem de ventilação referente ao melhor pulmão (nos unilaterais o melhor pulmão era o transplantado e nos bilaterais o pulmão com maior ventilação na posição sentada). Na ventilação espontânea os transplantes unilaterais por enfisema e fibrose tinham 79% e 83% da ventilação gerada pelo pulmão transplantado, enquanto para os bilaterais o melhor pulmão contribuía com 57% da ventilação. Houve redução significativa na desproporção da ventilação quando comparada a ventilação espontânea com a capacidade vital (p = 0,001). Na ventilação espontânea houve variação da ventilação de acordo com a posição analisada, o que não aconteceu na capacidade vital. A medida do ângulo de fase foi próxima a zero para os bilaterais, negativa para os unilaterais por enfisema e positiva para os unilaterais por fibrose, mostrando que nos bilaterais havia sincronia entre o esvaziamento dos dois pulmões e nos grupos unilaterais havia dissincronia (diferentes constantes de tempo). CONCLUSÃO: A TIE pode ser uma ferramenta útil para o estudo pacientes transplantados de pulmão, evidenciando diferenças ocultas na dinâmica ventilatória entre os pulmões nativos e os de pulmões transplantados. Como esperado, os pacientes de transplante de pulmão unilateral exibiram uma ventilação muito mais heterogênea regionalmente. O decúbito lateral e a ventilação espontânea amplificam tais diferenças. / INTRODUCTION: Ventilation monitoring in lung transplantation is still depending on static and global measurements from lung function testing and computed tomography, what is not enough to detect regional changes in lung parenchyma, which may be relevant in evaluating different causes of functional impairment. Electrical Impedance Tomography (EIT) is a noninvasive and radiation-free technique based on the measurement of electric potentials at the chest wall surface. The dynamic behavior and the quantitative information extracted from EIT images make it possible to assess regional differences in lung ventilation. OBJECTIVES: To assess regional ventilation with EIT, in patients who underwent single or bilateral lung transplantation and to evaluate ventilatory variations in several different body positions. METHODS: We performed the EIT in 18 lung transplanted patients (7 bilateral lung transplantation patients, 6 single lung transplantation patients with emphysema and 5 single lung transplantation patients with fibrosis), in seated, supine, right, left and ventral positions. Patients were asked to perform 30 cycles of spontaneous ventilation and then a slow vital capacity maneuver. RESULTS: The comparison between groups showed that there was difference between the percentage of ventilation related to the best lung (the best lung in single lung patients was the transplanted lung and in the bilateral patients was the lung with best ventilation in the sitting position). The ventilation generated by the transplanted lung on spontaneous ventilation in single lung patients for emphysema and fibrosis were 79% and 83% respectively, whereas for the bilateral group better lung contributed with 57% of ventilation. Significant reduction in the disparity of ventilation occurred comparing the spontaneous ventilation and the vital capacity maneuver (p = 0.001). Ventilation changed in accordance with the position analyzed in spontaneous ventilation, what did not happen in vital capacity. The measurement of phase angle was close to zero for the bilateral, negative for single lung emphysema group and positive for single lung fibrosis group, showing that we had synchronicity between the emptying of both lungs in the bilateral group and disynchronicity in the single lung groups (different time constants). CONCLUSION: EIT can be a useful tool to study lung transplant patients, evidencing occult differences in lung dynamics between the native and the transplanted lung. As expected, single lung transplant patients exhibited a much more disturbed regional ventilation. The lateral decubitus and the spontaneous ventilation amplified such differences