on an emergency basis

米国内で初のエボラ出血熱患者と診断されたトーマス・エリック・ダンカンさんが治療のかいもなく亡くなってしまいました。ここのon an emergency basisは「緊急措置として」ということかと思います。普通，新薬は治験など種々の手続きを経てFDAに認可されますが，今回はemergencyということで投与されたようです。結婚の予定で米国に向かわれたとありました。ご冥福をお祈りします。（Four）

Dallas Ebola Patient Dies, Hospital Says

Thomas Eric Duncan, 42, the patient with the first case of Ebola diagnosed in the United States and the Liberian man at the center of a widening public health scare, died in isolation at a hospital in Dallas on Thursday, hospital authorities said.

Mr. Duncan died at 7:51 a.m. at Texas Health Presbyterian Hospital, more than a week after the virus was detected in him on Sept. 30. His condition had worsened in recent days to critical from serious as medical personnel worked to support his fluid and electrolyte levels, crucial to recovery in a disease that causes bleeding, vomiting and diarrhea. Mr. Duncan was also treated with an experimental antiviral drug, brincidofovir, after the Food and Drug Administration approved its use on an emergency basis.

http://www.nytimes.com/2014/10/09/us/ebola-us-thomas-eric-duncan.html?emc=edit_na_20141008