The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
Giuseppe Miserocchi - One of the best experts on this subject based on the ideXlab platform.
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Changes in the mechanical properties of the respiratory system during the development of interstitial lung edema.
Respiratory research, 2008Co-Authors: Raffaele Dellaca, Emanuela Zannin, G Sancini, Ilaria Rivolta, Biagio Eugenio Leone, Antonio Pedotti, Giuseppe MiserocchiAbstract:Background Pulmonary edema induces changes in airway and lung tissues mechanical properties that can be measured by low-frequency forced oscillation technique (FOT). It is preceded by interstitial edema which is characterized by the accumulation of Extravascular Fluid in the interstitial space of the air-blood barrier. Our aim was to investigate the impact of the early stages of the development of interstitial edema on the mechanical properties of the respiratory system.
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Changes in the mechanical properties of the respiratory system during the development of interstitial lung edema
Respiratory Research, 2008Co-Authors: Raffaele Dellaca, Emanuela Zannin, G Sancini, Ilaria Rivolta, Biagio Eugenio Leone, Antonio Pedotti, Giuseppe MiserocchiAbstract:Background Pulmonary edema induces changes in airway and lung tissues mechanical properties that can be measured by low-frequency forced oscillation technique (FOT). It is preceded by interstitial edema which is characterized by the accumulation of Extravascular Fluid in the interstitial space of the air-blood barrier. Our aim was to investigate the impact of the early stages of the development of interstitial edema on the mechanical properties of the respiratory system. Methods We studied 17 paralysed and mechanically ventilated closed-chest rats (325–375 g). Total input respiratory system impedance (Zrs) was derived from tracheal flow and pressure signals by applying forced oscillations with frequency components from 0.16 to 18.44 Hz distributed in two forcing signals. In 8 animals interstitial lung edema was induced by intravenous infusion of saline solution (0.75 ml/kg/min) for 4 hours; 9 control animals were studied with the same protocol but without infusion. Zrs was measured at the beginning and every 15 min until the end of the experiment. Results In the treated group the lung wet-to-dry weight ratio increased from 4.3 ± 0.72 to 5.23 ± 0.59, with no histological signs of alveolar flooding. Resistance (Rrs) increased in both groups over time, but to a greater extent in the treated group. Reactance (Xrs) did not change in the control group, while it decreased significantly at all frequencies but one in the treated. Significant changes in Rrs and Xrs were observed starting after ~135 min from the beginning of the infusion. By applying a constant phase model to partition airways and tissue mechanical properties, we observed a mild increase in airways resistance in both groups. A greater and significant increase in tissue damping (from 603.5 ± 100.3 to 714.5 ± 81.9 cmH_2O/L) and elastance (from 4160.2 ± 462.6 to 5018.2 ± 622.5 cmH_2O/L) was found only in the treated group. Conclusion These results suggest that interstitial edema has a small but significant impact on the mechanical features of lung tissues and that these changes begin at very early stages, before the beginning of accumulation of Extravascular Fluid into the alveoli.
Göran Hedenstierna - One of the best experts on this subject based on the ideXlab platform.
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Thoracic Intravascular and Extravascular Fluid Volumes in Cardiac Surgical Patients
Anesthesiology, 1993Co-Authors: Thomas Hachenberg, Arne Tenling, Hans-ulrich Rothen, Sven-olov Nyström, Hans Tydén, Göran HedenstiernaAbstract:BACKGROUND One possible mechanism of impaired oxygenation in cardiac surgery with extracorporeal circulation (ECC) is the accumulation of Extravascular lung water (EVLW). Intrathoracic blood volume (ITBV) and pulmonary blood volume (PBV) also may increase after separation from ECC, which can influence both cardiac performance and pulmonary capillary Fluid filtration. This study tested whether there were any relationships between lung Fluid accumulation and pulmonary gas exchange during the perioperative period of cardiac surgery and ECC. METHODS Ten patients undergoing myocardial revascularization were studied. ITBV, PBV, and EVLW were determined from the mean transit times and decay times of the dye and thermal indicator curves obtained simultaneously in the descending aorta. Gas exchange was assessed by arterial and mixed venous partial pressure of oxygen (PO2) and carbon dioxide (PCO2), and calculation of alveolo-arterial PO2 gradient (PA-aO2) and venous admixture (QVA/QT). Recordings were made after induction of anesthesia, after sternotomy, 15 min after separation from ECC, and 4 and 20 h postoperatively. RESULTS After induction of anesthesia, EVLW (6.0 +/- 1.0 ml/kg, mean +/- SD), PBV (3.6 +/- 1.3 ml/kg), and ITBV (18.4 +/- 2.7 ml/kg) were within normal ranges. Oxygenation was moderately impaired, as indicated by an increased PA-aO2 (144 +/- 46 mmHg) and QVA/QT (11 +/- 4%). After separation from ECC, EVLW had increased to 9.1 +/- 2.6 ml/kg, which was accompanied by an increase of ITBV (26.0 +/- 4.4 ml/kg) and PBV (5.6 +/- 1.9 ml/kg). PAa-O2 (396 +/- 116 mmHg) and QVA/QT (29 +/- 7%) also were increased. ITBV and PBV remained increased 4 and 20 h postoperatively, but EVLW decreased to presurgery values. No correlations were found between thoracic intravascular and Extravascular Fluid volumes and gas exchange. CONCLUSIONS Cardiac surgery with the use of ECC induces alterations of thoracic intravascular and Extravascular Fluid volumes. Postoperatively, increased ITBV and PBV need not be associated with higher EVLW. Thus, sufficient mechanisms protecting against lung edema formation or providing resolution of EVLW probably are maintained after ECC. Since oxygenation is impaired during and after cardiac surgery, it is concluded that mechanisms other than or in addition to changes of ITBV, PBV, and EVLW predominantly influence gas exchange.
Thomas Hachenberg - One of the best experts on this subject based on the ideXlab platform.
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Gas exchange impairment in patients udergoing cardiac surgery : with reference to ventilation-perfusion relationships, thoracic intravascular and Extravascular Fluid volumes, pulmonary morphology and mechanical ventilation in the prone position
1995Co-Authors: Thomas HachenbergAbstract:Gas exchange impairment in patients undergoing cardiac surgery : with reference to ventilation-perfusion relationships, thoracic intravascular and Extravascular Fluid volumes, pulmonary morphology and mechanical ventilation in the prone position
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Thoracic Intravascular and Extravascular Fluid Volumes in Cardiac Surgical Patients
Anesthesiology, 1993Co-Authors: Thomas Hachenberg, Arne Tenling, Hans-ulrich Rothen, Sven-olov Nyström, Hans Tydén, Göran HedenstiernaAbstract:BACKGROUND One possible mechanism of impaired oxygenation in cardiac surgery with extracorporeal circulation (ECC) is the accumulation of Extravascular lung water (EVLW). Intrathoracic blood volume (ITBV) and pulmonary blood volume (PBV) also may increase after separation from ECC, which can influence both cardiac performance and pulmonary capillary Fluid filtration. This study tested whether there were any relationships between lung Fluid accumulation and pulmonary gas exchange during the perioperative period of cardiac surgery and ECC. METHODS Ten patients undergoing myocardial revascularization were studied. ITBV, PBV, and EVLW were determined from the mean transit times and decay times of the dye and thermal indicator curves obtained simultaneously in the descending aorta. Gas exchange was assessed by arterial and mixed venous partial pressure of oxygen (PO2) and carbon dioxide (PCO2), and calculation of alveolo-arterial PO2 gradient (PA-aO2) and venous admixture (QVA/QT). Recordings were made after induction of anesthesia, after sternotomy, 15 min after separation from ECC, and 4 and 20 h postoperatively. RESULTS After induction of anesthesia, EVLW (6.0 +/- 1.0 ml/kg, mean +/- SD), PBV (3.6 +/- 1.3 ml/kg), and ITBV (18.4 +/- 2.7 ml/kg) were within normal ranges. Oxygenation was moderately impaired, as indicated by an increased PA-aO2 (144 +/- 46 mmHg) and QVA/QT (11 +/- 4%). After separation from ECC, EVLW had increased to 9.1 +/- 2.6 ml/kg, which was accompanied by an increase of ITBV (26.0 +/- 4.4 ml/kg) and PBV (5.6 +/- 1.9 ml/kg). PAa-O2 (396 +/- 116 mmHg) and QVA/QT (29 +/- 7%) also were increased. ITBV and PBV remained increased 4 and 20 h postoperatively, but EVLW decreased to presurgery values. No correlations were found between thoracic intravascular and Extravascular Fluid volumes and gas exchange. CONCLUSIONS Cardiac surgery with the use of ECC induces alterations of thoracic intravascular and Extravascular Fluid volumes. Postoperatively, increased ITBV and PBV need not be associated with higher EVLW. Thus, sufficient mechanisms protecting against lung edema formation or providing resolution of EVLW probably are maintained after ECC. Since oxygenation is impaired during and after cardiac surgery, it is concluded that mechanisms other than or in addition to changes of ITBV, PBV, and EVLW predominantly influence gas exchange.
Raffaele Dellaca - One of the best experts on this subject based on the ideXlab platform.
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Changes in the mechanical properties of the respiratory system during the development of interstitial lung edema.
Respiratory research, 2008Co-Authors: Raffaele Dellaca, Emanuela Zannin, G Sancini, Ilaria Rivolta, Biagio Eugenio Leone, Antonio Pedotti, Giuseppe MiserocchiAbstract:Background Pulmonary edema induces changes in airway and lung tissues mechanical properties that can be measured by low-frequency forced oscillation technique (FOT). It is preceded by interstitial edema which is characterized by the accumulation of Extravascular Fluid in the interstitial space of the air-blood barrier. Our aim was to investigate the impact of the early stages of the development of interstitial edema on the mechanical properties of the respiratory system.
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Changes in the mechanical properties of the respiratory system during the development of interstitial lung edema
Respiratory Research, 2008Co-Authors: Raffaele Dellaca, Emanuela Zannin, G Sancini, Ilaria Rivolta, Biagio Eugenio Leone, Antonio Pedotti, Giuseppe MiserocchiAbstract:Background Pulmonary edema induces changes in airway and lung tissues mechanical properties that can be measured by low-frequency forced oscillation technique (FOT). It is preceded by interstitial edema which is characterized by the accumulation of Extravascular Fluid in the interstitial space of the air-blood barrier. Our aim was to investigate the impact of the early stages of the development of interstitial edema on the mechanical properties of the respiratory system. Methods We studied 17 paralysed and mechanically ventilated closed-chest rats (325–375 g). Total input respiratory system impedance (Zrs) was derived from tracheal flow and pressure signals by applying forced oscillations with frequency components from 0.16 to 18.44 Hz distributed in two forcing signals. In 8 animals interstitial lung edema was induced by intravenous infusion of saline solution (0.75 ml/kg/min) for 4 hours; 9 control animals were studied with the same protocol but without infusion. Zrs was measured at the beginning and every 15 min until the end of the experiment. Results In the treated group the lung wet-to-dry weight ratio increased from 4.3 ± 0.72 to 5.23 ± 0.59, with no histological signs of alveolar flooding. Resistance (Rrs) increased in both groups over time, but to a greater extent in the treated group. Reactance (Xrs) did not change in the control group, while it decreased significantly at all frequencies but one in the treated. Significant changes in Rrs and Xrs were observed starting after ~135 min from the beginning of the infusion. By applying a constant phase model to partition airways and tissue mechanical properties, we observed a mild increase in airways resistance in both groups. A greater and significant increase in tissue damping (from 603.5 ± 100.3 to 714.5 ± 81.9 cmH_2O/L) and elastance (from 4160.2 ± 462.6 to 5018.2 ± 622.5 cmH_2O/L) was found only in the treated group. Conclusion These results suggest that interstitial edema has a small but significant impact on the mechanical features of lung tissues and that these changes begin at very early stages, before the beginning of accumulation of Extravascular Fluid into the alveoli.
Yiya Kong - One of the best experts on this subject based on the ideXlab platform.
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an Extravascular Fluid transport system based on structural framework of fibrous connective tissues in human body
Cell Proliferation, 2019Co-Authors: Chongqing Yang, Yajun Yin, Fang Wang, Min Chen, Naili Wang, Di Zhang, Xiaoxia Wang, Yiya KongAbstract:OBJECTIVE Interstitial Fluid in extracellular matrices may not be totally fixed but partially flow through long-distance oriented fibrous connective tissues via physical mechanisms. We hypothesized there is a long-distance interstitial Fluid transport network beyond vascular circulations. MATERIALS AND METHODS We first used 20 volunteers to determine hypodermic entrant points to visualize long-distance Extravascular pathway by MRI. We then investigated the Extravascular pathways initiating from the point of thumb in cadavers by chest compressor. The distributions and structures of long-distance pathways from extremity ending to associated visceral structures were identified. RESULTS Using fluorescent tracer, the pathways from right thumb to right atrium wall near chest were visualized in seven of 10 subjects. The cutaneous pathways were found in dermic, hypodermic and fascial tissues of hand and forearm. The perivascular pathways were along the veins of arm, axillary sheath, superior vena cava and into the superficial tissues on right atrium. Histological and micro-CT data showed these pathways were neither blood nor lymphatic vessels but long-distance oriented fibrous matrices, which contained the longitudinally assembled micro-scale fibres consistently from thumb to superficial tissues on right atrium. CONCLUSIONS These data revealed the structural framework of the fibrous extracellular matrices in oriented fibrous connective tissues was of the long-distance assembled fibres throughout human body. Along fibres, interstitial Fluid can systemically transport by certain driving-transfer mechanisms beyond vascular circulations.
