Influential factors of cerebral oxygen saturation in pediatric cardiovascular surgery / 中南大学学报(医学版)

Objective:To determine the intervention measures for the decrease of cerebral tissue oxygen saturation during anesthesia for the congenital heart disease in children.Methods:Twenty-eight children with cardiac surgery were enrolled.Anesthesia was deepened with propofol (3 mg/kg) intravenous injection.The data of cerebral tissue oxygen saturation(SctO2),mean arterial pressure (MAP),HR,bispectral index (BIS),arterial partial pressure of oxygen (PaO2),arterial partial pressure of carbon dioxide (PaCO2),hemoglobin (Hb) and middle cerebral artery (MCA) mean flow velocity (Vm) at different points were collected after intravenous injection ofpropofol at 3 mg/kg.The changes of SctO2 and the influential factors were analyzed.Results:SctO2 decreased by 4.99％ after deepen anesthesia,with 95％ CI 4.33％ to 5.65％ (P＞0.05).There was no significant differince in MAP,PaO2,PaCO2,and Hb between the time points after deepen anesthesia and the baseline (P＞0.05).MCA Vm decreased obviously after deepen anesthesia for 1,5,10 min (P＜0.05).The decrease in MAP,HR,PaCO2 and MCAVm is positively correlated with the decrease in SctO2.Conclusion:The decrease of MAP,HR,PaCO2,and MCAVm is the risk factor for SctO2.To avoid the decrease,it needs to maintain the stability of SctO2 and prevent neurological complications.

(Longitudinal Follow-up of Middle Cerebral Artery Stenosis with Transcranial Doppler Ultrasonography: Preliminary Study)

BACKGROUND: The natural history of intracranial arterial stenoses, particularly the middle cerebral artery (MCA), remains unknown. To monitor the progression of MCA stenoses over time, we conducted a prospective study using transcranial Doppler (TCD) study. METHODS: We performed TCD study on 14 stroke patients with angiographically documented MCA stenosis. The findings were compared to repeat TCD studies conducted more than 2 months apart with respect to changes in mean flow velocities (mFV) of the stenotic segment. RESULTS: Fourteen patients (13 men and 1 woman; mean age, 51 years) with 18 MCA stenoses were identified. During a mean follow-up period of 7.7 months, mFV corresponding to the areas of stenosis was increased in 7 (39%) arteries, demonstrating TCD evidence of stenosis progression. Three of those with MCA stenosis progression detected on TCD were confirmed with magnetic resonance angiogram. Flow velocities were not significantly changed in the remainder of the stenotic MCAs. Two patients whose MCA stenosis progressed also showed the suspicious development of new stenosis (mFV increase 119% and 41%, respectively) in the initially normal contralateral MCA. CONCLUSION: These findings suggest that MCA stenoses are dynamic lesions, and that they can evolve and cause further reductions of the arterial diameters after relatively short periods of time. TCD can noninvasively detect these changes.

Transcranial Doppler Ultrasound Recording of Flow Velocity in Basal Cerebral Arteries: Examination Technique and Normal Values in Korean

We present the examination technique and normal values of flow velocity from intracranial basal cerebral arteries for a recently developed pulsed Doppler system operating at 2 MHz emitting frequency. Peak systolic, peak diastolic, and mean flow velocity values are analyzed from fast-Fourier transformed(FFT) Doppler spectra at selected depths for 50 presumed normal subjects ranging in age from 18 to 72 years. Interindividual variation is high for peak flow but moderate for mean flow velocity values, which hence are more likely to discriminate normal from abnormal. Flow velocity values within the posterior cerebral attery(PCA) and the basilar artery(BA) are significantly lower than in the anterior cerebral artery(ACA) and the middle cerebral artery(MCA), which is also unique in showing significantly decreasing values with increasing age. Calculated mean flow velocities are 61+/-14 cm/s in the middle cerebral artery(MCA) and 51+/-14 cm/s in the anterior cerebral artery(ACA), and 45+/-11 cm/s in the posterior cerebral artery(PCA) through the temporal window and 43+/-14 cm/s in the basilar artery through the suboccipital window and 15+/-5 cm/s in the ophthalmic artery and 47+/-13 cm/s in the internal carotid artery(lCA) through the transorbital window. A new scanning system is introduced, which we suggest will reduce interindividual variations and improve the accurate separation of nearby vessels, which are major causes of the comparatively large standard deviations at present.