On laparoscopic photoplethysmography and pulse oximetry.

Here we comment on the paper entitled "A novel laparoscopic pulse oximeter device. An easy, efficient and cost-effective way of detecting arterial structures." authored by Theodosopoulos et al., and recently published in the April issue of the Journal of Clinical Monitoring and Computing.

Transmittance photoplethysmography with near-infrared laser diodes in intra-peritoneal organs.

Photoplethysmography and pulse oximetry are techniques based on optical principles, which are widely used in medical practice for non-invasive monitoring. There are some processes which may affect specific organs or parts without a significant repercussion on the information provided non-invasively. Here, we report on the preliminary results obtained by transmittance photoplethysmography in pig intra-peritoneal organs along a surgical intervention, using a measurement system based on two near-infrared laser diodes. Analysis of the signals recorded at 750 nm and 850 nm in the mesentery root, mesocolon, gastric wall and aorta artery has shown the affordability of performing in situ photoplethysmography for visceral perfusion evaluation.

Aportaciones fisiológicas de la medida continua de la saturación de oxígeno en atletas de ambos sexos que realizan pruebas de esfuerzo máximas / Physiological contributions of the continues measurement of the saturation of oxygen in athletes of both sexes during the accomplishment of an exercise stress test

El objetivo de este estudio se centra en la monitorización continua de la saturación de oxígeno en sangre en deportistas durante la realización de una prueba de esfuerzo máxima. El conocimiento de la evolución de la saturación de oxígeno durante el ejercicio podría ser un parámetro útil para la valoración de la mejora del rendimiento deportivo. La medida continua de la saturación de oxígeno en sangre mediante oximetría de pulso no necesita de un montaje de aparatos de medida tan sofisticado como los utilizados en las pruebas de esfuerzo en la actualidad. Para este trabajo se han tomado medidas durante la prueba de esfuerzo máxima en tapiz rodante y la recuperación (5 min) en una población de 51 deportistas sanos voluntarios (25 deportistas varones y 26 deportistas mujeres). Esta medida se ha realizado con dos oxímetros de pulso, uno comercial portátil de última generación (Pulsos-3i de Minolta) y otro un prototipo desarrollado en el Instituto de microelectrónica de Madrid. Los resultados obtenidos con este tipo de medidas oximétricas han presentado coeficientes de correlación elevados (r= 0,88), para ambos sexos, entre el consumo máximo de oxígeno y el tiempo de duración de la prueba y correlaciones muy elevadas entre el tiempo en aparecer el segundo umbral ventilatorio y el tiempo en que aparece el valor más bajo de saturación de oxígeno en sangre (r= 0,87). Esto es de gran interés, porque nos indica la saturación de oxígeno como un valor con potencial futuro en la ayuda a la determinación del segundo umbral ventilatorio (AU)

The objective of this study is the continuous measurement of blood oxygen saturation in athletes while performing an exercise stress test. The knowledge of the evolution of oxygen saturation during exercise could be a useful parameter for evaluating the improvement in sports performance. The continuous measurement of blood oxygen saturation by means of pulse oximetry requires less sophisticated apparatus than current measurements. The study was performed in 51 voluntary healthy athletes (25 males and 26 females). Measurements have been performed with two pulse oximeters, one commercial portable of last generation (Pulsos-3i of Minolta) and another one that is a prototype developed at the Institute of Microelectronics of Madrid, during a treadmill test and the recovery period. The results obtained with this type of measurements presented high correlation coefficients (r= 0.88) in both sexes between VO2 max and the time of duration of the test and between the time the second threshold appeared and the time in which the lowest value of saturation of oxygen in blood (r=0.87) appeared. This is of great interest because saturation of oxygen could be a value with future potential in the determination of the second ventilatory threshold (AU)

Simultaneous determination of human plasma levels of four selective serotonin reuptake inhibitors by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatography (HPLC) method with fluorimetric detection, which allows the simultaneous determination of plasma concentrations of four selective serotonin reuptake inhibitors (SSRIs) is presented. Fluvoxamine, paroxetine, sertraline, and fluoxetine were extracted from plasma with ethyl acetate and then derivatized with dansyl chloride. The analytes were separated using Hypersyl ODS C18 (5 microm) 250 x 4.6 mm column (ThermoQuest, Runcorn, UK). For continuous gradient separation, the mobile phase consists of two eluents, acetonitrile and potassium phosphate buffer (10 mmol/L, pH 7.2) at total flow rate of 1.5 mL/min. Detection was carried out at lambda exc = 366 nm and lambda em = 490 nm. The authors found recoveries of 90% to 95% for fluvoxamine, 94% to 100% for paroxetine, 88% to 95% for sertraline, 93% to 100% for fluoxetine, and 97% to 100% for internal standard (nortriptyline). Imprecision of the method ranged from 2.5% to 8.9%. The assay was linear from 10 to 1500 ng/mL for sertraline, and from 5 to 1500 ng/mL for the other drugs. The authors conclude that this method is suitable for monitoring antidepressant therapy. In addition, the authors report the effects of adding paroxetine to fluvoxamine on plasma levels in a group of patients in combined drug therapy.