A new volume accumulating expiratory gas analysis system Meeting Abstract
| Authors: | Miodownik, S.; Melendez, J. |
| Abstract Title: | A new volume accumulating expiratory gas analysis system |
| Meeting Title: | CHEST World Congress 1996 |
| Abstract: | PURPOSE: The measurement of O2 consumption, CO2 production and other metabolic parameters can be useful in managing mechanically ventilated patients in the intensive care setting. A large number of constraints in this environment render conventional devices for this purpose ineffective and inaccurate. We have developed a novel technique for the continuous measurement of gas exchange that requires no flow measuring device and can maintain an acceptable degree of accuracy over a wide range of FIO2. METHODS: Two 60 liter Douglas gas collection bags are alternately connected to the subject's exhaled gases via an automated valve manifold system controlled by a laptop computer. As one bag is being analyzed, the other collects. Volume is determined by indicator dilution technique and is totally independent of the flow pattern of the expired gas. Gas concentrations are automatically measured by a Marquette Electronics RAMS quadrupole Mass Spectrometer. At the completion of analysis, the collected bag is evacuated and made ready for the next collection. Each collection interval is 120 sec. long and results are displayed in comparable intervals. All results are expressed in meann ± S.D. RESULTS: The system and software were easy to use and, once initialized, measurements proceeded continuously and automatically. In simulations, we have successfully measured volumes over the range of 5 to 50 liters with a S.D. of 1-3%. These volumes were collected at FIO2 of 0.21, 0.4, 0.5, and 0.8. Additional tests with a methanol burning lung model yielded repeatable RQ values of 0.67±0.01. CONCLUSIONS: We have developed a novel and accurate system for collecting and measuring respired gases that has the potential to operate and provide accurate results in the demanding critical care environment of high FiO2. Unlike other systems, this method has the flexibility of studying other expiratory gases. CLINICAL IMPLICATIONS: The inaccuracy of gas exchange measurements in a high FiO2 setting has precluded the wide spread use of the metabolic monitoring of the critically ill patient. Our technique may provide the opportunity to study metabolics at high FiO2. The integrated expired sample available via our technique may provide a window into many aspects of metabolic activity beyond VCO2 and VO2. |
| Journal Title: | Chest |
| Volume: | 110 |
| Issue: | 4 Suppl. |
| Meeting Dates: | 1996 Oct 27-31 |
| Meeting Location: | San Francisco, CA |
| ISSN: | 0012-3692 |
| Publisher: | American College of Chest Physicians |
| Date Published: | 1996-10-01 |
| Start Page: | 138S |
| Language: | English |
| PROVIDER: | scopus |
| DOI: | 10.1378/chest.110.4_Supplement.138S |
| PUBMED: | 8885851 |
| DOI/URL: | |
| Notes: | Meeting Abstract -- Export Date: 22 November 2017 -- Source: Scopus |
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