Document Detail

Sitting posture decreases collapsibility of the passive pharynx in anesthetized paralyzed patients with obstructive sleep apnea.
MedLine Citation:
PMID:  20823756     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Obstructive sleep apnea (OSA) is an independent risk factor for difficult and/or impossible mask ventilation during anesthesia induction. Postural change from supine to sitting improves nocturnal breathing in patients with OSA. The purpose of this study was to evaluate the effect of patient position on collapsibility of the pharyngeal airway in anesthetized and paralyzed patients with OSA. The authors tested the hypothesis that the passive pharynx is structurally less collapsible during sitting than during supine posture. METHOD: Total muscle paralysis was induced with general anesthesia in nine patients with OSA, eliminating neuromuscular factors contributing to pharyngeal patency. The cross-sectional area of the pharynx was measured endoscopically at different static airway pressures. Comparison of static pressure-area plots between the supine and sitting (62° head-up) allowed assessment of the postural differences of the mechanical properties of the pharynx. RESULTS:: Maximum cross-sectional area was greater during sitting than during supine posture at both retropalatal (median (10th-90th percentile): 1.91 (1.52-3.40) versus 1.25 (0.65-1.97) cm) and retroglossal (2.42 (1.72-3.84) versus 1.75 (0.47-2.35) cm) airways. Closing pressure of the passive pharynx was significantly lower during sitting than supine posture. Differences of the closing pressures between the postures are 5.89 (3.73-11.6) and 6.74 (4.16-9.87) cm H2O, at retropalatal and retroglossal airways, respectively, and did not differ between the pharyngeal segments. CONCLUSIONS: Postural change from supine to sitting significantly improves collapsibility of pharyngeal airway in anesthetized and paralyzed patients with OSA.
Yugo Tagaito; Shiroh Isono; Atsuko Tanaka; Teruhiko Ishikawa; Takashi Nishino
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  113     ISSN:  1528-1175     ISO Abbreviation:  Anesthesiology     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-24     Completed Date:  2010-10-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  812-8     Citation Subset:  AIM; IM    
Department of Anesthesiology, Teikyo University Chiba Medical Center, Ichihara, Japan.
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MeSH Terms
Anatomy, Cross-Sectional
Anesthesia, General*
Middle Aged
Palate / surgery
Paralysis / chemically induced,  physiopathology
Pharynx / anatomy & histology*,  surgery
Posture / physiology*
Sleep Apnea, Obstructive / physiopathology*,  surgery*
Uvula / surgery

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

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