Haemoglobin oxygen saturation, leucocyte count and lactate dehydrogenase are predictors of elevated cerebral blood flow velocity in Nigerian children with sickle cell anaemia

Abstract

Background: Transcranial Doppler ultrasound (TCD) scan, which measures blood flow velocity through the time-averaged mean of maximum velocities (TAMMVs) in the internal carotid arteries and middle cerebral arteries, is a useful screening tool for predicting stroke risk in children with sickle cell anaemia (SCA).Aim: To investigate which clinical and laboratory indices predict abnormal TCD velocity in children with SCA.Methods: Fifty-four SCA patients with normal TCD (TAMMV < 170 cm/s), classified as negative TCD (NTCD), and 93 patients with conditional and abnormal TCD velocities (TAMMV ≥ 170 cm/s) classified as positive TCD were recruited. The haemoglobin oxygen saturation, haematological variables, nitric oxide metabolites and lactate dehydrogenase activity of the patients were analysed.Results: The mean (SD) age was 7.16 (3.84) years (range 2–16). The median SpO2 of the patients in the positive TCD group was significantly lower than that of the negative TCD group (p = 0.002). Multivariate logistic regression analysis indicated that the MCV [odds ratio (OR) 1.12, 95% confidence interval (CI) 1.04–1.22, p = 0.01)], MCH (OR 1.34, 95% CI 1.02–1.77, p = 0.04), leucocyte count (OR 1.26, 95% CI 1.07–1.49, p = 0.01) and lactate dehydrogenase (LDH) level (OR 1.00, 95% CI 1.00–1.01, p = 0.01) were independent predictors of high cerebral blood flow velocities.Conclusions: These clinical and laboratory indices are characteristic of chronic hypoxia and severe anaemia and are predictors of abnormal cerebral blood flow velocity. They can be used to predict stroke risk in children with SCA when access to TCD screening is limited.