Tissue oxygen available as a criterion for the effectiveness of continuous positive pressure breathing

ABSTRACT Summary: As little as 3–5 cm H2O increase in proximal airway pressure applied to normal lung reduces cardiac output. It is postulated that decreased pulmonary compliance in

respiratory distress syndrome (RDS) acts as a barrier thus offsetting this effect. Since cardiac output is not routinely measured, severe reduction in it could accompany regression of

disease while maintaining -the same airway pressure. This study was undertaken to determine whether tissue oxygen available (O2a) could be used to detect changes in perfusion during

continuous positive pressure breathing (CPPB). CPPB was evaluated in 10 normal rabbits (C1 = 9.5 ± 1.8 cc/g at 25 cm H2O) and in 10 pulmonary-damaged rabbits (CL = 5.5 ± 1.4 cc/g at 25 cm

H2O) produced by subjecting them to 100% O2. Airway pressure was increased from 0–15 cm H2O in 3 cm H2O increments at 10-min intervals. O2a and PaO2 were monitored continuously. In the

normal group, O2a decreased at 3 cm H2O airway pressure, reaching 22% of control at 12 cm H2O, at which pressure PaO2 decreased. Breathing 100% O2 at this airway pressure increased PaO2 to

408 mm Hg, whereas O2a returned to 45% of control. In the experimental group, O2a decreased at 9 cm H2O airway pressure, at 12 cm H2O it was 36% of control at which pressure PaO2 decreased

slightly. Breathing 100% O2 at this airway pressure increased PaO2 to 316 mm Hg, and increased O2a to 200% of control. These data indicate that with excessive airway pressure, muscle hypoxia

may exist during systemic hyperoxemia and that a low compliance lung exerts a protective effect on O2a. Since changes in cardiac output during CPPB are compliance dependent, and since O2a

is perfusion dependent, tissue oxygen available could provide a means of selecting optimal airway pressure during CPPB. Speculation: This study indicates that in the presence of normal PaO2

or every hyperoxemia, an excessive increase in airway pressure can produce a decrease in cardiac output and local oxygen supply to the tissues. The airway pressure required to produce

optimal oxygenation without interference with cardiac output is lung compliance dependent. For the most efficient application of CPPB in clinical situations, measurement of physiologic

variables which would reflect changes in perfusion in addition to systemic oxygenation are suggested. SIMILAR CONTENT BEING VIEWED BY OTHERS SLOWING LUNG DEFLATION BY INCREASING THE

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ASPHYXIAL CARDIAC ARREST Article Open access 28 July 2023 ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Pediatrics, College of Medicine, University of California,

Irvine, California, USA Anthony V Beran, Robert F Huxtable, Kenneth G Proctor & Donald R Sperling Authors * Anthony V Beran View author publications You can also search for this author

inPubMed Google Scholar * Robert F Huxtable View author publications You can also search for this author inPubMed Google Scholar * Kenneth G Proctor View author publications You can also

search for this author inPubMed Google Scholar * Donald R Sperling View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and

permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Beran, A., Huxtable, R., Proctor, K. _et al._ Tissue Oxygen Available as a Criterion for the Effectiveness of Continuous Positive Pressure

Breathing. _Pediatr Res_ 11, 779–782 (1977). https://doi.org/10.1203/00006450-197706000-00017 Download citation * Issue Date: 01 June 1977 * DOI:

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