Perioperative Hemodynamic Monitoring:An Overview of Current Methods

Perioperative hemodynamic monitoring is an essential part of anesthetic care. In this review, we aim to give an overview of methods currently used in the clinical routine and experimental methods under development. The technical aspects of the mentioned methods are discussed briefly. This review includes methods to monitor blood pressures, for example, arterial pressure, mean systemic filling pressure and central venous pressure, and volumes, for example, global end-diastolic volume (GEDV) and extravascular lung water. In addition, monitoring blood flow (cardiac output) and fluid responsiveness (preload) will be discussed

Which type of fluid to use perioperatively?

Fluid administration in the perioperative period is daily clinical practice for all anesthesiologists. The goal of fluid administration is to increase cardiac output in order to ultimately improve oxygen delivery to the tissues. Fluid therapy can be given as maintenance or as replacement fluid therapy. For both of these therapies balanced crystalloids belong to the first line of treatment. Colloids are used for fluid replacement as well, but are given for more specific indications such as hypovolemia as a consequence of blood loss. Fluids, as any other intravenous drug, have indications, contra-indications, and potential side-effects. No conclusive evidence exists over the way and amount of fluids that should be administered, and several strategies have been developed, e.g., restrictive or liberal fluid therapy or perioperative goal-directed therapy (PGDT). Restrictive fluid therapy uses limited amounts of fluid compared to liberal fluid therapy, however no clear definitions of restricted or liberal fluid therapy are available. PGDT uses hemodynamic variables to assess fluid responsiveness and to guide fluid therapy in order to optimize the hemodynamic status of the patient. Future directions in fluid administration are to use personalized hemodynamic target values and to use PGDT in closed-loop systems. Most important, fluids should be administered with the same caution that is used with any intravenous drug

Cerebral monitoring in surgical ICU patients

PURPOSE OF REVIEW: To give an overview of cerebral monitoring techniques for surgical ICU patients. RECENT FINDINGS: As the burden of postsurgical neurological and neurocognitive complications becomes increasingly recognized, cerebral monitoring in the surgical ICU might gain a relevant role in detecting and possibly preventing adverse outcomes. However, identifying neurological alterations in surgical ICU patients, who are often sedated and mechanically ventilated, can be challenging. Various noninvasive and invasive techniques are available for cerebral monitoring, providing an assessment of cortical electrical activity, cerebral oxygenation, blood flow autoregulation, intracranial pressure, and cerebral metabolism. These techniques can be used for the diagnosis of subclinical seizures, the assessment of sedation depth and delirium, the detection of an impaired cerebral blood flow, and the diagnosis of neurosurgical complications. SUMMARY: Cerebral monitoring can be a valuable tool in the early detection of adverse outcomes in surgical ICU patients, but the evidence is limited, and clear clinical indications are still lacking

Evolving Symbolic Controllers

International audienceThe idea of symbolic controllers tries to bridge the gap between the top-down manual design of the controller architecture, as advocated in Brooks' subsumption architecture, and the bottom-up designer-free approach that is now standard within the Evolutionary Robotics community. The designer provides a set of elementary behavior, and evolution is given the goal of assembling them to solve complex tasks. Two experiments are presented, demonstrating the efficiency and showing the recursiveness of this approach. In particular, the sensitivity with respect to the proposed elementary behaviors, and the robustness w.r.t. generalization of the resulting controllers are studied in detail