Individualized hemodynamic optimization guided by indirect measurement of the respiratory exchange ratio in major surgery: study protocol for a randomized controlled trial (the OPHIQUE study).

Background: Observational studies have suggested that a high respiratory exchange ratio (RER) is associated with the occurrence of postoperative complications. The study's primary objective is to demonstrate that the incidence of postoperative complications is lower in an interventional group (patients monitored using a hemodynamic algorithm that incorporates the RER) than in a control group (treated according to standard practice).

Methods: We shall perform a prospective, multicenter, randomized, open-label, superiority trial of consecutive patients undergoing major noncardiac surgery (i.

Hybrid recursive regularized lattice Boltzmann simulation of humid air with application to meteorological flows.

An extended version of the hybrid recursive regularized lattice-Boltzmann model which incorporates external force is developed to simulate humid air flows with phase change mechanisms under the Boussinesq approximation. Mass and momentum conservation equations are solved by a regularized lattice Boltzmann approach well suited for high Reynolds number flows, whereas the energy and humidity related equations are solved by a finite volume approach. Two options are investigated to account for cloud formation in atmospheric flow simulations.

Superimposed elastic stockings: pressure measurements.

Background: High-compression stockings over 40 mmHg are often difficult or even impossible to apply. A specific technique is frequently used to overcome this problem: a high-compression stocking is replaced by two or even three lower compression stockings that are applied on top of each other, thereby reducing the effort of application. To our knowledge, however, no study concerning therapeutic stockings has demonstrated that the forces exerted by two or three superimposed stockings are additive.