Anesthetic Considerations in the Evaluation of Children with Glaucoma and Associated Conditions

Glaucoma in the pediatric population can be difficult to diagnose and treat without a child’s cooperation. Examination and intervention under anesthesia play a critical role in the management of childhood glaucoma, as detailed elsewhere. This requires a change in setting from the office to the operating room with the availability and assistance of a pediatric anesthesiologist, who may have to sedate or anesthetize the child repeatedly, sometimes even just to confirm the glaucoma diagnosis. An anesthesiologist with specialty training in pediatrics is pertinent, as childhood glaucoma can often be associated with syndromes involving other organ systems, hence making their anesthetic complicated and at times potentially dangerous. Once the glaucoma diagnosis is established, these children may have to return to the operating room multiple times for examinations and/or treatments; thus, having prior anesthetic records with any previous complications can offer vital information to both the pediatric anesthesiologist and pediatric glaucoma specialist. This chapter focuses on the preoperative workup of pediatric patients to ensure that they are optimized medically to undergo sedation and general anesthesia with the lowest possible risk. The intraoperative course is also described, including why sedation may be chosen over general anesthesia and how the various anesthetic drugs such as volatile anesthetics or intravenous induction agents can affect intraocular pressure measurements. The chapter finishes by describing potential postoperative complications related to anesthesia: nausea, vomiting, postoperative delirium, and agitation, along with a brief discussion on various syndromes that could potentially affect the delivery and choice of anesthetic

Forward Error Correction for Optical Transponders

Forward error correction is an essential technique required in almost all communication systems to guarantee reliable data transmission close to the theoretical limits. In this chapter, we discuss the state-of-the-art forward error correction (FEC) schemes for fiber-optic communications. Following a historical overview of the evolution of FEC schemes, we first introduce the fundamental theoretical limits of common communication channel models and show how to compute them. These limits provide the reader with guidelines for comparing different FEC codes under various assumptions. We then provide a brief introduction to the general basic concepts of FEC, followed by an in-depth introduction to the main classes of codes for soft decision decoding and hard decision decoding. We include a wide range of performance curves, compare the different schemes, and give the reader guidelines on which FEC scheme to use. We also introduce the main techniques to combine coding and higher-order modulation (coded modulation), including constellation shaping. Finally, we include a guide on how to evaluate the performance of FEC in transmission experiments. We conclude the chapter with an overview of the properties of some state-of-the-art FEC schemes used in optical communications and an outlook

How the microbiota shapes rheumatic diseases

The human gut harbours a tremendously diverse and abundant microbial community that correlates with, and even modulates, many health-related processes. The mucosal interfaces are particularly active sites of microorganism-host interplay. Growing insight into the characteristic composition and functionality of the mucosal microbiota has revealed that the microbiota is involved in mucosal barrier integrity and immune function. This involvement affects proinflammatory and anti-inflammatory processes not only at the epithelial level, but also at remote sites such as the joints. Here, we review the role of the gut microbiota in shaping local and systemic immune responses and how disturbances in the host-microorganism interplay can potentially affect the development and progression of rheumatic diseases. Increasing our understanding of how to promote host-microorganism homeostasis could therefore reveal novel strategies for the prevention or alleviation of rheumatic disease