Definition, significance and measurement of quantities pertaining to the oxygen carrying properties of human blood

A consistent set of definitions is given of the principal quantities pertaining to the oxygen transport by the blood, and of their mutual relationships, in relation to the methods used in their measurement. At the core is the correct definition of oxygen saturation, the deviation of which has recently been the cause of considerable confusion, especially concerning pulse oximetry. The occurrence, properties, determination, and pathophysiological and clinical significance of dyshaemoglobins, such as carboxyhemoglobin, methemoglobin, and sulfhemoglobin, are briefly described, together with possible consequences for diagnosis and therapy. In addition, attention is payed to the use of some haemoglobin derivatives, such as methaemoglobin and cyanmethaemoglobin, for clinical chemical and therapeutic purposes

Lyophilized bovine hemoglobin as a possible reference material for the determination of hemoglobin derivatives in human blood

We investigated the suitability of a lyophilized bovine hemoglobin (LBH) preparation containing various fractions of oxyhemoglobin (O(2)Hb), carboxyhemoglobin (COHb), and methemoglobin (MetHb) for quality assessment in multicomponent analysis (MCA) of hemoglobin derivatives. It was demonstrated that a stable preparation of these components after reconstitution yields a hemoglobin solution that is spectrophotometrically equivalent with a fresh bovine hemoglobin solution. The preparation was found to be stable for at least 1 year when it is kept at 2-8 degrees C and for 1 h after reconstitution. We determined the fractions of O(2)Hb, COHb, and MetHb of several LBH preparations, using the complete spectra of 480-650 nm with 2-nm intervals and absorptivities as determined for pure LBH solutions. A field trial involving various types of multiwavelength hemoglobin photometers showed the suitability of LBH as a quality-control material. Computer models of the various common multiwavelength hemoglobin photometers may be useful for establishing more accurate target values of LBH preparations for each type of photometer and for studying the importance of the influence of specific factors such as wavelength selection, absorptivity values, and interfering dyes

ON THE RELIABILITY OF THE HENDERSON-HASSELBALCH EQUATION IN ROUTINE CLINICAL ACID-BASE CHEMISTRY

This paper deals with the variability of the practical coefficient of the first ionisation equilibrium of carbonic acid as related to the CO2 in the liquid phase (Henderson-Hasselbalch equation) [Formula: see text] and that of the practical coefficient of the first ionisation equilibrium of carbonic acid as related to the CO2 in the gas phase (modified Henderson-Hasselbalch equation) [Formula: see text] </jats:p