The investigators have developed a non-steady state, five compartment pulmonary model of gas kinetics that incorporates interactions between O2 and CO2 in the lung, blood, and tissues. New methodology has been developed that includes both O2 uptake per breath (uses a new humidity sensor) and esophageal Doppler measure of cardiac output (QT). The computer model has formulated the following hypotheses: 1) Acute decreases in cardiac output (QT) by patient position change will transiently decrease pulmonary O2 consumption (VO2), but the decrease in CO2 elimination (VCO2) is sustained because tissue CO2 stores are a hundred fold greater than O2. 2) Positive end-expiratory pressure decreases VO2 and VCO2 due to decreases in QT and alveolar ventilation (VA) and appearance of high VA/Q. 3) Pulmonary shunting decreases VCO2, because redistribution of VA to the rest of the lung contributes only to CO2 and not O2 exchange. 4) Changes in global tissue metabolic activity can monitor anesthetic depth, and changes in regional body function can be measured by pulmonary gas exchange. 5) These and other cardiovascular, pulmonary, and metabolic pathophysiology cause specific and unique changes in non-steady state O2 and CO2 kinetics by mechanisms elucidated by the computer model. Determining the mechanisms underlying acute pathophysiology will advance the understanding of O2 and CO2 kinetics during non-steady state, and allow the non-invasive diagnosis of critical events during clinical anesthesia.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL042637-09
Application #
6182711
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Project Start
1990-01-01
Project End
2003-07-31
Budget Start
2000-08-01
Budget End
2003-07-31
Support Year
9
Fiscal Year
2000
Total Cost
$242,943
Indirect Cost
Name
University of California Irvine
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
Breen, Peter H (2010) How do changes in exhaled CO? measure changes in cardiac output? A numerical analysis model. J Clin Monit Comput 24:413-9
Rosenbaum, Abraham; Howard, Heike C; Breen, Peter H (2008) Novel portable device measures preoperative patient metabolic gas exchange. Anesth Analg 106:509-16, table of contents
Rosenbaum, Abraham; Kirby, Christopher; Breen, Peter H (2007) New metabolic lung simulator: development, description, and validation. J Clin Monit Comput 21:71-82
Rosenbaum, Abraham; Kirby, Christopher W; Breen, Peter H (2007) Bymixer system can measure O2 uptake and CO2 elimination in the anesthesia circle circuit. Can J Anaesth 54:430-40
Rosenbaum, Abraham; Kirby, Christopher; Breen, Peter H (2004) Measurement of oxygen uptake and carbon dioxide elimination using the bymixer: validation in a metabolic lung simulator. Anesthesiology 100:1427-37
Rosenbaum, Abraham; Breen, Peter H (2003) Novel, adjustable, clinical bymixer measures mixed expired gas concentrations in anesthesia circle circuit. Anesth Analg 97:1414-20