Desenvolvimento de Dispositivo para Detecção de Monóxido de Carbono em Sistema de Anestesia

Abstract

Carbon monoxide (CO) has a high affinity for hemoglobin (HB) and concentrations above 0.1% produce toxicity, with repercussions on different organs and systems. During general anesthesia, the patient will be under the action of different types of venous and inhaled drugs, which withdraw consciousness, produce muscle relaxation and block autonomic responses. As all inhaled anesthetics can be degraded by soda lime, CO production may occur endogenously and / or exogenously, gradually or dramatically; in any patient who is under general anesthesia. This intoxication will translate into complications in oxygen transport - reducing the rate of peripheral tissue extraction at the cellular level - and direct intracellular changes. All of these will contribute to the appearance of different perioperative and / or late systemic repercussions. The absence of clear signs and symptoms, accurate laboratory tests and specific monitoring equipment for this type of intoxication, makes both early and accurate diagnosis and timely treatment difficult. Given the above, the aim of this study was to evaluate the ability to detect carbon monoxide (CO) in the anesthesia circuit using a prototype. To this end, the work was divided into four phases: (1) study and development of a device for detecting carbon monoxide (CO) levels; (2) positioning the carbon monoxide sensor in the “Y” connection, used in the ventilation circuit of the Anesthesia Machine; (3) carrying out a controlled experimental study, with the injection of known concentrations of CO monoxide in the circular system, for tests of efficiency and functionality of the proposed prototype; (4) quantitative measurement of CO levels in the ventilation system. The stages of the work were developed in specialized laboratories. It is noteworthy that, since these are not real patients, the functionality of the device was based on simulated tests, using, as a source of carbon monoxide, a known and measurable chemical reaction, responsible for the production of this gas. Only in the third version of the experiment, the final prototype was obtained. The results obtained in the experiments demonstrated that the prototype showed functionality and efficiency, since it performed reading in a few seconds, with the quantification within that specified by the sensor manufacturer. It is concluded, therefore, that this work consists of steps in the direction of contributing to the lack of data and the scarcity of research that establish a foundation regarding the levels of safety and human tolerance to CO, in the anesthesia procedure.