Assuntos
Gasometria/métodos , Dióxido de Carbono/sangue , Cromatografia Gasosa/métodos , Oxigênio/sangue , Animais , Cateterismo , CãesRESUMO
The influence of oxygenation in respiratory and metabolic acid-base disturbances on erythocyte pH has been studied on normal human blood "in vitro". In physiological pH range, pHe-pHi relationship is the same for PCO2 variations at constant metabolic level and for metablic level variations at constant PCO2. A "global" pHe-pHi relationship has been calculated at 0 and 100% SO2. The oxygen-linked pH shift depends on pH level and PCO2 and is different in plasma and erythrocyte. From these results arise conclusions on pHi and pHe dependency, physiological role of saturation level of hemoglobin and conditions of P50 normalisation at pH 7.4.
Assuntos
Desequilíbrio Ácido-Base/sangue , Eritrócitos/metabolismo , Dióxido de Carbono/sangue , Eritrócitos/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Lactatos/farmacologia , Oxirredução , Oxigênio/sangue , Plasma/efeitos dos fármacos , Plasma/metabolismo , Análise de Regressão , Hidróxido de Sódio/farmacologiaRESUMO
The effect of osmolality on intra-erythrocytic pH and haemoglobin oxygen affinity of red cells was studied at three different osmolality levels (the mean osmolalities were respectively 257, 294 and 341 mOsmol). No osmotically induced alteration of the pHe-pHi relationship was observed. In contrast, P50(7.4) increased (namely: 24.5, 24.9 and 25.6 torr) as osmolality rose. This increase was accompanied by a simultaneous increment of both MCHC (respectively 30.5, 33.4 and 36.3 g percent) and 2,3-DPG concentration (4.495, 4.924 and 5.392 mM/l red cells) while the 2,3-DPG/Hb molar ratio remained constant. The different factors that might induce such a change in haemoglobin affinity for oxygen were discussed. It would be best explained by a modification in the amount of haemoglobin-bound 2,3-DPG when 2,3-DPG and haemoglobin concentrations in red cell vary simultaneously.
