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The need for upkeep and management of medical technology has fostered the creation of a large number of under graduate programs in the field of biomedical Engineering. In Latin America alone, there are over 85 programs dedicated to this. This contrasts with programs in other regions where most of the undergraduates continue on to pursue graduate degrees or work as research and development engineers in the biomedical industry. In this work we analyze the situation regarding curricular design in the 48 BME programs in Mexico and compare this to suggestions and classifications of programs according to needs and possibilities. We then focus on a particular institution, Universidad Autónoma Metropolitana and due to its characteristics and performance we propose that it should redefine its aims from the undergraduate program on, in order to not only generate research but also to provide a nurturing environment for a budding biomedical industry in Mexico.

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No useful method to directly monitor the level of end organ tissue injury is currently available clinically. Gastric reactance has been proposed to measure changes in a tissue structure caused by ischemia. The purpose of this study was to assess whether gastric reactance is a reliable, clinically relevant predictor of complications and a potentially useful tool to assess hypoperfusion in cardiovascular surgery patients. The value of gastric reactance measurements, standard hemodynamic and regional perfusion variables, and scores to predict postoperative complications were compared in 55 higher risk cardiovascular surgery patients with cardiopulmonary bypass. Low frequency gastric reactance, X(L), had a significant predictive value of postoperative persistent shock requiring more than 48 h of vasopressors and associated complications, before, during and after surgery (p < 0.05). Results suggest that reactance is an earlier predictor of patients at risk than all other variables tested. Patients with a high reactance (X(L) > 26) before surgery had a significantly higher incidence of complications, higher mortality and more days in the ICU than patients with a low reactance (X(L) < 13). X(L) was found to be a reliable and clinically relevant measurement. These results justify further clinical research to explore how this information may be used to improve patient management.

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This work proposes the clino-ortho maneuver to analyze the metabolic energy expenditure variability by Indirect Calorimetry (IC). This analysis uses a hybrid calorimeter which includes simultaneously the mixing-chamber (MC) and the breath by breath (BbB) IC techniques. VO2 and VCO2 short-term variability was characterized as metabolic variability in the MC technique by intra-group standard deviation averages. When the BbB technique was used the metabolic variability characterization was done by VO2 and VCO2 discrete time series power spectrum analysis in the 0-0.5 Hz band. Thus a statistical population of 17 young healthy volunteers was studied using a clino-ortho maneuver with 30-30 minutes in each position after 8 hours of fasting. The results showed an energy expenditure change of 40% in Kcal/day (p<0.01). The metabolic variability was partially significant using the MC technique while BbB total power spectrum changed from 35 to 60 for the VO2 and from 24 to 37 for the VCO2 (ml/bth)(2), (p<0.05) in the region from 0 to 0.04 Hz. It was concluded that using this new measurement technique and the clino-ortho maneuver metabolic variability information not yet studied was revealed.

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Impedance spectroscopy has been proposed as a method of monitoring mucosal injury due to hypoperfusion and ischemia in critically ill patients. The present study characterizes human gastric impedance spectral changes under gastric hypoperfusion in patients undergoing cardiovascular surgery, and evaluates spectral differences between patients with no evidence of gastric ischemia and complications, and patients who developed ischemia and complications. Cole and Kun parameters were calculated over time to characterize changes as tissue injury progresses. Gastric ischemia was determined by air tonometry. Impedance spectroscopy spectra were obtained from 63 cardiovascular surgery patients. The recorded spectra were classified into three groups: group 1 for patients without ischemia or complications, group 2 for patients with a short period of ischemia (less than 2 h) and group 3 for patients with more than 4 h of gastric ischemia and complications. Two distinct dispersion regions of the spectra centered at about 316 Hz and 215 kHz become clearer as tissue damage develops. The average spectrum in group 3 shows a significant difference in tissue impedance at all frequencies relative to group 1. The parameters obtained for human gastric tissue show significant changes that occur at different times and at different frequencies as ischemia progresses, and could be correlated with patient outcome. This confirms our hypothesis that hypoperfusion and ischemia cause evident changes in the impedance spectra of the gastric wall. Therefore, this technology may be a useful prognostic and diagnostic monitoring tool.

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This paper proposes a discrete random time series modeling for the VO2 and VCO2 measurement in the indirect calorimetry technique (ICT). Mathematical equations are developed in order to establish clear differences between the breath-by-breath and mixing chamber measurement based calorimeters. This simple model offers not only a physiological ICT definition approach but also defines the idea of VO2 and VCO2 short-term variability information for research. The preliminary results show a new physiological information when a computer oriented algorithm model implementation was applied to a data acquisition system in order to obtain the power spectrum analysis from a typical observation subject submitted to the clino-ortho maneuver.

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Manufacturing process of medical grade silicon rubber trileaflet valves for VADs could propitiate important leaflet thickness variations which could result in partial opening of the valve and affect its hydrodynamic performance. The leaflets of a total of 10 valves were measured to assess its thickness variability. Two experiments were performed to asses the impact of the leaflets thickness variation under hypothetical situations. The first experiment was divided into three hypothetical cases. In each case either none, one or two leaflets of different valves were mechanically blocked, resembling possible critical working circumstances. The second experiment was intended to know how the variation on the leaflets thickness affects the hydrodynamic performance of the valves. The results demonstrated a significant variation on the leaflets thickness was found. As for the first experiment, a small variation on the hydrodynamic performance was found above 4 L/min flow rates and a slightly higher energy loss was found in one of the cases. As for the second experiment, the results showed that the variation of the leaflet thickness does not affect the general hydrodynamic performance of the valves. No relationship between the thickness variability and the hydrostatic performance of the valves was found.

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Resting Metabolic Rate (RMR) is computed using VO2and VCO2short time 15-minute window measurement with Indirect Calorimetry (IC) instruments designed with mixing chamber. Steady state condition using a 10% variation coefficient criteria is the main objective to achieve metabolic long time prediction reliability. This study address how susceptible is the steady state VO2, VCO2measurement condition to the clino-orthostatic physiological maneuver. 30 young healthy subjects were analyzed. Only 18 passed the 10% variation coefficient inclusive criteria. They were exposed to 10 minutes clino-stage and 10 minutes orthostage. The hypothesis tests show not statistical significance (p< 0.1) in the average and variance analysis. It is concluded that the steady state is not influenced by the patient position IC test, probably because IC mixing chamber instruments are insensitive to detect a mayor physiological dynamics changes that can modify the steady state definition.