scholarly journals Moderately high frequency ventilation with a conventional ventilator allows reduction of tidal volume without increasing mean airway pressure

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Ricardo Luiz Cordioli ◽  
Marcelo Park ◽  
Eduardo Leite Vieira Costa ◽  
Susimeire Gomes ◽  
Laurent Brochard ◽  
...  
Keyword(s):  
Tidal Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
High Frequency Ventilation ◽  
Mean Airway Pressure ◽  
Frequency Ventilation

Mean airway pressure and alveolar pressure during high-frequency ventilation

1984 ◽  
Vol 57 (4) ◽  
pp. 1069-1078 ◽  
Author(s):  
B. A. Simon ◽  
G. G. Weinmann ◽  
W. Mitzner
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
High Frequency Ventilation ◽  
Alveolar Pressure ◽  
Mean Flow ◽  
Mean Airway Pressure ◽  
Expiratory Flow Limitation ◽  
Frequency Ventilation

Studies and applications of high-frequency ventilation (HFV) are often performed under conditions of controlled mean airway pressure (Paw). In the present study we tested the assumption that controlling Paw adequately controls lung volume during HFV by investigating the relationship between a reliably measured Paw and the mean alveolar pressure (Palv) of the lungs during HFV of healthy dogs. We minimized the errors of Paw measurement due to the Bernoulli effect and various technical factors by appropriate choice of transducers, amplifiers, and measurement site. Palv was estimated by clamping the ventilator tube during oscillation and measuring the equilibration pressure of the lung and airways. Paw and Palv were determined as functions of frequency (8–25 Hz), tidal volume (60–90 ml), Paw (-5 to 12 cmH2O), and position of the animal (supine vs. lateral). We found that Paw could significantly underestimate Palv and that the degree of underestimation increased at higher frequencies, larger tidal volumes, and lower Paw. Shifting the animal from the supine to the lateral position greatly accentuated this effect. The elevation of Palv above Paw was seen to be a function of mean flow and largely independent of the frequency-tidal volume combination which produced the flow. A possible explanation of this pressure difference is that it results from differences in inspiratory and expiratory airway impedances, which in turn depend on airway geometry, compliance, lung volume, and expiratory flow limitation.

A new system for ventilating with high-frequency oscillation

1982 ◽  
Vol 53 (6) ◽  
pp. 1638-1642 ◽  
Author(s):  
Y. K. Ngeow ◽  
W. Mitzner
Keyword(s):  
Tidal Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
Ventilation System ◽  
High Frequency Oscillation ◽  
High Frequency Ventilation ◽  
Mean Airway Pressure ◽  
Frequency Oscillation ◽  
Frequency Ventilation ◽  
New System

We describe simple high-frequency oscillation systems that incorporate a CO2 absorber and supply O2 on a need basis. These systems have the advantage of easy control of mean airway pressure and airway hydration and negligible loss of oscillatory tidal volume. Experiments done at constant tidal volume showed that as frequency (and hence total ventilation) increased, arterial CO2 tension (PaCO2) decreased. The fall in PaCO2 occurred until frequency reached approximately 20 Hz; above 20 Hz further increases in frequency had little or no effect on PaCO2. Because of their practical advantages the techniques described here may be quite useful in a clinical setting where an oscillator, rather than jet-type high-frequency, ventilation system is desired.

Effects of mean airway pressure on gas transport during high-frequency ventilation in dogs

1986 ◽  
Vol 61 (5) ◽  
pp. 1896-1902 ◽  
Author(s):  
Y. Yamada ◽  
J. G. Venegas ◽  
D. J. Strieder ◽  
C. A. Hales
Keyword(s):  
Lung Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
Gas Transport ◽  
Blood Gases ◽  
Co2 Production ◽  
High Frequency Ventilation ◽  
Mean Airway Pressure ◽  
Arterial Blood ◽  
Frequency Ventilation

In 10 anesthetized, paralyzed, supine dogs, arterial blood gases and CO2 production (VCO2) were measured after 10-min runs of high-frequency ventilation (HFV) at three levels of mean airway pressure (Paw) (0, 5, and 10 cmH2O). HFV was delivered at frequencies (f) of 3, 6, and 9 Hz with a ventilator that generated known tidal volumes (VT) independent of respiratory system impedance. At each f, VT was adjusted at Paw of 0 cmH2O to obtain a eucapnia. As Paw was increased to 5 and 10 cmH2O, arterial PCO2 (PaCO2) increased and arterial PO2 (PaO2) decreased monotonically and significantly. The effect of Paw on PaCO2 and PaO2 was the same at 3, 6, and 9 Hz. Alveolar ventilation (VA), calculated from VCO2 and PaCO2, significantly decreased by 22.7 +/- 2.6 and 40.1 +/- 2.6% after Paw was increased to 5 and 10 cmH2O, respectively. By taking into account the changes in anatomic dead space (VD) with lung volume, VA at different levels of Paw fits the gas transport relationship for HFV derived previously: VA = 0.13 (VT/VD)1.2 VTf (J. Appl. Physiol. 60: 1025–1030, 1986). We conclude that increasing Paw and lung volume significantly decreases gas transport during HFV and that this effect is due to the concomitant increase of the volume of conducting airways.

Respiratory therapy techniques

2011 ◽  
Author(s):  
Carl Waldmann ◽  
Neil Soni ◽  
Andrew Rhodes
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Prone Position ◽  
High Frequency ◽  
Airway Pressure ◽  
Oxygen Therapy ◽  
Positive Airway Pressure ◽  
Ventilatory Support ◽  
High Frequency Ventilation ◽  
Frequency Ventilation ◽  
Positive Airway Pressure Ventilation

Oxygen therapy 2Ventilatory support: indications 6IPPV—description of ventilators 8IPPV—modes of ventilation 10IPPV—adjusting the ventilator 12IPPV—barotrauma 14IPPV—weaning techniques 16High-frequency ventilation 18Positive end-respiratory pressure 22Continuous positive airway pressure ventilation (CPAP) 24Recruitment manoeuvres 26Prone position ventilation 28...

Tidal Volume and Frequency Dependence of Carbon Dioxide Elimination by High-Frequency Ventilation

1982 ◽  
Vol 26 (5) ◽  
pp. 277-278
Author(s):  
T. H. ROSSING ◽  
A. S. SLUTSKY ◽  
J. L. LEHR ◽  
P. A. DRINKER ◽  
R. KAMM ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Frequency Dependence ◽  
High Frequency ◽  
High Frequency Ventilation ◽  
Carbon Dioxide Elimination ◽  
Frequency Ventilation

scholarly journals 1826 TRANSTHORACIC IMPEDANCE AS A METHOD OF MEASURING TIDAL VOLUME DURING HIGH FREQUENCY VENTILATION

1985 ◽  
Vol 19 (4) ◽  
pp. 415A-415A
Author(s):  
Kenneth L Sandberg ◽  
Elizabeth P Krueger ◽  
Daniel P Lindstrom ◽  
Hakan Sundell ◽  
Robert B Cotton
Keyword(s):  
Tidal Volume ◽  
High Frequency ◽  
High Frequency Ventilation ◽  
Transthoracic Impedance ◽  
Frequency Ventilation

Physiological dead space during high-frequency ventilation in dogs

1984 ◽  
Vol 57 (3) ◽  
pp. 881-887 ◽  
Author(s):  
G. G. Weinmann ◽  
W. Mitzner ◽  
S. Permutt
Keyword(s):  
Gas Exchange ◽  
Tidal Volume ◽  
Dead Space ◽  
High Frequency ◽  
Minute Ventilation ◽  
Alveolar Ventilation ◽  
High Frequency Ventilation ◽  
Physiological Dead Space ◽  
Frequency Ventilation ◽  
Normal Ventilation

Tidal volumes used in high-frequency ventilation (HFV) may be smaller than anatomic dead space, but since gas exchange does take place, physiological dead space (VD) must be smaller than tidal volume (VT). We quantified changes in VD in three dogs at constant alveolar ventilation using the Bohr equation as VT was varied from 3 to 15 ml/kg and frequency (f) from 0.2 to 8 Hz, ranges that include normal as well as HFV. We found that VD was relatively constant at tidal volumes associated with normal ventilation (7–15 ml/kg) but fell sharply as VT was reduced further to tidal volumes associated with HFV (less than 7 ml/kg). The frequency required to maintain constant alveolar ventilation increased slowly as tidal volume was decreased from 15 to 7 ml/kg but rose sharply with attendant rapid increases in minute ventilation as tidal volumes were decreased to less than 7 ml/kg. At tidal volumes less than 7 ml/kg, the data deviated substantially from the conventional alveolar ventilation equation [f(VT - VD) = constant] but fit well a model derived previously for HFV. This model predicts that gas exchange with volumes smaller than dead space should vary approximately as the product of f and VT2.

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