Haemoglobin oxygen dissociation curve in patients on regular haemodialysis.
Changes in the haemoglobin-oxygen dissociation curve (Hb-O2) and the factors which influence its position were studied before and after dialysis in 7 patients on regular haemodialysis during 20 dialyses. Seven normal subjects were used as controls. Haemoglobin showed a lower than normal affinity for O2 in uraemic patients before haemodialysis (p50in vivo = 33.09 +/- 0.92 mmHg and p507.4 = 31.51 +/- 0.73 mmHg, P less than 0.001), and this could be considered as a protection against tissue anoxia. After dialysis Hb-O2 affinity at the patient's pH (p50 in vivo = 27.97 +/- 0.57 mmHg, P less than 0.001). This probably eliminates the benefits of the predialysis balance of tissue oxygenation, producing a degree of hypoxia, and may play a role in the genesis of post-dialysis symptoms. Measures should be taken to improve oxygenation of high risk patients with latent heart failure or respiratory disturbances during and after dialysis.
Haemoglobin oxygen dissociation curve in patients on regular haemodialysis. Changes in the haemoglobin-oxygen dissociation curve (Hb-O2) and the factors which influence its position were studied before and after dialysis in 7 patients on regular haemodialysis during 20 dialyses. Seven normal subjects were used as controls. Haemoglobin showed a lower than normal affinity for O2 in uraemic patients before haemodialysis (p50in vivo = 33.09 +/- 0.92 mmHg and p507.4 = 31.51 +/- 0.73 mmHg, P less than 0.001), and this could be considered as a protection against tissue anoxia. After dialysis Hb-O2 affinity at the patient's pH (p50 in vivo = 27.97 +/- 0.57 mmHg, P less than 0.001). This probably eliminates the benefits of the predialysis balance of tissue oxygenation, producing a degree of hypoxia, and may play a role in the genesis of post-dialysis symptoms. Measures should be taken to improve oxygenation of high risk patients with latent heart failure or respiratory disturbances during and after dialysis.