Critical outlook and trends for environmental reference materials at the Measurements & Testing Generic Activity (European Commission).

It is now well recognised that the quality control (QC) of all types of analyses, including environmental analyses depends on the appropriate use of reference materials. One of the ways to check the accuracy of methods is based on the use of Certified Reference Materials (CRMs), whereas other types of (not certified) Reference Materials (RMs) are used for routine quality control (establishment of control charts) and interlaboratory testing (e.g. proficiency testing). The perception of these materials, in particular with respect to their production and use, differs widely according to various perspectives (e.g. RM producers, routine laboratories, researchers). This review discusses some critical aspects of RM use and production for the QC of environmental analyses and describes the new approach followed by the Measurements & Testing Generic Activity (European Commission) to tackle new research and production needs.

The effect of immersion on haemodynamic and fetal measures in uncomplicated pregnancies of nulliparous women.

OBJECTIVE: To evaluate the effect of immersion in water on maternal haemodynamic measures and fetal heart rate patterns in healthy nulliparous women. DESIGN: A randomised cross-over study. PARTICIPANTS: Twenty pregnant women were studied between 26-29 weeks and between 34-37 weeks of gestation. METHODS: The women were either immersed in water for 35 minutes or rested on a bed for a similar period of time. Maternal blood pressure, thoracic electrical bioimpedance, urine and blood samples, and fetal heart rate patterns were obtained before and after immersion or bedrest. RESULTS: Compared with bedrest and pre-immersion values, immersion resulted in a significant decrease in blood pressure, which returned to baseline values within 1.5 hour. Urine production increased for a short period after immersion, but 24 hour samples showed no difference compared with bedrest. Sodium, potassium and creatinine levels in urine remained constant. No significant changes were found for the other haemodynamic measures. There were no effects on fetal heart rate nor on its variation. CONCLUSION: In healthy pregnant women immersion for 35 minutes has a clear effect on blood pressure and urine production. However, these effects are short lasting.