The F.D.A. has been supplying logistical help to companies, providing fuel for the generators and assisting with moving finished products off the island. Dr. Gottlieb said some companies had gotten down to a 24-hour supply of diesel fuel, and representatives for the medical-device industry had said some generators were beginning to break down, requiring emergency repair.

Pharmacists at half a dozen hospitals, from Utah to North Carolina, said in interviews that the fluid bag shortage had had a domino effect, leading to scarcities of a range of products as administrators race to stock up on the supplies they need to keep their hospitals running smoothly. Even products like empty bags and plastic tubing, which are also made by Baxter in Puerto Rico, have been hard to come by, some said.

“With drug shortages, it is often a race to see who can find a supply of the drug on shortage and also any alternatives,” said Philip J. Trapskin, who is the program manager of medication use strategy and innovation at UW Health, the University of Wisconsin-Madison’s health system. “We have been able to get what we need to avoid disruptions in patient care, but the mix of products is not ideal and there are no guarantees we will continue to get the supplies we need.”

Baxter recently announced that the F.D.A. had allowed it to import bags from the company’s factories in Ireland and Australia, and said production in Puerto Rico was slowly resuming. The company, which is based in Deerfield, Ill., said it was also helping its employees on the island, including distributing generators and propane-powered cooktops for the workers’ use. “While the storm devastated the island in a day, the recovery will take time,” the company said in a statement.

Baxter did not provide a timeline for when the bags would be back in stock, and pharmacists said they anticipated that the bags might not be available for many more weeks or months. “This is a big deal for hospitals across the country,” said Scott Knoer, the chief pharmacy officer at the Cleveland Clinic. “We’re really still trying to get the information we need to manage it.”