Document Detail


Effects of fiberoptic bronchoscopy during mechanical ventilation in a lung model.
MedLine Citation:
PMID:  10988208     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY OBJECTIVES: To evaluate the effects of fiberoptic bronchoscopy (FOB) on delivered volumes and pressures during mechanical ventilation, utilizing a lung model.
DESIGN: Bench study.
SETTING: Laboratory.
MATERIALS AND METHODS: Using varying-sized endotracheal tubes (ETTs), we ventilated a lung model at two levels of compliance utilizing different modes and parameters of ventilation. After establishing baseline measurements, the bronchoscope was inserted and measurements repeated.
MEASUREMENTS AND RESULTS: During controlled mechanical ventilation (CMV) with a preset high-pressure limit (HPL), tidal volumes (VTs) were reduced from 700 mL to 0 to 500 mL following insertion of the bronchoscope. Increasing the HPL to 120 cm H(2)O resulted in a VT of 40 to 680 mL. Changing from square to decelerating flow waveform resulted in no consistent difference in VT. Auto-positive end-expiratory pressure (auto-PEEP) of 0 to 41 cm H(2)O was present under most conditions. Higher rates and lower peak inspiratory flows were associated with higher levels of auto-PEEP. In the pressure-control (PC) mode, using a preset inspiratory pressure level (IP), VT was reduced from 700 mL to 40 to 280 mL following insertion of the bronchoscope. Maximum IP (100 cm H(2)O) increased VT to 260 to 700 mL. Auto-PEEP was less in the PC mode.
CONCLUSIONS: Extreme care must be taken when bronchoscopy is performed on a patient receiving mechanical ventilation. Extremely low VT and significant auto-PEEP may develop unless flow, respiratory rate, mode, and ETT size are carefully selected. The PC mode delivered more volume than did the CMV mode. When performing FOB during mechanical ventilation, the inside diameter of the ETT should be > or = 2.0-mm larger than the outside diameter of the bronchoscope to maintain volume delivery and minimize the development of auto-PEEP.
Authors:
R W Lawson; J I Peters; D C Shelledy
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Chest     Volume:  118     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2000-10-12     Completed Date:  2000-10-12     Revised Date:  2014-07-28    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  824-31     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Airway Resistance / physiology
Bronchoscopy / methods*
Fiber Optic Technology*
Humans
Inspiratory Capacity / physiology
Intubation, Intratracheal
Lung / physiology*
Lung Compliance / physiology
Models, Anatomic
Positive-Pressure Respiration*

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


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