scholarly journals Influence of bronchodilatation on impedance of the respiratory system in mechanically ventilated COPD patients

Critical Care ◽  
10.1186/cc216 ◽  
1998 ◽  
Vol 2 (Suppl 1) ◽  
pp. P086
Author(s):  
C Gysbrechts ◽  
H Dits ◽  
E Frans ◽  
A Michels ◽  
A Wilmer ◽  
...  
Keyword(s):  
Respiratory System ◽  
Mechanically Ventilated ◽  
Copd Patients

Flow and volume dependence of expiratory resistance in anesthetized cats

1989 ◽  
Vol 67 (3) ◽  
pp. 1013-1019 ◽  
Author(s):  
M. Skaburskis ◽  
F. Shardonofsky ◽  
J. Milic-Emili
Keyword(s):  
Respiratory System ◽  
Volume Flow ◽  
Flow Profile ◽  
Pressure Flow ◽  
Lung Inflation ◽  
Mechanically Ventilated ◽  
Volume Dependence ◽  
Flow Dependence ◽  
Lung Deflation ◽  
Respiratory Muscle Activity

In five anesthetized paralyzed cats, mechanically ventilated with tidal volumes of 36–48 ml, the isovolume pressure-flow relationships of the lung and respiratory system were studied. The expiratory pressure was altered between 3 and -12 cmH2O for single tidal expirations. Isovolume pressure-flow plots for three lung volumes showed that the resistive pressure-flow relationships were curvilinear in all cases, fitting Rohrer's equation: P = K1V + K2V2, where P is the resistive pressure loss, K1 and K2 are Rohrer's coefficients, and V is flow. Values of K1 and K2 declined with lung inflation, consistent with the volume dependence of pulmonary (RL) and respiratory system resistances (Rrs). During lung deflation against atmospheric pressure, RL and Rrs tended to remain constant through most of expiration, resulting in a nearly linear volume-flow relationship. In the presence of a fixed respiratory system elastance, the shape of the volume-flow profile depended on the balance between the volume and the flow dependence of RL and Rrs. However, the flow dependence of RL and Rrs indicates that their measured values will be affected by all factors that modify expiratory flow, e.g., respiratory system elastance, equipment resistance, and the presence of respiratory muscle activity.

scholarly journals Influence of respiratory efforts on b2-agonist induced bronchodilation in mechanically ventilated COPD patients: A prospective clinical study

2007 ◽  
Vol 101 (2) ◽  
pp. 300-307 ◽  
Author(s):  
P. Malliotakis ◽  
E. Mouloudi ◽  
G. Prinianakis ◽  
E. Kondili ◽  
D. Georgopoulos
Keyword(s):  
Clinical Study ◽  
Prospective Clinical Study ◽  
Mechanically Ventilated ◽  
Copd Patients

Partitioning of work of breathing in mechanically ventilated COPD patients

1993 ◽  
Vol 75 (4) ◽  
pp. 1711-1719 ◽  
Author(s):  
M. L. Coussa ◽  
C. Guerin ◽  
N. T. Eissa ◽  
C. Corbeil ◽  
M. Chasse ◽  
...  
Keyword(s):  
Work Of Breathing ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Mechanically Ventilated ◽  
Airway Occlusion ◽  
Copd Patients ◽  
Additional Resistance ◽  
Work Done ◽  
Inspiratory Muscle Fatigue

In 10 sedated paralyzed mechanically ventilated chronic obstructive pulmonary disease (COPD) patients, we measured the inspiratory mechanical work done per breath on the respiratory system (WI,rs). We measured the tracheal and esophageal pressures to assess the lung (L) and chest wall (W) components of WI and used the technique of rapid airway occlusion during constant-flow inflation to partition WI into static work [Wst, including work due to intrinsic positive end-expiratory pressure (WPEEPi)], dynamic work due to airway resistance, and the additional resistance offered by the respiratory tissues. Although the patients were hyperinflated, the slope of the static volume-pressure relationships of the lung did not decrease with inflation volume up to 0.8 liter. WI,W was similar in COPD patients and normal subjects. All components of WI,L were higher in COPD patients. The increase in Wst,rs was due entirely to WPEEPi. Our data suggest that, during spontaneous breathing, COPD patients would probably develop inspiratory muscle fatigue, unless continuous positive airway pressure were applied to reduce WPEEPi.

Sign in / Sign up

Export Citation Format

Share Document