scholarly journals Novel method of transpulmonary pressure measurement with an air-filled esophageal catheter

2021 ◽  
Author(s):  
Paul B Massion ◽  
J Berg ◽  
N Samalea ◽  
G Parzibut ◽  
B Lambermont ◽  
...  
Keyword(s):  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Pressure Change ◽  
Esophageal Pressure ◽  
Protective Ventilation ◽  
Suction Catheter ◽  
Reproducible Method ◽  
Novel Method ◽  
Flush Device

Abstract Background There is a strong rationale for proposing transpulmonary pressure-guided protective ventilation in acute respiratory distress syndrome (ARDS). The reference esophageal balloon catheter method requires complex in vivo calibration and dedicated ventilator with auxiliary pressure port. A simple, inexpensive, accurate and reproducible method of measuring esophageal pressure would greatly facilitate the measure of transpulmonary pressure to individualize protective ventilation in the intensive care unit. Results We propose an air-filled esophageal catheter method without balloon, using disposable catheter and transducer that allows reproducible esophageal pressure measurements, and that does not require any specific ventilator equipment. We use a 49 cm-long thin low compliance polyvinyl 10 Fr suction catheter, positioned in the lower third of the esophagus and connected to an air-filled disposable blood pressure transducer bound to the monitor. To guarantee air transmission, the transducer is pressurized by an air-filled infusion bag allowing its integrated flush device to deliver continuous air flow and to obtain a stable esophageal waveform. Calibration requires simple zeroing the transducer open to atmospheric pressure. Esophageal pressures recorded on the monitoring are expressed in mmHg and need to be converted in cmH2O. We tested our novel method in 10 consecutive intubated patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. We calculated the target transpulmonary pressures for protective lung and diaphragm ventilation, both in passive and spontaneously breathing conditions. Esophageal to airway pressure change ratio was close to one in both conditions (median [P25;P75] = 0.94 [0.92;1.00] and 0.98 [0.96;1.01]). We adjusted ventilator settings towards recommended pressure targets to limit atelectrauma, barotrauma, inspiratory effort and lung stress, by modifying positive end-expiratory pressure, tidal volume, or inspiratory pressure accordingly. Conclusions We propose a simple, inexpensive and reproducible method for esophageal pressure monitoring with an air-filled esophageal catheter without balloon. It holds the promise of widespread bedside use of transpulmonary pressure-guided protective ventilation in patients with ARDS.

scholarly journals Novel method of transpulmonary pressure measurement with an air-filled esophageal catheter

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Paul Bernard Massion ◽  
Julien Berg ◽  
Nicolas Samalea Suarez ◽  
Gilles Parzibut ◽  
Bernard Lambermont ◽  
...  
Keyword(s):  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Protective Ventilation ◽  
Pleural Pressure ◽  
Good Precision ◽  
Pressure Measurements ◽  
Reproducible Method ◽  
Assisted Modes

Abstract Background There is a strong rationale for proposing transpulmonary pressure-guided protective ventilation in acute respiratory distress syndrome. The reference esophageal balloon catheter method requires complex in vivo calibration, expertise and specific material order. A simple, inexpensive, accurate and reproducible method of measuring esophageal pressure would greatly facilitate the measure of transpulmonary pressure to individualize protective ventilation in the intensive care unit. Results We propose an air-filled esophageal catheter method without balloon, using a disposable catheter that allows reproducible esophageal pressure measurements. We use a 49-cm-long 10 Fr thin suction catheter, positioned in the lower-third of the esophagus and connected to an air-filled disposable blood pressure transducer bound to the monitor and pressurized by an air-filled infusion bag. Only simple calibration by zeroing the transducer to atmospheric pressure and unit conversion from mmHg to cmH2O are required. We compared our method with the reference balloon catheter both ex vivo, using pressure chambers, and in vivo, in 15 consecutive mechanically ventilated patients. Esophageal-to-airway pressure change ratios during the dynamic occlusion test were close to one (1.03 ± 0.19 and 1.00 ± 0.16 in the controlled and assisted modes, respectively), validating the proper esophageal positioning. The Bland–Altman analysis revealed no bias of our method compared with the reference and good precision for inspiratory, expiratory and delta esophageal pressure measurements in both the controlled (largest bias −0.5 cmH2O [95% confidence interval: −0.9; −0.1] cmH2O; largest limits of agreement −3.5 to 2.5 cmH2O) and assisted modes (largest bias −0.3 [−2.6; 2.0] cmH2O). We observed a good repeatability (intra-observer, intraclass correlation coefficient, ICC: 0.89 [0.79; 0.96]) and reproducibility (inter-observer ICC: 0.89 [0.76; 0.96]) of esophageal measurements. The direct comparison with pleural pressure in two patients and spectral analysis by Fourier transform confirmed the reliability of the air-filled catheter-derived esophageal pressure as an accurate surrogate of pleural pressure. A calculator for transpulmonary pressures is available online. Conclusions We propose a simple, minimally invasive, inexpensive and reproducible method for esophageal pressure monitoring with an air-filled esophageal catheter without balloon. It holds the promise of widespread bedside use of transpulmonary pressure-guided protective ventilation in ICU patients.

In vivo estimation of tracheal distensibility and hysteresis in normal adults

1987 ◽  
Vol 63 (6) ◽  
pp. 2482-2489 ◽  
Author(s):  
V. Hoffstein ◽  
R. G. Castile ◽  
C. R. O'Donnell ◽  
G. M. Glass ◽  
D. J. Strieder ◽  
...  
Keyword(s):  
Lung Volume ◽  
Transpulmonary Pressure ◽  
Lung Parenchyma ◽  
Esophageal Pressure ◽  
Transmural Pressure ◽  
Variable Degree ◽  
Cross Sectional ◽  
Acoustic Reflection ◽  
Direct Measurements

We used the acoustic reflection technique to measure the cross-sectional area of tracheal and bronchial airway segments of eight healthy adults. We measured airway area during a slow continuous expiration from total lung capacity (TLC) to residual volume (RV) and during inspiration back to TLC. Lung volume and esophageal pressure were monitored continuously during this quasi-static, double vital capacity maneuver. We found that 1) the area of tracheal and bronchial segments increases with increasing lung volume and transpulmonary pressure, 2) the trachea and bronchi exhibit a variable degree of hysteresis, which may be greater or less than that of the lung parenchyma, 3) extrathoracic and intrathoracic tracheal segments behaved as if they were subjected to similar transmural pressure and had similar elastic properties, and 4) specific compliance (means +/- SE) for the intrathoracic and bronchial segments, calculated with the assumption that transmural pressure is equal to the transpulmonary pressure, was significantly (P less than 0.05) smaller for the intrathoracic segment than for the bronchial segment: (2.1 +/- 2.0) X 10(-3) cmH2O-–1 vs. (9.1 +/- 2.1) X 10(-3) cmH2O–1. Direct measurements of airway area using acoustic reflections are in good agreement with previous estimates of airway distensibility in vivo, obtained by radiography or endoscopy.

scholarly journals In Vivo Measurement of Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Holger Sudhoff ◽  
Philipp Mittmann ◽  
Ingo Todt
Keyword(s):  
Middle Ear ◽  
Mechanism Of Action ◽  
Balloon Catheter ◽  
Pressure Change ◽  
Chronic Obstructive ◽  
In Vivo Measurement ◽  
Middle Ear Pressure ◽  
Balloon Eustachian Tuboplasty ◽  
Pressure Changes

Background. Balloon Eustachian tuboplasty (BET) is known as a treatment for chronic obstructive Eustachian tube dysfunction (OETD). The precise mechanism of action is not fully understood. Observations in sheep cadavers and human cadavers have shown specific middle ear pressure changes related to BET. Methods. In this prospective study using a microfibre optical pressure sensor, pressure changes during BET were for the first time monitored transtympanically in five normal human middle ears in vivo. Results. Middle ear pressure changes during 21 BETs consisted of five stages (insertion, inflation, deflation, withdrawal, and recovery). The highest pressure change occurred in most of the cases during the withdrawal of the balloon catheter. Withdrawal pressure yielded a mean middle ear pressure of 4.76 mmHg (61.89 daPa) with a maximum of 13.88 mmHg (179.55 daPa). Pressure amplitudes capable of causing barotrauma to ear structures were not detected. Internal carotid artery dehiscences were detected as causative of sinusidual pressure changes. Conclusion. The middle ear pressure changes detected in vivo during BET can be attributed to the balloon inflation. Further human studies with patients affected by OETD are necessary to gain more insight into the mechanism of action of BET to clarify a possible pressure related second mechanism of action of BET.

Volume-related and volume-independent effects of posture on esophageal and transpulmonary pressures in healthy subjects

2006 ◽  
Vol 100 (3) ◽  
pp. 753-758 ◽  
Author(s):  
George R. Washko ◽  
Carl R. O'Donnell ◽  
Stephen H. Loring
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Healthy Subjects ◽  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Wide Range ◽  
Ventilator Management ◽  
Volume Characteristics ◽  
Independent Effects

Ventilator management decisions in acute lung injury could be better informed with knowledge of the patient's transpulmonary pressure, which can be estimated using measurements of esophageal pressure. Esophageal manometry is seldom used for this, however, in part because of a presumed postural artifact in the supine position. Here, we characterize the magnitude and variability of postural effects on esophageal pressure in healthy subjects to better assess its significance in patients with acute lung injury. We measured the posture-related changes in relaxation volume and total lung capacity in 10 healthy subjects in four postures: upright, supine, prone, and left lateral decubitus. Then, in the same subjects, we measured static pressure-volume characteristics of the lung over a wide range of lung volumes in each posture by using an esophageal balloon catheter. Transpulmonary pressure during relaxation (Plrel) averaged 3.7 (SD 2.0) cmH2O upright and −3.3 (SD 3.2) cmH2O supine. Approximately 58% of the decrease in Plrel between the upright and supine postures was due to a corresponding decrease in relaxation volume. The remaining 2.9-cmH2O difference is consistent with reported values of a presumed postural artifact. Relaxation volumes and pressures in prone and lateral postures were intermediate. To correct estimated transpulmonary pressure for the effect of lying supine, we suggest adding 3 cmH2O (95% confidence interval: −1 to +7 cmH2O). We conclude that postural differences in estimated transpulmonary pressure at a given lung volume are small compared with the substantial range of Plrel in patients with acute lung injury.

scholarly journals A Novel Method to Predict Drug-Target Interactions Based on Large-Scale Graph Representation Learning

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2111
Author(s):  
Bo-Wei Zhao ◽  
Zhu-Hong You ◽  
Lun Hu ◽  
Zhen-Hao Guo ◽  
Lei Wang ◽  
...  
Keyword(s):  
Drug Target ◽  
Large Scale ◽  
Computational Models ◽  
Structural Information ◽  
Characteristic Curve ◽  
Representation Learning ◽  
Graph Representation ◽  
Convolutional Network ◽  
Novel Method

Identification of drug-target interactions (DTIs) is a significant step in the drug discovery or repositioning process. Compared with the time-consuming and labor-intensive in vivo experimental methods, the computational models can provide high-quality DTI candidates in an instant. In this study, we propose a novel method called LGDTI to predict DTIs based on large-scale graph representation learning. LGDTI can capture the local and global structural information of the graph. Specifically, the first-order neighbor information of nodes can be aggregated by the graph convolutional network (GCN); on the other hand, the high-order neighbor information of nodes can be learned by the graph embedding method called DeepWalk. Finally, the two kinds of feature are fed into the random forest classifier to train and predict potential DTIs. The results show that our method obtained area under the receiver operating characteristic curve (AUROC) of 0.9455 and area under the precision-recall curve (AUPR) of 0.9491 under 5-fold cross-validation. Moreover, we compare the presented method with some existing state-of-the-art methods. These results imply that LGDTI can efficiently and robustly capture undiscovered DTIs. Moreover, the proposed model is expected to bring new inspiration and provide novel perspectives to relevant researchers.

Relation between transpulmonary pressure and right ventricular isovolumetric pressure change during respiratory support

1989 ◽  
Vol 16 (4) ◽  
pp. 215-220 ◽  
Author(s):  
François Jardin ◽  
Dominique Brun-Ney ◽  
Pierre Cazaux ◽  
Olivier Dubourg ◽  
Anne Hardy ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Transpulmonary Pressure ◽  
Pressure Change ◽  
Respiratory Support

Effect of ventilatory frequency on regional transpulmonary pressure in normal adults

1981 ◽  
Vol 51 (3) ◽  
pp. 678-685 ◽  
Author(s):  
W. Hida ◽  
S. Suzuki ◽  
H. Sasaki ◽  
Y. Fujii ◽  
T. Sasaki ◽  
...  
Keyword(s):  
Balloon Catheter ◽  
Transpulmonary Pressure ◽  
Dynamic Compliance ◽  
Local Dynamic ◽  
Ventilatory Frequency ◽  
Catheter System ◽  
Residual Capacity ◽  
Resistive Component ◽  
Normal Adults ◽  
Zero Frequency

The relation between the ventilatory frequency and the elastic (delta Pel) or resistive (delta Prs) components of changes of the regional pleural pressure (delta PL) was studied at functional residual capacity (FRC) in six normal adults. The regional delta PL was measured simultaneously at three levels in the esophagus using a three-balloon-catheter system. Elastic components of regional delta PL normalized by overall tidal volume (delta Pel/delta V) increased with frequency at all three balloon positions; the percentages of delta Pel/delta V at 60 breaths/min to those at zero frequency were 107, 119, and 157% in the upper, middle, and lower balloon, respectively. The resistive component of regional delta PL normalized by overall air flow (delta Prs/delta V) did not show significant dependence on frequency at any of the three positions and was almost the same everywhere. It is suggested that the increase of local delta Pel with frequency might reflect mainly the frequency dependence of local dynamic compliance (Cdyn) and that the change of the local Cdyn with frequency might be larger in dependent than in upper lung.

Identification of Perilipin-2 as a lipid droplet protein regulated in oocytes during maturation

2010 ◽  
Vol 22 (8) ◽  
pp. 1262 ◽  
Author(s):  
Xing Yang ◽  
Kylie R. Dunning ◽  
Linda L.-Y. Wu ◽  
Theresa E. Hickey ◽  
Robert J. Norman ◽  
...  
Keyword(s):  
Lipid Droplet ◽  
Lipid Content ◽  
Lipid Droplets ◽  
Intracellular Lipids ◽  
Epidermal Growth ◽  
Novel Method ◽  
Perilipin 2 ◽  
Lipid Droplet Protein

Lipid droplet proteins regulate the storage and utilisation of intracellular lipids. Evidence is emerging that oocyte lipid utilisation impacts embryo development, but lipid droplet proteins have not been studied in oocytes. The aim of the present study was to characterise the size and localisation of lipid droplets in mouse oocytes during the periovulatory period and to identify lipid droplet proteins as potential biomarkers of oocyte lipid content. Oocyte lipid droplets, visualised using a novel method of staining cumulus–oocyte complexes (COCs) with BODIPY 493/503, were small and diffuse in oocytes of preovulatory COCs, but larger and more centrally located after maturation in response to ovulatory human chorionic gonadotrophin (hCG) in vivo, or FSH + epidermal growth factor in vitro. Lipid droplet proteins Perilipin, Perilipin-2, cell death-inducing DNA fragmentation factor 45-like effector (CIDE)-A and CIDE-B were detected in the mouse ovary by immunohistochemistry, but only Perilipin-2 was associated with lipid droplets in the oocyte. In COCs, Perilipin-2 mRNA and protein increased in response to ovulatory hCG. IVM failed to induce Perilipin-2 mRNA, yet oocyte lipid content was increased in this context, indicating that Perilipin-2 is not necessarily reflective of relative oocyte lipid content. Thus, Perilipin-2 is a lipid droplet protein in oocytes and its induction in the COC concurrent with dynamic reorganisation of lipid droplets suggests marked changes in lipid utilisation during oocyte maturation.

scholarly journals Molar mass characterization of hydrophilic copolymers, 2 Size exclusion chromatography of cationic (meth)acrylate copolymers

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Martina Adler ◽  
Harald Pasch ◽  
Christian Meier ◽  
Raimund Senger ◽  
Hans-Günter Koban ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Size Exclusion Chromatography ◽  
Molar Mass ◽  
Extended Period ◽  
Size Exclusion ◽  
Viscosity Data ◽  
Exclusion Chromatography ◽  
Reproducible Method ◽  
Novel Method ◽  
Sec System

AbstractA robust and reproducible method for the molar mass analysis of cationic copolymers based on dimethylaminoethyl methacrylate or trimethylammonioethyl methacrylate and different (meth)acrylates has been developed. Size exclusion chromatography (SEC) using a novel polyester-based packing as the stationary phase and dimethylacetamide (DMAC) as the mobile phase yields highly accurate results for copolymers with an amino comonomer content up to 50 wt.-%. To suppress the different polar and ionic interactions between sample molecules, stationary phase and eluent, DMAC was modified with LiBr and tris(hydroxymethylamino) methane (TRIS). Calibrating the SEC system with poly(methyl methacrylate) of narrow polydispersity, molar masses were obtained that are in good agreement with viscosity data. Reproducibility and robustness of the novel method were proven by running samples for an extended period of two weeks.

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