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Objective: To investigate the efficacy of high frequency oscillation with perfluorocarbon (PFC) in rabbits with acute lung injury (ALI)., Methods: Twenty four rabbits with ALI induced by repeated saline lung lavage were randomly assigned to four groups: conventional mechanical ventilation (CMV) group, CMV + PFC group, high frequency oscillation (HFO) group and HFO + PFC group. All rabbits were ventilated for two hours. Blood gases, respiratory system dynamic compliance (Cdyn) and intrapulmonary shunt fraction (Qs/Qt) were measured and calculated at 30, 60, and 120 min during experiment., Results: Compared with the CMV, statistically improvements were shown in gas exchange, Cdyn and Qs/Qt at 30 min in the CMV + PFC group [PaO(2) 122 mm Hg +/- 15 mm Hg vs. 692 mm Hg +/- 82 mm Hg, PaCO(2) 29.1 mm Hg +/- 2.7 mm Hg vs. 47.1 mm Hg +/- 2.9 mm Hg, Cdyn (1.35 +/- 0.13) vs (0.97 +/- 0.13) ml.cm H(2)O(-1).kg(-1), Qs/Qt 18.1 +/- 1.1 vs.24.5 +/- 2.9] (P < 0.01 approximately 0.05) and remained stable for two hours. Compared with HFO, HFO + PFC improved oxygenation and ventilation more rapidly than HFO did. At 30 min intervals gas exchange and Qs/Qt were significantly improved (PaO(2) 174.9 +/- 18.5 vs 132.3 +/- 19.4, PaCO(2) 26.1 +/- 2.6 vs 34.9 +/- 4.6, Qs/Qt 17.1 +/- 2.4 vs 19.8 +/- 0.9) (P < 0.05)and remained stable to 60 min. The same differences were seen at 60 min., Conclusion: In rabbits with ALI, CMV + PFC could induce a significant improvement in gas exchange and Cdyn. HFO + PFC leads more rapidmy to reach best gas exchange and Cdyn.

Objective: To evaluate the effects of a double-lumen, two-stage endotracheal tube on gas exchanges (ventilatory efficiency) during conventional mechanical ventilation, using a ventilator in rabbits., Design: Prospective, randomized, crossover laboratory animal trial., Setting: Research laboratory in the Beijing Children's Hospital., Subjects: Five adult New Zealand rabbits, weighing 3.2 to 3.7 kg., Interventions: A new type of endotracheal tube-the double-lumen two-stage endotracheal tube-was designed and tested for ventilation efficiency in rabbits with normal and injured lungs. The new tube (size 3.0 mm) was made out of two Portex endotracheal tubes (size 3.0 mm) by adhering two vertical cross-sections at the distal end of the two tubes. The new tube and a conventional endotracheal tube of the same size (inner diameter 3.0 mm) were randomly used in pressure control ventilation. Each trial was maintained for 30 mins., Measurements and Main Results: Effects from the two endotracheal tubes on pulmonary mechanics, hemodynamics, and gas exchange were observed. We measured peak inspiratory pressure, positive end-expiratory pressure (PEEP), intrinsic PEEP, mean airway pressure, and arterial blood and mixed expired gas variables (Pao2, Paco2, pH, and mixed expired gas Pco2). The new endotracheal tube acutely increased CO2 elimination in all animals with normal and injured lungs. Paco2 decreased from 46 +/- 4 to 36 +/- 5 torr (6.1 +/- 0.5 to 4.8 +/- 0.7 kPa; p < .01) in normal lungs and from 48 +/- 5 to 36 +/- 5 (6.4 +/- 0.7 to 4.8 +/- 0.7 kPa; p < .01). Meanwhile, tidal volume fraction decreased from 0.48 +/- 0.07 to 0.35 +/- 0.05 (p < .01) and from 0.56 +/- 0.07 to 0.40 +/- 0.07 (p < .01) in normal and injured lungs, respectively. Intrinsic PEEP of the new tube slightly increased, but there were no significant differences in comparison with the conventional tube., Conclusion: Compared with the conventional endotracheal tube, the new double-lumen, two-stage endotracheal tube reduced Paco2 by decreasing anatomical deadspace in rabbits with normal and injured lungs under pressure control ventilation, thus enhancing ventilatory efficiency and reducing ventilator-induced injury.

In Yishan County, Guangxi Province, China, where malaria and Brugian filariasis are transmitted by vectors belonging to the Anopheles hyrcanus Pallas group, a study was conducted from June to November 1986 to evaluate the effectiveness of permethrin-impregnated mosquito bednets to reduce man/vector contact. In three experimental villages a total of 246 mosquito nets were treated with permethrin EC at a dosage of 0.5 g/m2. Control bioassays (1 h exposure) of treated nets gave up to 100% mortality of Armigeres subalbatus (Coquillett), Anopheles sinensis Wiedemann and Culex tritaeniorhynchus Giles for up to 19 weeks. During 5 months evaluation in the villages, permethrin-impregnated mosquito-nets reduced the number of mosquitoes found inside nets by 99.3% for Culex quinquefasciatus Say, by 94.4% for Anopheles sinensis Wiedemann and by 75% for Anopheles lesteri anthropophagus Xu & Feng. This measure could thus be considered an appropriate means of controlling vectors in villages.