Document Detail


Oxygen consumption of a pneumatically controlled ventilator in a field anesthesia machine.
MedLine Citation:
PMID:  19020137     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Field anesthesia machines (FAM) have been developed for remote locations where reliable supplies of compressed medical gases or electricity may be absent. In place of electricity, pneumatically controlled ventilators use compressed gas to power timing circuitry and actuate valves. We sought to determine the total O(2) consumption and ventilator gas consumption (drive gas [DG] plus pneumatic control [PC] gas) of a FAM's pneumatically controlled ventilator in mechanical models of high (HC) and low (LC) total thoracic compliance. METHODS: The amount of total O(2) consumed by the Magellan-2200 (Oceanic Medical Products, Atchison, KS) FAM with pneumatically controlled ventilator was calculated using the ideal gas law and the measured mass of O(2) consumed from E cylinders. DG to the bellows canister assembly was measured with the Wright Respirometer Mk 8 (Ferraris Respiratory Europe, Hertford, UK). PC gas consumption was calculated by subtracting DG and fresh gas flow (FGF) from the total O(2) consumed from the E cylinder. The delivered tidal volume (V(T)) was measured with a pneumotach (Hans Rudolph, KS City, MO). Three different V(T) were tested (500, 750, and 1000 mL) with two lung models (HC and LC) using the Vent Aid Training Test Lung (MI Instruments, Grand Rapids, MI). Respiratory variables included an I:E of 1:2, FGF of 1 L/min, and respiratory rate of 10 breaths/min. RESULTS: Total O(2) consumption was directly proportional to V(T) and inversely proportional to compliance. The smallest total O(2) consumption rate (including FGF) was 9.3 +/- 0.4 L/min in the HC-500 model and the largest was 15.9 +/- 0.5 L/min in the LC-1000 model (P < 0.001). The mean PC circuitry consumption was 3.9 +/- 0.24 L/min or 390 mL +/- 24 mL/breath. CONCLUSIONS: To prepare for loss of central DG supply, patient safety will be improved by estimating cylinder duration for low total thoracic compliance. Using data from the smaller compliance and greatest V(T) model (LC-1000), a full O(2) E cylinder would be depleted in <42 min, whereas a full H cylinder would last approximately 433 min.
Authors:
Dale F Szpisjak; Elizabeth N Javernick; Richard R Kyle; Paul N Austin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Anesthesia and analgesia     Volume:  107     ISSN:  1526-7598     ISO Abbreviation:  Anesth. Analg.     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-11-21     Completed Date:  2008-12-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1310650     Medline TA:  Anesth Analg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1907-11     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesiology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA. dszpisjak@usuhs.mil
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MeSH Terms
Descriptor/Qualifier:
Anesthesiology / instrumentation*
Humans
Oxygen Consumption*
Ventilators, Mechanical*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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