Document Detail


Effects of simulated altitude on ventilator performance.
MedLine Citation:
PMID:  19359962     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Aeromedical transport of critically ill casualties requires continued safe operation of medical equipment at altitude. We evaluated performance of two ventilators in an altitude chamber. METHODS: Two ventilators used by the United States Air Force (USAF) Critical Care Air Transport Teams were operated in an altitude chamber at barometric pressure of 754 mm Hg, 657 mm Hg, 563 mm Hg, and 428 mm Hg simulating altitudes of sea level, 4,000, 8,000, and 15,000 feet. At each altitude ventilators were set to deliver three tidal volumes (VT) from 0.25 L to 1.0 L. Airway pressure, timing, flow, and volumes were measured every breath. Measured parameters included VT, positive end-expiratory pressure (PEEP), inspiratory time, expiratory time, inspiratory flow, peak inspiratory pressure, expiratory flow, and respiratory rate. RESULTS: The Impact 754 compensated for changes in altitude maintaining the set VT within 10% of the sea level VT. Tidal volume delivery of the 754 was less precise during operation of the compressor at an inspired oxygen concentration of 0.21. With each increase in altitude, the LTV VT increased. At 8,000 feet VT increased by 10% and at 15,000 feet VT increased by 30% (p<0.001). Respiratory rate was not affected by altitude with either device. CONCLUSIONS: The Impact 754 compensates ventilator output to deliver the desired tidal volume regardless of changes in altitude and barometric pressure. The LTV-1000 does not compensate for changes in altitude resulting in delivery of increasing tidal volumes with falling barometric pressure. Clinicians should be aware of ventilator performance and ventilator limitations to provide safe and effective ventilation during transport.
Authors:
Dario Rodriquez; Richard D Branson; Warren Dorlac; Gina Dorlac; Stephen A Barnes; Jay A Johannigman
Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  The Journal of trauma     Volume:  66     ISSN:  1529-8809     ISO Abbreviation:  J Trauma     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-04-10     Completed Date:  2009-06-25     Revised Date:  2010-03-19    
Medline Journal Info:
Nlm Unique ID:  0376373     Medline TA:  J Trauma     Country:  United States    
Other Details:
Languages:  eng     Pagination:  S172-7     Citation Subset:  AIM; IM    
Affiliation:
Center for Sustainment of Trauma and Readiness Skills, United States Air Force, Cincinnati, Ohio, USA.
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MeSH Terms
Descriptor/Qualifier:
Air Ambulances*
Altitude*
Equipment Failure Analysis
Humans
Positive-Pressure Respiration
Tidal Volume / physiology
Ventilators, Mechanical*
Comments/Corrections
Comment In:
J Trauma. 2010 Jan;68(1):249; author reply 249-50   [PMID:  20065785 ]
J Trauma. 2010 Mar;68(3):749-50   [PMID:  20220433 ]

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


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