In an obstructive sleep apnea rabbit model, heliox never abolishes tidal inspiratory flow limitation (IFL), but increases and volume, substantially in some nearly nil other animals. Positive response to cannot be predicted on the basis of breathing pattern characteristics or upper airway resistance that preceded IFL onset, is related mechanical geometrical features collapsible segment, as indic...

We studied chest wall kinematics and respiratory muscle action in five untrained healthy men walking on a motor-driven treadmill at 2 and 4 miles/h with constant grade (0%). The chest wall volume (Vcw), assessed by using the ELITE system, was modeled as the sum of the volumes of the lung-apposed rib cage (Vrc,p), diaphragm-apposed rib cage (Vrc,a), and abdomen (Vab). Esophageal and gastric pres...

To determine whether patients with chronic airflow limitation have a specific alteration in skeletal muscle performance, the strength and endurance of inspiratory and limb muscles were compared in 11 patients with chronic airflow limitation and 11 control subjects during maximal voluntary contractions. Peak inspiratory pressure at observed functional residual capacity (FRC) was significantly le...

BACKGROUND Respiratory muscles are affected after cardiac surgeries. OBJECTIVE To verify whether the preoperative conditioning of the inspiratory muscles might help to decrease postoperative respiratory dysfunction. METHODS Thirty volunteers of both genders and with a minimum age of 50 years, while waiting for myocardial revascularization and/or cardiac valve surgery, were randomly assigned...

AIMS The aim of this study was to assess inspiratory performance at rest and during exercise in patients with chronic heart failure in comparison with healthy controls using a non-invasive index: the tension-time index of inspiratory muscles (TTMUS). METHODS We studied 13 patients with chronic heart failure (57 +/- 7 years) and 10 control subjects (58 +/- 6 years) at rest and during an increm...

Introduction Physiology of Carbon Dioxide PACO2 PaCO2 The Concept of Dead Space Measurement of Dead Space Bohr Enghoff Langley Alveolar Ejection Volume Causes of Elevated Dead Space in Mechanically Ventilated Patients Pulmonary Embolism COPD ARDS Effects of Mechanical Ventilation on Dead Space Effect of VT Effect of PEEP Effect of Inspiratory Flow Waveforms and End-Inspiratory Pause Prone Posit...

Increasing lung volume improves upper airway airflow dynamics via passive mechanisms such as reducing upper airway extraluminal tissue pressures (ETP) and increasing longitudinal tension via tracheal displacement. We hypothesized a threshold lung volume for optimal mechanical effects on upper airway airflow dynamics. Seven supine, anesthetized, spontaneously breathing New Zealand White rabbits ...

In a group of 37 heavy snorers with obstructive sleep apnoea (OSA, Group 1) and a group of 23 heavy snorers without OSA (Group 2) cephalometric indices, ENT indices related to upper airway collapsibility, and nocturnal O2 desaturation indices were related to variables from maximal expiratory and inspiratory flow-volume (MEFV and MIFV) curves. The cephalometric indices used were the length and d...