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Synchronized intermittent mandatory ventilation (SIMV) intermixes assisted and spontaneous breaths. Its ability as a weaning technique has been questioned on the basis that patients show little adaptation to ventilator assistance. We studied inspiratory effort and patient-ventilator interaction at different levels (SIMV, 100, 50, and 0%) of flow-triggered SIMV versus pressure-triggered SIMV in patients during the weaning period. The two triggering systems were evaluated during constant flow and constant pressure mandatory SIMV breaths. Inspiratory effort was estimated as the esophageal pressure time product (PTP) per breath (PTP/b) and per minute (PTP/min). The PTP/b and PTP/min of both mandatory and spontaneous breaths were significantly lower during flow triggering than during pressure triggering SIMV, irrespective of the ventilatory mode. During pressure-triggered SIMV PTP/b and PTP/min were identical for mandatory and spontaneous breaths, whereas during flow-triggered SIMV PTP/b and PTP/min were significantly lower for mandatory than for spontaneous breaths. This difference was greatest when flow triggering and constant pressure ventilation were associated. These data show that flow triggering reduces inspiratory effort during both mandatory and spontaneous SIMV breaths and obtains a better patient-ventilator interaction.

Huge amounts of soil debris are produced during the underground excavation with Earth Pressure Balance-Tunnel Boring Machines (EPB-TBM). Soil debris may contain residual concentrations of the anionic surfactant sodium lauryl ether sulphate (SLES), the main component in some foaming agents used as excavation additives. The reuse of this debris or its discharge as waste is a critical environmental question in construction engineering. There are only few studies on ecotoxicological effects on soil debris coming from a real excavation site. The aim of this study was to evaluate the ecotoxicity of two deep soils, with different lithological compositions, conditioned with three foaming agents. In some cases, lime was added to the soil. The soils were placed in mesocosms (1 m 3) to simulate the temporary storage of the soil debris at a construction site. At fixed times, soil sub-samples were collected and ecotoxicological tests on terrestrial organisms (Lepidium sativum, Eisenia foetida) and an assessment of SLES concentration were performed with soils and aqueous elutriates produced from them. Results showed that at day 28, a SLES reduction was observed in both the soil and aqueous elutriates, with various rates of decrease. The differences were due to different soil lithological compositions and foaming agent products composition. In general, the two soils were not suitable for both plant growth and earthworm reproduction, but in Soil 1 the earthworm mortality was very low, except when lime was added. Tests with soil elutriates showed that 7 days after conditioning no toxic effect was found for the organisms tested.

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Degradation studies in soil of the insecticides aldicarb and carbofuran and their metabolites (aldicarb sulfoxide, aldicarb sulfone; 3-ketocarbofuran and 3-hydroxycarbofuran) were carried out using laboratory systems under controlled conditions (temperature, water content, light). The insecticides were added to soil samples and subsamples of the soil were analyzed at different times to assess both the bacterial abundance and the concentration of the different chemicals. The epifluorescence direct count method was applied to the subsamples to estimate microorganism numbers (N=g soil). Untreated samples of soil were used as controls for evaluating the effects of the application of the insecticides on microbial abundance. Subsamples treated with the pesticides were analyzed using HPLC and the DT 50 s of the different compounds studied were calculated.The DT 50 values show that neither the parent compounds nor the transformation products have a high persistence in soil and there is a general increase in the concentration of microorganisms as the pesticides diminish.

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