BACKGROUND Tracheal gas insufflation reduces inspired tidal volume and minute ventilation in spontaneously breathing patients and may facilitate weaning from mechanical ventilation. OBJECTIVE To determine if tracheal gas insufflation can reduce ventilatory demand during weaning trials in patients who require prolonged mechanical ventilation. METHODS A reduction in ventilatory demand was def...

Airway obstruction in asthma and chronic obstructive pulmonary disease (COPD) is often associated with lung hyperinflation. In this review, we examine the mechanisms that may cause functional residual capacity (FRC), residual volume (RV) and total lung capacity (TLC) to increase during acute and chronic airway obstruction. Normally, FRC at rest is determined by the static characteristics of the...

Internal solitary waves, which form such a prominent feature in remote sensing images of the coastal zone, are the far field expression of stratified flow over topography. Nonlinear evolution of large amplitude internal tides propagating over the continental shelf is one means by which they might be generated, but detailed observations of wave generation over topography in an inlet illustrate o...

The normal breathing pattern of the turtle, Chrysemys picta (Schneider), consists of periods of continuous breathing interspersed with periods of breath holding. During each ventilatory period respiratory frequency and tidal volume are controlled independently. There is a large variability in inspiratory and expiratory gas-flow rates yet tidal volumes are maintained within narrow limits by adju...

BACKGROUND In volume guarantee ventilation with the Dräger Babylog 8000 ventilator, inspiratory and expiratory flows are monitored and the expiratory tidal volume calculated following each inflation. The pressure for the next inflation is modified to ensure the expired tidal volume is close to the set value. AIM To investigate interrupted expiration observed during volume guarantee ventilatio...

This paper presents findings from an experimental study investigating the downstream wake response from marine current energy convertors operating in various degrees of vertical flow constraint. The paper investigates deep vertically unconstrained sites, mid-depth sites and there is a particular emphasis on shallow tidal stream sites. Shallow tidal resources could be utilised for the deployment...

A numerical model was developed based on the Cubic-Interpolated Pseudo-particle (CIP) Combined Unified Procedure (CIP-CUP or C-CUP) method equipped with a Large Eddy Simulation (LES) model and a re-initialization method. The model was validated and applied to the tidal bore flow with a weak breaking front. In the tidal bore flow, the model equipped with a LES turbulence model reproduced accurat...

It is generally accepted that there is little rebreathing of gas exhaled through the nose. A detailed physical model system has been used to quantify and identify the mechanisms responsible for this phenomenon. By the use of a cast of the upper respiratory tract and oscillating flows with a Reynolds number of 500 and nondimensional frequency of 1.6, corresponding to quiet tidal breathing throug...

M. J. S. Rudwick and others postulate ‘rhythmic-flow’ feeding for the Permian richthofeniacean bi-achiopods, whereas R. E. Grant claims that they fed by normal ciliary action. Suspension-feeding has two components, current generation and food capture; normal brachiopod lophophores d o both, but this is neither universal nor compulsory among animals. Opening and closing the richthofeniid shell g...