Blood flow velocities in the anterior cerebral artery and basilar artery in asphyxiated infants

A Scoping Review of Cerebral Doppler Arterial Waveforms in Infants

Cerebral Doppler ultrasound has been an important tool in pediatric diagnostics and prognostics for decades. Although the Doppler spectrum can provide detailed information on cerebral perfusion, the measured spectrum is often reduced to simple numerical parameters. To help pediatric clinicians recognize the visual characteristics of disease-associated Doppler spectra and identify possible areas for future research, a scoping review of primary studies on cerebral Doppler arterial waveforms in infants was performed. A systematic search in three online bibliographic databases yielded 4898 unique records. Among these, 179 studies included cerebral Doppler spectra for at least five infants below 1 y of age. The studies describe variations in the cerebral waveforms related to physiological changes (43%), pathology (62%) and medical interventions (40%). Characteristics were typically reported as resistance index (64%), peak systolic velocity (43%) or end-diastolic velocity (39%). Most studies focused on the anterior (59%) and middle (42%) cerebral arteries. Our review highlights the need for a more standardized terminology to describe cerebral velocity waveforms and for precise definitions of Doppler parameters. We provide a list of reporting variables that may facilitate unambiguous reports. Future studies may gain from combining multiple Doppler parameters to use more of the information encoded in the Doppler spectrum, investigating the full spectrum itself and using the possibilities for long-term monitoring with Doppler ultrasound.

Arterial pressure is not reflective of right ventricular function in neonates with hypoxic ischemic encephalopathy treated with therapeutic hypothermia

AIM

to evaluate the correlation of recovery of arterial pressure with physiological recovery among patients with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia.

METHODS

At 24 h postnatal age, we compared 53 neonates of whom 22 (41%) were inotrope-treated to those untreated with cardiovascular medications.

RESULTS

Inotrope-treated patients had persistent severe right ventricular (RV) dysfunction and evidence of abnormal brain tissue oxygen delivery, despite recovered arterial pressure.

CONCLUSION

Arterial pressure is not reflective of RV function and the need for inotropic agents may be reflective of abnormal brain tissue oxygen delivery.

Using Doppler sonography resistive index for the diagnosis of perinatal asphyxia: a multi-centered study

Background and objective

Inhere we evaluated the diagnostic utility of Doppler sonography (DS) of the anterior cerebral artery (ACA), middle cerebral artery (MCA) and the basilar arteries (BA) based on resistive index (RI) for the diagnosis of asphyxia.

Methods

In this multi-centered cross-sectional study, neonates with clinical diagnosis of asphyxia, were considered for study. During the first 24 h, neonates underwent DS. MRI was done for each neonate during the first month, after discharge or during hospital admission, after obtaining clinical stability. Staging based on DS was compared with staging based on MRI.

Results

Overall, 34 patients entered the study. DS of the ACA, MCA, BA all had significant correlation with MRI findings (regarding severity of asphyxia) (r > 0.8 and p < 0.001).

In the receiver-operating-characteristic analysis, ideal cut-off point for diagnoses of asphyxia based on ACA and BA was RI ≤ 0.62 [area under the curve (AUC) = 0.957 and 95% CI: 0.819–0.997; sensitivity = 95.65; specificity = 100; positive predictive value (PPV) = 100; negative predictive value (NPV) = 90.9 and negative likelihood ratio (NLR) = 0.043]. Regarding MCA, similarly, a RI ≤ 0.62 was ideal for differentiating between normal and asphyxiated neonates (AUC = 0.990 and 95% CI: 0.873–1; sensitivity = 91.30; specificity = 100; PPV = 91.2; NPV = 100 and NLR = 0.087).

Conclusion

For evaluating neonates clinically suspected of asphyxia, especially in centers with limited facilities such as MRI, DS can be used as a first line diagnostic modality and RI of ≤ 0.62 is an appropriate cut-off for the diagnosis of perinatal asphyxia.

A new index of ultrasonography for estimating cerebral circulation in newborn infants

PURPOSE

To quantitatively estimate the influence of ductal shunt on cerebral blood flow and establish a new index of ultrasonography for estimating cerebral circulation without the influence of ductal shunt in newborn infants.

METHODS

We retrospectively examined the records of anterior cerebral artery (ACA) and left pulmonary artery (LPA) blood flow velocity curves recorded by pulsed Doppler ultrasonography within 6 h after birth in 123 newborn infants without asphyxia (normal group) and in 31 newborn infants with asphyxia (asphyxia group).

RESULTS

In the normal group, the resistance index (RI) of the ACA showed a positive correlation with the ratio of LPA diastolic-to-systolic flow velocities (LPAD/LPAS) (P < 0.001, r = 0.58), and the estimated RI (eRI) of the ACA was calculated using the following formula: Y = 0.47X + 0.67 (Y estimated RI; X LPAD/LPAS). In the asphyxia group, the RI of the ACA showed a weak correlation to base excess (BE) (P < 0.05, r = 0.46). The eRI of the ACA was calculated by the LPAD/PLAS in the asphyxia group, and the difference between the RI and eRI showed a better correlation to BE than RI (P < 0.001, r = 0.64).

CONCLUSION

We determined the relation between cerebral blood flow RI and ductal shunt, and (RI - eRI) may be a new useful ultrasonographic index indicating cerebral circulation without the influence of ductal shunt in newborn infants.

Impaired Right Ventricular Performance Is Associated with Adverse Outcome after Hypoxic Ischemic Encephalopathy

Rationale: Asphyxiated neonates with hypoxic ischemic encephalopathy (HIE) are at risk of myocardial dysfunction; however, echocardiography studies are limited and little is known about the relationship between hemodynamics and brain injury.Objectives: To analyze the association between severity of myocardial dysfunction and adverse outcome as defined by the composite of death and/or abnormal magnetic resonance imaging.Methods: Neonates with HIE undergoing therapeutic hypothermia were enrolled. Participants underwent echocardiography at 24 hours, 72 hours (before rewarming), and 96 hours (after rewarming). Cerebral hemodynamics were monitored by near-infrared spectroscopy and middle cerebral artery Doppler.Measurements and Main Results: Fifty-three patients with a mean gestation and birthweight of 38.8 ± 2.0 weeks and 3.33 ± 0.6 kg, respectively, were recruited. Thirteen patients (25%) had mild encephalopathy, 27 (50%) had moderate encephalopathy, and 13 (25%) had severe encephalopathy. Eighteen patients (34%) had an adverse outcome. Severity of cardiovascular illness (P < 0.001) and severity of neurologic insult (P = 0.02) were higher in neonates with adverse outcome. Right ventricle (RV) systolic performance at 24 hours was substantially lower than published normative data in all groups. At 24 hours, lower tricuspid annular plane systolic excursion (P = 0.004) and RV fractional area change (P < 0.001), but not pulmonary hypertension, were independently associated with adverse outcome on logistic regression. High brain regional oxygen saturation (P = 0.007) and low middle cerebral artery resistive index (P = 0.04) were associated with RV dysfunction on post hoc analysis.Conclusions: RV dysfunction is associated with the risk of adverse outcome in asphyxiated patients with HIE undergoing hypothermia. Echocardiography may be a valuable diagnostic and prognostic tool in this vulnerable population.

Hemodynamic alterations associated with polycythemia and partial exchange transfusion

Polycythemia hyperviscosity syndrome has been associated with multiple systemic effects. There is dearth of data on the effects of polycythemia on cardiac function. This case presents a newborn infant with symptomatic polycythemia in whom detailed myocardial function analysis for systolic and diastolic performance, as well as end-organ perfusion assessment was carried out using transthoracic echocardiography. Hemodynamic information in polycythemic infants before and after partial exchange could improve our understanding of the impact on myocardial performance.