PolyMedica Corp., Woburn, Mass., reported record sales of $28.8 million for the third quarter of fiscal 1998, ended December 31, 1998, up from $20.7 million from the previous year. Net income rose from $1.4 million to $1.7 million.

I-Flow Corp., Lake Forest, Calif., reported revenue nearly doubled in the fourth quarter, ended December 31, 1998, to $7 million, while revenue for the fiscal year rose 33 percent to $23.5 million. Net income for the quarter was $576,000; for the year, it was $3.6 million.

Mallinckrodt Inc., St. Louis, has reported a 5 percent increase in revenue for the second quarter ended December 31, 1998, to $636.7 million, compared with $607.3 million for the same period a year ago. Respiratory group sales were also up 5 percent, from $275.7 million to $290.3 million, over a year ago.

Net income was $35.1 million, or 49 cents per share, for its fiscal 1999 second quarter. For the same quarter the previous year, the company had a net loss of $4.9 million, or a loss of 7 cents per share. Results included charges related to the acquisition of Nellcor Puritan Bennett.

Mallinckrodt officials said they have concluded discussions with the SEC over the purchase of Nellcor and have agreed to recalculate and restate some charges.

ResMed Corp., San Diego, assured investors in late February that the company would meet earnings estimates for 1999 in an attempt to halt a drop in the value of the company's stock triggered by rumors of accounting and earnings problems.

Chief executive officer Peter Farrell said the company "rigorously" follows a conservative accounting policy, has reported record revenue and income for 15 consecutive quarters, and is comfortable with analysts' earnings estimates of 99 cents a share for 1999.

ResMed shares, which peaked at $52.12 in January 1999, slid to $29.78 in late February 1999.

Invacare Corp., Elyria, Ohio, declared a cash dividend of $0.0125 a share on its common shares and $0.011364 a share on its Class B common shares payable April 15, 1999, to shareholders of record on April 1, 1999.

Fresenius AG, Bad Homburg, Germany, reported revenue of $3.51 billion for its fiscal 1998 ended December 31, 1998, up 18 percent from $2.97 billion the previous year. Net income rose 27 percent to $132 million, or $1.62 a share, from $104 million, or $1.34 a share, for fiscal 1997. The company generated 57 percent of its sales in North America.

Caire Inc.'s Parent Company Acquired by Chart Industries Mayfield Heights, Ohio Chart Industries, a leading supplier of engineered equipment to the industrial gas and hydrocarbon processing markets, has acquired the parent company of liquid oxygen systems manufacturer Caire Inc. for $240 million.

Chart purchased MVE Holdings, Burnsville, Minn., to complement its position in the global cryogenic products market, said Arthur Holmes, Chart's chairman and chief executive officer.

"The combined company will be stronger than either Chart or MVE separately," said John Kucharik, MVE's president and CEO. "We'll be able to provide a broader range of cryogenic products and services to our cryogenic customers."

Mike Brown, a Caire spokesman, said the company will "continue to operate as it has."-K.S.