>Special forces also knocked out the windows to let gas out. No one's
>identified the gas as of yet, but speculation has it that effective
>dose may have been near lethal dose.
>NEW SCIENTIST NEWSFLASH
>
>Russian gas clues point to cocktail
>
>Further clues to the identity of the knock-out agent used to end the
>Moscow hostage crisis have emerged, indicating that a likely
>candidate is a cocktail of an opioid narcotic such as fentanyl
>supplemented by halothane, a common anaesthetic. The two are
>commonly used together in clinical anaesthesia.
>
>To read the full story on NewScientist.com click here
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>
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>Full text of story:
>
>Russian gas clues point to cocktail
>
>Further evidence about the Moscow knock-out agent suggests a mixture
>of anaesthetic and opioids
>
>Further clues to the identity of the knock-out agent used to end the
>Moscow hostage crisis have emerged, indicating that a likely
>candidate is a cocktail of an opioid narcotic such as fentanyl
>supplemented by halothane, a common anaesthetic. The two are
>commonly used together in clinical anaesthesia.
>
>The Russian authorities are maintaining their silence on the
>identity of the gas, which they used to incapacitate the Chechen
>hostage-takers on Saturday. But the gas is believed to have killed
>all but two of the 117 hostages who died. The first funerals have
>already been held.
>
>Late on Tuesday, doctors in Munich reported that chemical analysis
>had identified halothane in blood and urine samples taken from two
>surviving German hostages within 24 hours of the rescue.
>
>But David Whittaker of the Association of Anaesthetists of Great
>Britain cautions that the two may have received halothane as an
>emergency treatment for bronchospasm induced by inhaling vomit,
>which happened to many hostages. If this true, it is probable that
>an opioid was used alone.
>
>Peter Hutton, president of Britain's Royal College of Anaesthetists,
>adds: "Halothane would take several minutes to get people even
>partially asleep." The gas used in Moscow rendered hostage-takers
>unconscious much more quickly, preventing them from donning gas
>masks or detonating their explosives.
>
>However halothane in the agent would at least agree with what little
>Russian officials have said - "it was a medical gas used in
>anaesthesiology".
>
>Opiate intoxication
>
>Doctors at the US embassy in Moscow say the two American survivors
>they examined had the telltale signs of opiate intoxication.
>Moreover, Moscow doctors have reportedly been treating survivors
>successfully with naloxone, which blocks the action of opiate drugs.
>And breathing failure and inhalation of vomit, said to be the most
>common cause of death in the hostages, are caused by opiates.
>
>"There is already an inhalable opiate available - fentanyl, a
>short-acting, rather potent narcotic," says Alan Zelicoff, a
>chemical and biological warfare expert at Sandia National Laboratory
>in New Mexico, US. "The clinical utility of this drug is that it
>acts very quickly."
>
>Fentanyl is commonly combined with halothane in order to minimise
>halothane's toxic side effects. And halothane may have been used to
>extend the effect of the agent, as the fentanyl wore off. But at
>high doses fentanyl alone may have been sufficiently long lasting.
>Both compounds must be administered as an aerosol suspension -
>tallying with the "grey" mist reported by some hostages.
>
>Lethal dose
>
>The most likely cause of the terrible number of hostage deaths is
>the side effects of fentanyl, say observers. Martin Furmanski, a
>medical historian in Newport Beach, California, says administering
>enough of an opiate drug to cause rapid anaesthesia almost always
>causes a patient to stop breathing - not a problem in a
>fully-equipped operating theatre, but a tragedy in the Moscow
>theatre.
>
>Similar opioids are used in tranquilising darts for anaesthetising
>large animals. In these cases, the lethal dose is just six times
>greater than the dose needed for anaesthesia.
>
>That implies that if the Moscow hostage-takers were exposed to
>enough of the mixture to knock them out within one minute, hostages
>who kept breathing it would have acquired a lethal dose within six
>minutes.
>
>If this analysis is correct, notes Furmanski, the poor physical
>condition of the hostages, or a dosage miscalculation is not
>necessary to explain the mass deaths. "It was probably inevitable
>that many hostages would die if the aerosol opiate concentration was
>high enough to cause rapid unconsciousness in the terrorists," he
>says.
>
>Short of Russian officials naming the agent, the next information is
>likely to come from the examination of the remains of two US
>hostages who died, and clothing from a British family, now being
>examined at the UK's chemical defense lab at Porton Down. However,
>rapid breakdown of short-acting opioids such as fentanyl might mean
>analysts will have to look for longer-lived breakdown products of
>the drug.