Nellcor is a brand of pulse oximetry systems sold by the Medtronic Corporation, following its acquisition of Covidien.

1981: Nellcor was started by Dr. William NE w, Jack LL oyd Jim COR enman and Bob Smith in Hayward, California to develop and market pulse oximetry systems.

1983: Nellcor introduced its pulse oximeter and quickly wins market share from Biox.

1995: Nellcor expands into respiratory-related products by acquiring Puritan-Bennett.

Company renamed Nellcor Puritan Bennett.

1997: Nellcor Puritan Bennett is purchased by Mallinckrodt Inc..

2000: Mallinckrodt is purchased by Tyco International Ltd.. Tyco established Nellcor and Puritan Bennett as separate businesses under the Tyco Healthcare umbrella.

2007: Covidien becomes a publicly traded company after being spun out of Tyco. Continues to market the Nellcor brand, ^[1] which dominates the market together with Masimo. ^[2]

2015: Medtronic acquires Covidien and continues to market the Nellcor brand.

Pulse oximetry is based on a technology originally developed in 1972, by Takuo Aoyagi and Michio Kishi at Nihon Kohden using the ratio of red to infrared light absorption of pulsating components at the measuring site and first commercialized by BIOX/Ohmeda in 1981. ^[3]