Astrup, P., Rorth, M. & Thorshauge, C. Dependency on Acid-base Status of Oxyhemoglobin Dissociation and 2,3-Diphosphoglycerate Level in Human Erythrocytes. 11. In Vivo Studies. Scand. 1. clin Lab. Invest. 26, [47][48][49][50][51][52] 1970.The intraerythrocytic level of 2,3-diphosphoglycerate and the oxygen affinity of hemoglobin in the red cell are shown to be strongly dependent on the intraerythrocytic pH. This effect should be taken into account when evaluating the increase in 2,3-diphosphoglycerate found at hypoxemic and anemic hypoxia. It was also demonstrated that high concentrations of inorganic phosphate in serum influence the intraerythrocytic 2,3-diphosphoglycerate concentration.tions of acid-base status, intraerythrocytic pH, Tao value, concentration of 2,3-DPG and of other blood constituents. Frequently the analyses were repeated on following days. All the Scand J Clin Lab Invest Downloaded from informahealthcare.com by Cornell University on 12/26/14For personal use only.

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The effect on cerebral haemodynamics of arterial hypotension induced by sodium nitroprusside infusion was studied in nine patients at the end of operations for intracranial aneurysms under N2O-O2-halothane anaesthesia. Cerebral blood flow (CBF), using the intraarterial 133Xe injection method, and cerebral jugular venous blood gases were monitored before, during and after the induced hypotension. CBF and jugular venous oxygen tension (PvO2) remained constant during the hypotensive period. Following its termination, a 13% increase in CBF occurred (P less than 0.05) and PvO2 showed the same trend, a 5% increase (P less than 0.30). Regional CBF recordings (rCBF) in 16 small areas within the cerebral hemisphere were obtained at each measurement. In four of the patients, rCBF abnormalities were present in the form of hyperaemic regions, probably induced by the operation or the disease itself. The focal abnormalities were not accentuated during hypotension nor were ischaemic regions disclosed. It is concluded that sodium nitroprusside has only a minor influence on cerebral haemodynamics in the anaesthetized state.

The haemodynamic effects of nitroprusside (SNP) were studied in six patients undergoing surgery for intracranial aneurysm under controlled hypotension in endotracheal anaesthesia with halothane-nitrous oxide during hypocapnia. Mean arterial pressure was reduced with SNP from mean 12.25 kPa to mean 8.29 kPa (32%). There were concomitant statistically significant decreases in systemic vascular resistance (-21%), cardiac index (-17%), stroke index (-23%), pulmonary arterial mean pressure (-27%) and pulmonary capillary wedge pressure (-27%). Heart rate, central venous pressure and pulmonary vascular resistance did not change significantly. After the infusion of SNP was discontinued all parameters, except cardiac index and heart rate, returned to values not significantly different from the control values. The hypotension induced by SNP resulted from reductions in cardiac index and systemic vascular resistance. The reduction in cardiac index did not reach a critical level in any of the patients.

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