Experiences with a new direct-reading oxygen saturation photometer using ultrasound for hemolyzing the blood.

The new oxygen saturation meter (OSM2, Radiometer A/S, Copenhagen) is fully automatic and measures the oxygen saturation and the hemoglobin concentration of whole blood or packed red cells. Volume requirement 20 mul, time 40 s. The blood is hemolyzed directly in the capillary cuvette by means of ultrasound generated piezo-electrically. The instrument measures the absorbance at wave lengths of 505 nm and 600 nm. Absorbance range 0-3. The results are calculated electronically and appear in digital display. Other applications are (1) determination of the oxygen affinity of the hemoglobin (P50) after equilibrating the blood with a known pO2 or after measuring the pO2 in the blood sample, (2) determination of carboxyhemoglobin after complete reduction of the hemoglobin by means of dithionite, (3) determination of methemoglobin after complete oxygenation of the blood.