纠结的一道CR题

xingxc11

Of patients over 65 years old who survived coronary bypass surgery—a procedure widely prescribed for people with heart disease—only 75 percent benefited from the surgery.  Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense, were more interested in an opportunity to practice their skills and in their fee than in helping the patient.
Which of the following, if true, most seriously undermines the argument?
A. Many of the patients who receive coronary bypass surgery are less than 55 years old.
B. Possible benefits of coronary bypass surgery include both relief from troubling symptoms and prolongation of life.
C. Most of the patients in the survey decided to undergo coronary bypass surgery because they were advised that the surgery would reduce their risk of future heart attacks.
D. The patients over 65 years old who did not benefit from the coronary bypass surgery were as fully informed as those who did benefit from the surgery as to the risks of the surgery prior to undergoing it.
E. The patients who underwent coronary bypass surgery but who did not benefit from it were medically indistinguishable, prior to their surgery, from the patients who did benefit.

答案是E 令我费解的是为什么不选D呢？

rabbit1937

发现这道题目大家 没有注意理解only 75 percent benefited from the surgery的含义，仅仅有75%能够从中获益，直接表明 75%的人获益于手术——而剩下25%的人完全不能够获益与手术（还有风险和费用），即他们根本就不该做手术！

所以，但凡能够区分谁benefit from the surgery 谁 do not at all，就知道了谁一定不该做手术，不管有没有什么所谓的通知（否则，病人得知100%自己做了就死还会做么？）；反之，patients who cannot benefit 也做了手术的唯一可能就是，不知道自己能不能获益。

所以B选项直接out of scope (因为只是说受益者）
C选项直接反前提(因为根本不受益）
D选项——结合结论即：可以区分，但是医生建议他们做了，仅仅因为也告知他们他们必死，所以就有医德了，是大错特错的了！

猪小王

D选项无法说明医生有没有故意引导那25%不能获益的病人做手术。我们经常碰到这种情况，比如做个小手术，医生说了风险，我们还是无法拿主意到底做不做这个手术，这个时候，如果医生有偏向性地告知90%的病人都做了，都缓解了病情，那我们没准会偏向于做手术。这个例子说明医生告知risk，即对于结果的某种不好的预期，是可以引导病人做出判断的。因此，D选项无法排除医生想赚钱和练手的可能。我们思维里的误区在于：认为告知风险，就是告诉结果可能不好，那样病人还是要求做手术，说明责任不在医生。如何告知风险，告知什么风险，都是可能掺杂医生的私心的。

E选项说的是medically indistinguishable. 类似的情况有CT无法告知某些病人长的是恶性瘤还是良性瘤，所以医生建议做手术。但是做完手术发现瘤是良性的，即使不切除，也对身体无害。民间经常有人认为医生无良，故意骗钱，其实未必，因为医生也受限于科技，不能从影像对结果进行判断，所以需要手术进行进一步判断和治疗，这个答案排除了医生预先知道结果的可能。