Effect of tracheal gas insufflation on gas exchange in canine oleic acid-induced lung injury

Background Perfluorocarbon (PFC) liquids are known to improve gas exchange and pulmonary function in various models of acute respiratory failure. Vaporization has been recently reported as a new method of delivering PFC to the lung. Our aim was to study the effect of PFC vapor on the ventilation/perfusion (VA/Q) matching and relative pulmonary blood flow (Qrel) distribution. Methods In nine sheep, lung injury was induced using oleic acid. Four sheep were treated with vaporized perfluorohexane (PFX) for 30 min, whereas the remaining sheep served as control animals. Vaporization was achieved using a modified isoflurane vaporizer. The animals were studied for 90 min after vaporization. VA/Q distributions were estimated using the multiple inert gas elimination technique. Change in Qrel distribution was assessed using fluorescent-labeled microspheres. Results Treatment with PFX vapor improved oxygenation significantly and led to significantly lower shunt values (P < 0.05, repeated-measures analysis of covariance). Analysis of the multiple inert gas elimination technique data showed that animals treated with PFX vapor demonstrated a higher VA/Q heterogeneity than the control animals (P < 0.05, repeated-measures analysis of covariance). Microsphere data showed a redistribution of Qrel attributable to oleic acid injury. Qrel shifted from areas that were initially high-flow to areas that were initially low-flow, with no difference in redistribution between the groups. After established injury, Qrel was redistributed to the nondependent lung areas in control animals, whereas Qrel distribution did not change in treatment animals. Conclusion In oleic acid lung injury, treatment with PFX vapor improves gas exchange by increasing VA/Q heterogeneity in the whole lung without a significant change in gravitational gradient.

Download Full-text

Distal effects of tracheal gas insufflation: changes with catheter position and oleic acid lung injury

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.3.1121 ◽

1996 ◽

Vol 81 (3) ◽

pp. 1121-1127 ◽

Cited By ~ 16

Author(s):

A. Nahum ◽

S. A. Ravenscraft ◽

A. B. Adams ◽

J. J. Marini

Keyword(s):

Oleic Acid ◽

Lung Injury ◽

Dead Space ◽

Minute Ventilation ◽

Catheter Position ◽

Tracheal Gas Insufflation ◽

Before And After ◽

Dead Space Volume ◽

Catheter Tip ◽

Conducting Airways

We separated distal (turbulence-related) and proximal (dead space washout-related) effects of tracheal gas insufflation (TGI) by comparing the effects of straight and inverted catheters. We reasoned that the inverted catheter was unlikely to remove CO2 from conducting airways distal to its orifice. In six normal dogs during TGI at 10 l/min, advancing the catheters from 10 to 1 cm above the main carina decreased dead space volume by 29 +/- 12 and 12 +/- 6 ml (P < 0.04) with the straight and inverted catheters, respectively. By comparison, the tracheal volume between 10 and 1 cm above the carina was 15 +/- 2 ml. In another set of dogs (n = 5), we examined the distal effects of TGI before and after oleic acid-induced lung injury. During TGI at 10 l/min before and after oleic acid injury, the differences in arterial PCO2 between the straight and inverted catheters were 5 +/- and 9 +/- 6 Torr (P < 0.18), respectively. Our data suggest that distal effects of TGI become more pronounced as the catheter tip is positioned closer to the main carina. The distal effects of TGI were not diminished after oleic acid injury when minute ventilation was maintained constant.

Download Full-text

Continuous tracheal gas insufflation during partial liquid ventilation in juvenile rabbits with acute lung injury

Journal of Applied Physiology ◽

10.1152/japplphysiol.01121.2003 ◽

2004 ◽

Vol 96 (4) ◽

pp. 1415-1424 ◽

Cited By ~ 10

Author(s):

Guangfa Zhu ◽

Thomas H. Shaffer ◽

Marla R. Wolfson

Keyword(s):

Acute Lung Injury ◽

Gas Exchange ◽

Lung Injury ◽

Combined Treatment ◽

Peak Inspiratory Pressure ◽

Oxygenation Index ◽

Lung Mechanics ◽

Partial Liquid Ventilation ◽

Liquid Ventilation ◽

Tracheal Gas Insufflation

To examine the hypothesis that combined treatment with tracheal gas insufflation (TGI) and partial liquid ventilation (PLV) may improve pulmonary outcome relative to either treatment alone in acute lung injury (ALI), saline lavage lung injury was induced in 24 anesthetized, ventilated juvenile rabbits that were then randomly assigned to receive ( n = 6/group) 1) conventional mechanical ventilation (CMV) alone, 2) continuous TGI at 0.5 l/min, 3) PLV with perfluorochemical liquid, and 4) combined TGI and PLV (TGI + PLV), and subsequently ventilated with minimized pressures and tidal volume (Vt) to keep arterial Po2 (PaO2) >100 Torr and arterial Pco2 (PaCO2) at 45-60 Torr for 4 h. Gas exchange, lung mechanics, myeloperoxidase, IL-8, and histomorphometry [including expansion index (EI)] were assessed. The CMV group showed no improvement in lung mechanics and gas exchange; all treated groups had significant increases in compliance, PaO2, ventilation efficacy index (VEI), and EI, and decreases in PaCO2, oxygenation index, physiological dead space-to-Vt ratio (Vd/Vt), myeloperoxidase, and IL-8, relative to the CMV group. TGI resulted in lower peak inspiratory pressure, Vt, Vd/Vt, and greater VEI vs. PLV group; PLV resulted in greater compliance, PaO2, and EI vs. TGI. TGI + PLV resulted in decreased peak inspiratory pressure, Vt, Vd/Vt, and increased VEI compared with TGI, improved compliance and EI compared with PLV, and a further increase in PaO2 and oxygenation index and a decrease in PaCO2 vs. either treatment alone. These results indicate that combined treatment of TGI and PLV results in improved pulmonary outcome than either treatment alone in this animal model of ALI.

Download Full-text

Partial liquid ventilation improves gas exchange and increases EELV in acute lung injury

Journal of Applied Physiology ◽

10.1152/jappl.1998.84.5.1566 ◽

1998 ◽

Vol 84 (5) ◽

pp. 1566-1572 ◽

Cited By ~ 26

Author(s):

Paul G. Gauger ◽

Michael C. Overbeck ◽

Sean D. Chambers ◽

Christine I. Cailipan ◽

Ronald B. Hirschl

Keyword(s):

Acute Lung Injury ◽

Oleic Acid ◽

Gas Exchange ◽

Lung Injury ◽

Null Point ◽

Partial Liquid Ventilation ◽

Body Plethysmography ◽

Liquid Ventilation ◽

Before And After ◽

Point Body

Gas exchange is improved during partial liquid ventilation with perfluorocarbon in animal models of acute lung injury. The specific mechanisms are unproved. We measured end-expiratory lung volume (EELV) by null-point body plethysmography in anesthetized sheep. Measurements of gas exchange and EELV were made before and after acute lung injury was induced with intravenous oleic acid to decrease EELV and worsen gas exchange. Measurements of gas exchange and EELV were again performed after partial liquid ventilation with 30 ml/kg of perfluorocarbon and compared with gas-ventilated controls. Oxygenation was significantly improved during partial liquid ventilation, and EELV (composite of gas and liquid) was significantly increased, compared with preliquid ventilation values and gas-ventilated controls. We conclude that partial liquid ventilation may directly recruit consolidated alveoli in the lung-injured sheep and that this may be one mechanism whereby gas exchange is improved.

Download Full-text

Changes in breath sound power spectra during experimental oleic acid-induced lung injury in pigs

Journal of Applied Physiology ◽

10.1152/japplphysiol.00651.2013 ◽

2014 ◽

Vol 116 (1) ◽

pp. 61-66 ◽

Cited By ~ 5

Author(s):

Jukka Räsänen ◽

Michael E. Nemergut ◽

Noam Gavriely

Keyword(s):

Acute Lung Injury ◽

Oleic Acid ◽

Gas Exchange ◽

Lung Injury ◽

Power Spectra ◽

Lung Mechanics ◽

Sound Power ◽

Frequency Spectra ◽

Mechanically Ventilated ◽

Breath Sounds

To evaluate the effect of acute lung injury on the frequency spectra of breath sounds, we made serial acoustic recordings from nondependent, midlung and dependent regions of both lungs in ten 35- to 45-kg anesthetized, intubated, and mechanically ventilated pigs during development of acute lung injury induced with intravenous oleic acid in prone or supine position. Oleic acid injections rapidly produced severe derangements in the gas exchange and mechanical properties of the lung, with an average increase in venous admixture from 16 ± 12 to 62 ± 16% ( P < 0.01), and a reduction in dynamic respiratory system compliance from 25 ± 4 to 14 ± 4 ml/cmH2O ( P < 0.01). A concomitant increase in sound power was seen in all lung regions ( P < 0.05), predominantly in frequencies 150–800 Hz. The deterioration in gas exchange and lung mechanics correlated best with concurrent spectral changes in the nondependent lung regions. Acute lung injury increases the power of breath sounds likely secondary to redistribution of ventilation from collapsed to aerated parts of the lung and improved sound transmission in dependent, consolidated areas.

Download Full-text

Comparative Effects of Vaporized Perfluorohexane and Partial Liquid Ventilation in Oleic Acid– induced Lung Injury

Anesthesiology ◽

10.1097/00000542-200602000-00013 ◽

2006 ◽

Vol 104 (2) ◽

pp. 278-289 ◽

Cited By ~ 27

Author(s):

Marcelo Gama de Abreu ◽

André Domingues Quelhas ◽

Peter Spieth ◽

Götz Bräuer ◽

Lilla Knels ◽

...

Keyword(s):

Oleic Acid ◽

Gas Exchange ◽

Lung Injury ◽

Diffuse Alveolar Damage ◽

Lung Mechanics ◽

Partial Liquid Ventilation ◽

Positive End Expiratory Pressure ◽

Liquid Ventilation ◽

Mechanically Ventilated ◽

Residual Capacity

Background It is currently not known whether vaporized perfluorohexane is superior to partial liquid ventilation (PLV) for therapy of acute lung injury. In this study, the authors compared the effects of both therapies in oleic acid-induced lung injury. Methods Lung injury was induced in 30 anesthetized and mechanically ventilated pigs by means of central venous infusion of oleic acid. Animals were assigned to one of the following groups: (1) control or gas ventilation (GV), (2) 2.5% perfluorohexane vapor, (3) 5% perfluorohexane vapor, (4) 10% perfluorohexane vapor, or (5) PLV with perfluorooctane (30 ml/kg). Two hours after randomization, lungs were recruited and positive end-expiratory pressure was adjusted to obtain minimal elastance. Ventilation was continued during 4 additional hours, when animals were killed for lung histologic examination. Results Gas exchange and elastance were comparable among vaporized perfluorohexane, PLV, and GV before the open lung approach was used and improved in a similar fashion in all groups after positive end-expiratory pressure was adjusted to optimal elastance (P < 0.05). A similar behavior was observed in functional residual capacity (FRC) in animals treated with vaporized perfluorohexane and GV. Lung resistance improved after recruitment (P < 0.05), but values were higher in the 10% perfluorohexane and PLV groups as compared with GV (P < 0.05). Interestingly, positive end-expiratory pressure values required to obtain minimal elastance were lower with 5% perfluorohexane than with PLV and GV (P < 0.05). In addition, diffuse alveolar damage was significantly lower in the 5% and 10% perfluorohexane vapor groups as compared with PLV and GV (P < 0.05). Conclusions Although the use of 5% vaporized perfluorohexane permitted the authors to reduce pressures needed to stabilize the lungs and was associated with better histologic findings than were PLV and GV, none of these perfluorocarbon therapies improved gas exchange or lung mechanics as compared with GV.

Download Full-text

Meclofenamate enhances blood oxygenation in acute oleic acid lung injury

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.2.710 ◽

1988 ◽

Vol 64 (2) ◽

pp. 710-718 ◽

Cited By ~ 12

Author(s):

L. L. Schulman ◽

P. F. Lennon ◽

S. J. Ratner ◽

Y. Enson

Keyword(s):

Oleic Acid ◽

Gas Exchange ◽

Lung Injury ◽

Significant Degree ◽

Blood Oxygenation ◽

Base Line ◽

Lung Water ◽

Shunt Flow ◽

The Difference ◽

Arterial Po2

To assess the role of vasoactive prostanoids in acute lung injury, we studied 16 dogs after intravenous injection of oleic acid (OA; 0.08 ml/kg). Animals were ventilated with 100% O2 and zero end-expiratory pressure. Base-line hemodynamic and blood gas observations were obtained 90–120 min following OA. Observations were repeated 30 min after infusion of meclofenamate (2 mg/kg; n = 10), or after saline (n = 6). Resistance to pulmonary blood flow was assessed using the difference between pulmonary arterial diastolic and left atrial pressures (PDG). Ventilation-perfusion (VA/Q) distributions were derived with the multiple inert gas technique. Prior to infusion, there were no significant differences between the two groups. PDG was elevated mildly above normal levels, and shunt flow was the principal gas exchange disturbance. Saline induced no significant changes in hemodynamics or gas exchange. Meclofenamate enhanced PDG to a small, significant degree and effected a 32% reduction in shunt flow (P less than 0.01). Perfusion was redistributed to normal VA/Q units with little change in low VA/Q perfusion or in overall flow. Arterial PO2 rose from 75 +/- 36 to 184 +/- 143 Torr (P less than 0.05). At autopsy, there were no significant differences in wet to dry lung weights. Prostaglandin inhibition redistributes perfusion from shunt to normal VA/Q units, thereby improving arterial PO2, without altering lung water acutely.

Download Full-text

Pathophysiological patterns of resolution from acute oleic acid lung injury in the dog

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.2.472 ◽

1984 ◽

Vol 56 (2) ◽

pp. 472-481 ◽

Cited By ~ 33

Author(s):

R. B. Schoene ◽

H. T. Robertson ◽

D. R. Thorning ◽

S. C. Springmeyer ◽

M. P. Hlastala ◽

...

Keyword(s):

Oleic Acid ◽

Gas Exchange ◽

Lung Injury ◽

Control Period ◽

Lung Damage ◽

Acute Injury ◽

Saline Control ◽

Time Interval ◽

Inflammatory Reactions ◽

Pulmonary Arterial

Lungs of mongrel dogs with permanent tracheostomies and implanted systemic pulmonary arterial catheters were injured by intravenous infusion of oleic acid (0.09 mg/kg). Injury resulted in extensive, multifocal, and nonrandomly distributed lung damage. Awake dogs were studied during a control period and 1, 4, and 7 days following injection of oleic acid. Standard gas exchange measurements, the inert gas elimination technique, and subsegmental bronchoalveolar lavage (BAL) were used. Five oleic acid dogs and two saline control dogs were killed after each study period for morphological evaluation. Control dogs did not develop significant gas exchange abnormalities but did have localized inflammatory reactions at the lavage site. The oleic acid dogs developed significant shunt at day 1 with resolution of shunt by day 7. The multifocal sites of oleic acid injury were virtually identical in appearance at a given time interval; they consisted of alveolar cell necrosis with varying amounts of hemorrhagic inflammatory exudation at day 1 followed by a proliferative reparative reaction resulting in substantial restoration of alveolar structure at day 7. BAL showed a suppurative inflammatory response with hemorrhage on day 1 and an increased number of macrophages by day 7. The oleic acid model of acute diffuse lung injury demonstrates several pathophysiological alterations that could be compared with pathomorphological changes during the acute injury phase and during the subsequent reparative phase.

Download Full-text