Evaluation of the performance of C.S.I.O. pulse oximeter

The oxygen present in blood is almost entirely loosely combined with haemoglobin. Oxygen capacity and oxygen content have long been measured by the Van Slyke volumetric and manometric apparatus. A number of workers have used spectrophotometric readings of blood at different wavelengths to estimate oxygen saturation. Instruments using reflection oximetry which use the difference in reflection of light by oxyhaemoglobin and haemoglobin are also used. CSIO has developed a Pulse Oximeter in which oxygen saturation is calculated by measuring the difference between the absorption spectra of oxygenated haemoglobin and deoxygenated haemoglobin with noninvasive means. The instrument is calibrated with Ohmeda and Nellcor instrument. Blood oxygen saturation (SaO₂) of student trainees in the age group of 20-25 years and CSIO employees in the age group of 40-45 years were compared with the assay of the same person using the Nellcor Instrument. A good correlation was found between the results from the two instruments. The mean deviation and standard deviation between two instruments were found to be within acceptable limits. The results obtained at PGI Chandigarh during clinical trials on neonates are also discussed