Shares of Goleta-based Inogen climbed 4.3 percent in after-hours trading on Tuesday as the medical-device maker reported better-than-expected second-quarter revenue and profit.

The company, which went public earlier this year, makes portable at-home oxygen concentrators. Its second-quarter revenue soared 50.8 percent to $30.4 million, beating the Capital IQ Consensus Estimate by $6.5 million.

Product sales revenue was up 60.5 percent to $20.5 million and rental revenue rose 34.1 percent to $9.9 million. Inogen said more than 25,100 patients were renting its devices by the end of the second quarter, up 38.7 percent compared to a year earlier.

Inogen’s second-quarter profits rose 16.6 percent to $2.3 million, or 11 cents per diluted common share. That beat analysts’ earnings expectations by 4 cents per share, according to the Capital IQ estimate.

“We are very encouraged with the level of productivity and traction we’ve seen throughout the first half of this year, with revenues reaching $54 million, a 50.5 percent increase over revenues for the first half of 2013,” Inogen President and CEO Raymond Huggenberger said in a statement.

In June, Inogen announced that it had received approval from the U.S. Food and Drug Administration to sell a stationary oxygen concentrator. Inogen, a UC Santa Barbara spinout, has experienced rapid growth by selling a portable oxygen concentrator called the Inogen One that is lighter and easier to maintain than tank-based systems.

The company said its new stationary device, called Inogen At Home, will be released later this year and will weigh only 18 pounds, a full 10 to 20 pounds lighter than competing systems.

The company also raised its earnings outlook for the year.

The firm said net income is expected to be $4.5 to $5.5 million, for the year, updated from previous guidance of $4 million o $5 million. It now expects revenue for 2014 to be in the range of $102 million to $106 million, it said, representing an increase of between 35.2 percent and 40.5 percent when compared to last year. It had previously projected that revenue for the year would be in the $92 million to $96 million range.

Inogen now expects adjusted earnings before interest, taxes, depreciation and amortization of between $19 million and $20.5 million, up from a previous projection of $18 million to $19.5 million.

Inogen’s shares traded up 4.3 percent to $19 in after-hours trading following its earnings release.