Calculation of Bovine Haemoglobin Oxygen Saturation by Algorithms Integrating Age, Haemoglobin Content, Blood pH, Partial Pressures of Oxygen and Carbon Dioxide in the Blood, and Temperature
University of Liège, Luik, Wallonia, BelgiumThe Veterinary Journal (Impact Factor: 1.76). 06/2003; 165(3):258-65. DOI: 10.1016/S1090-0233(02)00167-3
In human and veterinary medicine, arterial and venous haemoglobin oxygen saturations are often used to estimate the severity of a disease and to guide therapeutic decisions. In veterinary medicine, haemoglobin oxygen saturation (SO(2)) is usually calculated using a blood gas analyser and algorithms developed for humans. It is possible, therefore, that the values obtained in animals may be distorted, particularly in animals with a high haemoglobin oxygen affinity, like young calves. In order to verify this hypothesis, we compared the arterial (SaO(2)) and venous (SvO(2)) haemoglobin oxygen saturations calculated using three different algorithms, and the oxygen exchange fraction (OEF) at the tissue level, which is the degree of haemoglobin desaturation between arterial and venous blood (SaO(2)-SvO(2)), with the values obtained from the whole bovine oxygen equilibrium curve (OEC) determined by a reference method. The blood gas analysers underestimated SvO(2) values; consequently, the OEF was overestimated (by about 10%). Two methods of reducing these errors were assessed. As the haemoglobin oxygen affinity decreases during the first month of life in calves a relationship between PO(2) at 50% haemoglobin saturation (P50) and age was established in order to correct the calculated values of venous and arterial SO(2), taking into account the estimated position of the OEC. This method markedly reduced the error for SvO(2) and OEF. Secondly, the SO(2) was calculated using a mathematical model taking into account the age of the animal and the specific effects of pH, PCO(2), and temperature on the bovine OEC. Using this method, the mean difference between the OEF values calculated using the mathematical model and those calculated by the reference method was close to zero. The errors produced by blood gas analysers can thus be minimised in two ways: firstly, by simply introducing a P50 estimated from the age of the calf into the analyser before the measurement; and secondly, by calculating the SO(2) using a mathematical model applied to the bovine OEC.
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ABSTRACT: The authors examined and analyzed animal blood RBC (RBC. O2, RBC. CO2), Hb (HbO2, HbCO2) and the human body's skin surface flowing blood in oxygenation-deoxidization conditions and revealed the characteristic of OD value in the imaginable and unimaginable visible spectrum domain and this gave a foundation for the technology to be applied in the vitiligo sickness epidermis melanin pellet examination. Using different spectrum and in vitro and in vivo methods, the authors did statistics for the information of OD value under different state and wavelength. Examination of in vitro: Experimented rabbit's blood Hb. O2 and RBC. O2 both have 367, 414 nm (the Soret cingulum) and 541, 576 (the Q cingulum) nm absorption peaks in the visible domain and both have 432 nm (Soret cingulum) and 553 nm (Q cingulum) absorption peaks, but blood had no change in the absorption peak position. No matter under what RBC and Hb condition, there was only completely independent absorption peak under the acidification and deoxidization condition. There is a significant difference (p < 0.01) between OD values under conditions of blood RBC cell and Hb hemolysis. Examination of in vivo: By using back skin surface specimen of the in vivo hand, absorption peaks were found at 540 and 576 nm for RBC. O2 condition and at 555 and 755 nm for RBC. CO2. Having selected the specimen of hand back skin (a: Nail, b: refers to skin, c: hand back skin), wavelengths were examined for the three dots. Among them, 545 nm absorption peak has average OD values of absorbency, which are 0.83 +/- 0.001, 0.73 +/- 0.001 and 0.62 +/- 0.001, and differences are notable (p < 0.01). Each absorption peak position of in vitro examination for RBC and Hb is invariable, but OD value of absorbency is different. Examination results under RBC condition are close to the aboriginality of RBC in vivo blood cell organization. The in vivo examination does not show any attack and damage to the human body, its sensitivity is high, testing time is short, and it has the superiority of taking in-phase test for the wavelength and the position information and so on. It is hopeful for the direct examination of epidermis black element and colored pellet.
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