Rigid versus soft catheter for less invasive surfactant administration: A crossover randomized controlled manikin trial.

BACKGROUND: We compared surfactant administration with a rigid versus soft catheter in a manikin simulating an extremely preterm infant. METHODS: Randomized controlled crossover (AB/BA) trial. Fifty tertiary hospital consultants and pediatric residents. The primary outcome was the time of device positioning. The secondary outcomes were the success of the first attempt, the number of attempts, and the participant's opinion. RESULTS: Median time of device positioning was 19 s (interquartile range [IQR]: 15-25) with rigid catheter and 40 s (IQR: 28-66) with soft catheter (p < 0.0001). Success at first attempt was 92% with rigid catheter and 74% with soft catheter (p = 0.01). Median number of attempts was 1 (IQR: 1-1) with rigid catheter and 1 (IQR: 1-2) with soft catheter (p = 0.009). Participants found the rigid catheter easier to use (p < 0.0001). CONCLUSIONS: In a preterm manikin model, using a rigid catheter for less invasive surfactant administration was quicker and easier to use than a soft catheter.

Marked versus unmarked tip catheter for less invasive surfactant administration: A crossover randomised controlled manikin trial.

AIM: Less invasive surfactant administration is becoming increasingly popular, but health-care providers may experience some difficulties in achieving the correct positioning of the catheter in the trachea. We compared catheters with marked versus unmarked tips in terms of correct depth positioning in the trachea, total time, number of attempts and participant's opinion on using the device in a manikin model. METHODS: A randomised controlled crossover trial of surfactant administration with less invasive surfactant administration catheters with marked versus unmarked tip in a preterm infant manikin. Fifty tertiary hospital consultants and paediatric residents with previous experience in surfactant administration participated. The primary outcome measure was the positioning of the device at the correct depth in the trachea. The secondary outcome measures were the total time and the number of attempts for positioning the device in the trachea, and participant's opinion on using the device. RESULTS: Correct depth in the trachea was achieved by 38 (76%) and 28 (56%) participants using the catheters with marked and unmarked tip, respectively (P = 0.04). Median time of device positioning (P = 0.08) and number of attempts (P = 0.13) were not statistically different between the two catheters. Participants found the catheter with the marked tip easier to use (P = 0.007), especially concerning the insertion in the trachea (P = 0.04) and the positioning at the correct depth (P = 0.004). CONCLUSIONS: In a preterm manikin model, the marked tip catheter offered a higher chance of achieving the correct depth of the device in the trachea and was favoured by the participants.

Carbon isotope ratio of endogenous urinary steroids of the Cuban population of athletes studied for doping purposes.

The aim of this work was to validate the gas chromatography/combustion/isotope ratio mass spectrometry method in Havana Antidoping Laboratory and verify its implementation with a study of the Cuban population. The method was precise and accurate inside the linear working range; the limit of quantification and the uncertainty were compliant with TD2019IRMS. The study of the Cuban population showed no differences in δ13 C values between females and males. Only three values of Δδ13 C showed significant differences between sexes (PD-T, OHA-T, and 11-keto-Et-T). The values of δ13 C between -17.8‰ and -21.2‰ (upper and lower limits based on normal distribution) were consistent with other populations where C4 plant derivatives prevail in the diet.

Cuantificación simultánea de andrógenos, estrógenos, corticoides y pregnanos mediante cromatografía de gases acoplada a espectrometría de masas / Simultaneous quantification of androgens, estrogens, corticoids and pregnanes thorugh the gas chromatography-mass spectrometry method

INTRODUCCIÓN: la evaluación de hormonas en pacientes de endocrinología y bioquímica clínica, entre otros, se realiza actualmente por métodos de inmunoensayo con las desventajas inherentes a este tipo de análisis (ejemplo: reacciones cruzadas). Con la aplicación de la espectrometría de masas acoplada a cromatografía de gases es posible aumentar la sensibilidad y especificidad de los análisis. OBJETIVO: validar un ensayo que permita la cuantificación de 21 hormonas mediante la técnica de cromatografía de gases-espectrometría de masas con propósitos de pesquizaje. MÉTODOS: el ensayo se basó en una extracción en fase sólida con columnas DetectabuseTM y posterior extracción líquido-líquido a pH básico. Los derivados trimetilsilil se analizaron con un cromatógrafo de gases Hewlett-Packard 6890 acoplado a un espectrómetro de masas cuadrupolar serie 5973. La columna capilar fue HP Ultra-1 (17 m x 0,20 mm x 0,11 µm). La adquisición fue realizada en modo SIM (monitoreo selectivo de iones). RESULTADOS: los resultados del proceso de validación cumplieron con los criterios de aceptación de una manera adecuada correspondiente a un método con propósitos de pesquizaje. El método resultó ser específico para los 21 compuestos estudiados, lineal (r2= 0,900-0,996) y preciso (CV entre 1,4-9,6 por ciento). El rendimiento de extracción se mantuvo entre 69-117 por ciento. La robustez con variación de disolvente mostró recobrados entre 69-139 por ciento. CONCLUSIONES: los resultados demuestran que la técnica analítica desarrollada para la cuantificación de los 21 compuestos esteroidales en orina, es exacta, específica, lineal, precisa y robusta para su aplicación con propósitos de pesquizaje en estudios endocrinológicos clínicos(AU)

INTRODUCTION: the evaluation of hormones on endocrinology and clinical biochemistry patients, among others, is presently performed, using inmunoassays with its intrinsic disadvantages such as cross reactions. The application of gas chromatography coupled to mass spectrometry allows increasing the sensitivity and specificity of this analysis. OBJECTIVE: to validate an assay for quantitation of 21 hormones by the analytical technique of gas chromatography - mass spectrometry for screening purposes. METHODS: the assay followed a solid-phase extraction using DetectabuseTM columns and subsequently liquid-liquid extraction at basic pH. Trimethylsilyl derivatives were evaluated on Hewlett-Packard 6890 gas chromatograph coupled to serial 5973 quadrupolar mass spectrometer. The capillary column was HP Ultra-1 (17 m x 0.20 mm x 0.11 µm). Data was gathered following SIM mode (selective ion monitoring). RESULTS: the results of the validation process adequately fulfilled the acceptance criteria for screening purposes. The assay proved to be specific for all studied compounds, linear (r2= 0.900-0.996) and precise (VC 1.4-9.6 percent). The extraction yield was kept at 69-117 percent. The robustness assay with varying dissolvent showed extraction yields ranging 69-139 percent. CONCLUSIONS: results of the validation process show that the developed assay to simultaneously quantify 21 steroidal compounds in urine is exact, linear, precise, robust and specific for its application in clinical endocrine studies for screening purposes(AU)

Qualitative confirmation procedure for ephedrines as acetonide derivatives in doping urine samples by gas chromatography/electron ionization mass spectrometry.

Ephedrines are sympathomimetic amines which have central nervous system stimulating properties and, for this reason, some of them are forbidden in sport by the World Antidoping Agency (WADA). They are screened and quantitated in urine by several published techniques and confirmed by gas chromatography/mass spectrometry (GC/MS). In this paper, a simple and easy confirmation procedure for norpseudoephedrine, norephedrine, ephedrine and pseudoephedrine in human urine by GC/electron ionization (EI)-MS is described. After the addition of diphenylamine as internal standard, a liquid-liquid extraction procedure under alkaline conditions with tert-butyl methyl ether was applied to the samples. The analytes were derivatized with acetone and pyridine to form the correspondent oxazolidine derivatives (acetonide). The EI mass spectra of all the studied substances have many diagnostic ions with relative abundance in accordance with WADA requirements and show great structural information content. The fragmentation of theses derivatives is discussed.

Electron ionization mass spectra of ephedrines in a doping confirmatory procedure: a curious migration of the trimethylsilyl group in the N-acetyl-O-trimethylsilyl derivatives.

Ephedrines have central nervous system stimulating properties and, for this reason, some of them are forbidden in sport by the World Antidoping Agency (WADA). They are screened and quantitated in urine by several published techniques and confirmed by gas chromatography/mass spectrometry (GC/MS). In this paper, a simple confirmation procedure for norpseudoephedrine, norephedrine, ephedrine and pseudoephedrine in human urine by GC/electron ionization (EI)-MS is described. After the addition of levallorphane as internal standard, a liquid-liquid extraction procedure under alkaline conditions with tert-butyl methyl ether was applied to the samples. The analytes were derivatized with acetic acid anhydride and N-methyl-N-trimethylsilyltrifluoroacetamide to form N-acetyl-O-trimethylsilyl derivatives. The EI mass spectra of all the studied substances have many diagnostic ions with relative abundance in accordance with WADA requirements and show great structural information content. A curious migration of the trimethylsilyl group is proposed.