Uso de la mediana para la valoración de los resultados de la automedición de presión arterial / Use of the median to assess blood pressure self measurement result

Objetivo. Uno de los inconvenientes de la automedición de la presión arterial estriba en que obliga al médico a realizar calculos engorrosos con múltiples cifras durante la consulta médica. Se ha valorado el uso de la mediana como criterio diagnóstico frente al uso habitual de las medias de la presión arterial. Diseño y métodos. Se recogieron las automediciones de 157 pacientes (edad media: 58,9 ± 12,3 años; 44 % varones y 56 % mujeres; 47 % recibían tratamiento hipotensor). Cada enfermo recibió un monitor OMROM 705 para realizar mediciones de presión arterial en su domicilio. Se realizaron 12 mediciones en total durante tres días (dos por la mañana y dos por la tarde cada día). Se han calculado la media y la mediana de las mediciones en cada caso. Resultados. La mediana de la presión arterial sistólica (143,01 ± 18,85 mmHg) no era diferente de la media (143,04 ± 18,53 mmHg). Lo mismo ocurría con la presión arterial diastólica (mediana: 82,25 ± 9,56; media: 82,26 ± 9,39 mmHg). Tampoco hubo diferencias significativas en la clasificación de los pacientes según se usara la media o la mediana. El 47,3 % de las mediciones tenían una presión arterial sistólica media < 135 y un 79,8 % tenían una presión arterial diastólica media < 85 mmHg. Usando la mediana, la presión arterial sistólica era < 135 en el 48,4 % de los casos y la presión arterial diastólica < 85 en el 82,01 %. Las diferencias no son significativas. La sensibilidad de la mediana para la presión arterial sistólica era 100 % y la especificidad 98,9 %. Los falsos positivos fueron 1,05 % y no hubo falsos negativos 0,0 %. La sensibilidad de la mediana para la presión arterial diastólica fue 100 % y la especificidad 96,8 %. Los falsos positivos fueron 4,25 % y no hubo falsos negativos 0,0 %. Conclusiones. La mediana parece una medida alternativa a la media en la valoración de los resultados de la automedición de la presión arterial con buena sensibilidad y especificidad y mayor sencillez de realización en la práctica diaria

Objective. One of the disadvantages of blood pressure self measurement (BPSM) is because the physician must make tiresome calculations with many numbers during the medical visit. The use of the median as diagnostic criteria versus the common use of the BP means has been assessed. Design and methods. Self-measurements were collected from 157 patients (mean age: 58.9 ± 12.3 years, 44 % men and 56 % women, 47 % of whom received antihypertensive treatment). Each patient received an OMROM 705 monitor to perform BP measures in their home. A total of 12 measures in all were performed during 3 days (2 in the morning and two in the afternoon of each day). The mean and median of the measurements were calculated in each case. Results. The median of SBP (143.01 ± 18.85 mmHg) was not different from the mean (143.04 ± 18.53 mmHg). The same occurred with DBP (median: 82.25 ± 9.56; mean 82.26 ± 9.39 mmHg). There were also no significant differences in the classification of the patients when the mean or median was used. A total of 47.3 % of the measurements had a mean SBP < 135 and 79.8 % had a mean DBP < 85 mmHg. Using the median, the SBP was < 135 in 48.4 % of the cases and the DBP < 85 in 82.01 %. The differences are not significant. Sensitivity of the median for SPB was 100 % and specificity 98.9 %. False positives were 1.05 % and there were no false negatives 0.0 %. Sensitivity of the median for DBP was 100 % and specificity 96.8 %. False positives were 4.25 % and there were no false negatives 0.0 %. Conclusions. The medians seems to be an alternative measure to the mean in assessment of BPSM results with good sensitivity and specificity and is easier to perform in the daily practiceObjective. One of the disadvantages of blood pressure self measurement (BPSM) is because the physician must make tiresome calculations with many numbers during the medical visit. The use of the median as diagnostic criteria versus the common use of the BP means has been assessed. Design and methods. Self-measurements were collected from 157 patients (mean age: 58.9 ± 12.3 years, 44 % men and 56 % women, 47 % of whom received antihypertensive treatment). Each patient received an OMROM 705 monitor to perform BP measures in their home. A total of 12 measures in all were performed during 3 days (2 in the morning and two in the afternoon of each day). The mean and median of the measurements were calculated in each case. Results. The median of SBP (143.01 ± 18.85 mmHg) was not different from the mean (143.04 ± 18.53 mmHg). The same occurred with DBP (median: 82.25 ± 9.56; mean 82.26 ± 9.39 mmHg). There were also no significant differences in the classification of the patients when the mean or median was used. A total of 47.3 % of the measurements had a mean SBP < 135 and 79.8 % had a mean DBP < 85 mmHg. Using the median, the SBP was < 135 in 48.4 % of the cases and the DBP < 85 in 82.01 %. The differences are not significant. Sensitivity of the median for SPB was 100 % and specificity 98.9 %. False positives were 1.05 % and there were no false negatives 0.0 %. Sensitivity of the median for DBP was 100 % and specificity 96.8 %. False positives were 4.25 % and there were no false negatives 0.0 %. Conclusions. The medians seems to be an alternative measure to the mean in assessment of BPSM results with good sensitivity and specificity and is easier to perform in the daily practice

Covalently bonded polysaccharide derivatives as chiral stationary phases in high-performance liquid chromatography.

Polysaccharide derivatives have been extensively used as chromatographic chiral selectors in chiral stationary phases (CSPs) for the separation of enantiomers by HPLC. When coated onto a silica matrix, they represent nowadays one of the most popular type of CSPs. However, they are only compatible with a limited choice of solvents. The main drawback of these CSPs is related to the solubility of the chiral selector in a number of solvents, which limits their applicability. The different attempts which have been described up to now to overcome this problem by covalently fixing the chiral selector to a matrix are reviewed in this paper.

Characterization of doubly substituted polysaccharide derivatives.

Derivatives of cellulose, amylose and chitosan, bearing simultaneously 10-undecenoyl and arylaminocarbonyl or benzoyl groups were characterized by the combined use of 1H NMR and elemental analysis. The mathematical manipulation of elemental analysis data permits the calculation of the degree of substitution for each kind of substituent. The method was validated and is applicable to other derivatives.

Preparation of mixed 10-undecenoyl/phenylaminocarbonyl or benzoyl derivatives of chitosan.

The preparation of mixed 10-undecenoyl/phenylaminocarbonyl or benzoyl derivatives of chitosan is described. Several mixed derivatives were prepared using differently substituted aryl isocyanates or benzoyl chlorides. The reactivity of the starting polysaccharide was found to be influenced by the acetyl content.