Isono, Shiroh, John E Remmers, Atsuko Tanaka, Yasuhide Sho, Jiro Sato, and Takashi Nishino. Anatomy of pharynx in patients with obstructive sleep apnea normal subjects. J. Appl. Physiol. 82(4): 1319–1326, 1997.—Anatomic abnormalities the are thought to play a role pathogenesis (OSA), but their contribution has never been conclusively proven. The present study tested this anatomic hypothesis by comparing mechanics paralyzed OSA According evaluation sleep-disordered breathing (SDB) nocturnal...

Obesity and craniofacial abnormalities may contribute to the pathogenesis of obstructive sleep apnea. The purpose this study was evaluate influence body habitus characteristics on types pharyngeal closure. closure were determined by endoscopic evaluations closing pressures passive pharynx in 54 paralyzed anesthetized patients with sleep-disordered breathing (SDB). Assessment SDB 24 normal subjects made lateral cephalometry. As compared subjects, demonstrated receded mandibles long lower...

Based on previous studies, we hypothesized that the pharynx collapses at multiple sites in most patients with obstructive sleep apnea (OSA). The purpose of this study was to document, a population apneic subjects, site(s) narrowing and closing pressure hypotonic pharynx. We endoscopically examined 45 OSA during while they received nasal continuous positive airway (CRAP), which produces hypotonia pharyngeal muscles. Intrapharyngeal images pressures were obtained end expiration single-breath...

Collapsibility of the active pharynx, where contraction upper airway muscles is evident, was previously reported to be higher in children with obstructive sleep apnea (OSA) than those primary snoring during sleep. Contribution neuromuscular and anatomic factors increased collapsibility, however, not estimated. We therefore evaluated collapsibility passive which muscle activities were eliminated. Our aim present study test hypothesis that sleep-disordered breathing (SDB) have a structurally...

The velopharynx is the most common site of obstruction in patients with obstructive sleep apnea (OSA). Advancement mandible effectively reverses pharyngeal obstruction. Accordingly, we hypothesized that mandibular advancement increases cross-sectional area several segments upper airway, including and oropharynx. We examined pressure-area properties airway 13 OSA. Under general anesthesia total muscle paralysis, pharynx was visualized an endoscope connected to a video-recording system. During...

Background Obesity and craniofacial abnormalities such as small maxilla mandible are common features of patients with obstructive sleep apnea (OSA). The authors hypothesized that anatomical imbalance between the upper airway soft-tissue volume size (rather than each alone) may result in pharyngeal obstruction during sleep, therefore development OSA. Methods Blind measurements tongue cross-sectional area dimensions were performed through lateral cephalograms 50 adult male OSA 55 non-OSA...

Uvulopalatopharyngoplasty (UPPP), an operation that enlarges the pharyngeal airway at level of soft palate, improves respiratory status during sleep in only 50% patients with obstructive apnea (OSA). This poor outcome suggests narrowing nonpalatal sites contributes to process many OSA. We have used a novel endoscopic method identify regions passive most susceptible or complete closure. In order test hypothesis nasopharynx predicts favorable surgical outcome, we preoperatively assessed local...

The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. purpose the present study was to characterize respiratory and laryngeal responses irritation during increasing doses fentanyl under propofol anesthesia.Twenty-two female patients anesthetized with breathing through mask were randomly allocated three groups: (1) eight who received cumulative total 200 microg given in form two 50 one dose 100 spaced 6 min mechanical controlled ventilation while...

The static mechanics of the hypotonic pharynx were endoscopically evaluated in nine sleeping patients with obstructive sleep apnea, having a primary narrowing only at velopharynx. velopharynx closed completely mean pressure 0.18 +/- 1.21 cmH2O, and half-dilation was 1.93 cmH2O above closing pressure. dependence area on distinctly curvilinear, being steep near asymptotically approaching maximum (mean = 1.32 cm2). data for each patient satisfactorily fitted by an exponential function R2 0.98),...

Background Reduction of nocturnal obstructive events during lateral position in patients with sleep apnea was previously reported. However, little information is available regarding mechanisms the improvement and precise pharyngeal site influenced by position. The authors tested hypothesis that structural properties passive pharynx change changing body from supine to lateral. Method Total muscle paralysis induced general anesthesia eight apnea, eliminating neuromuscular factors contributing...

Background During anesthesia in humans, anterior displacement of the mandible is often helpful to relieve airway obstruction. However, it appears be less useful obese patients. The authors tested possibility that obesity limits effectiveness maneuver. Methods Total muscle paralysis was induced under general a group persons (n = 9; body mass index, 32 +/- 3 kg[-2]) and nonobese mas 21 2 kg[-2]). Nocturnal oximetry confirmed none them had sleep-disordered breathing. cross-sectional area...

A collapsible tube surrounded by soft material within a rigid box was proposed as two-dimensional mechanical model for the pharyngeal airway. This predicts that changes in size (pharyngeal bony enclosure anatomically defined cross-sectional area bounded inside edge of structures such mandible, maxilla, and spine, being perpendicular to airway) influence patency tube. We examined whether either with head positioning or bite opening collapsibility Static properties passive pharynx were...

Lung volume dependence of pharyngeal airway patency suggests involvement lung in pathogenesis obstructive sleep apnea. We examined the structural interaction between passive and independent neuromuscular factors. Static mechanical properties pharynx were compared before during inflation eight anesthetized paralyzed patients with sleep-disordered breathing. The respiratory system was increased by applying negative extrathoracic pressure, thereby leaving transpharyngeal pressure unchanged....

The placement of an endotracheal tube (ETT) may promote laryngeal swelling, which is important cause upper airway obstruction after extubation. authors hypothesized that swelling ETT increases resistance and tested hypothesis by comparing postoperative patency between patients with those a Laryngeal Mask Airway trade mark (LMA).Fourteen adult who underwent elective minor surgeries were randomly allocated to two groups whose would be managed through ETTs (the group) or LMAs LMA during the...

Background Appropriate bag-and-mask ventilation with patent airway is mandatory during induction of general anesthesia. Although the sniffing neck position a traditionally recommended head and this critical period, knowledge influences on pharyngeal patency still inadequate. Methods Total muscle paralysis was induced anesthesia in 12 patients obstructive sleep apnea, eliminating neuromuscular factors contributing to patency. The cross-sectional area pharynx measured endoscopically at...

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 evaluate the effect patient position on collapsibility pharyngeal airway anesthetized and paralyzed authors tested hypothesis that passive pharynx structurally less collapsible than posture. Method Total muscle paralysis...

Recent studies suggest advantages of muscle relaxants for facemask ventilation. However, direct effects on mask ventilation remain unclear because these did not control mechanical factors influencing We tested a hypothesis that relaxants, either rocuronium or succinylcholine, improve ventilation.In anesthetized adult persons with normal upper airway anatomy, tidal volumes during were measured while maintaining the neutral head and mandible positions pressures ventilator before paralysis...

Cuff-leak volume (CLV) tests are recommended to avoid extubation failure. We developed a novel cuff-leak pressure (CLP) test that quantitatively assesses upper airway resistance outside the tracheal tube. hypothesized CLP (airway during apnea with cuff deflated under 6 l/minute oxygen flow) would increase after surgery (primary outcome) and evaluated accuracy reproducibility of measurements by measuring CLV (difference in expiratory tidal before deflation tube cuff). were measured abdominal...

Isono, Shiroh, Thom R. Feroah, Eric A. Hajduk, Rollin Brant, William Whitelaw, and John E. Remmers. Interaction of cross-sectional area, driving pressure, airflow passive velopharynx. J. Appl. Physiol. 83(3): 851–859, 1997.—Previous studies have shown that, when the pharyngeal muscles are relaxed, velopharynx is a highly compliant segment pharynx. Thus, under these circumstances, area ( A VP ), pressure across (ΔP), inspiratory (V˙i) will be mutually interdependent variables. The purpose...

1 We do not fully understand the pathogenesis of nocturnal laryngeal stridor in patients with multiple system atrophy (MSA). Recent studies suggest that inspiratory thyroarytenoid (TA) muscle activation has a role development stridor. 2 The breathing pattern and firing timing TA were determined ten MSA patients, anaesthetized propofol through mask airway, while behaviour aperture was being observed endoscopically. 3 Two distinct patterns, i.e. no flow limitation (no-IFL) IFL, identified...

Abstract Background Depending on upper airway patency during anesthesia induction, tidal volume achieved by mask ventilation may vary. In 80 adult patients undergoing general anesthesia, the authors tested a hypothesis that is smaller in with sleep-disordered breathing priorly defined as apnea hypopnea index greater than 5 per hour. Methods One-hand constant ventilator setting (pressure-controlled ventilation) was started 20 s after injection of rocuronium and maintained for 1 min induction....