Shares of Irvine-based Masimo Corp. fell in early trading today after it said that it expects to post a lower profit than previously projected for the year, partially as a result of a recent acquisition.

The patient monitoring device maker’s shares were down 8% to a market value of $1.18 billion.

Masimo said that it now expects a profit of $64.4 million for the year, down from prior guidance of $66.8 million.

Analysts expect Masimo to post a full-year profit of $66.2 million.

Masimo raised its outlook on revenue for the year to $494 million from a previous forecast of $486 million.

The company said the reduction on guidance for profits came in part as a result of its recent $30.4 million buy of Sweden’s Phasein AB. Phasein makes devices used in capnometry, which involves measuring carbon dioxide in respired gases.

Masimo said in a regulatory filing that buying Phasein complements its patient monitoring products and it used existing cash and cash equivalents in the deal.