Japan: ‘killer’ nurse injected disinfectant into IV drips

A former nurse has confessed to poisoning at least 20 patients at a Japanese hospital by injecting their intravenous drips with disinfectant.

Ayumi Kuboki, 31, was arrested on Saturday by police investigating a string of suspicious deaths at Yokohama’s Oguchi hospital in 2016.

Under questioning, she admitted poisoning 88-year-old Sozo Nishikawa by injecting his IV drip with antiseptic solution.

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Traces of benzalkonium chloride, a compound used in common hospital disinfectants, were found in his body, as well as in the body of another elderly patient who died in the same hospital room two days later. The discovery sparked a police investigation focussed on the possibility that a staff member was behind the deaths.

Kuboki confessed to “repeatedly” tampering with the drip bags of around 20 patients, but investigators suspect she may have fatally poisoned dozens more.

Between July and late September 2016, 48 patients who died at the hospital were found to have disinfectant chemicals in their system, “including five patients on a single day in late August and four on one day in early September”, the Japan Times reports

According to The Asahi Shimbun newspaper, Kuboki “allegedly accelerated their deaths to avoid the task of explaining the circumstances of the patients’ deaths to relatives falling on her”, telling police she found such interactions “troublesome”.

She is said to have told detectives that she targeted sick, elderly patients whom she feared would die during her shift.

The timing of Nishikawa’s death suggests that he was poisoned when Kuboki arrived early for a scheduled night shift. When he died a couple of hours after, a day nurse broke the news to his family.

Other unusual incidents were also recorded at the hospital during this timeframe, including the disappearance of a patient’s records and a nurse who claimed her bottled drink had been spiked with bleach.

A former colleague from a previous hospital said that Kuboki was “considered competent”, but that fellow nurses found it “hard to figure out what she was really thinking”.