WASHINGTON — President Trump sought to dispel any perception of weakness on Sunday with a surprise and seemingly risky outing from his hospital bed to greet supporters even as his doctors once again rewrote the official narrative of his illness by acknowledging two alarming episodes they had previously not disclosed.
The doctors said that Mr. Trump’s blood oxygen level dropped twice in the two days after he was diagnosed with the coronavirus, requiring medical intervention, and that he had been put on steroids, suggesting his condition might be more serious than initially described. But they insisted that his situation had improved enough since then that he could be released from the hospital as early as Monday.
The acknowledgment of the episodes raised new questions about the credibility of the information provided about the commander in chief of a superpower as he is hospitalized with a disease that has killed more than 209,000 people in the United States. With the president determined not to concede weakness and facing an election in just 30 days, officials acknowledged providing rosy assessments to satisfy their prickly patient.
Determined to reassert himself on the political stage on his third day in the hospital, Mr. Trump made an unannounced exit from Walter Reed National Military Medical Center in the early evening, climbing into his armored Chevrolet Suburban to ride past supporters holding Trump flags gathered outside the building. Wearing a suit jacket and face mask but no tie, Mr. Trump waved at the crowd through a closed window as his motorcade slowly cruised by before returning him to the hospital.
“It’s been a very interesting journey,” Mr. Trump said in a one-minute video posted on Twitter, looking stronger and sounding more energetic than he had the last couple of days. “I learned a lot about Covid. I learned it by really going to school. This is the real school. This isn’t the let’s-read-the-books school. And I get it. And I understand it. And it’s a very interesting thing and I’m going to be letting you know about it.”
Mr. Trump’s camera-friendly, morale-boosting “surprise visit,” however, may have masked the reality of his condition, and his seeming energy may have reflected the fact that he was given the steroid dexamethasone, according to medical experts. Dexamethasone has been shown to help patients who are severely ill with Covid-19, but it is typically not used in mild or moderate cases of the disease.
Moreover, some medical experts said Mr. Trump’s trip out of the hospital was reckless, unnecessarily putting both hospital staff members and Secret Service agents at risk for a stunt. Others questioned the president’s statement in his video that he had met soldiers while at Walter Reed.
“Every single person in the vehicle during that completely unnecessary Presidential ‘drive-by’ just now has to be quarantined for 14 days,” Dr. James P. Phillips, an attending physician at Walter Reed, wrote on Twitter. “They might get sick. They may die. For political theater. Commanded by Trump to put their lives at risk for theater. This is insanity.”
In a telephone interview on Sunday night, Dr. Phillips also said the trip raised the alarming question of whether the president was directing his doctors.
“At what point does the physician-patient relationship end, and does the commander in chief and subordinate relationship begin, and were those doctors ordered to allow this to happen?” he said, noting that it violated standards of care and would not be an option open to any other patient. “When I first saw this, I thought, maybe he was being transported to another hospital.”
Judd Deere, a White House spokesman, said precautions were taken in organizing the excursion. “The movement was cleared by the medical team as safe to do,” he said.
But the criticism threatened to reinforce views of Mr. Trump’s handling of the pandemic as a whole, which has been widely criticized and remains his biggest political vulnerability.
Even as the White House released new details about the president’s condition on Sunday, it continued to withhold others, including when Mr. Trump had his last negative test for the coronavirus and his first positive one. Two administration officials speaking on the condition of anonymity acknowledged that he had an undisclosed positive result from a rapid test on Thursday evening after returning from a fund-raiser at his golf club in Bedminster, N.J. But he did not reveal it when he subsequently called into Sean Hannity’s Fox News show and, in a raspy voice, said he was still waiting for results.
Only after the television show did the results of another, more sophisticated PCR test come back confirming the positive reading, according to the officials, an account previously reported by The Wall Street Journal. It was that later test result that Mr. Trump announced on Twitter around 1 a.m. Friday.
Speaking with reporters on Sunday without wearing a mask, Kayleigh McEnany, the White House press secretary, would not specifically confirm the earlier test but said that “the first positive test he received was after he returned from Bedminster.”
Each passing day brings new information about those early hours of the illness that contradicts the version of events originally put out by the White House. Dr. Sean P. Conley, the White House physician, acknowledged on Sunday that Mr. Trump had a high fever and saw his oxygen drop on Friday morning, confirming reports by The New York Times and other news outlets.
That episode helped prompt the decision to transfer Mr. Trump to the hospital later in the day, a move initially described by the White House as simply a precautionary measure. Dr. Conley also disclosed for the first time another episode of falling blood oxygen level on Saturday.
Mr. Trump was put on supplemental oxygen during the Friday spell over the president’s strenuous objections, Dr. Conley confirmed. “He was fairly adamant that he didn’t need it,” he said. The doctor said he was not sure if the president was given oxygen on Saturday, but if so, it was “very, very limited.” The steroids were administered afterward.
Dr. Conley had refused repeatedly during his televised briefing on Saturday to say whether the president had received supplemental oxygen and provided such a relentlessly upbeat assessment that Mark Meadows, the White House chief of staff, afterward felt compelled to tell reporters off camera that the president’s situation had been more serious.
During his briefing on Sunday, Dr. Conley acknowledged that he had provided a rosy version of events to please his notoriously sensitive patient. “I didn’t want to give any information that might steer the course of illness in another direction, and in doing so, you know, it came off that we were trying to hide something, which wasn’t necessarily true,” he said.
Alyssa Farah, a White House communications adviser, conceded that Dr. Conley had been speaking to an audience of one during his Saturday briefing. “When you’re treating a patient, you want to project confidence, you want to lift their spirits, and that was the intent,” she said. She said that Mr. Meadows was trying “to be as transparent as we can” be by amending the report later.
But Dr. Conley and other doctors were nonetheless optimistic on Sunday that Mr. Trump was doing better and could be sent back to convalesce at the White House perhaps on Monday. “If he continues to look and feel as well as he does today, our hope is to plan for a discharge as early as tomorrow to the White House, where he can continue his treatment course,” said Dr. Brian Garibaldi, another physician treating the president.
In addition to the steroids, Mr. Trump has received an experimental antibody cocktail and is in the midst of a five-day course of remdesivir, an antiviral drug. The White House has a medical unit capable of responding to a president’s health troubles but not with the sophisticated equipment available at Walter Reed.
Mr. Trump, who historically hates hospitals and anything related to illness, has been hankering to get released, according to two people close to him, and some aides expressed fear that he would pressure Dr. Conley into releasing him by claiming to feel better than he actually does. But advisers were also troubled by the doctors’ prediction that they might release him on Monday because if they do not, it would signal that the president is not doing as well as indicated. They also worried that a premature return could lead to a second trip to the hospital if his condition worsens.
Mr. Trump was said to be working from his hospital suite, including receiving a briefing via secure video conference from Robert C. O’Brien, his national security adviser, as well as Secretary of State Mike Pompeo and Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff.
The president has also been watching lots of television, even more than usual, and has been exasperated by coverage of Saturday’s calamitous handling of his medical information by Dr. Conley and Mr. Meadows, as well as speculation about whether he would transfer powers to Vice President Mike Pence.
He was also angry that no one was on television defending him, as he often is when he cannot inject his own views into news media coverage, aides said. As a result, Rudolph W. Giuliani, his personal lawyer, was expected to appear on several television shows, as was Corey Lewandowski, who was Mr. Trump’s first campaign manager in the 2016 race.
The president was not the only one angry over the weekend. So were many people who work for him at the White House, frustrated at how little information they had received about the health concerns in their workplace. In addition to Mr. Trump, a number of others who work or visit the building regularly have tested positive, including Melania Trump; Hope Hicks, a senior adviser to the president; Nicholas Luna, the director of Oval Office operations; Bill Stepien, the campaign manager; Ronna McDaniel, the chairwoman of the Republican National Committee; and Kellyanne Conway, the president’s former counselor.
Two members of the White House residence staff tested positive for the virus a few weeks ago, two people briefed on their cases said, although they were said not to come in close contact with the president or the first lady. Nonetheless, the presence of the virus in the first couple’s personal quarters once again raised questions not just about what they have been exposed to, but whom they have made vulnerable with lax mask policies around the White House.
Ms. Farah told reporters that the White House would disclose the number of positive cases among the White House staff, but Ms. McEnany later seemed to reject that, citing “privacy concerns,” without explaining how a statistic without names would violate anyone’s privacy.
The White House has not sought help from the Centers for Disease Control and Prevention to trace the contacts of people who attended a celebration in the Rose Garden and a follow-up reception inside the White House on Sept. 26 for the Supreme Court nomination of Judge Amy Coney Barrett, the event seen as a likely source of the outbreak.
A federal official familiar with the matter said the C.D.C. had a team of experts on standby to help the White House but had not been approached to do so. Dr. Scott Gottlieb, a former commissioner of the Food and Drug Administration under Mr. Trump, said on Sunday that he had spoken to several officials who attended the Barrett event but had not been contacted by contact tracers.
“I think they have an obligation to understand how the infection was introduced into that environment,” he said of the White House, speaking on “Face the Nation” on CBS. “There doesn’t seem to be a very concerted effort underway.”
But after months of eschewing masks in keeping with the president’s scorn for face coverings, the White House was moving to finally enforce such practices. Mr. O’Brien said National Security Council staff members working at the White House complex must now wear face masks when around others or in common areas.
“Over the past couple days as this spread through the West Wing, notwithstanding the bubble that was created here in the testing, we made mask wearing mandatory for National Security Council staff,” Mr. O’Brien, who had a mild case of the virus himself in July, told reporters at the White House.