The automatic selection of ventilation parameters during the initial phase of mechanical ventilation.

OBJECTIVE: To test a method that allows automatic set-up of the ventilator controls at the onset of ventilation. DESIGN: Prospective randomized crossover study. SETTING: ICUs in one adult and one children's hospital in Switzerland. PATIENTS: Thirty intubated stable, critically ill patients (20 adults and 10 children). INTERVENTIONS: The patients were ventilated during two 20-min periods using a modified Hamilton AMADEUS ventilator. During the control period the ventilator settings were chosen immediately prior to the study. During the other period individual settings were automatically determined by the ventilatior (AutoInit). MEASUREMENTS AND RESULTS: Pressure, flow, and instantaneous CO2 concentration were measured at the airway opening. From these measurements, series dead space (V(DS)), expiratory time constant (RC), tidal volume (VT, total respiratory frequency (f(tot), minute ventilation (MV), and maximal and mean airway pressure (Paw, max and Paw, mean) were calculated. Arterial blood gases were analyzed at the end of each period. Paw, max was significantly less with the AutoInit ventilator settings while f(tot) was significantly greater (P < 0.05). The other values were not statistically significant. CONCLUSIONS: The AutoInit ventilator settings, which were automatically derived, were acceptable for all patients for a period of 20 min and were not found to be inferior to the control ventilator settings. This makes the AutoInit method potentially useful as an automatic start-up procedure for mechanical ventilation

Immunoglobulin A:Molecular mechanisms of function and role in immune defence

Our immune system produces more immunoglobulin A (IgA) than all of the other antibody classes combined. Much of this synthesis is directed towards protection of the mucosal surfaces which form a vast and vulnerable interface with the environment. As the predominant immunoglobulin class at these surfaces, IgA is an important first line of defence. In addition, IgA is also a major serum immunoglobulin. Both monomeric IgA in serum and polymeric secretory forms of IgA mediate a wide range of protective functions through interaction with numerous receptors and other mediators. It is telling that in order to gain better opportunities for invasion, certain pathogens have evolved mechanisms to thwart IgA function. An improved understanding of this multifaceted immunoglobulin is likely to inform strategies for improved treatments for infections and other diseases.</p