With 510 Covid patients admitted of which 142 are on high flow oxygen support, the Sir Ganga Ram Hospital on Thursday raised another SOS for immediate oxygen supply - for the second time in days.Responding to an IANS query, the hospital administration said it had estimated that the current oxygen stock would be able to tide over till Friday morning, but an increase in critical Covid patients and the need of more oxygen beds prompted it to use more high flow oxygen which resulted in a shortage again."We had expected that the current stock would last till next morning, but around 40 critical patients were admitted in the last few hours. Our oxygen supply comes late night, but the current stock would not cater for 142 patients with high flow oxygen beyond 1 a.m.""We are trying to find out help from all available resources... however, we are still trying," the hospital administration said.Before this, the hospital had raised alarm of oxygen shortage on Tuesday night, warning that several critical Covid-19 patients could be in jeopardy if fresh supplies were not provided urgently. However, the crisis was averted with supply of oxygen flowing in to the hospital the next morning as also subsequently.