Static Compliance Measurement as a Method of Assessing Damage

2006 ◽  
Author(s):  
B. L. Holloway ◽  
D. W. Radford ◽  
L. R. Weidner
Keyword(s):  
Static Compliance ◽  
Compliance Measurement

Biologically Variable Ventilation Improves Oxygenation and Respiratory Mechanics during One-lung Ventilation

2006 ◽  
Vol 105 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Michael C. McMullen ◽  
Linda G. Girling ◽  
M Ruth Graham ◽  
W Alan C. Mutch
Keyword(s):  
Tidal Volume ◽  
Respiratory Mechanics ◽  
Lung Ventilation ◽  
Group Effect ◽  
Shunt Fraction ◽  
Static Compliance ◽  
One Lung Ventilation ◽  
Time Interaction ◽  
Variable Ventilation ◽  
Dead Space Ventilation

Background Hypoxemia is common during one-lung ventilation (OLV). Atelectasis contributes to the problem. Biologically variable ventilation (BVV), using microprocessors to reinstitute physiologic variability to respiratory rate and tidal volume, has been shown to be advantageous over conventional monotonous control mode ventilation (CMV) in improving oxygenation during the period of lung reinflation after OLV in an experimental model. Here, using a porcine model, the authors compared BVV with CMV during OLV to assess gas exchange and respiratory mechanics. Methods Eight pigs (25-30 kg) were studied in each of two groups. After induction of anesthesia-tidal volume 12 ml/kg with CMV and surgical intervention-tidal volume was reduced to 9 ml/kg. OLV was initiated with an endobronchial blocker, and the animals were randomly allocated to either continue CMV or switch to BVV for 90 min. After OLV, a recruitment maneuver was undertaken, and both lungs were ventilated for a further 60 min. At predetermined intervals, hemodynamics, respiratory gases (arterial, venous, and end-tidal samples) and mechanics (airway pressures, static and dynamic compliances) were measured. Derived indices (pulmonary vascular resistance, shunt fraction, and dead space ventilation) were calculated. Results By 15 min of OLV, arterial oxygen tension was greater in the BVV group (group x time interaction, P = 0.003), and shunt fraction was lower with BVV from 30 to 90 min (group effect, P = 0.0004). From 60 to 90 min, arterial carbon dioxide tension was lower with BVV (group x time interaction, P = 0.0001) and dead space ventilation was less from 60 to 90 min (group x time interaction, P = 0.0001). Static compliance was greater by 60 min of BVV and remained greater during return to ventilation of both lungs (group effect, P = 0.0001). Conclusions In this model of OLV, BVV resulted in superior gas exchange and respiratory mechanics when compared with CMV. Improved static compliance persisted with restoration of two-lung ventilation.

Mechanics of respiratory system in healthy anesthetized humans with emphasis on viscoelastic properties

1993 ◽  
Vol 75 (1) ◽  
pp. 132-140 ◽  
Author(s):  
B. Jonson ◽  
L. Beydon ◽  
K. Brauer ◽  
C. Mansson ◽  
S. Valind ◽  
...  
Keyword(s):  
Respiratory System ◽  
Driving Force ◽  
Viscoelastic Behavior ◽  
Elastic Recoil ◽  
Inspiratory Flow Rate ◽  
Static Compliance ◽  
Viscoelastic System ◽  
Flow Interruption ◽  
In Series ◽  
Flow Dependency

The classic model of the respiratory system (RS) is comprised of a Newtonian resistor in series with a capacitor and a viscoelastic unit including a resistor and a capacitor. The flow interruption technique has often been used to study the viscoelastic behavior under constant inspiratory flow rate. To study the viscoelastic behavior of the RS during complete respiratory cycles and to quantify viscoelastic resistance (Rve) and compliance (Cve) under unrestrained conditions, we developed an iterative technique based on a differential equation. We, as others, assumed Rve and Cve to be constant, which concords with volume and flow dependency of model behavior. During inspiration Newtonian resistance (R) was independent of flow and volume. During expiration R increased. Static elastic recoil showed no significant hysteresis. The viscoelastic behavior of the RS was in accordance with the model. The magnitude of Rve was 3.7 +/- 0.7 cmH2O.l-1 x s, i.e., two times R. Cve was 0.23 +/- 0.051 l/cmH2O, i.e., four times static compliance. The viscoelastic time constant, i.e., Cve.Rve, was 0.82 +/- 0.11s. The work dissipated against the viscoelastic system was 0.62 +/- 0.13 cmH2O x 1 for a breath of 0.56 liter, corresponding to 32% of the total energy loss within the RS. Viscoelastic recoil contributed as a driving force during the initial part of expiration.

scholarly journals Ex vivo lung perfusion in Brazil

2016 ◽  
Vol 42 (2) ◽  
pp. 95-98 ◽  
Author(s):  
Luis Gustavo Abdalla ◽  
Karina Andrighetti de Oliveira Braga ◽  
Natalia Aparecida Nepomuceno ◽  
Lucas Matos Fernandes ◽  
Marcos Naoyuki Samano ◽  
...  
Keyword(s):  
Respiratory Mechanics ◽  
Ex Vivo ◽  
Lung Perfusion ◽  
Improve Lung Function ◽  
Static Compliance ◽  
Ex Vivo Lung Perfusion ◽  
Time Points ◽  
Physiological Conditions ◽  
The Mean ◽  
A Prospective Study

Objective: To evaluate the use of ex vivo lung perfusion (EVLP) clinically to prepare donor lungs for transplantation. Methods: A prospective study involving EVLP for the reconditioning of extended-criteria donor lungs, the criteria for which include aspects such as a PaO2/FiO2 ratio < 300 mmHg. Between February of 2013 and February of 2014, the lungs of five donors were submitted to EVLP for up to 4 h each. During EVLP, respiratory mechanics were continuously evaluated. Once every hour during the procedure, samples of the perfusate were collected and the function of the lungs was evaluated. Results: The mean PaO2 of the recovered lungs was 262.9 ± 119.7 mmHg at baseline, compared with 357.0 ± 108.5 mmHg after 3 h of EVLP. The mean oxygenation capacity of the lungs improved slightly over the first 3 h of EVLP-246.1 ± 35.1, 257.9 ± 48.9, and 288.8 ± 120.5 mmHg after 1, 2, and 3 h, respectively-without significant differences among the time points (p = 0.508). The mean static compliance was 63.0 ± 18.7 mmHg, 75.6 ± 25.4 mmHg, and 70.4 ± 28.0 mmHg after 1, 2, and 3 h, respectively, with a significant improvement from hour 1 to hour 2 (p = 0.029) but not from hour 2 to hour 3 (p = 0.059). Pulmonary vascular resistance remained stable during EVLP, with no differences among time points (p = 0.284). Conclusions: Although the lungs evaluated remained under physiological conditions, the EVLP protocol did not effectively improve lung function, thus precluding transplantation.

scholarly journals Tolerance Compliance Measurement Using Terrestrial Laser Scanner

2018 ◽  
Author(s):  
Saeed Talebi ◽  
Lauri Koskela ◽  
Patricia Tzortzopoulos
Keyword(s):  
Laser Scanner ◽  
Terrestrial Laser Scanner ◽  
Compliance Measurement
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