Gas exchange in healthy rabbits during high-frequency oscillatory ventilation

1989 ◽  
Vol 66 (3) ◽  
pp. 1343-1351 ◽  
Author(s):  
B. R. Boynton ◽  
M. D. Hammond ◽  
J. J. Fredberg ◽  
B. G. Buckley ◽  
D. Villanueva ◽  
...  
Keyword(s):  
Gas Exchange ◽  
High Frequency ◽  
High Frequency Oscillatory Ventilation ◽  
Blood Gas ◽  
Mean Airway Pressure ◽  
Oscillatory Ventilation ◽  
Dead Space Volume ◽  
Alveolar Hypoventilation ◽  
High Frequency Oscillatory ◽  
Space Volume

We examined the effects of oscillatory frequency (f), tidal volume (VT), and mean airway pressure (Paw) on respiratory gas exchange during high-frequency oscillatory ventilation of healthy anesthetized rabbits. Frequencies from 3 to 30 Hz, VT from 0.4 to 2.0 ml/kg body wt (approximately 20–100% of dead space volume), and Paw from 5 to 20 cmH2O were studied. As expected, both arterial partial pressure of O2 and CO2 (PaO2 and PaCO2, respectively) were found to be related to f and VT. Changing Paw had little effect on blood gas tensions. Similar values of PaO2 and PaCO2 were obtained at many different combinations of f and VT. These relationships collapsed onto a single curve when blood gas tensions were plotted as functions of f multiplied by the square of VT (f. VT2). Simultaneous tracheal and alveolar gas samples showed that the gradient for PO2 and PCO2 increased as f. VT2 decreased, indicating alveolar hypoventilation. However, venous admixture also increased as f. VT2 decreased, suggesting that ventilation-perfusion inequality must also have increased.

scholarly journals Effects of a Combination of Prone Positioning and High-Frequency Oscillatory Ventilation on Blood Gas Exchange in an Experimental Pig Model of Acute Respiratory Distress Syndrome Efekti Kombinacije Ležećeg Položaja I Oscilatorne Plućne Ventilacije Visoke Frekvencije Na Razmenu Gasova U Krvi Na Modelu Sindroma Akutnog Respiratornog Šoka Kod Svinja

2014 ◽  
Vol 64 (3) ◽  
pp. 307-318
Author(s):  
Žurek Jiří ◽  
Dominik Petr ◽  
Košut Peter ◽  
Šeda Miroslav ◽  
Fedora Michal
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Gas Exchange ◽  
Prone Position ◽  
High Frequency ◽  
Distress Syndrome ◽  
High Frequency Oscillatory Ventilation ◽  
Prone Positioning ◽  
Blood Gas ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory

Abstract This animal study was conducted in order to verify the effects of combining highfrequency oscillatory ventilation and prone positioning and the order of application of both methods on blood gas exchange in an experimental model of acute respiratory distress syndrome. Forty domestic pigs were used for the study. Saline solution washout was produced by bilateral lung lavage. The lavage process was repeated until adequate impairment of gas exchange (defined as PaO2 < 100 mmHg) 60 min following the last lavage was achieved. Subsequently, lung injury was established and each model was randomized to one of five groups, with differences in the type of mechanical ventilation used (conventional mechanical ventilation in accordance with the principles of protective lung ventilation or high-frequency oscillatory ventilation) and also in the positioning of the experimental model (supine position or mode changing prone and supine positions in a ratio 18:6 hours). The best oxygenation was achieved in the group prone position + high-frequency oscillatory ventilation. The most favorable combination in terms of carbon dioxide elimination is the high-frequency oscillatory ventilation + prone position. The best results in terms of oxygenation index value were obtained in the combination of a prone position with the high-frequency oscillatory ventilation and in the prone position. In conclusion, by using combinations of prone positioning and high-frequency oscillatory ventilation, one can achieve better blood gas parameters during acute respiratory distress syndrome.

Effect of the Ti/Te ratio on mean intratracheal pressure in high-frequency oscillatory ventilation

1998 ◽  
Vol 84 (5) ◽  
pp. 1520-1527 ◽  
Author(s):  
Ulrich Thome ◽  
Frank Pohlandt
Keyword(s):  
High Frequency ◽  
Airway Pressure ◽  
High Frequency Oscillatory Ventilation ◽  
Inspiratory Time ◽  
Mean Airway Pressure ◽  
Air Trapping ◽  
Oscillatory Ventilation ◽  
Mean Pressure ◽  
Oscillation Frequencies ◽  
High Frequency Oscillatory

In high-frequency oscillatory ventilation (HFOV), an adequate mean airway pressure is crucial for successful ventilation and optimal gas exchange, but air trapping cannot be detected by the usual measurement at the y piece. Intratracheal pressures produced by the high-frequency oscillators HFV-Infantstar (IS), Babylog 8000 (BL), and the SensorMedics 3100A (SM) [the latter with either 30% (SM30) or 50% (SM50) inspiratory time] were investigated in four anesthetized tracheotomized female piglets that were 1 day old and weighed 1.6–1.9 kg (mean 1.76 kg). The endotracheal tube was repeatedly clamped while the piglets were ventilated with an oscillation frequency of 10 Hz, and the airway pressure distal of the clamp was recorded as a measure of average intrapulmonary pressure during oscillation. Clamping resulted in a significant decrease of mean airway pressure when the piglets were ventilated with SM30(−0.86 cmH2O), BL (−0.66 cmH2O), and IS (−0.71 cmH2O), but airway pressure increased by a mean of 0.76 cmH2O with SM50. Intratracheal pressure, when measured by a catheter pressure transducer at various oscillation frequencies, was lower than at the y piece by 0.4–0.9 cmH2O (SM30), 0.3–3 cmH2O (BL), and 1–4.7 cmH2O (IS) but was 0.4–0.7 cmH2O higher with SM50. We conclude that the inspiratory-to-expiratory time (Ti/Te) ratio influences the intratracheal and intrapulmonary pressures in HFOV and may sustain a mean pressure gradient between the y piece and the trachea. A Ti/Te ratio < 1:1 may be useful to avoid air trapping when HFOV is used.

Setting Mean Airway Pressure during High-frequency Oscillatory Ventilation According to the Static Pressure–Volume Curve in Surfactant-deficient Lung Injury

2003 ◽  
Vol 99 (6) ◽  
pp. 1313-1322 ◽  
Author(s):  
Thomas Luecke ◽  
Juergen P. Meinhardt ◽  
Peter Herrmann ◽  
Gerald Weisser ◽  
Paolo Pelosi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
Static Pressure ◽  
High Frequency Oscillatory Ventilation ◽  
Mean Airway Pressure ◽  
Oscillatory Ventilation ◽  
Hemodynamic Variables ◽  
High Frequency Oscillatory

Background Numerous studies suggest setting positive end-expiratory pressure during conventional ventilation according to the static pressure-volume (P-V) curve, whereas data on how to adjust mean airway pressure (P(aw)) during high-frequency oscillatory ventilation (HFOV) are still scarce. The aims of the current study were to (1) examine the respiratory and hemodynamic effects of setting P(aw) during HFOV according to the static P-V curve, (2) assess the effect of increasing and decreasing P(aw) on slice volumes and aeration patterns at the lung apex and base using computed tomography, and (3) study the suitability of the P-V curve to set P(aw) by comparing computed tomography findings during HFOV with those obtained during recording of the static P-V curve at comparable pressures. Methods Saline lung lavage was performed in seven adult pigs. P-V curves were obtained with computed tomography scanning at each volume step at the lung apex and base. The lower inflection point (Pflex) was determined, and HFOV was started with P(aw) set at Pflex. The pigs were provided five 1-h cycles of HFOV. P(aw), first set at Pflex, was increased to 1.5 times Pflex (termed 1.5 Pflex(inc)) and 2 Pflex and decreased thereafter to 1.5 times Pflex and Pflex (termed 1.5 Pflex(dec) and Pflex(dec)). Hourly measurements of respiratory and hemodynamic variables as well as computed tomography scans at the apex and base were made. Results High-frequency oscillatory ventilation at a P(aw) of 1.5 Pflex(inc) reestablished preinjury arterial oxygen tension values. Further increase in P(aw) did not change oxygenation, but it decreased oxygen delivery as a result of decreased cardiac output. No differences in respiratory or hemodynamic variables were observed when comparing HFOV at corresponding P(aw) during increasing and decreasing P(aw). Variation in total slice lung volume (TLVs) was far less than expected from the static P-V curve. Overdistended lung volume was constant and less than 3% of TLVs. TLVs values during HFOV at Pflex, 1.5 Pflex(inc), and 2 Pflex were significantly greater than TLVs values at corresponding tracheal pressures on the inflation limb of the static P-V curve and located near the deflation limb. In contrast, TLVs values during HFOV at decreasing P(aw) (i.e., 1.5 Pflex(dec) and Pflex(dec)) were not significantly greater than corresponding TLV on the deflation limb of the static P-V curves. The marked hysteresis observed during static P-V curve recordings was absent during HFOV. Conclusions High-frequency oscillatory ventilation using P(aw) set according to a static P-V curve results in effective lung recruitment, and slice lung volumes during HFOV are equal to those from the deflation limb of the static P-V curve at equivalent pressures.

scholarly journals Effect of frequency on pressure cost of ventilation and gas exchange in newborns receiving high-frequency oscillatory ventilation

2017 ◽  
Vol 82 (6) ◽  
pp. 994-999 ◽  
Author(s):  
Emanuela Zannin ◽  
Raffaele L Dellaca' ◽  
Giulia Dognini ◽  
Lara Marconi ◽  
Martina Perego ◽  
...  
Keyword(s):  
Gas Exchange ◽  
High Frequency ◽  
High Frequency Oscillatory Ventilation ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory

scholarly journals Nasal High Frequency Oscillatory Ventilation for Respiratory Failure due to Respiratory Syncytial Virus Bronchiolitis: Case Report

2020 ◽  
Vol 10 (03) ◽  
pp. e253-e254
Author(s):  
Pio Liberatore ◽  
Gianfranco Maffei
Keyword(s):  
Respiratory Failure ◽  
High Frequency ◽  
Orotracheal Intubation ◽  
High Frequency Oscillatory Ventilation ◽  
Blood Gas ◽  
Invasive Ventilation ◽  
High Flow Nasal Cannula ◽  
Oscillatory Ventilation ◽  
Syncytial Virus ◽  
High Frequency Oscillatory

AbstractThe authors describe a case of acute respiratory failure due to severe bronchiolitis. During high-flow nasal cannula ventilation, the blood's high levels of hypercapnia had taken them to plan the sedation and the orotracheal intubation. However, before attempting intubation, a nasal high frequency oscillatory ventilation cycle was performed and it led to a marked improvement in the blood gas, avoiding in this way the invasive ventilation.

HEMODYNAMIC AND BLOOD GAS EFFECTS OF HIGH FREQUENCY OSCILLATORY VENTILATION

1981 ◽  
Vol 9 (3) ◽  
pp. 192 ◽  
Author(s):  
Joseph A. Armengol ◽  
Allan Wells ◽  
Godfrey C.W. Man ◽  
E. Gamer King
Keyword(s):  
High Frequency ◽  
High Frequency Oscillatory Ventilation ◽  
Blood Gas ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory

scholarly journals Impairment of Hemodynamics with Increasing Mean Airway Pressure during High-Frequency Oscillatory Ventilation

1988 ◽  
Vol 23 (6) ◽  
pp. 628-631 ◽  
Author(s):  
Jay H Traverse ◽  
Heikki Korvenranta ◽  
E Merrill Adams ◽  
David A Goldthwait ◽  
Waldemar A Carlo
Keyword(s):  
High Frequency ◽  
Airway Pressure ◽  
High Frequency Oscillatory Ventilation ◽  
Mean Airway Pressure ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory
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