The major determinants of VO2 resp and, thus, diaphragmatic endurance are the tension-time index, work rate and lung volume. Changes in breathing pattern that adversely affect any of these factors can impair diaphragmatic endurance. A TTdi above 0.15-0.18 indicates a potentially fatiguing pattern of contraction. However, fatigue may occur at a TTdi below 0.15 if the work rate is sufficiently hi...

The aim of the study was to determine the acute effects of positive expiratory pressure (PEP) on breathing pattern, operational volumes and shortening velocity of respiratory muscles on patients with Parkinson's disease. It was evaluated 15 patients and healthy controls, by optoelectronic plethysmography, using PEP in three different levels (10, 15 and 20cmH2O). Breathing pattern changed in bot...

The physiologic effects of noninvasive ventilation (NIV) on work of breathing (WOB) and breathing pattern, respiratory-system mechanics, and hemodynamic function were examined via a literature review of clinical studies done between 1990 and 2008. Forty-one relevant studies were found; the majority examined patients with chronic obstructive pulmonary disease, whereas some also included patients...

OBJECTIVE To measure the imposed power of breathing (imposed work of breathing per minute) associated with spontaneous breathing through an active impedance threshold device and a sham impedance threshold device. DESIGN Prospective randomized blinded protocol. SETTING University medical center. PATIENTS Nineteen healthy, normotensive volunteers (10 males, 9 females, age range 20-56 y, mea...

BACKGROUND Traditionally the radiological assessment of diaphragmatic movement has relied on fluoroscopy. Ultrasound scanning has recently been shown to be a sensitive and reproducible method of assessing hemidiaphragmatic movement in normal subjects. A study was undertaken to examine how movement of the diaphragm measured by ultrasound scanning relates to inspired lung volumes measured by spir...

Numerous experimental studies demonstrate key aspects of mechanical ventilation which initiate or exacerbate acute lung injury, characterized by proteinaceous edema, inflammation, and hemorrhage. The great majority these investigations into Ventilator-Induced Lung Injury (VILI) have focused on the characteristics directly regulated clinician, including individual tidal cycle-tidal volume, inspi...

Short pauses or "transition-periods" at the end of expiration and prior to subsequent inspiration are commonly observed during sleep in humans. However, the role of transition periods in regulating ventilation during physiological challenges such as partial airway obstruction (PAO) has not been investigated. Twenty-nine obstructive sleep apnea patients and eight controls underwent overnight pol...

Pulmonary impairments have long been recognized as major causes of morbidity and mortality in individuals with advanced multiple sclerosis (MS). This study was designed to determine if a 10-week home exercise inspiratory training program in community-dwelling persons with MS improves pulmonary muscle strength and endurance. Forty-six ambulatory individuals with clinically diagnosed MS [Expanded...

STUDY OBJECTIVE To determine pulmonary function test (PFT) profile and respiratory muscle strength (RMS) of a group of obese individuals who did not have evidence of obstructive airway disease or other underlying diseases affecting their respiratory system. DESIGN Prospective, open. SETTING PFT laboratory, VA Medical Center. PARTICIPANTS Sixty-three consecutive obese (body mass index grea...

BACKGROUND Although self-inflating bags are widely used for manual hyperinflation, they do not allow ventilation parameters, such as pressure or volume, to be set. We studied the ventilation performance of neonatal and pediatric self-inflating bags. METHODS We asked 22 physiotherapists to manually hyperinflate 2 lung models (neonatal and pediatric), using self-inflating bags from 3 manufactur...