Thoracic-Abdominal Continuous External Negative Pressure Improves Lung Mechanics During Positive Pressure Ventilation in Pigs

2019 ◽  
Author(s):  
M. Scharffenberg ◽  
J.J.M. Wittenstein ◽  
M. Herzog ◽  
L. Vivona ◽  
R. Huhle ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Positive Pressure Ventilation ◽  
Lung Mechanics ◽  
Positive Pressure

scholarly journals Effects of Various Modes of Mechanical Ventilation in Normal Rats

2014 ◽  
Vol 120 (4) ◽  
pp. 943-950 ◽  
Author(s):  
Matteo Pecchiari ◽  
Ario Monaco ◽  
Antonia Koutsoukou ◽  
Patrizia Della Valle ◽  
Guendalina Gentile ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Inflammatory Response ◽  
Negative Pressure ◽  
Positive Pressure Ventilation ◽  
Lung Mechanics ◽  
Whole Body ◽  
Positive Pressure ◽  
Negative Pressure Ventilation ◽  
Cytokine Levels

Abstract Background: Recent studies in healthy mice and rats have reported that positive pressure ventilation delivered with physiological tidal volumes at normal end-expiratory volume worsens lung mechanics and induces cytokine release, thus suggesting that detrimental effects are due to positive pressure ventilation per se. The aim of this study in healthy animals is to assess whether these adverse outcomes depend on the mode of mechanical ventilation. Methods: Rats were subjected to 4 h of spontaneous, positive pressure, and whole-body or thorax-only negative pressure ventilation (N = 8 per group). In all instances the ventilatory pattern was that of spontaneous breathing. Lung mechanics, cytokines concentration in serum and broncho–alveolar lavage fluid, lung wet-to-dry ratio, and histology were assessed. Values from eight animals euthanized shortly after anesthesia served as control. Results: No evidence of mechanical ventilation–dependent lung injury was found in terms of lung mechanics, histology, or wet-to-dry ratio. Relative to control, cytokine levels and recruitment of polymorphonuclear leucocytes increased slightly, and to the same extent with spontaneous, positive pressure, and whole-body negative pressure ventilation. Thorax-only negative pressure ventilation caused marked chest and lung distortion, reversible increase of lung elastance, and higher polymorphonuclear leucocyte count and cytokine levels. Conclusion: Both positive and negative pressure ventilation performed with tidal volumes and timing of spontaneous, quiet breathing neither elicit an inflammatory response nor cause morpho-functional alterations in normal animals, thus supporting the notion of the presence of a critical volume threshold above which acute lung injury ensues. Distortion of lung parenchyma can induce an inflammatory response, even in the absence of volotrauma.

Simple Device for Producing Continuous Negative Pressure in Infants With IRDS

PEDIATRICS ◽  
1973 ◽  
Vol 52 (1) ◽  
pp. 128-131
Author(s):  
Eduardo Bancalari ◽  
Tilo Gerhardt ◽  
Ellen Monkus
Keyword(s):  
Intensive Care Unit ◽  
Negative Pressure ◽  
Positive Pressure Ventilation ◽  
Newborn Infants ◽  
Transpulmonary Pressure ◽  
Intermittent Positive Pressure Ventilation ◽  
Positive Pressure ◽  
School Of Medicine ◽  
Newborn Intensive Care Unit ◽  
Newborn Intensive Care

Increasing experience with the use of continuous transpulmonary pressure, either positive or negative, during the last years has clearly demonstrated the success of this mode of therapy in IRDS.1-3 Forty newborn infants with this disease have been treated with continuous negative pressure (CNP) in the Newborn Intensive Care Unit, Department of Pediatrics, University of Miami School of Medicine, using a modified incubator-respirator.* Twenty-one required only CNP, three of whom died (14%). Among the 19 who needed CNP plus intermittent positive pressure ventilation, nine died (47%). All required more than 70% oxygen to maintain a Pao2 over 50 mm Hg before using CNP.

scholarly journals Lung mechanical and vascular changes during positive- and negative-pressure lung inflations: importance of reference pressures in the pulmonary vasculature

2009 ◽  
Vol 106 (3) ◽  
pp. 935-942 ◽  
Author(s):  
Ferenc Peták ◽  
Gergely Albu ◽  
Enikö Lele ◽  
Zoltán Hantos ◽  
Denis R. Morel ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Time Windows ◽  
Low Frequency ◽  
Lung Mechanics ◽  
Pulmonary Vasculature ◽  
Positive Pressure ◽  
Vascular Changes ◽  
Inflation Pressure ◽  
Lung Inflation ◽  
Impedance Data

The continuous changes in lung mechanics were related to those in pulmonary vascular resistance (Rv) during lung inflations to clarify the mechanical changes in the bronchoalveolar system and the pulmonary vasculature. Rv and low-frequency lung impedance data (Zl) were measured continuously in isolated, perfused rat lungs during 2-min inflation-deflation maneuvers between transpulmonary pressures of 2.5 and 22 cmH2O, both by applying positive pressure at the trachea and by generating negative pressure around the lungs in a closed box. Zl was averaged and evaluated for 2-s time windows; airway resistance (Raw), parenchymal damping and elastance (H) were determined in each window. Lung inflation with positive and negative pressures led to very similar changes in lung mechanics, with maximum decreases in Raw [−68 ± 4 (SE) vs. −64 ± 18%] and maximum increases in H (379 ± 36 vs. 348 ± 37%). Rv, however, increased with positive inflation pressure (15 ± 1%), whereas it exhibited mild decreases during negative-pressure expansions (−3 ± 0.3%). These results demonstrate that pulmonary mechanical changes are not affected by the opposing modes of lung inflations and confirm the importance of relating the pulmonary vascular pressures in interpreting changes in Rv.

Ventilation with external high frequency oscillation around a negative baseline increases pulmonary blood flow after the Fontan operation

1992 ◽  
Vol 2 (3) ◽  
pp. 277-280 ◽  
Author(s):  
Daniel J. Penny ◽  
Zamir Hayek ◽  
Peter Rawle ◽  
Michael L. Rigby ◽  
Andrew N. Redington
Keyword(s):  
Blood Flow ◽  
Negative Pressure ◽  
High Frequency ◽  
Pulmonary Blood Flow ◽  
Positive Pressure Ventilation ◽  
Fontan Operation ◽  
Intermittent Positive Pressure Ventilation ◽  
High Frequency Oscillation ◽  
Positive Pressure ◽  
Frequency Oscillation

AbstractIn this prospective study, pulmonary blood flow was measured using transesophageal Doppler echocardiography to assess whether ventilation by means of external high frequency oscillation around a negative pressure baseline can increase pulmonary blood flow, compared to intermittent positive pressure ventilation, in five patients after the Fontan operation. Pulmonary blood flow was measured when patients were ventilated by means of intermittent positive pressure ventilation and again during equivalent negative pressure ventilation using the external oscillatory technique. When compared to that with intermittent positive pressure ventilation, ventilation using external high frequency oscillation increased pulmonary blood flow by 116 ±61.5% (p=0.013). These results show that ventilation using an external oscillatory device with a mean negative chamber pressure may provide hemodynamic advantages in patients requiring assisted ventilation after the Fontan operation.

Noninvasive positive pressure ventilation in patients with perioperative negative pressure pulmonary edema

2010 ◽  
Vol 24 (3) ◽  
pp. 464-468 ◽  
Author(s):  
Masayuki Furuichi ◽  
Shinhiro Takeda ◽  
Shinji Akada ◽  
Hidetaka Onodera ◽  
Yuko Yoshida ◽  
...  
Keyword(s):  
Pulmonary Edema ◽  
Negative Pressure ◽  
Positive Pressure Ventilation ◽  
Noninvasive Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Negative Pressure Pulmonary Edema

scholarly journals Respiratory pump maintains cardiac stroke volume during hypovolemia in young, healthy volunteers

2018 ◽  
Vol 124 (5) ◽  
pp. 1319-1325 ◽  
Author(s):  
Maria Skytioti ◽  
Signe Søvik ◽  
Maja Elstad
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Healthy Volunteers ◽  
Negative Pressure ◽  
Spontaneous Breathing ◽  
Positive Pressure Ventilation ◽  
Control Mode ◽  
Positive Pressure ◽  
Beneficial Effects ◽  
Cardiac Stroke Volume

Spontaneous breathing has beneficial effects on the circulation, since negative intrathoracic pressure enhances venous return and increases cardiac stroke volume. We quantified the contribution of the respiratory pump to preserve stroke volume during hypovolemia in awake, young, healthy subjects. Noninvasive stroke volume, cardiac output, heart rate, and mean arterial pressure (Finometer) were recorded in 31 volunteers (19 women), 19–30 yr old, during normovolemia and hypovolemia (approximating 450- to 500-ml reduction in central blood volume) induced by lower-body negative pressure. Control-mode noninvasive positive-pressure ventilation was employed to reduce the effect of the respiratory pump. The ventilator settings were matched to each subject’s spontaneous respiratory pattern. Stroke volume estimates during positive-pressure ventilation and spontaneous breathing were compared with Wilcoxon matched-pairs signed-rank test. Values are overall medians. During normovolemia, positive-pressure ventilation did not affect stroke volume or cardiac output. Hypovolemia resulted in an 18% decrease in stroke volume and a 9% decrease in cardiac output ( P < 0.001). Employing positive-pressure ventilation during hypovolemia decreased stroke volume further by 8% ( P < 0.001). Overall, hypovolemia and positive-pressure ventilation resulted in a reduction of 26% in stroke volume ( P < 0.001) and 13% in cardiac output ( P < 0.001) compared with baseline. Compared with the situation with control-mode positive-pressure ventilation, spontaneous breathing attenuated the reduction in stroke volume induced by moderate hypovolemia by 30% (i.e., −26 vs. −18%). In the patient who is critically ill with hypovolemia or uncontrolled hemorrhage, spontaneous breathing may contribute to hemodynamic stability, whereas controlled positive-pressure ventilation may result in circulatory decompensation. NEW & NOTEWORTHY Maintaining spontaneous respiration has beneficial effects on hemodynamic compensation, which is clinically relevant for patients in intensive care. We have quantified the contribution of the respiratory pump to cardiac stroke volume and cardiac output in healthy volunteers during normovolemia and central hypovolemia. The positive hemodynamic effect of the respiratory pump was abolished by noninvasive, low-level positive-pressure ventilation. Compared with control-mode positive-pressure ventilation, spontaneous negative-pressure ventilation attenuated the fall in stroke volume by 30%.

scholarly journals Negative pressure ventilation enhances acinar perfusion in isolated rat lungs

2017 ◽  
Vol 8 (1) ◽  
pp. 204589321775359 ◽  
Author(s):  
Kal E. Watson ◽  
Gilad S. Segal ◽  
Robert L. Conhaim
Keyword(s):  
Negative Pressure ◽  
Pulmonary Circulation ◽  
Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Latex Particles ◽  
Negative Pressure Ventilation ◽  
Rat Lungs ◽  
Confocal Images ◽  
Negative Pressures ◽  
Isolated Rat

We compared acinar perfusion in isolated rat lungs ventilated using positive or negative pressures. The lungs were ventilated with air at transpulmomary pressures of 15/5 cm H2O, at 25 breaths/min, and perfused with a hetastarch solution at Ppulm art/PLA pressures of 10/0 cm H2O. We evaluated overall perfusability from perfusate flows, and from the venous concentrations of 4-µm diameter fluorescent latex particles infused into the pulmonary circulation during perfusion. We measured perfusion distribution from the trapping patterns of those particles within the lung. We infused approximately 9 million red fluorescent particles into each lung, followed 20 min later by an infusion of an equal number of green particles. In positive pressure lungs, 94.7 ± 2.4% of the infused particles remained trapped within the lungs, compared to 86.8 ± 5.6% in negative pressure lungs ( P ≤ 0.05). Perfusate flows averaged 2.5 ± 0.1 mL/min in lungs ventilated with positive pressures, compared to 5.6 ± 01 mL/min in lungs ventilated with negative pressures ( P ≤ 0.05). Particle infusions had little effect on perfusate flows. In confocal images of dried sections of each lung, red and green particles were co-localized in clusters in positive pressure lungs, suggesting that acinar vessels that lacked particles were collapsed by these pressures thereby preventing perfusion through them. Particles were more broadly and uniformly distributed in negative pressure lungs, suggesting that perfusion in these lungs was also more uniformly distributed. Our results suggest that the acinar circulation is organized as a web, and further suggest that portions of this web are collapsed by positive pressure ventilation.

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