Document Detail


Evaluating humidity recovery efficiency of currently available heat and moisture exchangers: a respiratory system model study.
MedLine Citation:
PMID:  19578664     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate.
INTRODUCTION: Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers' humidifying performance.
METHODS: Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37 degrees C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting.
RESULTS: Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow.
CONCLUSIONS: Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers.
Authors:
Jeanette Janaina Jaber Lucato; Alexander Bernard Adams; Rogério Souza; Jamili Anbar Torquato; Carlos Roberto Ribeiro Carvalho; John J Marini
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Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  Clinics (São Paulo, Brazil)     Volume:  64     ISSN:  1980-5322     ISO Abbreviation:  Clinics (Sao Paulo)     Publication Date:  2009  
Date Detail:
Created Date:  2009-07-06     Completed Date:  2010-12-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101244734     Medline TA:  Clinics (Sao Paulo)     Country:  Brazil    
Other Details:
Languages:  eng     Pagination:  585-90     Citation Subset:  IM    
Affiliation:
Pulmonary Division, Respiratory ICU, Hospital das Clinicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil. jeanettejaber@yahoo.com
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MeSH Terms
Descriptor/Qualifier:
Hot Temperature*
Humans
Humidity*
Respiration, Artificial*
Respiratory Rate / physiology
Tidal Volume / physiology
Ventilators, Mechanical*
Comments/Corrections

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