Goleta-based Inogen has boosted the amount it plans to raise in its initial public offering to a possible $91.3 million.

Inogen makes portable oxygen concentrators for medical patients and was spun out of UC Santa Barbara in 2001 by a group of undergraduate students. The company filed for an $86.2 million IPO late last year, but it said Feb. 4 that it will price shares at between $16 and $18, which could boost the amount raised.

The pricing is a sign that Inogen and its underwriters — J.P. Morgan, Leerink Partners, William Blair and Stifel — believe there’s strong demand for its shares.

Inogen notched 354 percent revenue growth between 2009 and 2012, bringing 2012 sales to $48.6 million and eking out a modest profit. For the first nine months of this year, revenue expanded to $55.7 million, and operating profits stand at $3.9 million.

Inogen underwent a major overhaul in 2009, switching to selling and renting its devices directly to consumers. In its filings, the company said it is the only portable oxygen concentrator in the U.S. that sells directly to its customers. In the first part of 2013, Inogen got about 28.7 percent, or $15.9 million, of its revenue from Medicare in the form of reimbursements for rentals of its units.

Inogen is also the first company in the Tri-Counties to go public under new, looser disclosure rules brought about by the JOBS Act. The company took advantage of provisions that allowed it to file a secret draft of its filing with the U.S. Securities and Exchange Commission before announcing its IPO and is disclosing less data about executive pay than it otherwise would have to.

Inogen has disclosed that it has serious problems with its internal financial controls. Under the JOBS Act, however, it will not be required to have an accounting firm test those controls once they are fixed.