Desperate Indians are calling Switzerland for oxygen concentrators Desperate Indians are calling Switzerland for oxygen concentrators For the past two weeks, retailers Raphael Koch and Dino Vivarelli have been busy fielding a flurry of phone calls, mostly from Indians looking for oxygen concentrators. Text Size: A+ Geneva/Mumbai: Raphael Koch, a retailer of medical devices in the small Swiss town of Wil, has been busy for the past two weeks fielding a flurry of phone calls. Most are from Indians or India-based companies looking for oxygen concentrators, with some even wanting as many as 500 at once. But Koch’s Oxymed store barely has any stock left of the little known machines that separate the critical gas from air and assist patients with low blood-oxygen levels. And he isn’t expecting fresh supplies from manufacturers at least until mid-June.