DISEÑO DE UN CIRCUITO DE CONTROL DE ILUMINACIÓN PARA UN SISTEMA FORMADOR DE IMÁGENES DE PURKINJE

ResumenLas imágenes de Purkinje son generadas por reflexión de la luz en las diferentes interfaces oculares (córnea anterior y posterior, y cristalino anterior y posterior). El estudio de estas imágenes es de suma importancia tanto en la optometría como en la oftalmología. En la UAM Azcapotzalco se ha desarrollado un sistema formador de imágenes de Purkinje, el cual permite generar y detectar dichas imágenes de indivuduos in-vivo. El sistema optoelectrónico presentado, consta de una iluminación infrarroja a 840nm, alimentada por un convertidor digital/analógico (current-steering DAC) con salida de corriente, el cual fue diseñado con transistores y multiplexores analógicos CMOS. El DAC entrega de 6.5 a 7.5 mA de corriente por LED en pasos de 0.25 mA (n bits de resolución), en las diferentes matrices. De este modo, las matrices funcionan apropiadamente sin saturarse, y por ende es posible generar las Imágenes de Purkinje sin reflexión y sin ruido de fondo, con lo cual se ha reducido el intervalo de la prueba (con tiempos de 10 a 15 minutos por sujeto).Palabras Claves: DAC de corriente, iluminación LED, imágenes de Purkinje, sistema ocular humano, tecnología CMOS. DESIGN OF A LIGHTING CONTROL CIRCUIT FOR A PURKINJE IMAGING SYSTEMAbstractPurkinje images are generated by the light reflection at different ocular interfaces (anterior and posterior cornea, anterior and posterior lens). The study of these images is of paramount importance in both optometry and ophthalmology. In UAM-Azcapotzalco, a Purkinje image-forming system has been developed, which allows the generation and detection of such images of in-vivo. The optoelectronic system presented, consists of an infrared illumination at 840nm, powered by a current-steering DAC with current output, which was designed with analogue CMOS transistors and multiplexers. The DAC delivers from 6.5 to 7.5 mA of current by LED in steps of 0.25 mA (n bits of resolution), in the different matrices. In this way, the matrices function properly without saturation, and therefore it is possible to generate the Purkinje Images without reflection and without background noise, which has reduced the interval of the test (with times of 10 to 15 minutes per subject).Keywords: Current DAC, human eye system CMOS technology, LED lighting, Purkinje images

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

International Nosocomial Infection Control Consortiu (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module

We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care–associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line–associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN