问题 单项选择题

对Ⅰ型呼吸衰竭患者若给予高浓度氧疗仍无效,其原因很可能为()

A.严重肺通气功能障碍

B.严重肺动-静脉样分流

C.通气/血流比例增大

D.肺弥散功能障碍

E.耗氧量增加

答案

参考答案:B

解析:肺内动-静脉解剖分流增加是指肺动脉内的静脉血未经氧合直接流入肺静脉,导致PaO2降低,是通气/血流比例失调的特例。在这种情况下,提高吸氧浓度并不能提高分流静脉血的血氧分压。分流量越大,吸氧后提高动脉血氧分压的效果越差;若分流量超过30%,吸氧并不能明显提高PaO2常见于肺动-静脉瘘。正常成人静息状态下,通气/血流比值约为0.8,部分肺泡血流不足时,通气/血流比值增大,肺泡通气不能被充分利用。弥散障碍系指O2、CO2等气体通过肺泡膜进行交换的物理弥散过程发生障碍,O2的弥散能力仅为CO2的1/20,故在弥散障碍的时候,通常以低氧血症为主。发热、寒战、呼吸困难和抽搐均增加氧耗量,正常人借助增加通气量以防止缺氧,故氧耗量增加的患者,若同时伴有通气功能障碍,则会出现严重的低氧血症。

判断题
阅读理解

These days it’s cheaper to throw that broken DVD player, cell-phone or TV out and buy a new one. This “ replace-rather-than-repair” mentality is polluting the planet with electronic waste. According to the UN Environment Program, we are throwing away an estimated 50 million metric tonnes of electronics waste    (e-waste) per year. But this is not ordinary garbage. Our electronics leak harmful heavy metals — such as mercury and arsenic — along with equally poisonous chemicals that end up in our soil and eventually our water.

You’ve probably participated in a community recycling event and left feeling good about shipping off that old computer to be recycled. Chances are it was shipped overseas where it’s polluting someone else’community.

Guiyu city in Southeastern China has become known as the e-waste city where low-paid workers use whatever means available to remove electronics in hopes of recovering the copper, microchips, aluminum, gold and silver and plastic that can be resold. Any leftover waste is simply thrown into the nearby river or piled up high in the streets, poisoning the children growing up here.

So what can you do with your e-waste? Robert Houghton, President and founder of Redemtech, an asset management and recovery firm, recommends you vote with your dollar. Buy from companies who have a take-back program that guarantees your discarde electronics are handled proper.

“ Consumers want to do business with companies who are demonstrably    good with corporate responsibility and dealing with e-waste, ” said Houghton.

There are   plenty of charitable   organizations that will    take your  used electronics and donate them for charitable causes:

• Electronic Recycling  Association (Canada) (ERA) collects old    computers for donation to libraries and other organizations across Canada.

• eBay’s Rethink Initiative pairs up consumers with businesses that refurbish (再磨光)old computers for donation.

• TechSoup has a thorough   listing of resources for those who would  like   to donate or recycle hardware,buy recycled hardware or find a refurbisher.

• The Charitable    Recycling Program  accepts all cell-phones    and    has a listing of charities it helps with its program.

• Call2 Recycle has set up drop off points across Canada in a number of stores. You can drop off your cell-phone and also your rechargeable batteries from handheld electronic products.

小题1:When there is something wrong with electronics, what is a popular trend among people nowadays?

A.To keep a DIY way.

B.To put them away themselves.

C.To purchase what they like.

D.To donate them to charities.小题2:Guiyu city in Southeastern China is mentioned here to show us ____.

A.there is an ideal place in the world for e-waste

B.there is a good example in the world for recycling

C.the recycling events in Canada benefit people overseas

D.people should find a scientific and thorough way to recycle小题3:In the     writer’s opinion, who can first shoulder the   great responsibility to guarantee e-waste is handled proper in the future?

A.The UN Environment Program.

B.Consumers who buy electronics.

C.President and founder of Redemtech.

D.Guiyu city in Southeastern China.小题4:In Canada, which charity organization will    most possibly take all  your unwanted electronics?

A.Call2 Recycle.

B.TechSoup.

C.eBay’s Rethink Initiative.

D.Electronic Recycling Association.