scholarly journals Influence of catheter diameter, endotracheal tube diameter, suction pressure, and PEEP on the tracheal pressure and lung volume during endotracheal suctioning using a lung model

Critical Care ◽  
2012 ◽  
Vol 16 (S1) ◽  
Author(s):  
KJ Snijders ◽  
PE Spronk ◽  
TW Fiks ◽  
H Boon ◽  
T Ten Kleij ◽  
...  
Keyword(s):  
Endotracheal Tube ◽  
Lung Volume ◽  
Tube Diameter ◽  
Lung Model ◽  
Suction Pressure ◽  
Endotracheal Suctioning ◽  
Tracheal Pressure

Lung volume changes by electric impedance tomography (EIT) during endotracheal suctioning

2004 ◽  
Vol 21 (Supplement 32) ◽  
pp. 73
Author(s):  
S. Lindgren ◽  
H. Odenstedt ◽  
C. Olegard ◽  
S. Lundin ◽  
O. Stenqvist
Keyword(s):  
Lung Volume ◽  
Electric Impedance ◽  
Volume Changes ◽  
Endotracheal Suctioning ◽  
Electric Impedance Tomography ◽  
Impedance Tomography

Effect of preinspiratory lung volume on closing volume determination by nitrogen method

1975 ◽  
Vol 38 (1) ◽  
pp. 10-15 ◽  
Author(s):  
K. Kaneko ◽  
J. Mohler ◽  
O. Balchum
Keyword(s):  
Lung Volume ◽  
Inflection Point ◽  
Model Analysis ◽  
Lung Model ◽  
Closing Volume ◽  
Terminal Portion ◽  
Volume Determination ◽  
Modified Method ◽  
Initial Rise ◽  
N2 Method

The effect of preinspiratory lung volume on the N2 closing volume (CV) was studied in simulated CV determination in a lung model. The model analysis supports our hypothesis that inspiration of O2 initiated at the “closing capacity” (CC = CV ;V) will improve the resolution of the inflection point between phases III and IV. It further indicates that if the inflection point is located by extrapolating the terminal portion of phase IV, then the original N2 method could underestimate CV systematically as much as 5% VC because of the relatively small initial rise in N2 concentration. Conversely, the CV obtained by the modified method should be closer to the value obtained by the “bolus method.” In practice, the modification can be done simply by adding a dead space (DS) with its capacity equal to CV (600–700 ml in male adults). The theoretical lung model analysis was confirmed by the experimental study, which showed that CV with DS was consistently larger than CV without DS (a mean difference of 4.7% VC).

Fluid dynamic factors in tracheal pressure measurement

1981 ◽  
Vol 51 (1) ◽  
pp. 218-225 ◽  
Author(s):  
H. K. Chang ◽  
J. P. Mortola
Keyword(s):  
Endotracheal Tube ◽  
Pressure Measurement ◽  
Fluid Dynamic ◽  
Theoretical Explanation ◽  
Apparent Paradox ◽  
Cross Sectional ◽  
Tracheal Cannula ◽  
Dynamic Factors ◽  
Tracheal Pressure

Because tracheal pressure measurement generally involves the use of a cannula or an endotracheal tube, fluid dynamic factors may cause a considerable artifact. We present a theoretical explanation of the observed apparent paradox in which the resistance of a tracheal cannula or an endotracheal tube is isolation was found to exceed the resistance of the airways plus the cannula or the tube in situ. By estimating the viscous dissipation and the kinetic energy change in a conduit with sudden variation of cross-sectional area, a predictive model is derived. The predictions are verified by a series of in vitro experiments with both steady and oscillatory flows. The experiments showed that the pressure recorded from the sidearm of a tracheal cannula or endotracheal tube contains an error which, in general, increased with the mean Reynolds' number of the through flow and also depends on the diameter ratio between the trachea and the tube or cannula, the position of the pressure tap, and the frequency of ventilation. When feasible, direct measurement with a needle in the trachea is suggested as a way to avoid the possible artifacts arising from the use fo a side tap of the cannula. Theoretical considerations, as well as in vitro and animal experiments, indicate that adding a properly chosen expansion to the tracheal cannula makes it possible to alter inspiratory and expiratory pressures selectively. This device may prove useful in control of breathing studies.

Effect of endotracheal tube leak on capnographic measurements in a ventilated neonatal lung model

2012 ◽  
Vol 33 (10) ◽  
pp. 1631-1641 ◽  
Author(s):  
G Schmalisch ◽  
S Al-Gaaf ◽  
H Proquitté ◽  
C C Roehr
Keyword(s):  
Endotracheal Tube ◽  
Lung Model ◽  
Neonatal Lung

Flow limitation and wheezes in a constant flow and volume lung preparation

1988 ◽  
Vol 64 (1) ◽  
pp. 17-20 ◽  
Author(s):  
N. Gavriely ◽  
J. B. Grotberg
Keyword(s):  
Lung Model ◽  
Acoustic Properties ◽  
Flow Limitation ◽  
Suction Pressure ◽  
Constant Flow ◽  
Additional Increase ◽  
Suction Pump ◽  
Pleural Surface ◽  
Pulmonary Airways ◽  
Lung Preparation

To facilitate the study of respiratory wheezes in an animal lung model, an isovolume, constant-flow excised dog lung preparation was developed. Dog lungs were inflated to 26 +/- 4 cmH2O and coated with layers of epoxy glue and polyester compound. A rigid shell 2 mm thick was obtained around the entire pleural surface and the extra-pulmonary airways. The adhesive forces between the pleura and the shell were strong enough to hold the lung distended after the inflation pressure was removed. Holes 2 mm diam were drilled through the shell over one of the lung lobes in an array, 4 cm across. The holes penetrated the pleural surface, so that constant flow could be maintained in the expiratory direction by activating a suction pump connected to the trachea. Downstream suction pressure and flow rate were measured with a mercury manometer and a rotameter, respectively. Sounds were recorded by a small (0.6 cm OD) microphone inserted into the trachea. When suction pressure was increased, flow initially increased to 31 +/- 3 l/min. Further increase of suction pressure caused only very slight additional increase in flow (i.e., flow limitation). During this plateau of flow, a pure tone was generated with acoustic properties similar to respiratory wheezes. Both the flow plateau and the wheezing sounds could be eliminated by freezing the lungs. It is concluded that wheezing sounds were associated with flow limitation in this preparation. It is suggested that the stable acoustic properties obtained by this preparation may become useful in the analysis of mechanisms of wheezing lung sounds generation.

Lung hyperinflation in isolated dog lungs during high-frequency oscillation

1988 ◽  
Vol 65 (3) ◽  
pp. 1172-1179 ◽  
Author(s):  
E. J. Cha ◽  
E. Chow ◽  
H. K. Chang ◽  
S. M. Yamashiro
Keyword(s):  
Flow Rate ◽  
Lung Volume ◽  
High Frequency ◽  
High Frequency Oscillation ◽  
Forced Expiration ◽  
Frequency Oscillation ◽  
Expiratory Flow Limitation ◽  
Lung Hyperinflation ◽  
Tracheal Pressure ◽  
Expiratory Flow

To study the phenomenon of lung hyperinflation (LHI), i.e., an increase in lung volume without a concomitant rise in airway pressure, we measured lung volume changes in isolated dog lungs during high-frequency oscillation (HFO) with air, He, and SF6 and with mean tracheal pressure controlled at 2.5, 5.0, and 7.5 cmH2O. The tidal volume and frequency used were 1.5 ml/kg body wt and 20 Hz, respectively. LHI was observed during HFO in all cases except for a few trials with He. The degree of LHI was inversely related to mean tracheal pressure and varied directly with gas density. Maximum expiratory flow rate (Vmax) was measured during forced expiration induced by a vacuum source (-150 cmH2O) at the trachea. Vmax was consistently higher than the peak oscillatory flow rate (Vosc) during HFO, demonstrating that overall expiratory flow limitation did not cause LHI in isolated dog lungs. Asymmetry of inspiratory and expiratory impedances seems to be one cause of LHI, although other factors are involved.

scholarly journals Paediatric Endotracheal Suction

1974 ◽  
Vol 2 (2) ◽  
pp. 131-141 ◽  
Author(s):  
John L. Poole ◽  
N. Abrahams ◽  
G. C. Fisk
Keyword(s):  
Endotracheal Tube ◽  
Negative Pressure ◽  
Air Flow ◽  
Lung Compliance ◽  
Artificial Lung ◽  
Endotracheal Suction ◽  
Tracheal Pressure ◽  
Catheter Size ◽  
Paediatric Practice

Catheters for paediatric endotracheal suction were studied using an artificial lung with compliances in the range encountered in paediatric practice. With various combinations of “lung” compliance, size of endotracheal tube, endotracheal connector and catheter,” tracheal” pressure and air flow between endotracheal tube and catheter were measured. Recommendations for combinations of endotracheal tube, connector and catheter size are made. The maximum negative pressure applied to the catheter should be limited.

scholarly journals Can ventilator settings reduce the negative effects of endotracheal suctioning? Investigations in a mechanical lung model

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Espen R. Nakstad ◽  
Helge Opdahl ◽  
Fridtjof Heyerdahl ◽  
Fredrik Borchsenius ◽  
Ole H. Skjønsberg
Keyword(s):  
Lung Model ◽  
Negative Effects ◽  
Endotracheal Suctioning ◽  
Mechanical Lung ◽  
Ventilator Settings
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