Applicability and feasibility of systematic review for performing evidence-based risk assessment in food and feed safety.

Food and feed safety risk assessment uses multi-parameter models to evaluate the likelihood of adverse events associated with exposure to hazards in human health, plant health, animal health, animal welfare, and the environment. Systematic review and meta-analysis are established methods for answering questions in health care, and can be implemented to minimize biases in food and feed safety risk assessment. However, no methodological frameworks exist for refining risk assessment multi-parameter models into questions suitable for systematic review, and use of meta-analysis to estimate all parameters required by a risk model may not be always feasible. This paper describes novel approaches for determining question suitability and for prioritizing questions for systematic review in this area. Risk assessment questions that aim to estimate a parameter are likely to be suitable for systematic review. Such questions can be structured by their "key elements" [e.g., for intervention questions, the population(s), intervention(s), comparator(s), and outcome(s)]. Prioritization of questions to be addressed by systematic review relies on the likely impact and related uncertainty of individual parameters in the risk model. This approach to planning and prioritizing systematic review seems to have useful implications for producing evidence-based food and feed safety risk assessment.

[Posture-dependent changes in lung function and cardiovascular parameters in pregnant females at delivery date]. / Lageabhängige Veränderungen von Lungenfunktions- und Kreislaufparametern bei graviden Frauen am Geburtstermin.

The objective of the investigation was to clarify whether, from the pulmonary or cardiological viewpoint, preference should be given to delivery in the sitting or lying position. For this purpose a spirometry was carried out in 28 pregnant women, average age 26 (19 to 35) and 15 control persons, average age 30 (20 to 41). In addition, the cardiac output of 12 pregnant women at the final date of confinement as well as of 10 persons of corresponding age for comparison purposes was determined by means of the CO2 rebreathing method. In none of the women investigated had labour set in. There were no significant differences of the VC, the IRV, the ERV and the FEV1 in the two groups examined, either in the lying or in the sitting position. Both in the sitting and in the lying position the arterial oxygen partial pressure of the pregnant women at rest was significantly above that of the control group. After stress both groups showed an increase of PaO2 and no longer differed significantly from one another. A difference in the PaCO2 depending on the position was not ascertainable in either group. However, the pregnant women had a significantly lower PaCO2 than the control group. The cardiac output of pregnant women did not differ significantly in the sitting position from those of the control group (4.7 +/- 1.3 and 5.3 +/- 1.5 1/min. respectively). Whereas the cardiac output of the comparison group rose in the lying position to 5.2 +/- 0.9 1/min, in the case of the pregnant women it dropped significantly (p less than 0.01) to 3.6 +/- 1.2 1/min. These findings show that a decision as to whether the delivery should take place in the sitting or lying position cannot be taken on the basis of parameters that analyse the lung function. The significant reduction of the cardiac output of those women lying on their back during labour, caused by the compression of the vena cava inferior and of the aorta by the uterus, indicates that the second stage of labor is better carried out in a position other than lying, e.g. the sitting position.