scholarly journals DYNAMIC LUNG STRAIN AND DRIVING PRESSURE IN ARDS

CHEST Journal ◽  
2020 ◽  
Vol 158 (4) ◽  
pp. A580
Author(s):  
Omar Mahmoud ◽  
James Salonia
Keyword(s):  
Driving Pressure ◽  
Lung Strain

scholarly journals The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients – a posthoc propensity score–weighted cohort analysis of the LAS VEGAS study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Guido Mazzinari ◽  
◽  
Ary Serpa Neto ◽  
Sabrine N. T. Hemmes ◽  
Goran Hedenstierna ◽  
...  
Keyword(s):  
Propensity Score ◽  
Adverse Events ◽  
Abdominal Surgery ◽  
Las Vegas ◽  
Cohort Analysis ◽  
Risk Difference ◽  
Pulmonary Complications ◽  
Driving Pressure ◽  
Postoperative Pulmonary Complications ◽  
Open Abdominal Surgery

Abstract Background It is uncertain whether the association of the intraoperative driving pressure (ΔP) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time–weighted average ΔP (ΔPTW) with PPCs. We also tested the association of ΔPTW with intraoperative adverse events. Methods Posthoc retrospective propensity score–weighted cohort analysis of patients undergoing open or closed abdominal surgery in the ‘Local ASsessment of Ventilatory management during General Anaesthesia for Surgery’ (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events. Results The analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. ΔP was lower in open abdominal surgery patients, but ΔPTW was not different between groups. The association of ΔPTW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P <  0.001 versus 1.05 [95%CI 1.05 to 1.05], P <  0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P <  0.001). The association of ΔPTW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12– to 1.14], P <  0.001 versus 1.07 [95%CI 1.05 to 1.10], P <  0.001; risk difference 0.05 [95%CI 0.030.07], P <  0.001). Conclusions ΔP is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery. Trial registration LAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223).

Pulmonary fluid balance following pulmocutaneous baroreceptor denervation in the toad

1986 ◽  
Vol 61 (1) ◽  
pp. 331-337 ◽  
Author(s):  
A. W. Smits ◽  
N. H. West ◽  
W. W. Burggren
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Venous Pressure ◽  
Driving Pressure ◽  
Pulmonary Hemodynamics ◽  
Pulmonary Capillaries ◽  
Neural Input ◽  
Order Of Magnitude ◽  
Capillary Resistance ◽  
Recurrent Laryngeal Nerves

Pulmonary hemodynamics and net transcapillary fluid flux (NTFF) were measured in conscious toads before and following bilateral denervation of the recurrent laryngeal nerves (rLN), which contain afferents from baroreceptors located in the pulmocutaneous arteries. Denervation caused an acute doubling of the arterial-venous pressure gradient across the lung and a threefold increase in pulmonary blood flow. Calculated pulmonary vascular resistance fell and remained below control values through the period of experimentation. NTFF increased by an order of magnitude (0.74–7.77 ml X kg-1 X min-1), as filtration increased in response to the hemodynamic changes caused by rLN denervation. There was a better correlation between NTFF and pulmonary blood flow than between NTFF and pulmonary driving pressure. Our results support the view that tonic neural input from pulmocutaneous baroreceptors protects the anuran lung from edema by restraining pulmonary driving pressure and blood flow and perhaps by reflexly maintaining vascular tone in the extrinsic pulmonary artery, therefore tending to increase the pre-to-postpulmonary capillary resistance ratio and biasing the Starling relationship in the pulmonary capillaries against filtration.

Effect of Driving Pressure and Nebulizer Model on Aerosol Output during Intermittent Delivery with a Dosimeter

2002 ◽  
Vol 15 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Stephan A. Alkins ◽  
Kenneth M. Hurwitz ◽  
Angel Sierra
Keyword(s):  
Driving Pressure

scholarly journals Product of driving pressure and respiratory rate for predicting weaning outcomes

2021 ◽  
Vol 49 (5) ◽  
pp. 030006052110100
Author(s):  
Ju Gong ◽  
Bibo Zhang ◽  
Xiaowen Huang ◽  
Bin Li ◽  
Jian Huang
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Rate ◽  
Spontaneous Breathing ◽  
Spontaneous Breathing Trial ◽  
Plateau Pressure ◽  
Driving Pressure ◽  
Failure Group ◽  
Rapid Shallow Breathing Index ◽  
Weaning Failure ◽  
Shallow Breathing

Objective Clinicians cannot precisely determine the time for withdrawal of ventilation. We aimed to evaluate the performance of driving pressure (DP)×respiratory rate (RR) to predict the outcome of weaning. Methods Plateau pressure (Pplat) and total positive end-expiratory pressure (PEEPtot) were measured during mechanical ventilation with brief deep sedation and on volume-controlled mechanical ventilation with a tidal volume of 6 mL/kg and a PEEP of 0 cmH2O. Pplat and PEEPtot were measured by patients holding their breath for 2 s after inhalation and exhalation, respectively. DP was determined as Pplat minus PEEPtot. The rapid shallow breathing index was measured from the ventilator. The highest RR was recorded within 3 minutes during a spontaneous breathing trial. Patients who tolerated a spontaneous breathing trial for 1 hour were extubated. Results Among the 105 patients studied, 44 failed weaning. During ventilation withdrawal, DP×RR was 136.7±35.2 cmH2O breaths/minute in the success group and 230.2±52.2 cmH2O breaths/minute in the failure group. A DP×RR index >170.8 cmH2O breaths/minute had a sensitivity of 93.2% and specificity of 88.5% to predict failure of weaning. Conclusions Measurement of DP×RR during withdrawal of ventilation may help predict the weaning outcome. A high DP×RR increases the likelihood of weaning failure. Statement: This manuscript was previously posted as a preprint on Research Square with the following link: https://www.researchsquare.com/article/rs-15065/v3 and DOI: 10.21203/rs.2.24506/v3

scholarly journals Investigation of Air Pocket Behavior in Pipelines Using Rigid Column Model and Contributions of Time Integration Schemes

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 785
Author(s):  
Arman Rokhzadi ◽  
Musandji Fuamba
Keyword(s):  
Transient Flow ◽  
Time Integration ◽  
Driving Pressure ◽  
Implicit Time ◽  
Numerical Dissipation ◽  
Integration Scheme ◽  
Time Step ◽  
Column Model ◽  
Integration Schemes ◽  
Backward Euler

This paper studies the air pressurization problem caused by a partially pressurized transient flow in a reservoir-pipe system. The purpose of this study is to analyze the performance of the rigid column model in predicting the attenuation of the air pressure distribution. In this regard, an analytic formula for the amplitude and frequency will be derived, in which the influential parameters, particularly, the driving pressure and the air and water lengths, on the damping can be seen. The direct effect of the driving pressure and inverse effect of the product of the air and water lengths on the damping will be numerically examined. In addition, these numerical observations will be examined by solving different test cases and by comparing to available experimental data to show that the rigid column model is able to predict the damping. However, due to simplified assumptions associated with the rigid column model, the energy dissipation, as well as the damping, is underestimated. In this regard, using the backward Euler implicit time integration scheme, instead of the classical fourth order explicit Runge–Kutta scheme, will be proposed so that the numerical dissipation of the backward Euler implicit scheme represents the physical dissipation. In addition, a formula will be derived to calculate the appropriate time step size, by which the dissipation of the heat transfer can be compensated.

Driving Pressure and Survival in the Acute Respiratory Distress Syndrome

2015 ◽  
Vol 372 (8) ◽  
pp. 747-755 ◽  
Author(s):  
Marcelo B.P. Amato ◽  
Maureen O. Meade ◽  
Arthur S. Slutsky ◽  
Laurent Brochard ◽  
Eduardo L.V. Costa ◽  
...  
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Driving Pressure

scholarly journals Feedback modulation of surrounding pressure determines the onset of negative effort dependence in a collapsible tube bench model of the pharyngeal airway

2017 ◽  
Vol 123 (5) ◽  
pp. 1118-1125 ◽  
Author(s):  
Christopher Lambeth ◽  
Benjamin Kolevski ◽  
Terence Amis ◽  
Kristina Kairaitis
Keyword(s):  
Longitudinal Strain ◽  
Initial Conditions ◽  
Driving Pressure ◽  
Chamber Pressure ◽  
Collapsible Tube ◽  
Moderate Amount ◽  
Tissue Pressure ◽  
Pharyngeal Airway ◽  
Obstructive Sleep ◽  
Bench Model

Negative effort dependence (NED), decreased airflow despite increased driving pressure, has been proposed as a specific obstructive sleep apnea (OSA) phenotypic characteristic. We examined conditions under which NED occurs in a collapsible tube, pharyngeal airway bench model with the chamber enclosed, focusing on relationships with surrounding pressure levels and longitudinal strain. Using a vacuum source, graded airflows (V̇; 0–5 l/s) were generated through a thin-walled latex tube enclosed within a rigid, cylindrical chamber, sealed with initial chamber pressures (Pci) of 0–5 cmH2O (separate runs), or opened to the atmosphere. Upstream minus downstream pressure (Pu − Pd), maximum airflow (V̇max), and chamber pressure (Pc) were measured at 0–50% longitudinal strain. NED occurred across the range of Pci and strains studied but was most pronounced for the chamber open condition. With a sealed chamber, V̇ increased and Pc decreased with increasing Pu − Pd until the onset of NED at V̇max and a Pc value that was designated as critical (Pcc). Pcc was lowest (−17 cmH20) and V̇max was highest (~5 l/s) with chamber sealed: Pci = 0 cmH2O and 12.5 to 25% strain. We conclude that for our collapsible tube model, the achievable V̇max before the onset of NED depends on both the initial conditions (Pci and strain) and the dynamics of feedback between driving pressure and chamber pressure (chamber sealed vs. open). NED-based phenotypic analyses for OSA may need to focus on potential feedback control mechanisms (eg lung volume change, muscle activity) that may link peripharyngeal tissue pressure levels to driving pressures for airflow. NEW & NOTEWORTHY A collapsible tube, pharyngeal airway bench model was used to study the role of surrounding pressure and longitudinal wall strain at the onset of negative effort dependence (NED). NED occurred to varying degrees across all conditions tested, but maximum airflow was achieved with 1) low initial surrounding pressure, 2) a feedback mechanism between surrounding pressure and driving pressure; and 3) a moderate amount of strain applied. Potential impacts on OSA phenotypic analyses are discussed.

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