[A comparative study of 5 infusion pumps: an evaluation of their suitability for administering parenteral nutrition]. / Estudio comparativo de cinco bombas de infusión: evaluación de su idoneidad para la administración de nutrición parenteral.

To facilitate the control of administering parenteral nutrition (PN), the tendency is to replace traditional infusion equipment with infusion pumps. The aim of this study is to determine the characteristics that a pump should have for infusing PN mixtures and, based on these, to evaluate five models available on the market. The pumps evaluated, all with volumetric programming were: Becton Dickinson VIP II (Prim); Life-Care Pump Model 4 (Abbot-Shaw); Infusomat Secura 1.000 (Braun); Flo-gard (tm) 6,200 (Baxter) and IVAC-591 (Ivac). The following method was used: a) Definition of 16 basic requisites and 7 secondary requisites considered necessary in a PN pump, in accordance with the following criteria: safety, practical usage, comfort and hospital circuits. b) Review and checking of the technical reports on each pump. c) Laboratory tests simulating PN infusion, evaluating the regularity and precision of the infusion speed, and d) Subjective evaluation survey. All the pumps under study complied with the basic requisites. There were differences in the subjective evaluation, although with regard to all concepts and models a score of over 2.5 was reached in a scale of 0 to 5. The highest and lowest values with regard to regularity and precision were within the following ranges: +/- 0.6 ml/h(-)+/- 0.0 ml/h and + 3.4%(-)-1.6% respectively, and no instance of values outside the established ones was detected. The pumps only partly complied with the secondary requisites. Finally, the criteria for defining the most significant requisites was reviewed, based on the services offered by the existing pumps, as well as techniques for determining regularity and precision.(ABSTRACT TRUNCATED AT 250 WORDS)

99mTc-tetracycline radiopharmaceutical: physical chemistry study related to the preparation and reaction products and thermodynamic stability.

The labelling of tetracycline hydrochloride with 99mTc at neutral pH, using Sn2+ as reducing agent, has been investigated by chromatography, using a 4:1:5 n-butanol:acetic acid:H2O mixture as developing agent, with Whatman paper No 3. In such conditions, reduced 99mTc remained at the origin, while labelled 99mTc migrates at Rf approximately equal to 0.6. Radiochromatographic and u.v.-visible spectrophotometric results, demonstrated that the higher the tetracycline concentration the higher was the labelling of 99mTc to that ligand, obtaining a 50% labelling when the molar ratio of tetracycline:Sn2+ was approximately 20:1, independent of the Tc concentration level. The Tc oxidation state in the radiopharmaceutical is +4, deduced from iodimetric and radiometric techniques. Furthermore, it seems that time does not influence labelling, while pH does. The maximum labelling level occurs at physiological pH. The thermodynamic study performed with the radiopharmaceutical formation shows that the Tc-tetracycline complex has a 1:1 stoichiometry, thus a low stability constant (about 2 X 10(2)).