By Nancy Lapid (Reuters) – A flaw in a widely used medical device that measures oxygen levels causes critically ill Asians, Blacks and Hispanics to receive less supplemental oxygen to help them breathe than white patients, according to data from a large study published on Monday. Pulse oximeters clip onto a fingertip and pass red and infrared light through the skin to gauge oxygen levels in the blood. It has been known since the 1970s that skin pigmentation can throw off readings, but the discrepancies were not believed to affect patient care. Among 3,069 patients treated in a Boston intensive…