MARCELO BRITTO PASSOS AMATO
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Cardio-Pneumologia, Faculdade de Medicina - Docente
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/09 - Laboratório de Pneumologia, Hospital das Clínicas, Faculdade de Medicina
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/09 - Laboratório de Pneumologia, Hospital das Clínicas, Faculdade de Medicina
9 resultados
Resultados de Busca
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- Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep(2013) TUCCI, Mauro R.; COSTA, Eduardo L. V.; WELLMAN, Tyler J.; MUSCH, Guido; WINKLER, Tilo; HARRIS, R. Scott; VENEGAS, Jose G.; AMATO, Marcelo B. P.; MELO, Marcos F. VidalBackground: Lung derecruitment is common during general anesthesia. Mechanical ventilation with physiological tidal volumes could magnify derecruitment, and produce lung dysfunction and inflammation. The authors used positron emission tomography to study the process of derecruitment in normal lungs ventilated for 16 h and the corresponding changes in regional lung perfusion and inflammation. Methods: Six anesthetized supine sheep were ventilated with V-T = 8 ml/kg and positive end-expiratory pressure = 0. Transmission scans were performed at 2-h intervals to assess regional aeration. Emission scans were acquired at baseline and after 16 h for the following tracers: (1) F-18-fluorodeoxyglucose to evaluate lung inflammation and (2) (NN)-N-13 to calculate regional perfusion and shunt fraction. Results: Gas fraction decreased from baseline to 16 h in dorsal (0.31 +/- 0.13 to 0.14 +/- 0.12, P < 0.01), but not in ventral regions (0.61 +/- 0.03 to 0.63 +/- 0.07, P = nonsignificant), with time constants of 1.5-44.6 h. Although the vertical distribution of relative perfusion did not change from baseline to 16 h, shunt increased in dorsal regions (0.34 +/- 0.23 to 0.63 +/- 0.35, P < 0.01). The average pulmonary net F-18-fluorodeoxyglucose uptake rate in six regions of interest along the ventral-dorsal direction increased from 3.4 +/- 1.4 at baseline to 4.1 +/- 1.510(-3)/min after 16 h (P < 0.01), and the corresponding average regions of interest F-18-fluorodeoxyglucose phosphorylation rate increased from 2.0 +/- 0.2 to 2.5 +/- 0.210(-2)/min (P < 0.01). Conclusions: When normal lungs are mechanically ventilated without positive end-expiratory pressure, loss of aeration occurs continuously for several hours and is preferentially localized to dorsal regions. Progressive lung derecruitment was associated with increased regional shunt, implying an insufficient hypoxic pulmonary vasoconstriction. The increased pulmonary net uptake and phosphorylation rates of F-18-fluorodeoxyglucose suggest an incipient inflammation in these initially normal lungs.
- Alveolar Tipping Points in Changing Lungs Related to Positive End-expiratory Pressure(2023) WINKLER, Tilo; AMATO, Marcelo B. P.
- Lung Recruitment in Obese Patients with Acute Respiratory Distress Syndrome(2019) FUMAGALLI, Jacopo; SANTIAGO, Roberta R. S.; DROGHI, Maddalena Teggia; ZHANG, Changsheng; FINTELMANN, Florian J.; TROSCHEL, Fabian M.; MORAIS, Caio C. A.; AMATO, Marcelo B. P.; KACMAREK, Robert M.; BERRA, Lorenzo; PALMA, Sophia; LARSON, Grant M.; KANEKI, Shigeru W.; FISHER, Daniel; REZOAGLI, Emanuele; PIRRONE, Massimiliano; MARRAZZO, Francesco; ZHANG, Hui; ZHAO, JingBackground: Obese patients are characterized by normal chest-wall elastance and high pleural pressure and have been excluded from trials assessing best strategies to set positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS). The authors hypothesized that severely obese patients with ARDS present with a high degree of lung collapse, reversible by titrated PEEP preceded by a lung recruitment maneuver. Methods: Severely obese ARDS patients were enrolled in a physiologic crossover study evaluating the effects of three PEEP titration strategies applied in the following order: (1) PEEP ARDSNET : the low PEEP/Fio(2) ARDSnet table; (2) PEEP INCREMENTAL : PEEP levels set to determine a positive end-expiratory transpulmonary pressure; and (3) PEEP DECREMENTAL : PEEP levels set to determine the lowest respiratory system elastance during a decremental PEEP trial following a recruitment maneuver on respiratory mechanics, regional lung collapse, and overdistension according to electrical impedance tomography and gas exchange. Results: Fourteen patients underwent the study procedures. At PEEP ARDSNET (13 +/- 1 cm H2O) end-expiratory transpulmonary pressure was negative (-5 +/- 5 cm H2O), lung elastance was 27 +/- 12 cm H2O/L, and PaO2/Fio(2) was 194 +/- 111 mmHg. Compared to PEEP ARDSNET, at PEEP INCREMENTAL level (22 +/- 3 cm H2O) lung volume increased (977 +/- 708 ml), lung elastance decreased (23 +/- 7 cm H2O/l), lung collapse decreased (18 +/- 10%), and ventilation homogeneity increased thus rising oxygenation (251 +/- 105 mmHg), despite higher overdistension levels (16 +/- 12%), all values P < 0.05 versus PEEP ARDSnet. Setting PEEP according to a PEEP DECREMENTAL trial after a recruitment maneuver (21 +/- 4 cm H2O, P = 0.99 vs. PEEP INCREMENTAL) further lowered lung elastance (19 +/- 6 cm H2O/l) and increased oxygenation (329 +/- 82 mmHg) while reducing lung collapse (9 +/- 2%) and overdistension (11 +/- 2%), all values P < 0.05 versus PEEP ARDSnet and PEEP INCREMENTAL. All patients were maintained on titrated PEEP levels up to 24 h without hemodynamic or ventilation related complications. Conclusions: Among the PEEP titration strategies tested, setting PEEP according to a PEEP DECREMENTAL trial preceded by a recruitment maneuver obtained the best lung function by decreasing lung overdistension and collapse, restoring lung elastance, and oxygenation suggesting lung tissue recruitment.
- Continuous Negative Abdominal Pressure Reduces Ventilator-induced Lung Injury in a Porcine Model(2018) YOSHIDA, Takeshi; ENGELBERTS, Doreen; OTULAKOWSKI, Gail; KATIRA, Bhushan; POST, Martin; FERGUSON, Niall D.; BROCHARD, Laurent; AMATO, Marcelo B. P.; KAVANAGH, Brian P.Background: In supine patients with acute respiratory distress syndrome, the lung typically partitions into regions of dorsal atelectasis and ventral aeration (""baby lung""). Positive airway pressure is often used to recruit atelectasis, but often overinflates ventral (already aerated) regions. A novel approach to selective recruitment of dorsal atelectasis is by ""continuous negative abdominal pressure. Methods: A randomized laboratory study was performed in anesthetized pigs. Lung injury was induced by surfactant lavage followed by 1h of injurious mechanical ventilation. Randomization (five pigs in each group) was to positive end-expiratory pressure (PEEP) alone or PEEP with continuous negative abdominal pressure (-5 cm H2O via a plexiglass chamber enclosing hindlimbs, pelvis, and abdomen), followed by 4h of injurious ventilation (high tidal volume, 20ml/kg; low expiratory transpulmonary pressure, -3cm H2O). The level of PEEP at the start was approximate to 7 (vs. approximate to 3) cm H2O in the PEEP (vs. PEEP plus continuous negative abdominal pressure) groups. Esophageal pressure, hemodynamics, and electrical impedance tomography were recorded, and injury determined by lung wet/dry weight ratio and interleukin-6 expression. Results: All animals survived, but cardiac output was decreased in the PEEP group. Addition of continuous negative abdominal pressure to PEEP resulted in greater oxygenation (Pao(2)/fractional inspired oxygen 316134 vs. 80 +/- 24 mmHg at 4h, P = 0.005), compliance (14.2 +/- 3.0 vs. 10.3 +/- 2.2ml/cm H2O, P = 0.049), and homogeneity of ventilation, with less pulmonary edema (approximate to 10% less) and interleukin-6 expression (approximate to 30% less). Conclusions: Continuous negative abdominal pressure added to PEEP reduces ventilator-induced lung injury in a pig model compared with PEEP alone, despite targeting identical expiratory transpulmonary pressure.
- Pulmonary Aeration and Posterior Collapse Assessed by Electrical Impedance Tomography in Healthy Children: Contribution of Anesthesia and Controlled Mechanical Ventilation(2022) NASCIMENTO, Milena Siciliano; REBELLO, Celso Moura; COSTA, Eduardo Leite Vieira; ROSSI, Felipe de Souza; PRADO, Cristiane do; AMATO, Marcelo Britto Passos
- Lung Imaging Acquisition with Electrical Impedance Tomography: Tackling Common Pitfalls(2023) SANTIAGO, Roberta Ribeiro De Santis; XIN, Yi; GAULTON, Timothy G.; ALCALA, Glasiele; CAMARGO, Erick Dario Leon Bueno de; CEREDA, Maurizio; AMATO, Marcelo Britto Passos; BERRA, Lorenzo
- Phrenic Nerve Block and Respiratory Effort in Pigs and Critically Ill Patients with Acute Lung Injury(2022) PEREIRA, Sergio M.; SINEDINO, Bruno E.; V, Eduardo L. Costa; MORAIS, Caio C. A.; SKLAR, Michael C.; LIMA, Cristhiano Adkson Sales; NAKAMURA, Maria A. M.; RANZANI, Otavio T.; GOLIGHER, Ewan C.; TUCCI, Mauro R.; HO, Yeh-Li; TANIGUCHI, Leandro U.; VIEIRA, Joaquim E.; BROCHARD, Laurent; AMATO, Marcelo B. P.Background: Strong spontaneous inspiratory efforts can be difficult to control and prohibit protective mechanical ventilation. Instead of using deep sedation and neuromuscular blockade, the authors hypothesized that perineural administration of lidocaine around the phrenic nerve would reduce tidal volume (V-T) and peak transpulmonary pressure in spontaneously breathing patients with acute respiratory distress syndrome. Methods: An established animal model of acute respiratory distress syndrome with six female pigs was used in a proof-of-concept study. The authors then evaluated this technique in nine mechanically ventilated patients under pressure support exhibiting driving pressure greater than 15 cm H2O or V-T greater than 10 ml/kg of predicted body weight. Esophageal and transpulmonary pressures, electrical activity of the diaphragm, and electrical impedance tomography were measured in pigs and patients. Ultrasound imaging and a nerve stimulator were used to identify the phrenic nerve, and perineural lidocaine was administered sequentially around the left and right phrenic nerves. Results: Results are presented as median [interquartile range, 25th to 75th percentiles]. In pigs, V-T decreased from 7.4 ml/kg [7.2 to 8.4] to 5.9 ml/kg [5.5 to 6.6] (P < 0.001), as did peak transpulmonary pressure (25.8 cm H2O [20.2 to 27.2] to 17.7 cm H2O [13.8 to 18.8]; P < 0.001) and driving pressure (28.7 cm H2O [20.4 to 30.8] to 19.4 cm H2O [15.2 to 22.9]; P < 0.001). Ventilation in the most dependent part decreased from 29.3% [26.4 to 29.5] to 20.1% [15.3 to 20.8] (P < 0.001). In patients, V-T decreased (8.2 ml/ kg [7.9 to 11.1] to 6.0 ml/ kg [5.7 to 6.7]; P < 0.001), as did driving pressure (24.7 cm H2O [20.4 to 34.5] to 18.4 cm H2O [16.8 to 20.7]; P < 0.001). Esophageal pressure, peak transpulmonary pressure, and electrical activity of the diaphragm also decreased. Dependent ventilation only slightly decreased from 11.5% [8.5 to 12.6] to 7.9% [5.3 to 8.6] (P = 0.005). Respiratory rate did not vary. Variables recovered 1 to 12.7 h [6.7 to 13.7] after phrenic nerve block. Conclusions: Phrenic nerve block is feasible, lasts around 12 h, and reduces V-T and driving pressure without changing respiratory rate in patients under assisted ventilation.
- Individual Positive End-expiratory Pressure Settings Optimize Intraoperative Mechanical Ventilation and Reduce Postoperative Atelectasis(2018) PEREIRA, Sergio M.; TUCCI, Mauro R.; MORAIS, Caio C. A.; SIMOES, Claudia M.; TONELOTTO, Bruno F. F.; POMPEO, Michel S.; KAY, Fernando U.; PELOSI, Paolo; VIEIRA, Joaquim E.; AMATO, Marcelo B. P.Background: Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications after abdominal surgery. Although the protective role of a more physiologic tidal volume has been established, the added protection afforded by positive end-expiratory pressure (PEEP) remains uncertain. The authors hypothesized that a low fixed PEEP might not fit all patients and that an individually titrated PEEP during anesthesia might improve lung function during and after surgery. Methods: Forty patients were studied in the operating room (20 laparoscopic and 20 open-abdominal). They underwent elective abdominal surgery and were randomized to institutional PEEP (4 cm H2O) or electrical impedance tomography-guided PEEP (applied after recruitment maneuvers and targeted at minimizing lung collapse and hyperdistension, simultaneously). Patients were extubated without changing selected PEEP or fractional inspired oxygen tension while under anesthesia and submitted to chest computed tomography after extubation. Our primary goal was to individually identify the electrical impedance tomography-guided PEEP value producing the best compromise of lung collapse and hyperdistention. Results: Electrical impedance tomography-guided PEEP varied markedly across individuals (median, 12 cm H2O; range, 6 to 16 cm H2O; 95% CI, 10-14). Compared with PEEP of 4 cm H2O, patients randomized to the electrical impedance tomography-guided strategy had less postoperative atelectasis (6.2 +/- 4.1 vs. 10.8 +/- 7.1% of lung tissue mass; P = 0.017) and lower intraoperative driving pressures (mean values during surgery of 8.0 +/- 1.7 vs. 11.6 +/- 3.8 cm H2O; P < 0.001). The electrical impedance tomography-guided PEEP arm had higher intraoperative oxygenation (435 +/- 62 vs. 266 +/- 76 mmHg for laparoscopic group; P < 0.001), while presenting equivalent hemodynamics (mean arterial pressure during surgery of 80 +/- 14 vs. 78 +/- 15 mmHg; P = 0.821). Conclusions: PEEP requirements vary widely among patients receiving protective tidal volumes during anesthesia for abdominal surgery. Individualized PEEP settings could reduce postoperative atelectasis (measured by computed tomography) while improving intraoperative oxygenation and driving pressures, causing minimum side effects.
- Individualizing Intraoperative Ventilation: Reply(2019) TUCCI, Mauro R.; PEREIRA, Sergio M.; VIEIRA, Joaquim E.; AMATO, Marcelo B. P.