BRASILIA, July 14 (Reuters) - Brazilian President Jair Bolsonaro is being transferred to Sao Paulo to undergo tests for an obstructed intestine and could receive emergency surgery, the president"s office said on Wednesday, in his latest health complication from a 2018 stabbing. The news of Bolsonaro"s hospitalization comes as the far-right leader is sinking in opinion polls due to his handling of the world"s second-deadliest coronavirus pandemic, and a simmering corruption scandal over his government"s purchase of vaccines. It also caps days of questions over his health due to a chronic case of hiccups, a stubborn cough following a 2020 COVID-19 infection, and a series of surgeries after the campaign-trail stabbing shortly before his 2018 election victory. On his Facebook page, Bolsonaro posted a photo of himself smiling with his eyes closed and lying in a hospital bed covered in sensors and cables. What appears to be a priest, with a golden crucifix, stood by his side, placing his hand on the president"s shoulder. "I thank everyone for their support and prayers," Bolsonaro said in the post. Bolsonaro, 66, went to the military hospital in Brasilia early on Wednesday, with his office initially saying it was to undergo tests for chronic hiccups. But later on Wednesday, the president"s office said Antônio Luiz Macedo, the surgeon who operated on Bolsonaro in 2018, had decided the president should go to Sao Paulo for additional tests to investigate the obstructed intestine, and possible emergency surgery. Fábio Faria, Brazil"s communications minister, told a news conference that Bolsonaro had been sedated in the morning and would likely travel to the same hospital where he had previously been operated on by Macedo. He said the president"s schedule would be cleared for 48 hours. Bolsonaro"s son Flavio, talking to CNN Brasil, said that a procedure to remove liquid from his father"s stomach had been performed as a precaution. He added that if his father needed surgery, he had been assured it would not be a serious operation. Just after 4:45 p.m., local television images showed an ambulance carrying Bolsonaro leaving the hospital in Brasilia with a presidential motorcade on its way to a nearby air base. Bolsonaro nearly died after the stabbing in 2018, resulting in multiple follow-up surgeries. Recently, Bolsonaro had appeared unwell. In a national address on social media last Thursday, he struggled to express himself at one point, and said he had been suffering from hiccups for a week.